fix(ci): update security.yml

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.checkmake

@@ -0,0 +1,8 @@
+# checkmake configuration
+# See: https://github.com/mrtazz/checkmake#configuration
+
+[rules.timestampexpansion]
+disabled = true
+
+[rules.maxbodylength]
+disabled = true

.editorconfig

@@ -8,5 +8,19 @@ indent_size = 2
 indent_style = tab
 tab_width = 2
 
+[*.yml]
+indent_style = space
+
 [*.md]
 trim_trailing_whitespace = false
+
+[*.{yml,yaml,json}]
+indent_style = space
+max_line_length = 250
+
+[LICENSE]
+max_line_length = 80
+indent_size = 0
+indent_style = space
+trim_trailing_whitespace = true
+

.github/renovate.json

@@ -1,6 +1,4 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-  "extends": [
-    "github>ivuorinen/renovate-config"
-  ]
+  "extends": ["github>ivuorinen/renovate-config"]
 }

.github/workflows/build-test-publish.yml

@@ -0,0 +1,155 @@
+# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
+name: Build, Test, Coverage, and Publish
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  release:
+    types: [created]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: Run Tests with Coverage and SARIF
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write
+      checks: write
+      pull-requests: write
+      security-events: write
+      statuses: write
+
+    steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@ec9f2d5744a09debf3a187a3f4f675c53b671911 # v2.13.0
+        with:
+          egress-policy: audit
+
+      - name: Checkout code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Set up Go
+        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
+        with:
+          go-version-file: "./go.mod"
+          cache: true
+
+      - name: Install dependencies
+        run: go mod tidy
+
+      - name: Run tests
+        run: go test -json ./... > test-results.json
+
+      - name: Generate coverage report
+        run: go test -coverprofile=coverage.out ./...
+
+      - name: Check coverage
+        id: coverage
+        run: |
+          coverage="$(go tool cover -func=coverage.out | grep total | awk '{print substr($3, 1, length($3)-1)}')"
+          echo "total_coverage=$coverage" >> "$GITHUB_ENV"
+          echo "Coverage: $coverage%"
+
+      - name: Upload test results
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: test-results
+          path: test-results.json
+
+      - name: Cleanup
+        run: rm coverage.out
+
+      - name: Fail if coverage is below threshold
+        run: |
+          if (( $(echo "$total_coverage < 50" | bc -l) )); then
+            echo "Coverage ($total_coverage%) is below the threshold (50%)"
+            exit 1
+          fi
+
+  build:
+    name: Build Binaries
+    needs: test
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write
+      packages: write
+
+    strategy:
+      matrix:
+        goos: [linux, darwin, windows]
+        goarch: [amd64, arm64]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Set up Go
+        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
+        with:
+          go-version-file: "./go.mod"
+
+      - name: Run go mod tidy
+        run: go mod tidy
+
+      - name: Build binary for ${{ matrix.goos }}-${{ matrix.goarch }}
+        run: |
+          mkdir -p dist
+          GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }} go build \
+            -ldflags "-X main.Version=${{ github.ref_name }}" \
+            -o dist/gibidify-${{ matrix.goos }}-${{ matrix.goarch }}${{ matrix.goos == 'windows' && '.exe' || '' }} \
+            .
+
+      - name: Generate SHA256 checksum
+        run: |
+          cd dist
+          for f in gibidify-*; do
+            sha256sum "$f" > "$f.sha256"
+          done
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: gibidify-${{ matrix.goos }}-${{ matrix.goarch }}
+          path: dist/*
+
+  docker:
+    name: Build and Publish Docker Image
+    if: github.event_name == 'release'
+    needs: build
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Download Linux binaries
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
+        with:
+          name: gibidify-linux-amd64
+          path: .
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@e468171a9de216ec08956ac3ada2f0791b6bd435 # v3.11.1
+
+      - name: Log in to GitHub Container Registry
+        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login ghcr.io -u ${{ github.actor }} --password-stdin
+
+      - name: Build and push multi-arch Docker image
+        run: |
+          chmod +x gibidify-linux-amd64
+          mv gibidify-linux-amd64 gibidify
+          docker buildx build --platform linux/amd64,linux/arm64,linux/arm/v7 \
+            --tag ghcr.io/${{ github.repository }}/gibidify:${{ github.ref_name }} \
+            --tag ghcr.io/${{ github.repository }}/gibidify:latest \
+            --push \
+            --squash .

.github/workflows/ci.yml

@@ -1,63 +0,0 @@
----
-# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
-name: Build and Publish
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-  release:
-    types: [ created ]
-
-jobs:
-  build:
-    name: Build Binaries
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        goos: [ "linux", "darwin" ]
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Set up Go
-        uses: actions/setup-go@v5
-        with:
-          go-version: '1.23'
-
-      - name: Build binary for ${{ matrix.goos }}
-        shell: bash
-        run: |
-          GOOS=${{ matrix.goos }} GOARCH=amd64 go build \
-            -ldflags "-X main.Version=dev-$(date -u +%Y%m%d%H%M)" \
-            -o gibidify-${{ matrix.goos }} \
-            .
-
-      - name: Upload artifact for ${{ matrix.goos }}
-        uses: actions/upload-artifact@v4
-        with:
-          name: gibidify-${{ matrix.goos }}
-          path: gibidify-${{ matrix.goos }}
-
-  docker:
-    name: Build and Publish Docker Image
-    needs: build
-    runs-on: ubuntu-latest
-    if: github.event_name == 'release'
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Download Linux binary artifact
-        uses: actions/download-artifact@v4
-        with:
-          name: gibidify-linux
-          path: .
-
-      - name: Build Docker image
-        shell: bash
-        run: |
-          cp ./gibidify-linux ./gibidify
-          chmod +x ./gibidify
-          docker build -t ghcr.io/${{ github.repository }}/gibidify:${{ github.ref_name }} .

.github/workflows/pr-lint.yml

@@ -0,0 +1,27 @@
+---
+# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
+name: PR Lint
+
+# yamllint disable-line rule:truthy
+on:
+  push:
+    branches: [master, main]
+  pull_request:
+    branches: [master, main]
+
+permissions: read-all
+
+jobs:
+  Linter:
+    name: PR Lint
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      issues: write
+      pull-requests: write
+      statuses: write
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+      - uses: ivuorinen/actions/pr-lint@fa0232d3c4ba16d087b606296435354a69c01756 # 25.8.11

.github/workflows/security.yml

@@ -0,0 +1,143 @@
+name: Security Scan
+
+on:
+  push:
+    branches: [main, develop]
+  pull_request:
+    branches: [main, develop]
+  schedule:
+    # Run security scan weekly on Sundays at 00:00 UTC
+    - cron: '0 0 * * 0'
+
+permissions: read-all
+
+jobs:
+  security:
+    name: Security Analysis
+    runs-on: ubuntu-latest
+
+    permissions:
+      security-events: write
+      contents: read
+      actions: read
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: 'go.mod'
+
+      - name: Cache Go modules
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cache/go-build
+            ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+
+      # Security Scanning with gosec
+      - name: Run gosec Security Scanner
+        uses: securego/gosec@v2
+        with:
+          args: '-fmt sarif -out gosec-results.sarif ./...'
+
+      - name: Upload gosec results to GitHub Security tab
+        uses: github/codeql-action/upload-sarif@v3
+        if: always()
+        with:
+          sarif_file: gosec-results.sarif
+
+      # Dependency Vulnerability Scanning
+      - name: Run govulncheck
+        run: |
+          go install golang.org/x/vuln/cmd/govulncheck@latest
+          govulncheck -json ./... > govulncheck-results.json || true
+
+      - name: Parse govulncheck results
+        run: |
+          if [ -s govulncheck-results.json ]; then
+            echo "::warning::Vulnerability check completed. Check govulncheck-results.json for details."
+            if grep -q '"finding"' govulncheck-results.json; then
+              echo "::error::Vulnerabilities found in dependencies!"
+              cat govulncheck-results.json
+              exit 1
+            fi
+          fi
+
+      # Additional Security Linting
+      - name: Run security-focused golangci-lint
+        uses: golangci/golangci-lint-action@v6.0.1
+        with:
+          args: "--enable=gosec,gocritic,bodyclose,rowserrcheck,misspell,unconvert,unparam,unused --timeout=5m"
+
+      # Makefile Linting
+      - name: Run checkmake on Makefile
+        uses: Uno-Takashi/checkmake-action@v2
+        with:
+          config: .checkmake
+
+      # Shell Script Formatting Check
+      - name: Check shell script formatting
+        run: |
+          go install mvdan.cc/sh/v3/cmd/shfmt@latest
+          shfmt -d .
+
+      # YAML Linting
+      - name: Run YAML linting
+        run: |
+          go install github.com/excilsploft/yamllint@latest
+          yamllint -c .yamllint .
+
+      # Secrets Detection (basic patterns)
+      - name: Run secrets detection
+        run: |
+          echo "Scanning for potential secrets..."
+          # Look for common secret patterns
+          git log --all --full-history -- . | grep -i -E "(password|secret|key|token|api_key)" || true
+          find . -type f -name "*.go" -exec grep -H -i -E "(password|secret|key|token|api_key)\s*[:=]" {} \; || true
+
+      # Check for hardcoded IPs and URLs
+      - name: Check for hardcoded network addresses
+        run: |
+          echo "Scanning for hardcoded network addresses..."
+          find . -type f -name "*.go" -exec grep -H -E "([0-9]{1,3}\.){3}[0-9]{1,3}" {} \; || true
+          find . -type f -name "*.go" -exec grep -H -E "https?://[^/\s]+" {} \; | \
+            grep -v "example.com|localhost|127.0.0.1" || true
+
+      # Docker Security (if Dockerfile exists)
+      - name: Run Docker security scan
+        if: hashFiles('Dockerfile') != ''
+        run: |
+          docker run --rm -v "$PWD":/workspace \
+            aquasec/trivy:latest fs --security-checks vuln,config /workspace/Dockerfile || true
+
+      # SAST with CodeQL (if available)
+      - name: Initialize CodeQL
+        if: github.event_name != 'schedule'
+        uses: github/codeql-action/init@v3
+        with:
+          languages: go
+
+      - name: Autobuild
+        if: github.event_name != 'schedule'
+        uses: github/codeql-action/autobuild@v3
+
+      - name: Perform CodeQL Analysis
+        if: github.event_name != 'schedule'
+        uses: github/codeql-action/analyze@v3
+
+      # Upload artifacts for review
+      - name: Upload security scan results
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: security-scan-results
+          path: |
+            gosec-results.sarif
+            govulncheck-results.json
+          retention-days: 30

.github/workflows/sync-labels.yml

@@ -0,0 +1,25 @@
+---
+# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
+name: Sync labels
+
+permissions: read-all
+
+# yamllint disable-line rule:truthy
+on:
+  push:
+    paths:
+      - .github/workflows/sync-labels.yml
+      - .github/labels.yml
+  schedule:
+    - cron: "34 5 * * *"
+  workflow_call:
+  workflow_dispatch:
+
+jobs:
+  SyncLabels:
+    permissions:
+      contents: read
+      issues: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: ivuorinen/actions/sync-labels@fa0232d3c4ba16d087b606296435354a69c01756 # 25.8.11

.gitignore

@@ -7,3 +7,8 @@ gibidify.yaml
 output.json
 output.txt
 output.yaml
+coverage.out
+megalinter-reports/*
+coverage.*
+*.out
+gibidify-benchmark

.go-version

@@ -0,0 +1 @@
+1.23.0

.golangci.yml

@@ -0,0 +1,256 @@
+run:
+  timeout: 5m
+  tests: true
+  go: "1.24"
+  build-tags:
+    - test
+
+# golangci-lint configuration version
+version: 2
+
+output:
+  format: colored-line-number
+  print-issued-lines: true
+  print-linter-name: true
+  path-prefix: ""
+  sort-results: true
+
+linters:
+  enable-all: true
+  disable:
+    - depguard       # Too strict for general use
+    - exhaustruct    # Too many false positives
+    - ireturn        # Too restrictive on interfaces
+    - varnamelen     # Too opinionated on name length
+    - wrapcheck      # Too many false positives
+    - testpackage    # Tests in same package are fine
+    - paralleltest   # Not always necessary
+    - tparallel      # Not always necessary
+    - nlreturn       # Too opinionated on newlines
+    - wsl            # Too opinionated on whitespace
+    - nonamedreturns # Conflicts with gocritic unnamedResult
+
+linters-settings:
+  errcheck:
+    check-type-assertions: true
+    check-blank: true
+    exclude-functions:
+      - io.Copy
+      - fmt.Print
+      - fmt.Printf
+      - fmt.Println
+
+  govet:
+    enable-all: true
+
+  gocyclo:
+    min-complexity: 15
+
+  gocognit:
+    min-complexity: 20
+
+  goconst:
+    min-len: 3
+    min-occurrences: 3
+
+  gofmt:
+    simplify: true
+    rewrite-rules:
+      - pattern: 'interface{}'
+        replacement: 'any'
+
+  goimports:
+    local-prefixes: github.com/ivuorinen/gibidify
+
+  golint:
+    min-confidence: 0.8
+
+  lll:
+    line-length: 120
+    tab-width: 2  # EditorConfig: tab_width = 2
+
+  misspell:
+    locale: US
+
+  nakedret:
+    max-func-lines: 30
+
+  prealloc:
+    simple: true
+    range-loops: true
+    for-loops: true
+
+  revive:
+    enable-all-rules: true
+    rules:
+      - name: package-comments
+        disabled: true
+      - name: file-header
+        disabled: true
+      - name: max-public-structs
+        disabled: true
+      - name: line-length-limit
+        arguments: [120]
+      - name: function-length
+        arguments: [50, 100]
+      - name: cognitive-complexity
+        arguments: [20]
+      - name: cyclomatic
+        arguments: [15]
+      - name: add-constant
+        arguments:
+          - maxLitCount: "3"
+            allowStrs: "\"error\",\"\""
+            allowInts: "0,1,2"
+      - name: argument-limit
+        arguments: [6]
+      - name: banned-characters
+        disabled: true
+      - name: function-result-limit
+        arguments: [3]
+
+  gosec:
+    excludes:
+      - G104  # Handled by errcheck
+    severity: medium
+    confidence: medium
+    exclude-generated: true
+    config:
+      G301: "0750"
+      G302: "0640"
+      G306: "0640"
+
+  dupl:
+    threshold: 150
+
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - whyNoLint
+      - paramTypeCombine
+
+  gofumpt:
+    extra-rules: true
+
+  # EditorConfig compliance settings
+  # These settings enforce .editorconfig rules:
+  # - end_of_line = lf (enforced by gofumpt)
+  # - insert_final_newline = true (enforced by gofumpt)
+  # - trim_trailing_whitespace = true (enforced by whitespace linter)
+  # - indent_style = tab, tab_width = 2 (enforced by gofumpt and lll)
+
+  whitespace:
+    multi-if: false     # EditorConfig: trim trailing whitespace
+    multi-func: false   # EditorConfig: trim trailing whitespace
+
+  nolintlint:
+    allow-leading-space: false  # EditorConfig: trim trailing whitespace
+    allow-unused: false
+    require-explanation: false
+    require-specific: true
+
+  godox:
+    keywords:
+      - FIXME
+      - BUG
+      - HACK
+
+  mnd:
+    settings:
+      mnd:
+        checks:
+          - argument
+          - case
+          - condition
+          - operation
+          - return
+          - assign
+        ignored-numbers:
+          - '0'
+          - '1'
+          - '2'
+          - '10'
+          - '100'
+
+  funlen:
+    lines: 80
+    statements: 60
+
+  nestif:
+    min-complexity: 5
+
+  gomodguard:
+    allowed:
+      modules: []
+      domains: []
+    blocked:
+      modules: []
+      versions: []
+
+issues:
+  exclude-use-default: false
+  exclude-case-sensitive: false
+  max-issues-per-linter: 0
+  max-same-issues: 0
+  uniq-by-line: true
+
+  exclude-dirs:
+    - vendor
+    - third_party
+    - testdata
+    - examples
+    - .git
+
+  exclude-files:
+    - ".*\\.pb\\.go$"
+    - ".*\\.gen\\.go$"
+
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - dupl
+        - gosec
+        - goconst
+        - funlen
+        - gocognit
+        - gocyclo
+        - errcheck
+        - lll
+        - nestif
+
+    - path: main\.go
+      linters:
+        - gochecknoglobals
+        - gochecknoinits
+
+    - path: fileproc/filetypes\.go
+      linters:
+        - gochecknoglobals  # Allow globals for singleton registry pattern
+
+    - text: "Using the variable on range scope"
+      linters:
+        - scopelint
+
+    - text: "should have comment or be unexported"
+      linters:
+        - golint
+        - revive
+
+    - text: "don't use ALL_CAPS in Go names"
+      linters:
+        - golint
+        - stylecheck
+
+  exclude:
+    - "Error return value of .* is not checked"
+    - "exported (type|method|function) .* should have comment"
+    - "ST1000: at least one file in a package should have a package comment"
+
+severity:
+  default-severity: error
+  case-sensitive: false

.mega-linter.yml

@@ -0,0 +1,20 @@
+---
+# Configuration file for MegaLinter
+# See all available variables at
+# https://megalinter.io/configuration/ and in linters documentation
+
+APPLY_FIXES: all
+SHOW_ELAPSED_TIME: false # Show elapsed time at the end of MegaLinter run
+PARALLEL: true
+VALIDATE_ALL_CODEBASE: true
+FILEIO_REPORTER: false # Generate file.io report
+GITHUB_STATUS_REPORTER: true # Generate GitHub status report
+IGNORE_GENERATED_FILES: true # Ignore generated files
+JAVASCRIPT_DEFAULT_STYLE: prettier # Default style for JavaScript
+PRINT_ALPACA: false # Print Alpaca logo in console
+SARIF_REPORTER: true # Generate SARIF report
+SHOW_SKIPPED_LINTERS: false # Show skipped linters in MegaLinter log
+
+DISABLE_LINTERS:
+  - REPOSITORY_DEVSKIM
+  - REPOSITORY_TRIVY

.pre-commit-config.yaml

@@ -0,0 +1,15 @@
+repos:
+  - repo: https://github.com/golangci/golangci-lint
+    rev: v1.57.2
+    hooks:
+      - id: golangci-lint
+        args: ["--timeout=5m"]
+  - repo: https://github.com/tekwizely/pre-commit-golang
+    rev: v1.0.0-rc.1
+    hooks:
+      - id: go-build-mod
+        alias: build
+      - id: go-mod-tidy
+        alias: tidy
+      - id: go-fmt
+        alias: fmt

.vscode/extensions.json

@@ -0,0 +1,3 @@
+{
+  "recommendations": ["esbenp.prettier-vscode", "AquaSecurityOfficial.trivy-vulnerability-scanner", "Bridgecrew.checkov", "exiasr.hadolint", "ms-vscode.Go", "streetsidesoftware.code-spell-checker"]
+}

.yamllint

@@ -0,0 +1,40 @@
+# yamllint configuration
+# See: https://yamllint.readthedocs.io/en/stable/configuration.html
+
+extends: default
+
+# Ignore generated output files
+ignore: |
+  gibidify.yaml
+  gibidify.yml
+  output.yaml
+  output.yml
+
+rules:
+  # Allow longer lines for URLs and commands in GitHub Actions
+  line-length:
+    max: 120
+    level: warning
+
+  # Allow 2-space indentation to match EditorConfig
+  indentation:
+    spaces: 2
+    indent-sequences: true
+    check-multi-line-strings: false
+
+  # Allow truthy values like 'on' in GitHub Actions
+  truthy:
+    allowed-values: ['true', 'false', 'on', 'off']
+    check-keys: false
+
+  # Allow empty values in YAML
+  empty-values:
+    forbid-in-block-mappings: false
+    forbid-in-flow-mappings: false
+
+  # Relax comments formatting
+  comments:
+    min-spaces-from-content: 1
+
+  # Allow document start marker to be optional
+  document-start: disable

CLAUDE.md

@@ -0,0 +1,47 @@
+# CLAUDE.md
+
+Go CLI aggregating code files into LLM-optimized output. Supports markdown/JSON/YAML with concurrent processing.
+
+## Architecture (42 files, 8.2K lines)
+
+**Core**: `main.go` (37), `cli/` (4), `fileproc/` (27), `config/` (3), `utils/` (4), `testutil/` (2)
+
+**Modules**: Collection, processing, writers, registry (~63ns cache), resource limits
+
+**Patterns**: Producer-consumer, thread-safe registry, streaming, modular (50-200 lines)
+
+## Commands
+
+```bash
+make lint-fix && make lint && make test
+./gibidify -source <dir> -format markdown --verbose
+```
+
+## Config
+
+`~/.config/gibidify/config.yaml`
+Size limit 5MB, ignore dirs, custom types, 100MB memory limit
+
+## Quality
+
+**CRITICAL**: `make lint-fix && make lint` (0 issues), 120 chars, EditorConfig, 30+ linters
+
+## Testing
+
+**Coverage**: 84%+ (utils 90.9%, fileproc 83.8%), race detection, benchmarks
+
+## Standards
+
+EditorConfig (LF, tabs), semantic commits, testing required
+
+## Status
+
+**Health: 10/10** - Production-ready, 84%+ coverage, modular, memory-optimized
+
+**Done**: Errors, benchmarks, config, optimization, modularization, CLI (progress/colors), security (path validation, resource limits, scanning)
+
+**Next**: Documentation, output customization
+
+## Workflow
+
+1. `make lint-fix` first 2. >80% coverage 3. Follow patterns 4. Update docs

Dockerfile

@@ -1,5 +1,11 @@
 # Use a minimal base image
-FROM alpine:latest
+FROM alpine:3.21.2
+
+# Add user
+RUN useradd -ms /bin/bash gibidify
+
+# Use the new user
+USER gibidify
 
 # Copy the gibidify binary into the container
 COPY gibidify /usr/local/bin/gibidify

LICENSE

@@ -1,7 +1,20 @@
 MIT License Copyright (c) 2025 Ismo Vuorinen
 
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+Permission is hereby granted, free of charge, to any person obtaining a copy
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+ so, subject to the following conditions:
 
-The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software.
+The above copyright notice and this permission notice (including the next
+paragraph) shall be included in all copies or substantial portions of the
+Software.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

Makefile

@@ -0,0 +1,147 @@
+.PHONY: help install-tools lint lint-fix lint-verbose test coverage build clean all build-benchmark benchmark benchmark-collection benchmark-processing benchmark-concurrency benchmark-format security security-full vuln-check check-all dev-setup
+
+# Default target shows help
+.DEFAULT_GOAL := help
+
+# All target runs full workflow
+all: lint test build
+
+# Help target  
+help:
+	@cat scripts/help.txt
+
+# Install required tools
+install-tools:
+	@echo "Installing golangci-lint..."
+	@go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
+	@echo "Installing gofumpt..."
+	@go install mvdan.cc/gofumpt@latest
+	@echo "Installing goimports..."
+	@go install golang.org/x/tools/cmd/goimports@latest
+	@echo "Installing staticcheck..."
+	@go install honnef.co/go/tools/cmd/staticcheck@latest
+	@echo "Installing gosec..."
+	@go install github.com/securego/gosec/v2/cmd/gosec@latest
+	@echo "Installing gocyclo..."
+	@go install github.com/fzipp/gocyclo/cmd/gocyclo@latest
+	@echo "Installing checkmake..."
+	@go install github.com/mrtazz/checkmake/cmd/checkmake@latest
+	@echo "Installing shfmt..."
+	@go install mvdan.cc/sh/v3/cmd/shfmt@latest
+	@echo "Installing yamllint (Go-based)..."
+	@go install github.com/excilsploft/yamllint@latest
+	@echo "All tools installed successfully!"
+
+# Run linters
+lint:
+	@./scripts/lint.sh
+
+# Run linters with auto-fix
+lint-fix:
+	@echo "Running gofumpt..."
+	@gofumpt -l -w .
+	@echo "Running goimports..."
+	@goimports -w -local github.com/ivuorinen/gibidify .
+	@echo "Running go fmt..."
+	@go fmt ./...
+	@echo "Running go mod tidy..."
+	@go mod tidy
+	@echo "Running shfmt formatting..."
+	@shfmt -w -i 2 -ci .
+	@echo "Running golangci-lint with --fix..."
+	@golangci-lint run --fix ./...
+	@echo "Auto-fix completed. Running final lint check..."
+	@golangci-lint run ./...
+	@echo "Running checkmake..."
+	@checkmake --config=.checkmake Makefile
+	@echo "Running yamllint..."
+	@yamllint -c .yamllint .
+
+# Run linters with verbose output
+lint-verbose:
+	@echo "Running golangci-lint (verbose)..."
+	@golangci-lint run -v ./...
+	@echo "Running checkmake (verbose)..."
+	@checkmake --config=.checkmake --format="{{.Line}}:{{.Rule}}:{{.Violation}}" Makefile
+	@echo "Running shfmt check (verbose)..."
+	@shfmt -d .
+	@echo "Running yamllint (verbose)..."
+	@yamllint -c .yamllint -f parsable .
+
+# Run tests
+test:
+	@echo "Running tests..."
+	@go test -race -v ./...
+
+# Run tests with coverage
+coverage:
+	@echo "Running tests with coverage..."
+	@go test -race -coverprofile=coverage.out -covermode=atomic ./...
+	@go tool cover -html=coverage.out -o coverage.html
+	@echo "Coverage report generated: coverage.html"
+
+# Build the application
+build:
+	@echo "Building gibidify..."
+	@go build -ldflags="-s -w" -o gibidify .
+	@echo "Build complete: ./gibidify"
+
+# Clean build artifacts
+clean:
+	@echo "Cleaning build artifacts..."
+	@rm -f gibidify gibidify-benchmark
+	@rm -f coverage.out coverage.html
+	@echo "Clean complete"
+
+# CI-specific targets
+.PHONY: ci-lint ci-test
+
+ci-lint:
+	@golangci-lint run --out-format=github-actions ./...
+
+ci-test:
+	@go test -race -coverprofile=coverage.out -json ./... > test-results.json
+
+# Build benchmark binary
+build-benchmark:
+	@echo "Building gibidify-benchmark..."
+	@go build -ldflags="-s -w" -o gibidify-benchmark ./cmd/benchmark
+	@echo "Build complete: ./gibidify-benchmark"
+
+# Run benchmarks
+benchmark: build-benchmark
+	@echo "Running all benchmarks..."
+	@./gibidify-benchmark -type=all
+
+# Run specific benchmark types
+benchmark-collection: build-benchmark
+	@echo "Running file collection benchmarks..."
+	@./gibidify-benchmark -type=collection
+
+benchmark-processing: build-benchmark
+	@echo "Running file processing benchmarks..."
+	@./gibidify-benchmark -type=processing
+
+benchmark-concurrency: build-benchmark
+	@echo "Running concurrency benchmarks..."
+	@./gibidify-benchmark -type=concurrency
+
+benchmark-format: build-benchmark
+	@echo "Running format benchmarks..."
+	@./gibidify-benchmark -type=format
+
+# Security targets
+security:
+	@echo "Running comprehensive security scan..."
+	@./scripts/security-scan.sh
+
+security-full:
+	@echo "Running full security analysis..."
+	@./scripts/security-scan.sh
+	@echo "Running additional security checks..."
+	@golangci-lint run --enable-all --disable=depguard,exhaustruct,ireturn,varnamelen,wrapcheck --timeout=10m
+
+vuln-check:
+	@echo "Checking for dependency vulnerabilities..."
+	@go install golang.org/x/vuln/cmd/govulncheck@latest
+	@govulncheck ./...

README.md

@@ -7,11 +7,16 @@ file sections with separators, and a suffix.
 
 ## Features
 
-- Recursive scanning of a source directory.
-- File filtering based on size, glob patterns, and .gitignore rules.
-- Modular, concurrent file processing with progress bar feedback.
-- Configurable logging and configuration via Viper.
-- Cross-platform build with Docker packaging support.
+- **Recursive directory scanning** with smart file filtering
+- **Configurable file type detection** - add/remove extensions and languages
+- **Multiple output formats** - markdown, JSON, YAML
+- **Memory-optimized processing** - streaming for large files, intelligent back-pressure
+- **Concurrent processing** with configurable worker pools
+- **Comprehensive configuration** via YAML with validation
+- **Production-ready** with structured error handling and benchmarking
+- **Modular architecture** - clean, focused codebase with ~63ns registry lookups
+- **Enhanced CLI experience** - progress bars, colored output, helpful error messages
+- **Cross-platform** with Docker support
 
 ## Installation
 
@@ -26,9 +31,29 @@ go build -o gibidify .
 ## Usage
 
 ```bash
-./gibidify -source <source_directory> -destination <output_file> [--prefix="..."] [--suffix="..."]
+./gibidify \
+  -source <source_directory> \
+  -destination <output_file> \
+  -format markdown|json|yaml \
+  -concurrency <num_workers> \
+  --prefix="..." \
+  --suffix="..." \
+  --no-colors \
+  --no-progress \
+  --verbose
 ```
 
+Flags:
+
+- `-source`: directory to scan.
+- `-destination`: output file path (optional; defaults to `<source>.<format>`).
+- `-format`: output format (`markdown`, `json`, or `yaml`).
+- `-concurrency`: number of concurrent workers.
+- `--prefix` / `--suffix`: optional text blocks.
+- `--no-colors`: disable colored terminal output.
+- `--no-progress`: disable progress bars.
+- `--verbose`: enable verbose output and detailed logging.
+
 ## Docker
 
 A Docker image can be built using the provided Dockerfile:
@@ -41,13 +66,13 @@ Run the Docker container:
 
 ```bash
 docker run --rm \
-  -v $(pwd):/workspace \
-  -v $HOME/.config/gibidify:/config \
-  ghcr.io/ivuorinen/gibidify:<tag> \
-  -source /workspace/your_source_directory \
-  -destination /workspace/output.txt \
-  --prefix="Your prefix text" \
-  --suffix="Your suffix text"
+	-v $(pwd):/workspace \
+	-v $HOME/.config/gibidify:/config \
+	ghcr.io/ivuorinen/gibidify:<tag> \
+	-source /workspace/your_source_directory \
+	-destination /workspace/output.txt \
+	--prefix="Your prefix text" \
+	--suffix="Your suffix text"
 ```
 
 ## Configuration
@@ -69,11 +94,39 @@ ignoreDirectories:
   - dist
   - build
   - target
-  - bower_components
-  - cache
-  - tmp
+
+# FileType customization
+fileTypes:
+  enabled: true
+  # Add custom file extensions
+  customImageExtensions:
+    - .webp
+    - .avif
+  customBinaryExtensions:
+    - .custom
+  customLanguages:
+    .zig: zig
+    .odin: odin
+    .v: vlang
+  # Disable default extensions
+  disabledImageExtensions:
+    - .bmp
+  disabledBinaryExtensions:
+    - .exe
+  disabledLanguageExtensions:
+    - .bat
+
+# Memory optimization (back-pressure management)
+backpressure:
+  enabled: true
+  maxPendingFiles: 1000      # Max files in file channel buffer
+  maxPendingWrites: 100      # Max writes in write channel buffer
+  maxMemoryUsage: 104857600  # 100MB max memory usage
+  memoryCheckInterval: 1000  # Check memory every 1000 files
 ```
 
+See `config.example.yaml` for a comprehensive configuration example.
+
 ## License
 
 This project is licensed under [the MIT License](LICENSE).

TODO.md

@@ -0,0 +1,46 @@
+# TODO: gibidify
+
+Prioritized improvements by impact/effort.
+
+## ✅ Completed
+
+**Core**: Testing (84%+), config validation, structured errors, benchmarking ✅
+**Architecture**: Modularization (50-200 lines), CLI (progress/colors), security (path validation, resource limits, scanning) ✅
+
+## 🚀 Current Priorities
+
+### Metrics & Profiling
+- [ ] Processing stats, timing
+
+### Output Customization  
+- [ ] Templates, markdown config, metadata
+
+### Documentation
+- [ ] API docs, user guides
+
+## 🌟 Future
+
+**Plugins**: Custom handlers, formats
+**Git**: Commit filtering, blame
+**Rich output**: HTML, PDF, web UI  
+**Monitoring**: Prometheus, structured logging
+
+## Guidelines
+
+**Before**: `make lint-fix && make lint`, >80% coverage
+**Priorities**: Security → UX → Extensions
+
+## Status (2025-07-19)
+
+**Health: 10/10** - Production-ready, 42 files (8.2K lines), 84%+ coverage
+
+**Done**: Testing, config, errors, performance, modularization, CLI, security
+**Next**: Documentation → Output customization
+
+### Token Usage
+
+- TODO.md: 171 words (~228 tokens) - 35% reduction ✅
+- CLAUDE.md: 160 words (~213 tokens) - 25% reduction ✅
+- Total: 331 words (~441 tokens) - 30% reduction ✅
+
+*Optimized from 474 → 331 words while preserving critical information*

benchmark/benchmark.go

@@ -0,0 +1,405 @@
+// Package benchmark provides benchmarking infrastructure for gibidify.
+package benchmark
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sync"
+	"time"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/fileproc"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// BenchmarkResult represents the results of a benchmark run.
+type BenchmarkResult struct {
+	Name           string
+	Duration       time.Duration
+	FilesProcessed int
+	BytesProcessed int64
+	FilesPerSecond float64
+	BytesPerSecond float64
+	MemoryUsage    MemoryStats
+	CPUUsage       CPUStats
+}
+
+// MemoryStats represents memory usage statistics.
+type MemoryStats struct {
+	AllocMB      float64
+	SysMB        float64
+	NumGC        uint32
+	PauseTotalNs uint64
+}
+
+// CPUStats represents CPU usage statistics.
+type CPUStats struct {
+	UserTime   time.Duration
+	SystemTime time.Duration
+	Goroutines int
+}
+
+// BenchmarkSuite represents a collection of benchmarks.
+type BenchmarkSuite struct {
+	Name    string
+	Results []BenchmarkResult
+}
+
+// FileCollectionBenchmark benchmarks file collection operations.
+func FileCollectionBenchmark(sourceDir string, numFiles int) (*BenchmarkResult, error) {
+	// Load configuration to ensure proper file filtering
+	config.LoadConfig()
+
+	// Create temporary directory with test files if no source is provided
+	var cleanup func()
+	if sourceDir == "" {
+		tempDir, cleanupFunc, err := createBenchmarkFiles(numFiles)
+		if err != nil {
+			return nil, utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSAccess, "failed to create benchmark files")
+		}
+		cleanup = cleanupFunc
+		defer cleanup()
+		sourceDir = tempDir
+	}
+
+	// Measure memory before
+	var memBefore runtime.MemStats
+	runtime.ReadMemStats(&memBefore)
+
+	startTime := time.Now()
+
+	// Run the file collection benchmark
+	files, err := fileproc.CollectFiles(sourceDir)
+	if err != nil {
+		return nil, utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "benchmark file collection failed")
+	}
+
+	duration := time.Since(startTime)
+
+	// Measure memory after
+	var memAfter runtime.MemStats
+	runtime.ReadMemStats(&memAfter)
+
+	// Calculate total bytes processed
+	var totalBytes int64
+	for _, file := range files {
+		if info, err := os.Stat(file); err == nil {
+			totalBytes += info.Size()
+		}
+	}
+
+	result := &BenchmarkResult{
+		Name:           "FileCollection",
+		Duration:       duration,
+		FilesProcessed: len(files),
+		BytesProcessed: totalBytes,
+		FilesPerSecond: float64(len(files)) / duration.Seconds(),
+		BytesPerSecond: float64(totalBytes) / duration.Seconds(),
+		MemoryUsage: MemoryStats{
+			AllocMB:      float64(memAfter.Alloc-memBefore.Alloc) / 1024 / 1024,
+			SysMB:        float64(memAfter.Sys-memBefore.Sys) / 1024 / 1024,
+			NumGC:        memAfter.NumGC - memBefore.NumGC,
+			PauseTotalNs: memAfter.PauseTotalNs - memBefore.PauseTotalNs,
+		},
+		CPUUsage: CPUStats{
+			Goroutines: runtime.NumGoroutine(),
+		},
+	}
+
+	return result, nil
+}
+
+// FileProcessingBenchmark benchmarks full file processing pipeline.
+func FileProcessingBenchmark(sourceDir string, format string, concurrency int) (*BenchmarkResult, error) {
+	// Load configuration to ensure proper file filtering
+	config.LoadConfig()
+
+	var cleanup func()
+	if sourceDir == "" {
+		// Create temporary directory with test files
+		tempDir, cleanupFunc, err := createBenchmarkFiles(100)
+		if err != nil {
+			return nil, utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSAccess, "failed to create benchmark files")
+		}
+		cleanup = cleanupFunc
+		defer cleanup()
+		sourceDir = tempDir
+	}
+
+	// Create temporary output file
+	outputFile, err := os.CreateTemp("", "benchmark_output_*."+format)
+	if err != nil {
+		return nil, utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOFileCreate, "failed to create benchmark output file")
+	}
+	defer func() {
+		if err := outputFile.Close(); err != nil {
+			// Log error but don't fail the benchmark
+			fmt.Printf("Warning: failed to close benchmark output file: %v\n", err)
+		}
+		if err := os.Remove(outputFile.Name()); err != nil {
+			// Log error but don't fail the benchmark
+			fmt.Printf("Warning: failed to remove benchmark output file: %v\n", err)
+		}
+	}()
+
+	// Measure memory before
+	var memBefore runtime.MemStats
+	runtime.ReadMemStats(&memBefore)
+
+	startTime := time.Now()
+
+	// Run the full processing pipeline
+	files, err := fileproc.CollectFiles(sourceDir)
+	if err != nil {
+		return nil, utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "benchmark file collection failed")
+	}
+
+	// Process files with concurrency
+	err = runProcessingPipeline(context.Background(), files, outputFile, format, concurrency, sourceDir)
+	if err != nil {
+		return nil, utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingFileRead, "benchmark processing pipeline failed")
+	}
+
+	duration := time.Since(startTime)
+
+	// Measure memory after
+	var memAfter runtime.MemStats
+	runtime.ReadMemStats(&memAfter)
+
+	// Calculate total bytes processed
+	var totalBytes int64
+	for _, file := range files {
+		if info, err := os.Stat(file); err == nil {
+			totalBytes += info.Size()
+		}
+	}
+
+	result := &BenchmarkResult{
+		Name:           fmt.Sprintf("FileProcessing_%s_c%d", format, concurrency),
+		Duration:       duration,
+		FilesProcessed: len(files),
+		BytesProcessed: totalBytes,
+		FilesPerSecond: float64(len(files)) / duration.Seconds(),
+		BytesPerSecond: float64(totalBytes) / duration.Seconds(),
+		MemoryUsage: MemoryStats{
+			AllocMB:      float64(memAfter.Alloc-memBefore.Alloc) / 1024 / 1024,
+			SysMB:        float64(memAfter.Sys-memBefore.Sys) / 1024 / 1024,
+			NumGC:        memAfter.NumGC - memBefore.NumGC,
+			PauseTotalNs: memAfter.PauseTotalNs - memBefore.PauseTotalNs,
+		},
+		CPUUsage: CPUStats{
+			Goroutines: runtime.NumGoroutine(),
+		},
+	}
+
+	return result, nil
+}
+
+// ConcurrencyBenchmark benchmarks different concurrency levels.
+func ConcurrencyBenchmark(sourceDir string, format string, concurrencyLevels []int) (*BenchmarkSuite, error) {
+	suite := &BenchmarkSuite{
+		Name:    "ConcurrencyBenchmark",
+		Results: make([]BenchmarkResult, 0, len(concurrencyLevels)),
+	}
+
+	for _, concurrency := range concurrencyLevels {
+		result, err := FileProcessingBenchmark(sourceDir, format, concurrency)
+		if err != nil {
+			return nil, utils.WrapErrorf(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "concurrency benchmark failed for level %d", concurrency)
+		}
+		suite.Results = append(suite.Results, *result)
+	}
+
+	return suite, nil
+}
+
+// FormatBenchmark benchmarks different output formats.
+func FormatBenchmark(sourceDir string, formats []string) (*BenchmarkSuite, error) {
+	suite := &BenchmarkSuite{
+		Name:    "FormatBenchmark",
+		Results: make([]BenchmarkResult, 0, len(formats)),
+	}
+
+	for _, format := range formats {
+		result, err := FileProcessingBenchmark(sourceDir, format, runtime.NumCPU())
+		if err != nil {
+			return nil, utils.WrapErrorf(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "format benchmark failed for format %s", format)
+		}
+		suite.Results = append(suite.Results, *result)
+	}
+
+	return suite, nil
+}
+
+// createBenchmarkFiles creates temporary files for benchmarking.
+func createBenchmarkFiles(numFiles int) (string, func(), error) {
+	tempDir, err := os.MkdirTemp("", "gibidify_benchmark_*")
+	if err != nil {
+		return "", nil, utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSAccess, "failed to create temp directory")
+	}
+
+	cleanup := func() {
+		if err := os.RemoveAll(tempDir); err != nil {
+			// Log error but don't fail the benchmark
+			fmt.Printf("Warning: failed to remove benchmark temp directory: %v\n", err)
+		}
+	}
+
+	// Create various file types
+	fileTypes := []struct {
+		ext     string
+		content string
+	}{
+		{".go", "package main\n\nfunc main() {\n\tprintln(\"Hello, World!\")\n}"},
+		{".js", "console.log('Hello, World!');"},
+		{".py", "print('Hello, World!')"},
+		{".java", "public class Hello {\n\tpublic static void main(String[] args) {\n\t\tSystem.out.println(\"Hello, World!\");\n\t}\n}"},
+		{".cpp", "#include <iostream>\n\nint main() {\n\tstd::cout << \"Hello, World!\" << std::endl;\n\treturn 0;\n}"},
+		{".rs", "fn main() {\n\tprintln!(\"Hello, World!\");\n}"},
+		{".rb", "puts 'Hello, World!'"},
+		{".php", "<?php\necho 'Hello, World!';\n?>"},
+		{".sh", "#!/bin/bash\necho 'Hello, World!'"},
+		{".md", "# Hello, World!\n\nThis is a markdown file."},
+	}
+
+	for i := 0; i < numFiles; i++ {
+		fileType := fileTypes[i%len(fileTypes)]
+		filename := fmt.Sprintf("file_%d%s", i, fileType.ext)
+
+		// Create subdirectories for some files
+		if i%10 == 0 {
+			subdir := filepath.Join(tempDir, fmt.Sprintf("subdir_%d", i/10))
+			if err := os.MkdirAll(subdir, 0o755); err != nil {
+				cleanup()
+				return "", nil, utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSAccess, "failed to create subdirectory")
+			}
+			filename = filepath.Join(subdir, filename)
+		} else {
+			filename = filepath.Join(tempDir, filename)
+		}
+
+		// Create file with repeated content to make it larger
+		content := ""
+		for j := 0; j < 10; j++ {
+			content += fmt.Sprintf("// Line %d\n%s\n", j, fileType.content)
+		}
+
+		if err := os.WriteFile(filename, []byte(content), 0o644); err != nil {
+			cleanup()
+			return "", nil, utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOFileWrite, "failed to write benchmark file")
+		}
+	}
+
+	return tempDir, cleanup, nil
+}
+
+// runProcessingPipeline runs the processing pipeline similar to main.go.
+func runProcessingPipeline(ctx context.Context, files []string, outputFile *os.File, format string, concurrency int, sourceDir string) error {
+	fileCh := make(chan string, concurrency)
+	writeCh := make(chan fileproc.WriteRequest, concurrency)
+	writerDone := make(chan struct{})
+
+	// Start writer
+	go fileproc.StartWriter(outputFile, writeCh, writerDone, format, "", "")
+
+	// Get absolute path once
+	absRoot, err := utils.GetAbsolutePath(sourceDir)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSPathResolution, "failed to get absolute path for source directory")
+	}
+
+	// Start workers with proper synchronization
+	var workersDone sync.WaitGroup
+	for i := 0; i < concurrency; i++ {
+		workersDone.Add(1)
+		go func() {
+			defer workersDone.Done()
+			for filePath := range fileCh {
+				fileproc.ProcessFile(filePath, writeCh, absRoot)
+			}
+		}()
+	}
+
+	// Send files to workers
+	for _, file := range files {
+		select {
+		case <-ctx.Done():
+			close(fileCh)
+			workersDone.Wait() // Wait for workers to finish
+			close(writeCh)
+			<-writerDone
+			return ctx.Err()
+		case fileCh <- file:
+		}
+	}
+
+	// Close file channel and wait for workers to finish
+	close(fileCh)
+	workersDone.Wait()
+
+	// Now it's safe to close the write channel
+	close(writeCh)
+	<-writerDone
+
+	return nil
+}
+
+// PrintBenchmarkResult prints a formatted benchmark result.
+func PrintBenchmarkResult(result *BenchmarkResult) {
+	fmt.Printf("=== %s ===\n", result.Name)
+	fmt.Printf("Duration: %v\n", result.Duration)
+	fmt.Printf("Files Processed: %d\n", result.FilesProcessed)
+	fmt.Printf("Bytes Processed: %d (%.2f MB)\n", result.BytesProcessed, float64(result.BytesProcessed)/1024/1024)
+	fmt.Printf("Files/sec: %.2f\n", result.FilesPerSecond)
+	fmt.Printf("Bytes/sec: %.2f MB/sec\n", result.BytesPerSecond/1024/1024)
+	fmt.Printf("Memory Usage: +%.2f MB (Sys: +%.2f MB)\n", result.MemoryUsage.AllocMB, result.MemoryUsage.SysMB)
+	fmt.Printf("GC Runs: %d (Pause: %v)\n", result.MemoryUsage.NumGC, time.Duration(result.MemoryUsage.PauseTotalNs))
+	fmt.Printf("Goroutines: %d\n", result.CPUUsage.Goroutines)
+	fmt.Println()
+}
+
+// PrintBenchmarkSuite prints all results in a benchmark suite.
+func PrintBenchmarkSuite(suite *BenchmarkSuite) {
+	fmt.Printf("=== %s ===\n", suite.Name)
+	for _, result := range suite.Results {
+		PrintBenchmarkResult(&result)
+	}
+}
+
+// RunAllBenchmarks runs a comprehensive benchmark suite.
+func RunAllBenchmarks(sourceDir string) error {
+	fmt.Println("Running gibidify benchmark suite...")
+
+	// Load configuration
+	config.LoadConfig()
+
+	// File collection benchmark
+	fmt.Println("Running file collection benchmark...")
+	result, err := FileCollectionBenchmark(sourceDir, 1000)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "file collection benchmark failed")
+	}
+	PrintBenchmarkResult(result)
+
+	// Format benchmarks
+	fmt.Println("Running format benchmarks...")
+	formatSuite, err := FormatBenchmark(sourceDir, []string{"json", "yaml", "markdown"})
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "format benchmark failed")
+	}
+	PrintBenchmarkSuite(formatSuite)
+
+	// Concurrency benchmarks
+	fmt.Println("Running concurrency benchmarks...")
+	concurrencyLevels := []int{1, 2, 4, 8, runtime.NumCPU()}
+	concurrencySuite, err := ConcurrencyBenchmark(sourceDir, "json", concurrencyLevels)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "concurrency benchmark failed")
+	}
+	PrintBenchmarkSuite(concurrencySuite)
+
+	return nil
+}

benchmark/benchmark_test.go

@@ -0,0 +1,165 @@
+package benchmark
+
+import (
+	"runtime"
+	"testing"
+)
+
+// TestFileCollectionBenchmark tests the file collection benchmark.
+func TestFileCollectionBenchmark(t *testing.T) {
+	result, err := FileCollectionBenchmark("", 10)
+	if err != nil {
+		t.Fatalf("FileCollectionBenchmark failed: %v", err)
+	}
+
+	if result.Name != "FileCollection" {
+		t.Errorf("Expected name 'FileCollection', got %s", result.Name)
+	}
+
+	// Debug information
+	t.Logf("Files processed: %d", result.FilesProcessed)
+	t.Logf("Duration: %v", result.Duration)
+	t.Logf("Bytes processed: %d", result.BytesProcessed)
+
+	if result.FilesProcessed <= 0 {
+		t.Errorf("Expected files processed > 0, got %d", result.FilesProcessed)
+	}
+
+	if result.Duration <= 0 {
+		t.Errorf("Expected duration > 0, got %v", result.Duration)
+	}
+}
+
+// TestFileProcessingBenchmark tests the file processing benchmark.
+func TestFileProcessingBenchmark(t *testing.T) {
+	result, err := FileProcessingBenchmark("", "json", 2)
+	if err != nil {
+		t.Fatalf("FileProcessingBenchmark failed: %v", err)
+	}
+
+	if result.FilesProcessed <= 0 {
+		t.Errorf("Expected files processed > 0, got %d", result.FilesProcessed)
+	}
+
+	if result.Duration <= 0 {
+		t.Errorf("Expected duration > 0, got %v", result.Duration)
+	}
+}
+
+// TestConcurrencyBenchmark tests the concurrency benchmark.
+func TestConcurrencyBenchmark(t *testing.T) {
+	concurrencyLevels := []int{1, 2}
+	suite, err := ConcurrencyBenchmark("", "json", concurrencyLevels)
+	if err != nil {
+		t.Fatalf("ConcurrencyBenchmark failed: %v", err)
+	}
+
+	if suite.Name != "ConcurrencyBenchmark" {
+		t.Errorf("Expected name 'ConcurrencyBenchmark', got %s", suite.Name)
+	}
+
+	if len(suite.Results) != len(concurrencyLevels) {
+		t.Errorf("Expected %d results, got %d", len(concurrencyLevels), len(suite.Results))
+	}
+
+	for i, result := range suite.Results {
+		if result.FilesProcessed <= 0 {
+			t.Errorf("Result %d: Expected files processed > 0, got %d", i, result.FilesProcessed)
+		}
+	}
+}
+
+// TestFormatBenchmark tests the format benchmark.
+func TestFormatBenchmark(t *testing.T) {
+	formats := []string{"json", "yaml"}
+	suite, err := FormatBenchmark("", formats)
+	if err != nil {
+		t.Fatalf("FormatBenchmark failed: %v", err)
+	}
+
+	if suite.Name != "FormatBenchmark" {
+		t.Errorf("Expected name 'FormatBenchmark', got %s", suite.Name)
+	}
+
+	if len(suite.Results) != len(formats) {
+		t.Errorf("Expected %d results, got %d", len(formats), len(suite.Results))
+	}
+
+	for i, result := range suite.Results {
+		if result.FilesProcessed <= 0 {
+			t.Errorf("Result %d: Expected files processed > 0, got %d", i, result.FilesProcessed)
+		}
+	}
+}
+
+// TestCreateBenchmarkFiles tests the benchmark file creation.
+func TestCreateBenchmarkFiles(t *testing.T) {
+	tempDir, cleanup, err := createBenchmarkFiles(5)
+	if err != nil {
+		t.Fatalf("createBenchmarkFiles failed: %v", err)
+	}
+	defer cleanup()
+
+	if tempDir == "" {
+		t.Error("Expected non-empty temp directory")
+	}
+
+	// Verify files were created
+	// This is tested indirectly through the benchmark functions
+}
+
+// BenchmarkFileCollection benchmarks the file collection process.
+func BenchmarkFileCollection(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		result, err := FileCollectionBenchmark("", 50)
+		if err != nil {
+			b.Fatalf("FileCollectionBenchmark failed: %v", err)
+		}
+		if result.FilesProcessed <= 0 {
+			b.Errorf("Expected files processed > 0, got %d", result.FilesProcessed)
+		}
+	}
+}
+
+// BenchmarkFileProcessing benchmarks the file processing pipeline.
+func BenchmarkFileProcessing(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		result, err := FileProcessingBenchmark("", "json", runtime.NumCPU())
+		if err != nil {
+			b.Fatalf("FileProcessingBenchmark failed: %v", err)
+		}
+		if result.FilesProcessed <= 0 {
+			b.Errorf("Expected files processed > 0, got %d", result.FilesProcessed)
+		}
+	}
+}
+
+// BenchmarkConcurrency benchmarks different concurrency levels.
+func BenchmarkConcurrency(b *testing.B) {
+	concurrencyLevels := []int{1, 2, 4}
+
+	for i := 0; i < b.N; i++ {
+		suite, err := ConcurrencyBenchmark("", "json", concurrencyLevels)
+		if err != nil {
+			b.Fatalf("ConcurrencyBenchmark failed: %v", err)
+		}
+		if len(suite.Results) != len(concurrencyLevels) {
+			b.Errorf("Expected %d results, got %d", len(concurrencyLevels), len(suite.Results))
+		}
+	}
+}
+
+// BenchmarkFormats benchmarks different output formats.
+func BenchmarkFormats(b *testing.B) {
+	formats := []string{"json", "yaml", "markdown"}
+
+	for i := 0; i < b.N; i++ {
+		suite, err := FormatBenchmark("", formats)
+		if err != nil {
+			b.Fatalf("FormatBenchmark failed: %v", err)
+		}
+		if len(suite.Results) != len(formats) {
+			b.Errorf("Expected %d results, got %d", len(formats), len(suite.Results))
+		}
+	}
+}

cli/errors.go

@@ -0,0 +1,285 @@
+package cli
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// ErrorFormatter handles CLI-friendly error formatting with suggestions.
+type ErrorFormatter struct {
+	ui *UIManager
+}
+
+// NewErrorFormatter creates a new error formatter.
+func NewErrorFormatter(ui *UIManager) *ErrorFormatter {
+	return &ErrorFormatter{ui: ui}
+}
+
+// FormatError formats an error with context and suggestions.
+func (ef *ErrorFormatter) FormatError(err error) {
+	if err == nil {
+		return
+	}
+
+	// Handle structured errors
+	if structErr, ok := err.(*utils.StructuredError); ok {
+		ef.formatStructuredError(structErr)
+		return
+	}
+
+	// Handle common error types
+	ef.formatGenericError(err)
+}
+
+// formatStructuredError formats a structured error with context and suggestions.
+func (ef *ErrorFormatter) formatStructuredError(err *utils.StructuredError) {
+	// Print main error
+	ef.ui.PrintError("Error: %s", err.Message)
+
+	// Print error type and code
+	if err.Type != utils.ErrorTypeUnknown || err.Code != "" {
+		ef.ui.PrintInfo("Type: %s, Code: %s", err.Type.String(), err.Code)
+	}
+
+	// Print file path if available
+	if err.FilePath != "" {
+		ef.ui.PrintInfo("File: %s", err.FilePath)
+	}
+
+	// Print context if available
+	if len(err.Context) > 0 {
+		ef.ui.PrintInfo("Context:")
+		for key, value := range err.Context {
+			ef.ui.printf("  %s: %v\n", key, value)
+		}
+	}
+
+	// Provide suggestions based on error type
+	ef.provideSuggestions(err)
+}
+
+// formatGenericError formats a generic error.
+func (ef *ErrorFormatter) formatGenericError(err error) {
+	ef.ui.PrintError("Error: %s", err.Error())
+	ef.provideGenericSuggestions(err)
+}
+
+// provideSuggestions provides helpful suggestions based on the error.
+func (ef *ErrorFormatter) provideSuggestions(err *utils.StructuredError) {
+	switch err.Type {
+	case utils.ErrorTypeFileSystem:
+		ef.provideFileSystemSuggestions(err)
+	case utils.ErrorTypeValidation:
+		ef.provideValidationSuggestions(err)
+	case utils.ErrorTypeProcessing:
+		ef.provideProcessingSuggestions(err)
+	case utils.ErrorTypeIO:
+		ef.provideIOSuggestions(err)
+	default:
+		ef.provideDefaultSuggestions()
+	}
+}
+
+// provideFileSystemSuggestions provides suggestions for file system errors.
+func (ef *ErrorFormatter) provideFileSystemSuggestions(err *utils.StructuredError) {
+	filePath := err.FilePath
+
+	ef.ui.PrintWarning("Suggestions:")
+
+	switch err.Code {
+	case utils.CodeFSAccess:
+		ef.suggestFileAccess(filePath)
+	case utils.CodeFSPathResolution:
+		ef.suggestPathResolution(filePath)
+	case utils.CodeFSNotFound:
+		ef.suggestFileNotFound(filePath)
+	default:
+		ef.suggestFileSystemGeneral(filePath)
+	}
+}
+
+// provideValidationSuggestions provides suggestions for validation errors.
+func (ef *ErrorFormatter) provideValidationSuggestions(err *utils.StructuredError) {
+	ef.ui.PrintWarning("Suggestions:")
+
+	switch err.Code {
+	case utils.CodeValidationFormat:
+		ef.ui.printf("  • Use a supported format: markdown, json, yaml\n")
+		ef.ui.printf("  • Example: -format markdown\n")
+	case utils.CodeValidationSize:
+		ef.ui.printf("  • Increase file size limit in config.yaml\n")
+		ef.ui.printf("  • Use smaller files or exclude large files\n")
+	default:
+		ef.ui.printf("  • Check your command line arguments\n")
+		ef.ui.printf("  • Run with --help for usage information\n")
+	}
+}
+
+// provideProcessingSuggestions provides suggestions for processing errors.
+func (ef *ErrorFormatter) provideProcessingSuggestions(err *utils.StructuredError) {
+	ef.ui.PrintWarning("Suggestions:")
+
+	switch err.Code {
+	case utils.CodeProcessingCollection:
+		ef.ui.printf("  • Check if the source directory exists and is readable\n")
+		ef.ui.printf("  • Verify directory permissions\n")
+	case utils.CodeProcessingFileRead:
+		ef.ui.printf("  • Check file permissions\n")
+		ef.ui.printf("  • Verify the file is not corrupted\n")
+	default:
+		ef.ui.printf("  • Try reducing concurrency: -concurrency 1\n")
+		ef.ui.printf("  • Check available system resources\n")
+	}
+}
+
+// provideIOSuggestions provides suggestions for I/O errors.
+func (ef *ErrorFormatter) provideIOSuggestions(err *utils.StructuredError) {
+	ef.ui.PrintWarning("Suggestions:")
+
+	switch err.Code {
+	case utils.CodeIOFileCreate:
+		ef.ui.printf("  • Check if the destination directory exists\n")
+		ef.ui.printf("  • Verify write permissions for the output file\n")
+		ef.ui.printf("  • Ensure sufficient disk space\n")
+	case utils.CodeIOWrite:
+		ef.ui.printf("  • Check available disk space\n")
+		ef.ui.printf("  • Verify write permissions\n")
+	default:
+		ef.ui.printf("  • Check file/directory permissions\n")
+		ef.ui.printf("  • Verify available disk space\n")
+	}
+}
+
+// Helper methods for specific suggestions
+func (ef *ErrorFormatter) suggestFileAccess(filePath string) {
+	ef.ui.printf("  • Check if the path exists: %s\n", filePath)
+	ef.ui.printf("  • Verify read permissions\n")
+	if filePath != "" {
+		if stat, err := os.Stat(filePath); err == nil {
+			ef.ui.printf("  • Path exists but may not be accessible\n")
+			ef.ui.printf("  • Mode: %s\n", stat.Mode())
+		}
+	}
+}
+
+func (ef *ErrorFormatter) suggestPathResolution(filePath string) {
+	ef.ui.printf("  • Use an absolute path instead of relative\n")
+	if filePath != "" {
+		if abs, err := filepath.Abs(filePath); err == nil {
+			ef.ui.printf("  • Try: %s\n", abs)
+		}
+	}
+}
+
+func (ef *ErrorFormatter) suggestFileNotFound(filePath string) {
+	ef.ui.printf("  • Check if the file/directory exists: %s\n", filePath)
+	if filePath != "" {
+		dir := filepath.Dir(filePath)
+		if entries, err := os.ReadDir(dir); err == nil {
+			ef.ui.printf("  • Similar files in %s:\n", dir)
+			count := 0
+			for _, entry := range entries {
+				if count >= 3 {
+					break
+				}
+				if strings.Contains(entry.Name(), filepath.Base(filePath)) {
+					ef.ui.printf("    - %s\n", entry.Name())
+					count++
+				}
+			}
+		}
+	}
+}
+
+func (ef *ErrorFormatter) suggestFileSystemGeneral(filePath string) {
+	ef.ui.printf("  • Check file/directory permissions\n")
+	ef.ui.printf("  • Verify the path is correct\n")
+	if filePath != "" {
+		ef.ui.printf("  • Path: %s\n", filePath)
+	}
+}
+
+// provideDefaultSuggestions provides general suggestions.
+func (ef *ErrorFormatter) provideDefaultSuggestions() {
+	ef.ui.printf("  • Check your command line arguments\n")
+	ef.ui.printf("  • Run with --help for usage information\n")
+	ef.ui.printf("  • Try with -concurrency 1 to reduce resource usage\n")
+}
+
+// provideGenericSuggestions provides suggestions for generic errors.
+func (ef *ErrorFormatter) provideGenericSuggestions(err error) {
+	errorMsg := err.Error()
+
+	ef.ui.PrintWarning("Suggestions:")
+
+	// Pattern matching for common errors
+	switch {
+	case strings.Contains(errorMsg, "permission denied"):
+		ef.ui.printf("  • Check file/directory permissions\n")
+		ef.ui.printf("  • Try running with appropriate privileges\n")
+	case strings.Contains(errorMsg, "no such file or directory"):
+		ef.ui.printf("  • Verify the file/directory path is correct\n")
+		ef.ui.printf("  • Check if the file exists\n")
+	case strings.Contains(errorMsg, "flag") && strings.Contains(errorMsg, "redefined"):
+		ef.ui.printf("  • This is likely a test environment issue\n")
+		ef.ui.printf("  • Try running the command directly instead of in tests\n")
+	default:
+		ef.provideDefaultSuggestions()
+	}
+}
+
+// CLI-specific error types
+
+// CLIMissingSourceError represents a missing source directory error.
+type CLIMissingSourceError struct{}
+
+func (e CLIMissingSourceError) Error() string {
+	return "source directory is required"
+}
+
+// NewCLIMissingSourceError creates a new CLI missing source error with suggestions.
+func NewCLIMissingSourceError() error {
+	return &CLIMissingSourceError{}
+}
+
+// IsUserError checks if an error is a user input error that should be handled gracefully.
+func IsUserError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// Check for specific user error types
+	var cliErr *CLIMissingSourceError
+	if errors.As(err, &cliErr) {
+		return true
+	}
+
+	// Check for structured errors that are user-facing
+	if structErr, ok := err.(*utils.StructuredError); ok {
+		return structErr.Type == utils.ErrorTypeValidation ||
+			structErr.Code == utils.CodeValidationFormat ||
+			structErr.Code == utils.CodeValidationSize
+	}
+
+	// Check error message patterns
+	errMsg := err.Error()
+	userErrorPatterns := []string{
+		"flag",
+		"usage",
+		"invalid argument",
+		"file not found",
+		"permission denied",
+	}
+
+	for _, pattern := range userErrorPatterns {
+		if strings.Contains(strings.ToLower(errMsg), pattern) {
+			return true
+		}
+	}
+
+	return false
+}

cli/flags.go

@@ -0,0 +1,104 @@
+package cli
+
+import (
+	"flag"
+	"runtime"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// Flags holds CLI flags values.
+type Flags struct {
+	SourceDir   string
+	Destination string
+	Prefix      string
+	Suffix      string
+	Concurrency int
+	Format      string
+	NoColors    bool
+	NoProgress  bool
+	Verbose     bool
+}
+
+var (
+	flagsParsed bool
+	globalFlags *Flags
+)
+
+// ParseFlags parses and validates CLI flags.
+func ParseFlags() (*Flags, error) {
+	if flagsParsed {
+		return globalFlags, nil
+	}
+
+	flags := &Flags{}
+
+	flag.StringVar(&flags.SourceDir, "source", "", "Source directory to scan recursively")
+	flag.StringVar(&flags.Destination, "destination", "", "Output file to write aggregated code")
+	flag.StringVar(&flags.Prefix, "prefix", "", "Text to add at the beginning of the output file")
+	flag.StringVar(&flags.Suffix, "suffix", "", "Text to add at the end of the output file")
+	flag.StringVar(&flags.Format, "format", "markdown", "Output format (json, markdown, yaml)")
+	flag.IntVar(&flags.Concurrency, "concurrency", runtime.NumCPU(),
+		"Number of concurrent workers (default: number of CPU cores)")
+	flag.BoolVar(&flags.NoColors, "no-colors", false, "Disable colored output")
+	flag.BoolVar(&flags.NoProgress, "no-progress", false, "Disable progress bars")
+	flag.BoolVar(&flags.Verbose, "verbose", false, "Enable verbose output")
+
+	flag.Parse()
+
+	if err := flags.validate(); err != nil {
+		return nil, err
+	}
+
+	if err := flags.setDefaultDestination(); err != nil {
+		return nil, err
+	}
+
+	flagsParsed = true
+	globalFlags = flags
+	return flags, nil
+}
+
+// validate validates the CLI flags.
+func (f *Flags) validate() error {
+	if f.SourceDir == "" {
+		return NewCLIMissingSourceError()
+	}
+
+	// Validate source path for security
+	if err := utils.ValidateSourcePath(f.SourceDir); err != nil {
+		return err
+	}
+
+	// Validate output format
+	if err := config.ValidateOutputFormat(f.Format); err != nil {
+		return err
+	}
+
+	// Validate concurrency
+	if err := config.ValidateConcurrency(f.Concurrency); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// setDefaultDestination sets the default destination if not provided.
+func (f *Flags) setDefaultDestination() error {
+	if f.Destination == "" {
+		absRoot, err := utils.GetAbsolutePath(f.SourceDir)
+		if err != nil {
+			return err
+		}
+		baseName := utils.GetBaseName(absRoot)
+		f.Destination = baseName + "." + f.Format
+	}
+
+	// Validate destination path for security
+	if err := utils.ValidateDestinationPath(f.Destination); err != nil {
+		return err
+	}
+
+	return nil
+}

cli/processor_collection.go

@@ -0,0 +1,77 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/fileproc"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// collectFiles collects all files to be processed.
+func (p *Processor) collectFiles() ([]string, error) {
+	files, err := fileproc.CollectFiles(p.flags.SourceDir)
+	if err != nil {
+		return nil, utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "error collecting files")
+	}
+	logrus.Infof("Found %d files to process", len(files))
+	return files, nil
+}
+
+// validateFileCollection validates the collected files against resource limits.
+func (p *Processor) validateFileCollection(files []string) error {
+	if !config.GetResourceLimitsEnabled() {
+		return nil
+	}
+
+	// Check file count limit
+	maxFiles := config.GetMaxFiles()
+	if len(files) > maxFiles {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeResourceLimitFiles,
+			fmt.Sprintf("file count (%d) exceeds maximum limit (%d)", len(files), maxFiles),
+			"",
+			map[string]interface{}{
+				"file_count": len(files),
+				"max_files":  maxFiles,
+			},
+		)
+	}
+
+	// Check total size limit (estimate)
+	maxTotalSize := config.GetMaxTotalSize()
+	totalSize := int64(0)
+	oversizedFiles := 0
+
+	for _, filePath := range files {
+		if fileInfo, err := os.Stat(filePath); err == nil {
+			totalSize += fileInfo.Size()
+			if totalSize > maxTotalSize {
+				return utils.NewStructuredError(
+					utils.ErrorTypeValidation,
+					utils.CodeResourceLimitTotalSize,
+					fmt.Sprintf("total file size (%d bytes) would exceed maximum limit (%d bytes)", totalSize, maxTotalSize),
+					"",
+					map[string]interface{}{
+						"total_size":     totalSize,
+						"max_total_size": maxTotalSize,
+						"files_checked":  len(files),
+					},
+				)
+			}
+		} else {
+			oversizedFiles++
+		}
+	}
+
+	if oversizedFiles > 0 {
+		logrus.Warnf("Could not stat %d files during pre-validation", oversizedFiles)
+	}
+
+	logrus.Infof("Pre-validation passed: %d files, %d MB total", len(files), totalSize/1024/1024)
+	return nil
+}

cli/processor_processing.go

@@ -0,0 +1,100 @@
+package cli
+
+import (
+	"context"
+	"os"
+	"sync"
+
+	"github.com/ivuorinen/gibidify/fileproc"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// Process executes the main file processing workflow.
+func (p *Processor) Process(ctx context.Context) error {
+	// Create overall processing context with timeout
+	overallCtx, overallCancel := p.resourceMonitor.CreateOverallProcessingContext(ctx)
+	defer overallCancel()
+
+	// Configure file type registry
+	p.configureFileTypes()
+
+	// Print startup info with colors
+	p.ui.PrintHeader("🚀 Starting gibidify")
+	p.ui.PrintInfo("Format: %s", p.flags.Format)
+	p.ui.PrintInfo("Source: %s", p.flags.SourceDir)
+	p.ui.PrintInfo("Destination: %s", p.flags.Destination)
+	p.ui.PrintInfo("Workers: %d", p.flags.Concurrency)
+
+	// Log resource monitoring configuration
+	p.resourceMonitor.LogResourceInfo()
+	p.backpressure.LogBackpressureInfo()
+
+	// Collect files with progress indication
+	p.ui.PrintInfo("📁 Collecting files...")
+	files, err := p.collectFiles()
+	if err != nil {
+		return err
+	}
+
+	// Show collection results
+	p.ui.PrintSuccess("Found %d files to process", len(files))
+
+	// Pre-validate file collection against resource limits
+	if err := p.validateFileCollection(files); err != nil {
+		return err
+	}
+
+	// Process files with overall timeout
+	return p.processFiles(overallCtx, files)
+}
+
+// processFiles processes the collected files.
+func (p *Processor) processFiles(ctx context.Context, files []string) error {
+	outFile, err := p.createOutputFile()
+	if err != nil {
+		return err
+	}
+	defer func() {
+		utils.LogError("Error closing output file", outFile.Close())
+	}()
+
+	// Initialize back-pressure and channels
+	p.ui.PrintInfo("⚙️  Initializing processing...")
+	p.backpressure.LogBackpressureInfo()
+	fileCh, writeCh := p.backpressure.CreateChannels()
+	writerDone := make(chan struct{})
+
+	// Start writer
+	go fileproc.StartWriter(outFile, writeCh, writerDone, p.flags.Format, p.flags.Prefix, p.flags.Suffix)
+
+	// Start workers
+	var wg sync.WaitGroup
+	p.startWorkers(ctx, &wg, fileCh, writeCh)
+
+	// Start progress bar
+	p.ui.StartProgress(len(files), "📝 Processing files")
+
+	// Send files to workers
+	if err := p.sendFiles(ctx, files, fileCh); err != nil {
+		p.ui.FinishProgress()
+		return err
+	}
+
+	// Wait for completion
+	p.waitForCompletion(&wg, writeCh, writerDone)
+	p.ui.FinishProgress()
+
+	p.logFinalStats()
+	p.ui.PrintSuccess("Processing completed. Output saved to %s", p.flags.Destination)
+	return nil
+}
+
+// createOutputFile creates the output file.
+func (p *Processor) createOutputFile() (*os.File, error) {
+	// Destination path has been validated in CLI flags validation for path traversal attempts
+	outFile, err := os.Create(p.flags.Destination) // #nosec G304 - destination is validated in flags.validate()
+	if err != nil {
+		return nil, utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOFileCreate, "failed to create output file").WithFilePath(p.flags.Destination)
+	}
+	return outFile, nil
+}

cli/processor_stats.go

@@ -0,0 +1,40 @@
+package cli
+
+import (
+	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/config"
+)
+
+// logFinalStats logs the final back-pressure and resource monitoring statistics.
+func (p *Processor) logFinalStats() {
+	// Log back-pressure stats
+	backpressureStats := p.backpressure.GetStats()
+	if backpressureStats.Enabled {
+		logrus.Infof("Back-pressure stats: processed=%d files, memory=%dMB/%dMB",
+			backpressureStats.FilesProcessed, backpressureStats.CurrentMemoryUsage/1024/1024, backpressureStats.MaxMemoryUsage/1024/1024)
+	}
+
+	// Log resource monitoring stats
+	resourceStats := p.resourceMonitor.GetMetrics()
+	if config.GetResourceLimitsEnabled() {
+		logrus.Infof("Resource stats: processed=%d files, totalSize=%dMB, avgFileSize=%.2fKB, rate=%.2f files/sec",
+			resourceStats.FilesProcessed, resourceStats.TotalSizeProcessed/1024/1024,
+			resourceStats.AverageFileSize/1024, resourceStats.ProcessingRate)
+
+		if len(resourceStats.ViolationsDetected) > 0 {
+			logrus.Warnf("Resource violations detected: %v", resourceStats.ViolationsDetected)
+		}
+
+		if resourceStats.DegradationActive {
+			logrus.Warnf("Processing completed with degradation mode active")
+		}
+
+		if resourceStats.EmergencyStopActive {
+			logrus.Errorf("Processing completed with emergency stop active")
+		}
+	}
+
+	// Clean up resource monitor
+	p.resourceMonitor.Close()
+}

cli/processor_types.go

@@ -0,0 +1,44 @@
+package cli
+
+import (
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/fileproc"
+)
+
+// Processor handles the main file processing logic.
+type Processor struct {
+	flags           *Flags
+	backpressure    *fileproc.BackpressureManager
+	resourceMonitor *fileproc.ResourceMonitor
+	ui              *UIManager
+}
+
+// NewProcessor creates a new processor with the given flags.
+func NewProcessor(flags *Flags) *Processor {
+	ui := NewUIManager()
+
+	// Configure UI based on flags
+	ui.SetColorOutput(!flags.NoColors)
+	ui.SetProgressOutput(!flags.NoProgress)
+
+	return &Processor{
+		flags:           flags,
+		backpressure:    fileproc.NewBackpressureManager(),
+		resourceMonitor: fileproc.NewResourceMonitor(),
+		ui:              ui,
+	}
+}
+
+// configureFileTypes configures the file type registry.
+func (p *Processor) configureFileTypes() {
+	if config.GetFileTypesEnabled() {
+		fileproc.ConfigureFromSettings(
+			config.GetCustomImageExtensions(),
+			config.GetCustomBinaryExtensions(),
+			config.GetCustomLanguages(),
+			config.GetDisabledImageExtensions(),
+			config.GetDisabledBinaryExtensions(),
+			config.GetDisabledLanguageExtensions(),
+		)
+	}
+}

cli/processor_workers.go

@@ -0,0 +1,85 @@
+package cli
+
+import (
+	"context"
+	"sync"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/fileproc"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// startWorkers starts the worker goroutines.
+func (p *Processor) startWorkers(ctx context.Context, wg *sync.WaitGroup, fileCh chan string, writeCh chan fileproc.WriteRequest) {
+	for range p.flags.Concurrency {
+		wg.Add(1)
+		go p.worker(ctx, wg, fileCh, writeCh)
+	}
+}
+
+// worker is the worker goroutine function.
+func (p *Processor) worker(ctx context.Context, wg *sync.WaitGroup, fileCh chan string, writeCh chan fileproc.WriteRequest) {
+	defer wg.Done()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case filePath, ok := <-fileCh:
+			if !ok {
+				return
+			}
+			p.processFile(ctx, filePath, writeCh)
+		}
+	}
+}
+
+// processFile processes a single file with resource monitoring.
+func (p *Processor) processFile(ctx context.Context, filePath string, writeCh chan fileproc.WriteRequest) {
+	// Check for emergency stop
+	if p.resourceMonitor.IsEmergencyStopActive() {
+		logrus.Warnf("Emergency stop active, skipping file: %s", filePath)
+		return
+	}
+
+	absRoot, err := utils.GetAbsolutePath(p.flags.SourceDir)
+	if err != nil {
+		utils.LogError("Failed to get absolute path", err)
+		return
+	}
+
+	// Use the resource monitor-aware processing
+	fileproc.ProcessFileWithMonitor(ctx, filePath, writeCh, absRoot, p.resourceMonitor)
+
+	// Update progress bar
+	p.ui.UpdateProgress(1)
+}
+
+// sendFiles sends files to the worker channels with back-pressure handling.
+func (p *Processor) sendFiles(ctx context.Context, files []string, fileCh chan string) error {
+	defer close(fileCh)
+
+	for _, fp := range files {
+		// Check if we should apply back-pressure
+		if p.backpressure.ShouldApplyBackpressure(ctx) {
+			p.backpressure.ApplyBackpressure(ctx)
+		}
+
+		// Wait for channel space if needed
+		p.backpressure.WaitForChannelSpace(ctx, fileCh, nil)
+
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case fileCh <- fp:
+		}
+	}
+	return nil
+}
+
+// waitForCompletion waits for all workers to complete.
+func (p *Processor) waitForCompletion(wg *sync.WaitGroup, writeCh chan fileproc.WriteRequest, writerDone chan struct{}) {
+	wg.Wait()
+	close(writeCh)
+	<-writerDone
+}

cli/ui.go

@@ -0,0 +1,173 @@
+package cli
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/fatih/color"
+	"github.com/schollz/progressbar/v3"
+)
+
+// UIManager handles CLI user interface elements.
+type UIManager struct {
+	enableColors   bool
+	enableProgress bool
+	progressBar    *progressbar.ProgressBar
+	output         io.Writer
+}
+
+// NewUIManager creates a new UI manager.
+func NewUIManager() *UIManager {
+	return &UIManager{
+		enableColors:   isColorTerminal(),
+		enableProgress: isInteractiveTerminal(),
+		output:         os.Stderr, // Progress and colors go to stderr
+	}
+}
+
+// SetColorOutput enables or disables colored output.
+func (ui *UIManager) SetColorOutput(enabled bool) {
+	ui.enableColors = enabled
+	color.NoColor = !enabled
+}
+
+// SetProgressOutput enables or disables progress bars.
+func (ui *UIManager) SetProgressOutput(enabled bool) {
+	ui.enableProgress = enabled
+}
+
+// StartProgress initializes a progress bar for file processing.
+func (ui *UIManager) StartProgress(total int, description string) {
+	if !ui.enableProgress || total <= 0 {
+		return
+	}
+
+	ui.progressBar = progressbar.NewOptions(total,
+		progressbar.OptionSetWriter(ui.output),
+		progressbar.OptionSetDescription(description),
+		progressbar.OptionSetTheme(progressbar.Theme{
+			Saucer:        color.GreenString("█"),
+			SaucerHead:    color.GreenString("█"),
+			SaucerPadding: " ",
+			BarStart:      "[",
+			BarEnd:        "]",
+		}),
+		progressbar.OptionShowCount(),
+		progressbar.OptionShowIts(),
+		progressbar.OptionSetWidth(40),
+		progressbar.OptionThrottle(100*time.Millisecond),
+		progressbar.OptionOnCompletion(func() {
+			_, _ = fmt.Fprint(ui.output, "\n")
+		}),
+		progressbar.OptionSetRenderBlankState(true),
+	)
+}
+
+// UpdateProgress increments the progress bar.
+func (ui *UIManager) UpdateProgress(increment int) {
+	if ui.progressBar != nil {
+		_ = ui.progressBar.Add(increment)
+	}
+}
+
+// FinishProgress completes the progress bar.
+func (ui *UIManager) FinishProgress() {
+	if ui.progressBar != nil {
+		_ = ui.progressBar.Finish()
+		ui.progressBar = nil
+	}
+}
+
+// PrintSuccess prints a success message in green.
+func (ui *UIManager) PrintSuccess(format string, args ...interface{}) {
+	if ui.enableColors {
+		color.Green("✓ "+format, args...)
+	} else {
+		ui.printf("✓ "+format+"\n", args...)
+	}
+}
+
+// PrintError prints an error message in red.
+func (ui *UIManager) PrintError(format string, args ...interface{}) {
+	if ui.enableColors {
+		color.Red("✗ "+format, args...)
+	} else {
+		ui.printf("✗ "+format+"\n", args...)
+	}
+}
+
+// PrintWarning prints a warning message in yellow.
+func (ui *UIManager) PrintWarning(format string, args ...interface{}) {
+	if ui.enableColors {
+		color.Yellow("⚠ "+format, args...)
+	} else {
+		ui.printf("⚠ "+format+"\n", args...)
+	}
+}
+
+// PrintInfo prints an info message in blue.
+func (ui *UIManager) PrintInfo(format string, args ...interface{}) {
+	if ui.enableColors {
+		color.Blue("ℹ "+format, args...)
+	} else {
+		ui.printf("ℹ "+format+"\n", args...)
+	}
+}
+
+// PrintHeader prints a header message in bold.
+func (ui *UIManager) PrintHeader(format string, args ...interface{}) {
+	if ui.enableColors {
+		_, _ = color.New(color.Bold).Fprintf(ui.output, format+"\n", args...)
+	} else {
+		ui.printf(format+"\n", args...)
+	}
+}
+
+// isColorTerminal checks if the terminal supports colors.
+func isColorTerminal() bool {
+	// Check common environment variables
+	term := os.Getenv("TERM")
+	if term == "" || term == "dumb" {
+		return false
+	}
+
+	// Check for CI environments that typically don't support colors
+	if os.Getenv("CI") != "" {
+		// GitHub Actions supports colors
+		if os.Getenv("GITHUB_ACTIONS") == "true" {
+			return true
+		}
+		// Most other CI systems don't
+		return false
+	}
+
+	// Check if NO_COLOR is set (https://no-color.org/)
+	if os.Getenv("NO_COLOR") != "" {
+		return false
+	}
+
+	// Check if FORCE_COLOR is set
+	if os.Getenv("FORCE_COLOR") != "" {
+		return true
+	}
+
+	// Default to true for interactive terminals
+	return isInteractiveTerminal()
+}
+
+// isInteractiveTerminal checks if we're running in an interactive terminal.
+func isInteractiveTerminal() bool {
+	// Check if stderr is a terminal (where we output progress/colors)
+	fileInfo, err := os.Stderr.Stat()
+	if err != nil {
+		return false
+	}
+	return (fileInfo.Mode() & os.ModeCharDevice) != 0
+}
+
+// printf is a helper that ignores printf errors (for UI output).
+func (ui *UIManager) printf(format string, args ...interface{}) {
+	_, _ = fmt.Fprintf(ui.output, format, args...)
+}

cmd/benchmark/main.go

@@ -0,0 +1,145 @@
+// Package main provides a CLI for running gibidify benchmarks.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"runtime"
+	"strings"
+
+	"github.com/ivuorinen/gibidify/benchmark"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+var (
+	sourceDir       = flag.String("source", "", "Source directory to benchmark (uses temp files if empty)")
+	benchmarkType   = flag.String("type", "all", "Benchmark type: all, collection, processing, concurrency, format")
+	format          = flag.String("format", "json", "Output format for processing benchmarks")
+	concurrency     = flag.Int("concurrency", runtime.NumCPU(), "Concurrency level for processing benchmarks")
+	concurrencyList = flag.String("concurrency-list", "1,2,4,8", "Comma-separated list of concurrency levels")
+	formatList      = flag.String("format-list", "json,yaml,markdown", "Comma-separated list of formats")
+	numFiles        = flag.Int("files", 100, "Number of files to create for benchmarks")
+)
+
+func main() {
+	flag.Parse()
+
+	if err := runBenchmarks(); err != nil {
+		fmt.Fprintf(os.Stderr, "Benchmark failed: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func runBenchmarks() error {
+	fmt.Printf("Running gibidify benchmarks...\n")
+	fmt.Printf("Source: %s\n", getSourceDescription())
+	fmt.Printf("Type: %s\n", *benchmarkType)
+	fmt.Printf("CPU cores: %d\n", runtime.NumCPU())
+	fmt.Println()
+
+	switch *benchmarkType {
+	case "all":
+		return benchmark.RunAllBenchmarks(*sourceDir)
+	case "collection":
+		return runCollectionBenchmark()
+	case "processing":
+		return runProcessingBenchmark()
+	case "concurrency":
+		return runConcurrencyBenchmark()
+	case "format":
+		return runFormatBenchmark()
+	default:
+		return utils.NewValidationError(utils.CodeValidationFormat, "invalid benchmark type: "+*benchmarkType)
+	}
+}
+
+func runCollectionBenchmark() error {
+	fmt.Println("Running file collection benchmark...")
+	result, err := benchmark.FileCollectionBenchmark(*sourceDir, *numFiles)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "file collection benchmark failed")
+	}
+	benchmark.PrintBenchmarkResult(result)
+	return nil
+}
+
+func runProcessingBenchmark() error {
+	fmt.Printf("Running file processing benchmark (format: %s, concurrency: %d)...\n", *format, *concurrency)
+	result, err := benchmark.FileProcessingBenchmark(*sourceDir, *format, *concurrency)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "file processing benchmark failed")
+	}
+	benchmark.PrintBenchmarkResult(result)
+	return nil
+}
+
+func runConcurrencyBenchmark() error {
+	concurrencyLevels, err := parseConcurrencyList(*concurrencyList)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeValidation, utils.CodeValidationFormat, "invalid concurrency list")
+	}
+
+	fmt.Printf("Running concurrency benchmark (format: %s, levels: %v)...\n", *format, concurrencyLevels)
+	suite, err := benchmark.ConcurrencyBenchmark(*sourceDir, *format, concurrencyLevels)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "concurrency benchmark failed")
+	}
+	benchmark.PrintBenchmarkSuite(suite)
+	return nil
+}
+
+func runFormatBenchmark() error {
+	formats := parseFormatList(*formatList)
+	fmt.Printf("Running format benchmark (formats: %v)...\n", formats)
+	suite, err := benchmark.FormatBenchmark(*sourceDir, formats)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingCollection, "format benchmark failed")
+	}
+	benchmark.PrintBenchmarkSuite(suite)
+	return nil
+}
+
+func getSourceDescription() string {
+	if *sourceDir == "" {
+		return fmt.Sprintf("temporary files (%d files)", *numFiles)
+	}
+	return *sourceDir
+}
+
+func parseConcurrencyList(list string) ([]int, error) {
+	parts := strings.Split(list, ",")
+	levels := make([]int, 0, len(parts))
+
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		var level int
+		if _, err := fmt.Sscanf(part, "%d", &level); err != nil {
+			return nil, utils.WrapErrorf(err, utils.ErrorTypeValidation, utils.CodeValidationFormat, "invalid concurrency level: %s", part)
+		}
+		if level <= 0 {
+			return nil, utils.NewValidationError(utils.CodeValidationFormat, "concurrency level must be positive: "+part)
+		}
+		levels = append(levels, level)
+	}
+
+	if len(levels) == 0 {
+		return nil, utils.NewValidationError(utils.CodeValidationFormat, "no valid concurrency levels found")
+	}
+
+	return levels, nil
+}
+
+func parseFormatList(list string) []string {
+	parts := strings.Split(list, ",")
+	formats := make([]string, 0, len(parts))
+
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part != "" {
+			formats = append(formats, part)
+		}
+	}
+
+	return formats
+}

config.example.yaml

@@ -0,0 +1,84 @@
+# gibidify configuration example
+# Place this file in one of these locations:
+# - $XDG_CONFIG_HOME/gibidify/config.yaml
+# - $HOME/.config/gibidify/config.yaml
+# - Current directory (if no gibidify.yaml output file exists)
+
+# File size limit in bytes (default: 5MB)
+fileSizeLimit: 5242880
+
+# Directories to ignore during scanning
+ignoreDirectories:
+  - vendor
+  - node_modules
+  - .git
+  - dist
+  - build
+  - target
+  - bower_components
+  - cache
+  - tmp
+  - .next
+  - .nuxt
+
+# FileType registry configuration
+fileTypes:
+  # Enable/disable file type detection entirely (default: true)
+  enabled: true
+
+  # Add custom image extensions
+  customImageExtensions:
+    - .webp
+    - .avif
+    - .heic
+    - .jxl
+
+  # Add custom binary extensions
+  customBinaryExtensions:
+    - .custom
+    - .proprietary
+    - .blob
+
+  # Add custom language mappings
+  customLanguages:
+    .zig: zig
+    .odin: odin
+    .v: vlang
+    .grain: grain
+    .gleam: gleam
+    .roc: roc
+    .janet: janet
+    .fennel: fennel
+    .wast: wast
+    .wat: wat
+
+  # Disable specific default image extensions
+  disabledImageExtensions:
+    - .bmp  # Disable bitmap support
+    - .tif  # Disable TIFF support
+
+  # Disable specific default binary extensions
+  disabledBinaryExtensions:
+    - .exe  # Don't treat executables as binary
+    - .dll  # Don't treat DLL files as binary
+
+  # Disable specific default language extensions
+  disabledLanguageExtensions:
+    - .bat  # Don't detect batch files
+    - .cmd  # Don't detect command files
+
+# Maximum concurrency (optional)
+maxConcurrency: 16
+
+# Supported output formats (optional validation)
+supportedFormats:
+  - json
+  - yaml
+  - markdown
+
+# File patterns for filtering (optional)
+filePatterns:
+  - "*.go"
+  - "*.py"
+  - "*.js"
+  - "*.ts"

config.yaml.example

@@ -0,0 +1,79 @@
+# Gibidify Configuration Example
+# This file demonstrates all available configuration options
+
+# File size limit for individual files (in bytes)
+# Default: 5242880 (5MB), Min: 1024 (1KB), Max: 104857600 (100MB)
+fileSizeLimit: 5242880
+
+# Directories to ignore during traversal
+ignoreDirectories:
+  - vendor
+  - node_modules
+  - .git
+  - dist
+  - build
+  - target
+  - bower_components
+  - cache
+  - tmp
+
+# File type detection and filtering
+fileTypes:
+  enabled: true
+  customImageExtensions: []
+  customBinaryExtensions: []
+  customLanguages: {}
+  disabledImageExtensions: []
+  disabledBinaryExtensions: []
+  disabledLanguageExtensions: []
+
+# Back-pressure management for memory optimization
+backpressure:
+  enabled: true
+  maxPendingFiles: 1000     # Max files in channel buffer
+  maxPendingWrites: 100     # Max writes in channel buffer
+  maxMemoryUsage: 104857600 # 100MB soft memory limit
+  memoryCheckInterval: 1000 # Check memory every N files
+
+# Resource limits for DoS protection and security
+resourceLimits:
+  enabled: true
+  
+  # File processing limits
+  maxFiles: 10000                    # Maximum number of files to process
+  maxTotalSize: 1073741824          # Maximum total size (1GB)
+  
+  # Timeout limits (in seconds)
+  fileProcessingTimeoutSec: 30       # Timeout for individual file processing
+  overallTimeoutSec: 3600           # Overall processing timeout (1 hour)
+  
+  # Concurrency limits
+  maxConcurrentReads: 10            # Maximum concurrent file reading operations
+  
+  # Rate limiting (0 = disabled)
+  rateLimitFilesPerSec: 0           # Files per second rate limit
+  
+  # Memory limits
+  hardMemoryLimitMB: 512            # Hard memory limit (512MB)
+  
+  # Safety features
+  enableGracefulDegradation: true   # Enable graceful degradation on resource pressure
+  enableResourceMonitoring: true    # Enable detailed resource monitoring
+
+# Optional: Maximum concurrency for workers
+# Default: number of CPU cores
+# maxConcurrency: 4
+
+# Optional: Supported output formats
+# Default: ["json", "yaml", "markdown"]
+# supportedFormats:
+#   - json
+#   - yaml
+#   - markdown
+
+# Optional: File patterns to include
+# Default: all files (empty list means no pattern filtering)
+# filePatterns:
+#   - "*.go"
+#   - "*.py"
+#   - "*.js"

config/config.go

@@ -1,53 +1,5 @@
 // Package config handles application configuration using Viper.
+// This file contains the main configuration orchestration logic.
 package config
 
-import (
-	"os"
-	"path/filepath"
-
-	"github.com/sirupsen/logrus"
-	"github.com/spf13/viper"
-)
-
-// LoadConfig reads configuration from a YAML file.
-// It looks for config in the following order:
-// 1. $XDG_CONFIG_HOME/gibidify/config.yaml
-// 2. $HOME/.config/gibidify/config.yaml
-// 3. The current directory as fallback.
-func LoadConfig() {
-	viper.SetConfigName("config")
-	viper.SetConfigType("yaml")
-
-	if xdgConfig := os.Getenv("XDG_CONFIG_HOME"); xdgConfig != "" {
-		viper.AddConfigPath(filepath.Join(xdgConfig, "gibidify"))
-	} else if home, err := os.UserHomeDir(); err == nil {
-		viper.AddConfigPath(filepath.Join(home, ".config", "gibidify"))
-	}
-	viper.AddConfigPath(".")
-
-	if err := viper.ReadInConfig(); err != nil {
-		logrus.Infof("Config file not found, using default values: %v", err)
-		setDefaultConfig()
-	} else {
-		logrus.Infof("Using config file: %s", viper.ConfigFileUsed())
-	}
-}
-
-// setDefaultConfig sets default configuration values.
-func setDefaultConfig() {
-	viper.SetDefault("fileSizeLimit", 5242880) // 5 MB
-	// Default ignored directories.
-	viper.SetDefault("ignoreDirectories", []string{
-		"vendor", "node_modules", ".git", "dist", "build", "target", "bower_components", "cache", "tmp",
-	})
-}
-
-// GetFileSizeLimit returns the file size limit from configuration.
-func GetFileSizeLimit() int64 {
-	return viper.GetInt64("fileSizeLimit")
-}
-
-// GetIgnoredDirectories returns the list of directories to ignore.
-func GetIgnoredDirectories() []string {
-	return viper.GetStringSlice("ignoreDirectories")
-}
+// This file is now a minimal orchestration layer that delegates to the modular components.

config/config_filetype_test.go

@@ -0,0 +1,174 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/spf13/viper"
+)
+
+// TestFileTypeRegistryConfig tests the FileTypeRegistry configuration functionality.
+func TestFileTypeRegistryConfig(t *testing.T) {
+	// Test default values
+	t.Run("DefaultValues", func(t *testing.T) {
+		viper.Reset()
+		setDefaultConfig()
+
+		if !GetFileTypesEnabled() {
+			t.Error("Expected file types to be enabled by default")
+		}
+
+		if len(GetCustomImageExtensions()) != 0 {
+			t.Error("Expected custom image extensions to be empty by default")
+		}
+
+		if len(GetCustomBinaryExtensions()) != 0 {
+			t.Error("Expected custom binary extensions to be empty by default")
+		}
+
+		if len(GetCustomLanguages()) != 0 {
+			t.Error("Expected custom languages to be empty by default")
+		}
+
+		if len(GetDisabledImageExtensions()) != 0 {
+			t.Error("Expected disabled image extensions to be empty by default")
+		}
+
+		if len(GetDisabledBinaryExtensions()) != 0 {
+			t.Error("Expected disabled binary extensions to be empty by default")
+		}
+
+		if len(GetDisabledLanguageExtensions()) != 0 {
+			t.Error("Expected disabled language extensions to be empty by default")
+		}
+	})
+
+	// Test configuration setting and getting
+	t.Run("ConfigurationSetGet", func(t *testing.T) {
+		viper.Reset()
+
+		// Set test values
+		viper.Set("fileTypes.enabled", false)
+		viper.Set("fileTypes.customImageExtensions", []string{".webp", ".avif"})
+		viper.Set("fileTypes.customBinaryExtensions", []string{".custom", ".mybin"})
+		viper.Set("fileTypes.customLanguages", map[string]string{
+			".zig": "zig",
+			".v":   "vlang",
+		})
+		viper.Set("fileTypes.disabledImageExtensions", []string{".gif", ".bmp"})
+		viper.Set("fileTypes.disabledBinaryExtensions", []string{".exe", ".dll"})
+		viper.Set("fileTypes.disabledLanguageExtensions", []string{".rb", ".pl"})
+
+		// Test getter functions
+		if GetFileTypesEnabled() {
+			t.Error("Expected file types to be disabled")
+		}
+
+		customImages := GetCustomImageExtensions()
+		expectedImages := []string{".webp", ".avif"}
+		if len(customImages) != len(expectedImages) {
+			t.Errorf("Expected %d custom image extensions, got %d", len(expectedImages), len(customImages))
+		}
+		for i, ext := range expectedImages {
+			if customImages[i] != ext {
+				t.Errorf("Expected custom image extension %s, got %s", ext, customImages[i])
+			}
+		}
+
+		customBinary := GetCustomBinaryExtensions()
+		expectedBinary := []string{".custom", ".mybin"}
+		if len(customBinary) != len(expectedBinary) {
+			t.Errorf("Expected %d custom binary extensions, got %d", len(expectedBinary), len(customBinary))
+		}
+		for i, ext := range expectedBinary {
+			if customBinary[i] != ext {
+				t.Errorf("Expected custom binary extension %s, got %s", ext, customBinary[i])
+			}
+		}
+
+		customLangs := GetCustomLanguages()
+		expectedLangs := map[string]string{
+			".zig": "zig",
+			".v":   "vlang",
+		}
+		if len(customLangs) != len(expectedLangs) {
+			t.Errorf("Expected %d custom languages, got %d", len(expectedLangs), len(customLangs))
+		}
+		for ext, lang := range expectedLangs {
+			if customLangs[ext] != lang {
+				t.Errorf("Expected custom language %s -> %s, got %s", ext, lang, customLangs[ext])
+			}
+		}
+
+		disabledImages := GetDisabledImageExtensions()
+		expectedDisabledImages := []string{".gif", ".bmp"}
+		if len(disabledImages) != len(expectedDisabledImages) {
+			t.Errorf("Expected %d disabled image extensions, got %d", len(expectedDisabledImages), len(disabledImages))
+		}
+
+		disabledBinary := GetDisabledBinaryExtensions()
+		expectedDisabledBinary := []string{".exe", ".dll"}
+		if len(disabledBinary) != len(expectedDisabledBinary) {
+			t.Errorf("Expected %d disabled binary extensions, got %d", len(expectedDisabledBinary), len(disabledBinary))
+		}
+
+		disabledLangs := GetDisabledLanguageExtensions()
+		expectedDisabledLangs := []string{".rb", ".pl"}
+		if len(disabledLangs) != len(expectedDisabledLangs) {
+			t.Errorf("Expected %d disabled language extensions, got %d", len(expectedDisabledLangs), len(disabledLangs))
+		}
+	})
+
+	// Test validation
+	t.Run("ValidationSuccess", func(t *testing.T) {
+		viper.Reset()
+		setDefaultConfig()
+
+		// Set valid configuration
+		viper.Set("fileTypes.customImageExtensions", []string{".webp", ".avif"})
+		viper.Set("fileTypes.customBinaryExtensions", []string{".custom"})
+		viper.Set("fileTypes.customLanguages", map[string]string{
+			".zig": "zig",
+			".v":   "vlang",
+		})
+
+		err := ValidateConfig()
+		if err != nil {
+			t.Errorf("Expected validation to pass with valid config, got error: %v", err)
+		}
+	})
+
+	t.Run("ValidationFailure", func(t *testing.T) {
+		// Test invalid custom image extensions
+		viper.Reset()
+		setDefaultConfig()
+		viper.Set("fileTypes.customImageExtensions", []string{"", "webp"}) // Empty and missing dot
+
+		err := ValidateConfig()
+		if err == nil {
+			t.Error("Expected validation to fail with invalid custom image extensions")
+		}
+
+		// Test invalid custom binary extensions
+		viper.Reset()
+		setDefaultConfig()
+		viper.Set("fileTypes.customBinaryExtensions", []string{"custom"}) // Missing dot
+
+		err = ValidateConfig()
+		if err == nil {
+			t.Error("Expected validation to fail with invalid custom binary extensions")
+		}
+
+		// Test invalid custom languages
+		viper.Reset()
+		setDefaultConfig()
+		viper.Set("fileTypes.customLanguages", map[string]string{
+			"zig": "zig", // Missing dot in extension
+			".v":  "",    // Empty language
+		})
+
+		err = ValidateConfig()
+		if err == nil {
+			t.Error("Expected validation to fail with invalid custom languages")
+		}
+	})
+}

config/constants.go

@@ -0,0 +1,61 @@
+package config
+
+const (
+	// DefaultFileSizeLimit is the default maximum file size (5MB).
+	DefaultFileSizeLimit = 5242880
+	// MinFileSizeLimit is the minimum allowed file size limit (1KB).
+	MinFileSizeLimit = 1024
+	// MaxFileSizeLimit is the maximum allowed file size limit (100MB).
+	MaxFileSizeLimit = 104857600
+
+	// Resource Limit Constants
+
+	// DefaultMaxFiles is the default maximum number of files to process.
+	DefaultMaxFiles = 10000
+	// MinMaxFiles is the minimum allowed file count limit.
+	MinMaxFiles = 1
+	// MaxMaxFiles is the maximum allowed file count limit.
+	MaxMaxFiles = 1000000
+
+	// DefaultMaxTotalSize is the default maximum total size of files (1GB).
+	DefaultMaxTotalSize = 1073741824
+	// MinMaxTotalSize is the minimum allowed total size limit (1MB).
+	MinMaxTotalSize = 1048576
+	// MaxMaxTotalSize is the maximum allowed total size limit (100GB).
+	MaxMaxTotalSize = 107374182400
+
+	// DefaultFileProcessingTimeoutSec is the default timeout for individual file processing (30 seconds).
+	DefaultFileProcessingTimeoutSec = 30
+	// MinFileProcessingTimeoutSec is the minimum allowed file processing timeout (1 second).
+	MinFileProcessingTimeoutSec = 1
+	// MaxFileProcessingTimeoutSec is the maximum allowed file processing timeout (300 seconds).
+	MaxFileProcessingTimeoutSec = 300
+
+	// DefaultOverallTimeoutSec is the default timeout for overall processing (3600 seconds = 1 hour).
+	DefaultOverallTimeoutSec = 3600
+	// MinOverallTimeoutSec is the minimum allowed overall timeout (10 seconds).
+	MinOverallTimeoutSec = 10
+	// MaxOverallTimeoutSec is the maximum allowed overall timeout (86400 seconds = 24 hours).
+	MaxOverallTimeoutSec = 86400
+
+	// DefaultMaxConcurrentReads is the default maximum concurrent file reading operations.
+	DefaultMaxConcurrentReads = 10
+	// MinMaxConcurrentReads is the minimum allowed concurrent reads.
+	MinMaxConcurrentReads = 1
+	// MaxMaxConcurrentReads is the maximum allowed concurrent reads.
+	MaxMaxConcurrentReads = 100
+
+	// DefaultRateLimitFilesPerSec is the default rate limit for file processing (0 = disabled).
+	DefaultRateLimitFilesPerSec = 0
+	// MinRateLimitFilesPerSec is the minimum rate limit.
+	MinRateLimitFilesPerSec = 0
+	// MaxRateLimitFilesPerSec is the maximum rate limit.
+	MaxRateLimitFilesPerSec = 10000
+
+	// DefaultHardMemoryLimitMB is the default hard memory limit (512MB).
+	DefaultHardMemoryLimitMB = 512
+	// MinHardMemoryLimitMB is the minimum hard memory limit (64MB).
+	MinHardMemoryLimitMB = 64
+	// MaxHardMemoryLimitMB is the maximum hard memory limit (8192MB = 8GB).
+	MaxHardMemoryLimitMB = 8192
+)

config/getters.go

@@ -0,0 +1,157 @@
+package config
+
+import (
+	"strings"
+
+	"github.com/spf13/viper"
+)
+
+// GetFileSizeLimit returns the file size limit from configuration.
+func GetFileSizeLimit() int64 {
+	return viper.GetInt64("fileSizeLimit")
+}
+
+// GetIgnoredDirectories returns the list of directories to ignore.
+func GetIgnoredDirectories() []string {
+	return viper.GetStringSlice("ignoreDirectories")
+}
+
+// GetMaxConcurrency returns the maximum concurrency level.
+func GetMaxConcurrency() int {
+	return viper.GetInt("maxConcurrency")
+}
+
+// GetSupportedFormats returns the list of supported output formats.
+func GetSupportedFormats() []string {
+	return viper.GetStringSlice("supportedFormats")
+}
+
+// GetFilePatterns returns the list of file patterns.
+func GetFilePatterns() []string {
+	return viper.GetStringSlice("filePatterns")
+}
+
+// IsValidFormat checks if the given format is valid.
+func IsValidFormat(format string) bool {
+	format = strings.ToLower(strings.TrimSpace(format))
+	supportedFormats := map[string]bool{
+		"json":     true,
+		"yaml":     true,
+		"markdown": true,
+	}
+	return supportedFormats[format]
+}
+
+// GetFileTypesEnabled returns whether file types are enabled.
+func GetFileTypesEnabled() bool {
+	return viper.GetBool("fileTypes.enabled")
+}
+
+// GetCustomImageExtensions returns custom image extensions.
+func GetCustomImageExtensions() []string {
+	return viper.GetStringSlice("fileTypes.customImageExtensions")
+}
+
+// GetCustomBinaryExtensions returns custom binary extensions.
+func GetCustomBinaryExtensions() []string {
+	return viper.GetStringSlice("fileTypes.customBinaryExtensions")
+}
+
+// GetCustomLanguages returns custom language mappings.
+func GetCustomLanguages() map[string]string {
+	return viper.GetStringMapString("fileTypes.customLanguages")
+}
+
+// GetDisabledImageExtensions returns disabled image extensions.
+func GetDisabledImageExtensions() []string {
+	return viper.GetStringSlice("fileTypes.disabledImageExtensions")
+}
+
+// GetDisabledBinaryExtensions returns disabled binary extensions.
+func GetDisabledBinaryExtensions() []string {
+	return viper.GetStringSlice("fileTypes.disabledBinaryExtensions")
+}
+
+// GetDisabledLanguageExtensions returns disabled language extensions.
+func GetDisabledLanguageExtensions() []string {
+	return viper.GetStringSlice("fileTypes.disabledLanguageExtensions")
+}
+
+// Backpressure getters
+
+// GetBackpressureEnabled returns whether backpressure is enabled.
+func GetBackpressureEnabled() bool {
+	return viper.GetBool("backpressure.enabled")
+}
+
+// GetMaxPendingFiles returns the maximum pending files.
+func GetMaxPendingFiles() int {
+	return viper.GetInt("backpressure.maxPendingFiles")
+}
+
+// GetMaxPendingWrites returns the maximum pending writes.
+func GetMaxPendingWrites() int {
+	return viper.GetInt("backpressure.maxPendingWrites")
+}
+
+// GetMaxMemoryUsage returns the maximum memory usage.
+func GetMaxMemoryUsage() int64 {
+	return viper.GetInt64("backpressure.maxMemoryUsage")
+}
+
+// GetMemoryCheckInterval returns the memory check interval.
+func GetMemoryCheckInterval() int {
+	return viper.GetInt("backpressure.memoryCheckInterval")
+}
+
+// Resource limits getters
+
+// GetResourceLimitsEnabled returns whether resource limits are enabled.
+func GetResourceLimitsEnabled() bool {
+	return viper.GetBool("resourceLimits.enabled")
+}
+
+// GetMaxFiles returns the maximum number of files.
+func GetMaxFiles() int {
+	return viper.GetInt("resourceLimits.maxFiles")
+}
+
+// GetMaxTotalSize returns the maximum total size.
+func GetMaxTotalSize() int64 {
+	return viper.GetInt64("resourceLimits.maxTotalSize")
+}
+
+// GetFileProcessingTimeoutSec returns the file processing timeout in seconds.
+func GetFileProcessingTimeoutSec() int {
+	return viper.GetInt("resourceLimits.fileProcessingTimeoutSec")
+}
+
+// GetOverallTimeoutSec returns the overall timeout in seconds.
+func GetOverallTimeoutSec() int {
+	return viper.GetInt("resourceLimits.overallTimeoutSec")
+}
+
+// GetMaxConcurrentReads returns the maximum concurrent reads.
+func GetMaxConcurrentReads() int {
+	return viper.GetInt("resourceLimits.maxConcurrentReads")
+}
+
+// GetRateLimitFilesPerSec returns the rate limit files per second.
+func GetRateLimitFilesPerSec() int {
+	return viper.GetInt("resourceLimits.rateLimitFilesPerSec")
+}
+
+// GetHardMemoryLimitMB returns the hard memory limit in MB.
+func GetHardMemoryLimitMB() int {
+	return viper.GetInt("resourceLimits.hardMemoryLimitMB")
+}
+
+// GetEnableGracefulDegradation returns whether graceful degradation is enabled.
+func GetEnableGracefulDegradation() bool {
+	return viper.GetBool("resourceLimits.enableGracefulDegradation")
+}
+
+// GetEnableResourceMonitoring returns whether resource monitoring is enabled.
+func GetEnableResourceMonitoring() bool {
+	return viper.GetBool("resourceLimits.enableResourceMonitoring")
+}

config/loader.go

@@ -0,0 +1,90 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// LoadConfig reads configuration from a YAML file.
+// It looks for config in the following order:
+// 1. $XDG_CONFIG_HOME/gibidify/config.yaml
+// 2. $HOME/.config/gibidify/config.yaml
+// 3. The current directory as fallback.
+func LoadConfig() {
+	viper.SetConfigName("config")
+	viper.SetConfigType("yaml")
+
+	if xdgConfig := os.Getenv("XDG_CONFIG_HOME"); xdgConfig != "" {
+		// Validate XDG_CONFIG_HOME for path traversal attempts
+		if err := utils.ValidateConfigPath(xdgConfig); err != nil {
+			logrus.Warnf("Invalid XDG_CONFIG_HOME path, using default config: %v", err)
+		} else {
+			configPath := filepath.Join(xdgConfig, "gibidify")
+			viper.AddConfigPath(configPath)
+		}
+	} else if home, err := os.UserHomeDir(); err == nil {
+		viper.AddConfigPath(filepath.Join(home, ".config", "gibidify"))
+	}
+	// Only add current directory if no config file named gibidify.yaml exists
+	// to avoid conflicts with the project's output file
+	if _, err := os.Stat("gibidify.yaml"); os.IsNotExist(err) {
+		viper.AddConfigPath(".")
+	}
+
+	if err := viper.ReadInConfig(); err != nil {
+		logrus.Infof("Config file not found, using default values: %v", err)
+		setDefaultConfig()
+	} else {
+		logrus.Infof("Using config file: %s", viper.ConfigFileUsed())
+		// Validate configuration after loading
+		if err := ValidateConfig(); err != nil {
+			logrus.Warnf("Configuration validation failed: %v", err)
+			logrus.Info("Falling back to default configuration")
+			// Reset viper and set defaults when validation fails
+			viper.Reset()
+			setDefaultConfig()
+		}
+	}
+}
+
+// setDefaultConfig sets default configuration values.
+func setDefaultConfig() {
+	viper.SetDefault("fileSizeLimit", DefaultFileSizeLimit)
+	// Default ignored directories.
+	viper.SetDefault("ignoreDirectories", []string{
+		"vendor", "node_modules", ".git", "dist", "build", "target", "bower_components", "cache", "tmp",
+	})
+
+	// FileTypeRegistry defaults
+	viper.SetDefault("fileTypes.enabled", true)
+	viper.SetDefault("fileTypes.customImageExtensions", []string{})
+	viper.SetDefault("fileTypes.customBinaryExtensions", []string{})
+	viper.SetDefault("fileTypes.customLanguages", map[string]string{})
+	viper.SetDefault("fileTypes.disabledImageExtensions", []string{})
+	viper.SetDefault("fileTypes.disabledBinaryExtensions", []string{})
+	viper.SetDefault("fileTypes.disabledLanguageExtensions", []string{})
+
+	// Back-pressure and memory management defaults
+	viper.SetDefault("backpressure.enabled", true)
+	viper.SetDefault("backpressure.maxPendingFiles", 1000)     // Max files in file channel buffer
+	viper.SetDefault("backpressure.maxPendingWrites", 100)     // Max writes in write channel buffer
+	viper.SetDefault("backpressure.maxMemoryUsage", 104857600) // 100MB max memory usage
+	viper.SetDefault("backpressure.memoryCheckInterval", 1000) // Check memory every 1000 files
+
+	// Resource limit defaults
+	viper.SetDefault("resourceLimits.enabled", true)
+	viper.SetDefault("resourceLimits.maxFiles", DefaultMaxFiles)
+	viper.SetDefault("resourceLimits.maxTotalSize", DefaultMaxTotalSize)
+	viper.SetDefault("resourceLimits.fileProcessingTimeoutSec", DefaultFileProcessingTimeoutSec)
+	viper.SetDefault("resourceLimits.overallTimeoutSec", DefaultOverallTimeoutSec)
+	viper.SetDefault("resourceLimits.maxConcurrentReads", DefaultMaxConcurrentReads)
+	viper.SetDefault("resourceLimits.rateLimitFilesPerSec", DefaultRateLimitFilesPerSec)
+	viper.SetDefault("resourceLimits.hardMemoryLimitMB", DefaultHardMemoryLimitMB)
+	viper.SetDefault("resourceLimits.enableGracefulDegradation", true)
+	viper.SetDefault("resourceLimits.enableResourceMonitoring", true)
+}

config/loader_test.go

@@ -0,0 +1,120 @@
+package config_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+const (
+	defaultFileSizeLimit = 5242880
+	testFileSizeLimit    = 123456
+)
+
+// TestDefaultConfig verifies that if no config file is found,
+// the default configuration values are correctly set.
+func TestDefaultConfig(t *testing.T) {
+	// Create a temporary directory to ensure no config file is present.
+	tmpDir := t.TempDir()
+
+	// Point Viper to the temp directory with no config file.
+	originalConfigPaths := viper.ConfigFileUsed()
+	testutil.ResetViperConfig(t, tmpDir)
+
+	// Check defaults
+	defaultSizeLimit := config.GetFileSizeLimit()
+	if defaultSizeLimit != defaultFileSizeLimit {
+		t.Errorf("Expected default file size limit of 5242880, got %d", defaultSizeLimit)
+	}
+
+	ignoredDirs := config.GetIgnoredDirectories()
+	if len(ignoredDirs) == 0 {
+		t.Errorf("Expected some default ignored directories, got none")
+	}
+
+	// Restore Viper state
+	viper.SetConfigFile(originalConfigPaths)
+}
+
+// TestLoadConfigFile verifies that when a valid config file is present,
+// viper loads the specified values correctly.
+func TestLoadConfigFile(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	// Prepare a minimal config file
+	configContent := []byte(`---
+fileSizeLimit: 123456
+ignoreDirectories:
+- "testdir1"
+- "testdir2"
+`)
+
+	testutil.CreateTestFile(t, tmpDir, "config.yaml", configContent)
+
+	// Reset viper and point to the new config path
+	viper.Reset()
+	viper.AddConfigPath(tmpDir)
+
+	// Force Viper to read our config file
+	testutil.MustSucceed(t, viper.ReadInConfig(), "reading config file")
+
+	// Validate loaded data
+	if got := viper.GetInt64("fileSizeLimit"); got != testFileSizeLimit {
+		t.Errorf("Expected fileSizeLimit=123456, got %d", got)
+	}
+
+	ignored := viper.GetStringSlice("ignoreDirectories")
+	if len(ignored) != 2 || ignored[0] != "testdir1" || ignored[1] != "testdir2" {
+		t.Errorf("Expected [\"testdir1\", \"testdir2\"], got %v", ignored)
+	}
+}
+
+// TestLoadConfigWithValidation tests that invalid config files fall back to defaults.
+func TestLoadConfigWithValidation(t *testing.T) {
+	// Create a temporary config file with invalid content
+	configContent := `
+fileSizeLimit: 100
+ignoreDirectories:
+  - node_modules
+  - ""
+  - .git
+`
+
+	tempDir := t.TempDir()
+	configFile := tempDir + "/config.yaml"
+
+	err := os.WriteFile(configFile, []byte(configContent), 0o644)
+	if err != nil {
+		t.Fatalf("Failed to write config file: %v", err)
+	}
+
+	// Reset viper and set config path
+	viper.Reset()
+	viper.AddConfigPath(tempDir)
+
+	// This should load the config but validation should fail and fall back to defaults
+	config.LoadConfig()
+
+	// Should have fallen back to defaults due to validation failure
+	if config.GetFileSizeLimit() != int64(config.DefaultFileSizeLimit) {
+		t.Errorf("Expected default file size limit after validation failure, got %d", config.GetFileSizeLimit())
+	}
+	if containsString(config.GetIgnoredDirectories(), "") {
+		t.Errorf("Expected ignored directories not to contain empty string after validation failure, got %v", config.GetIgnoredDirectories())
+	}
+}
+
+// Helper functions
+
+func containsString(slice []string, item string) bool {
+	for _, s := range slice {
+		if s == item {
+			return true
+		}
+	}
+	return false
+}

config/validation.go

@@ -0,0 +1,307 @@
+package config
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// ValidateConfig validates the loaded configuration.
+func ValidateConfig() error {
+	var validationErrors []string
+
+	// Validate file size limit
+	fileSizeLimit := viper.GetInt64("fileSizeLimit")
+	if fileSizeLimit < MinFileSizeLimit {
+		validationErrors = append(validationErrors, fmt.Sprintf("fileSizeLimit (%d) is below minimum (%d)", fileSizeLimit, MinFileSizeLimit))
+	}
+	if fileSizeLimit > MaxFileSizeLimit {
+		validationErrors = append(validationErrors, fmt.Sprintf("fileSizeLimit (%d) exceeds maximum (%d)", fileSizeLimit, MaxFileSizeLimit))
+	}
+
+	// Validate ignore directories
+	ignoreDirectories := viper.GetStringSlice("ignoreDirectories")
+	for i, dir := range ignoreDirectories {
+		dir = strings.TrimSpace(dir)
+		if dir == "" {
+			validationErrors = append(validationErrors, fmt.Sprintf("ignoreDirectories[%d] is empty", i))
+			continue
+		}
+		if strings.Contains(dir, "/") {
+			validationErrors = append(validationErrors, fmt.Sprintf("ignoreDirectories[%d] (%s) contains path separator - only directory names are allowed", i, dir))
+		}
+		if strings.HasPrefix(dir, ".") && dir != ".git" && dir != ".vscode" && dir != ".idea" {
+			validationErrors = append(validationErrors, fmt.Sprintf("ignoreDirectories[%d] (%s) starts with dot - this may cause unexpected behavior", i, dir))
+		}
+	}
+
+	// Validate supported output formats if configured
+	if viper.IsSet("supportedFormats") {
+		supportedFormats := viper.GetStringSlice("supportedFormats")
+		validFormats := map[string]bool{"json": true, "yaml": true, "markdown": true}
+		for i, format := range supportedFormats {
+			format = strings.ToLower(strings.TrimSpace(format))
+			if !validFormats[format] {
+				validationErrors = append(validationErrors, fmt.Sprintf("supportedFormats[%d] (%s) is not a valid format (json, yaml, markdown)", i, format))
+			}
+		}
+	}
+
+	// Validate concurrency settings if configured
+	if viper.IsSet("maxConcurrency") {
+		maxConcurrency := viper.GetInt("maxConcurrency")
+		if maxConcurrency < 1 {
+			validationErrors = append(validationErrors, fmt.Sprintf("maxConcurrency (%d) must be at least 1", maxConcurrency))
+		}
+		if maxConcurrency > 100 {
+			validationErrors = append(validationErrors, fmt.Sprintf("maxConcurrency (%d) is unreasonably high (max 100)", maxConcurrency))
+		}
+	}
+
+	// Validate file patterns if configured
+	if viper.IsSet("filePatterns") {
+		filePatterns := viper.GetStringSlice("filePatterns")
+		for i, pattern := range filePatterns {
+			pattern = strings.TrimSpace(pattern)
+			if pattern == "" {
+				validationErrors = append(validationErrors, fmt.Sprintf("filePatterns[%d] is empty", i))
+				continue
+			}
+			// Basic validation - patterns should contain at least one alphanumeric character
+			if !strings.ContainsAny(pattern, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789") {
+				validationErrors = append(validationErrors, fmt.Sprintf("filePatterns[%d] (%s) appears to be invalid", i, pattern))
+			}
+		}
+	}
+
+	// Validate FileTypeRegistry configuration
+	if viper.IsSet("fileTypes.customImageExtensions") {
+		customImages := viper.GetStringSlice("fileTypes.customImageExtensions")
+		for i, ext := range customImages {
+			ext = strings.TrimSpace(ext)
+			if ext == "" {
+				validationErrors = append(validationErrors, fmt.Sprintf("fileTypes.customImageExtensions[%d] is empty", i))
+				continue
+			}
+			if !strings.HasPrefix(ext, ".") {
+				validationErrors = append(validationErrors, fmt.Sprintf("fileTypes.customImageExtensions[%d] (%s) must start with a dot", i, ext))
+			}
+		}
+	}
+
+	if viper.IsSet("fileTypes.customBinaryExtensions") {
+		customBinary := viper.GetStringSlice("fileTypes.customBinaryExtensions")
+		for i, ext := range customBinary {
+			ext = strings.TrimSpace(ext)
+			if ext == "" {
+				validationErrors = append(validationErrors, fmt.Sprintf("fileTypes.customBinaryExtensions[%d] is empty", i))
+				continue
+			}
+			if !strings.HasPrefix(ext, ".") {
+				validationErrors = append(validationErrors, fmt.Sprintf("fileTypes.customBinaryExtensions[%d] (%s) must start with a dot", i, ext))
+			}
+		}
+	}
+
+	if viper.IsSet("fileTypes.customLanguages") {
+		customLangs := viper.GetStringMapString("fileTypes.customLanguages")
+		for ext, lang := range customLangs {
+			ext = strings.TrimSpace(ext)
+			lang = strings.TrimSpace(lang)
+			if ext == "" {
+				validationErrors = append(validationErrors, "fileTypes.customLanguages contains empty extension key")
+				continue
+			}
+			if !strings.HasPrefix(ext, ".") {
+				validationErrors = append(validationErrors, fmt.Sprintf("fileTypes.customLanguages extension (%s) must start with a dot", ext))
+			}
+			if lang == "" {
+				validationErrors = append(validationErrors, fmt.Sprintf("fileTypes.customLanguages[%s] has empty language value", ext))
+			}
+		}
+	}
+
+	// Validate back-pressure configuration
+	if viper.IsSet("backpressure.maxPendingFiles") {
+		maxPendingFiles := viper.GetInt("backpressure.maxPendingFiles")
+		if maxPendingFiles < 1 {
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.maxPendingFiles (%d) must be at least 1", maxPendingFiles))
+		}
+		if maxPendingFiles > 100000 {
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.maxPendingFiles (%d) is unreasonably high (max 100000)", maxPendingFiles))
+		}
+	}
+
+	if viper.IsSet("backpressure.maxPendingWrites") {
+		maxPendingWrites := viper.GetInt("backpressure.maxPendingWrites")
+		if maxPendingWrites < 1 {
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.maxPendingWrites (%d) must be at least 1", maxPendingWrites))
+		}
+		if maxPendingWrites > 10000 {
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.maxPendingWrites (%d) is unreasonably high (max 10000)", maxPendingWrites))
+		}
+	}
+
+	if viper.IsSet("backpressure.maxMemoryUsage") {
+		maxMemoryUsage := viper.GetInt64("backpressure.maxMemoryUsage")
+		if maxMemoryUsage < 1048576 { // 1MB minimum
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.maxMemoryUsage (%d) must be at least 1MB (1048576 bytes)", maxMemoryUsage))
+		}
+		if maxMemoryUsage > 10737418240 { // 10GB maximum
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.maxMemoryUsage (%d) is unreasonably high (max 10GB)", maxMemoryUsage))
+		}
+	}
+
+	if viper.IsSet("backpressure.memoryCheckInterval") {
+		interval := viper.GetInt("backpressure.memoryCheckInterval")
+		if interval < 1 {
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.memoryCheckInterval (%d) must be at least 1", interval))
+		}
+		if interval > 100000 {
+			validationErrors = append(validationErrors, fmt.Sprintf("backpressure.memoryCheckInterval (%d) is unreasonably high (max 100000)", interval))
+		}
+	}
+
+	// Validate resource limits configuration
+	if viper.IsSet("resourceLimits.maxFiles") {
+		maxFiles := viper.GetInt("resourceLimits.maxFiles")
+		if maxFiles < MinMaxFiles {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.maxFiles (%d) must be at least %d", maxFiles, MinMaxFiles))
+		}
+		if maxFiles > MaxMaxFiles {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.maxFiles (%d) exceeds maximum (%d)", maxFiles, MaxMaxFiles))
+		}
+	}
+
+	if viper.IsSet("resourceLimits.maxTotalSize") {
+		maxTotalSize := viper.GetInt64("resourceLimits.maxTotalSize")
+		if maxTotalSize < MinMaxTotalSize {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.maxTotalSize (%d) must be at least %d", maxTotalSize, MinMaxTotalSize))
+		}
+		if maxTotalSize > MaxMaxTotalSize {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.maxTotalSize (%d) exceeds maximum (%d)", maxTotalSize, MaxMaxTotalSize))
+		}
+	}
+
+	if viper.IsSet("resourceLimits.fileProcessingTimeoutSec") {
+		timeout := viper.GetInt("resourceLimits.fileProcessingTimeoutSec")
+		if timeout < MinFileProcessingTimeoutSec {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.fileProcessingTimeoutSec (%d) must be at least %d", timeout, MinFileProcessingTimeoutSec))
+		}
+		if timeout > MaxFileProcessingTimeoutSec {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.fileProcessingTimeoutSec (%d) exceeds maximum (%d)", timeout, MaxFileProcessingTimeoutSec))
+		}
+	}
+
+	if viper.IsSet("resourceLimits.overallTimeoutSec") {
+		timeout := viper.GetInt("resourceLimits.overallTimeoutSec")
+		if timeout < MinOverallTimeoutSec {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.overallTimeoutSec (%d) must be at least %d", timeout, MinOverallTimeoutSec))
+		}
+		if timeout > MaxOverallTimeoutSec {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.overallTimeoutSec (%d) exceeds maximum (%d)", timeout, MaxOverallTimeoutSec))
+		}
+	}
+
+	if viper.IsSet("resourceLimits.maxConcurrentReads") {
+		maxReads := viper.GetInt("resourceLimits.maxConcurrentReads")
+		if maxReads < MinMaxConcurrentReads {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.maxConcurrentReads (%d) must be at least %d", maxReads, MinMaxConcurrentReads))
+		}
+		if maxReads > MaxMaxConcurrentReads {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.maxConcurrentReads (%d) exceeds maximum (%d)", maxReads, MaxMaxConcurrentReads))
+		}
+	}
+
+	if viper.IsSet("resourceLimits.rateLimitFilesPerSec") {
+		rateLimit := viper.GetInt("resourceLimits.rateLimitFilesPerSec")
+		if rateLimit < MinRateLimitFilesPerSec {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.rateLimitFilesPerSec (%d) must be at least %d", rateLimit, MinRateLimitFilesPerSec))
+		}
+		if rateLimit > MaxRateLimitFilesPerSec {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.rateLimitFilesPerSec (%d) exceeds maximum (%d)", rateLimit, MaxRateLimitFilesPerSec))
+		}
+	}
+
+	if viper.IsSet("resourceLimits.hardMemoryLimitMB") {
+		memLimit := viper.GetInt("resourceLimits.hardMemoryLimitMB")
+		if memLimit < MinHardMemoryLimitMB {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.hardMemoryLimitMB (%d) must be at least %d", memLimit, MinHardMemoryLimitMB))
+		}
+		if memLimit > MaxHardMemoryLimitMB {
+			validationErrors = append(validationErrors, fmt.Sprintf("resourceLimits.hardMemoryLimitMB (%d) exceeds maximum (%d)", memLimit, MaxHardMemoryLimitMB))
+		}
+	}
+
+	if len(validationErrors) > 0 {
+		return utils.NewStructuredError(
+			utils.ErrorTypeConfiguration,
+			utils.CodeConfigValidation,
+			"configuration validation failed: "+strings.Join(validationErrors, "; "),
+			"",
+			map[string]interface{}{"validation_errors": validationErrors},
+		)
+	}
+
+	return nil
+}
+
+// ValidateFileSize checks if a file size is within the configured limit.
+func ValidateFileSize(size int64) error {
+	limit := GetFileSizeLimit()
+	if size > limit {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeValidationSize,
+			fmt.Sprintf("file size (%d bytes) exceeds limit (%d bytes)", size, limit),
+			"",
+			map[string]interface{}{"file_size": size, "size_limit": limit},
+		)
+	}
+	return nil
+}
+
+// ValidateOutputFormat checks if an output format is valid.
+func ValidateOutputFormat(format string) error {
+	if !IsValidFormat(format) {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeValidationFormat,
+			fmt.Sprintf("unsupported output format: %s (supported: json, yaml, markdown)", format),
+			"",
+			map[string]interface{}{"format": format},
+		)
+	}
+	return nil
+}
+
+// ValidateConcurrency checks if a concurrency level is valid.
+func ValidateConcurrency(concurrency int) error {
+	if concurrency < 1 {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeValidationFormat,
+			fmt.Sprintf("concurrency (%d) must be at least 1", concurrency),
+			"",
+			map[string]interface{}{"concurrency": concurrency},
+		)
+	}
+
+	if viper.IsSet("maxConcurrency") {
+		maxConcurrency := GetMaxConcurrency()
+		if concurrency > maxConcurrency {
+			return utils.NewStructuredError(
+				utils.ErrorTypeValidation,
+				utils.CodeValidationFormat,
+				fmt.Sprintf("concurrency (%d) exceeds maximum (%d)", concurrency, maxConcurrency),
+				"",
+				map[string]interface{}{"concurrency": concurrency, "max_concurrency": maxConcurrency},
+			)
+		}
+	}
+
+	return nil
+}

config/validation_test.go

@@ -0,0 +1,245 @@
+package config_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// TestValidateConfig tests the configuration validation functionality.
+func TestValidateConfig(t *testing.T) {
+	tests := []struct {
+		name        string
+		config      map[string]interface{}
+		wantErr     bool
+		errContains string
+	}{
+		{
+			name: "valid default config",
+			config: map[string]interface{}{
+				"fileSizeLimit":     config.DefaultFileSizeLimit,
+				"ignoreDirectories": []string{"node_modules", ".git"},
+			},
+			wantErr: false,
+		},
+		{
+			name: "file size limit too small",
+			config: map[string]interface{}{
+				"fileSizeLimit": config.MinFileSizeLimit - 1,
+			},
+			wantErr:     true,
+			errContains: "fileSizeLimit",
+		},
+		{
+			name: "file size limit too large",
+			config: map[string]interface{}{
+				"fileSizeLimit": config.MaxFileSizeLimit + 1,
+			},
+			wantErr:     true,
+			errContains: "fileSizeLimit",
+		},
+		{
+			name: "empty ignore directory",
+			config: map[string]interface{}{
+				"ignoreDirectories": []string{"node_modules", "", ".git"},
+			},
+			wantErr:     true,
+			errContains: "ignoreDirectories",
+		},
+		{
+			name: "ignore directory with path separator",
+			config: map[string]interface{}{
+				"ignoreDirectories": []string{"node_modules", "src/build", ".git"},
+			},
+			wantErr:     true,
+			errContains: "path separator",
+		},
+		{
+			name: "invalid supported format",
+			config: map[string]interface{}{
+				"supportedFormats": []string{"json", "xml", "yaml"},
+			},
+			wantErr:     true,
+			errContains: "not a valid format",
+		},
+		{
+			name: "invalid max concurrency",
+			config: map[string]interface{}{
+				"maxConcurrency": 0,
+			},
+			wantErr:     true,
+			errContains: "maxConcurrency",
+		},
+		{
+			name: "valid comprehensive config",
+			config: map[string]interface{}{
+				"fileSizeLimit":     config.DefaultFileSizeLimit,
+				"ignoreDirectories": []string{"node_modules", ".git", ".vscode"},
+				"supportedFormats":  []string{"json", "yaml", "markdown"},
+				"maxConcurrency":    8,
+				"filePatterns":      []string{"*.go", "*.js", "*.py"},
+			},
+			wantErr: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Reset viper for each test
+			viper.Reset()
+
+			// Set test configuration
+			for key, value := range tt.config {
+				viper.Set(key, value)
+			}
+
+			// Load defaults for missing values
+			config.LoadConfig()
+
+			err := config.ValidateConfig()
+
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("Expected error but got none")
+					return
+				}
+				if tt.errContains != "" && !strings.Contains(err.Error(), tt.errContains) {
+					t.Errorf("Expected error to contain %q, got %q", tt.errContains, err.Error())
+				}
+
+				// Check that it's a structured error
+				var structErr *utils.StructuredError
+				if !errorAs(err, &structErr) {
+					t.Errorf("Expected structured error, got %T", err)
+					return
+				}
+				if structErr.Type != utils.ErrorTypeConfiguration {
+					t.Errorf("Expected error type %v, got %v", utils.ErrorTypeConfiguration, structErr.Type)
+				}
+				if structErr.Code != utils.CodeConfigValidation {
+					t.Errorf("Expected error code %v, got %v", utils.CodeConfigValidation, structErr.Code)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("Expected no error but got: %v", err)
+				}
+			}
+		})
+	}
+}
+
+// TestValidationFunctions tests individual validation functions.
+func TestValidationFunctions(t *testing.T) {
+	t.Run("IsValidFormat", func(t *testing.T) {
+		tests := []struct {
+			format string
+			valid  bool
+		}{
+			{"json", true},
+			{"yaml", true},
+			{"markdown", true},
+			{"JSON", true},
+			{"xml", false},
+			{"txt", false},
+			{"", false},
+			{"  json  ", true},
+		}
+
+		for _, tt := range tests {
+			result := config.IsValidFormat(tt.format)
+			if result != tt.valid {
+				t.Errorf("IsValidFormat(%q) = %v, want %v", tt.format, result, tt.valid)
+			}
+		}
+	})
+
+	t.Run("ValidateFileSize", func(t *testing.T) {
+		viper.Reset()
+		viper.Set("fileSizeLimit", config.DefaultFileSizeLimit)
+
+		tests := []struct {
+			name    string
+			size    int64
+			wantErr bool
+		}{
+			{"size within limit", config.DefaultFileSizeLimit - 1, false},
+			{"size at limit", config.DefaultFileSizeLimit, false},
+			{"size exceeds limit", config.DefaultFileSizeLimit + 1, true},
+			{"zero size", 0, false},
+		}
+
+		for _, tt := range tests {
+			err := config.ValidateFileSize(tt.size)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("%s: ValidateFileSize(%d) error = %v, wantErr %v", tt.name, tt.size, err, tt.wantErr)
+			}
+		}
+	})
+
+	t.Run("ValidateOutputFormat", func(t *testing.T) {
+		tests := []struct {
+			format  string
+			wantErr bool
+		}{
+			{"json", false},
+			{"yaml", false},
+			{"markdown", false},
+			{"xml", true},
+			{"txt", true},
+			{"", true},
+		}
+
+		for _, tt := range tests {
+			err := config.ValidateOutputFormat(tt.format)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ValidateOutputFormat(%q) error = %v, wantErr %v", tt.format, err, tt.wantErr)
+			}
+		}
+	})
+
+	t.Run("ValidateConcurrency", func(t *testing.T) {
+		tests := []struct {
+			name           string
+			concurrency    int
+			maxConcurrency int
+			setMax         bool
+			wantErr        bool
+		}{
+			{"valid concurrency", 4, 0, false, false},
+			{"minimum concurrency", 1, 0, false, false},
+			{"zero concurrency", 0, 0, false, true},
+			{"negative concurrency", -1, 0, false, true},
+			{"concurrency within max", 4, 8, true, false},
+			{"concurrency exceeds max", 16, 8, true, true},
+		}
+
+		for _, tt := range tests {
+			viper.Reset()
+			if tt.setMax {
+				viper.Set("maxConcurrency", tt.maxConcurrency)
+			}
+
+			err := config.ValidateConcurrency(tt.concurrency)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("%s: ValidateConcurrency(%d) error = %v, wantErr %v", tt.name, tt.concurrency, err, tt.wantErr)
+			}
+		}
+	})
+}
+
+func errorAs(err error, target interface{}) bool {
+	if err == nil {
+		return false
+	}
+	if structErr, ok := err.(*utils.StructuredError); ok {
+		if ptr, ok := target.(**utils.StructuredError); ok {
+			*ptr = structErr
+			return true
+		}
+	}
+	return false
+}

fileproc/backpressure.go

@@ -0,0 +1,196 @@
+// Package fileproc provides back-pressure management for memory optimization.
+package fileproc
+
+import (
+	"context"
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/config"
+)
+
+// BackpressureManager manages memory usage and applies back-pressure when needed.
+type BackpressureManager struct {
+	enabled             bool
+	maxMemoryUsage      int64
+	memoryCheckInterval int
+	maxPendingFiles     int
+	maxPendingWrites    int
+	filesProcessed      int64
+	mu                  sync.RWMutex
+	memoryWarningLogged bool
+	lastMemoryCheck     time.Time
+}
+
+// NewBackpressureManager creates a new back-pressure manager with configuration.
+func NewBackpressureManager() *BackpressureManager {
+	return &BackpressureManager{
+		enabled:             config.GetBackpressureEnabled(),
+		maxMemoryUsage:      config.GetMaxMemoryUsage(),
+		memoryCheckInterval: config.GetMemoryCheckInterval(),
+		maxPendingFiles:     config.GetMaxPendingFiles(),
+		maxPendingWrites:    config.GetMaxPendingWrites(),
+		lastMemoryCheck:     time.Now(),
+	}
+}
+
+// CreateChannels creates properly sized channels based on back-pressure configuration.
+func (bp *BackpressureManager) CreateChannels() (chan string, chan WriteRequest) {
+	var fileCh chan string
+	var writeCh chan WriteRequest
+
+	if bp.enabled {
+		// Use buffered channels with configured limits
+		fileCh = make(chan string, bp.maxPendingFiles)
+		writeCh = make(chan WriteRequest, bp.maxPendingWrites)
+		logrus.Debugf("Created buffered channels: files=%d, writes=%d", bp.maxPendingFiles, bp.maxPendingWrites)
+	} else {
+		// Use unbuffered channels (default behavior)
+		fileCh = make(chan string)
+		writeCh = make(chan WriteRequest)
+		logrus.Debug("Created unbuffered channels (back-pressure disabled)")
+	}
+
+	return fileCh, writeCh
+}
+
+// ShouldApplyBackpressure checks if back-pressure should be applied.
+func (bp *BackpressureManager) ShouldApplyBackpressure(ctx context.Context) bool {
+	if !bp.enabled {
+		return false
+	}
+
+	// Check if we should evaluate memory usage
+	filesProcessed := atomic.AddInt64(&bp.filesProcessed, 1)
+	if int(filesProcessed)%bp.memoryCheckInterval != 0 {
+		return false
+	}
+
+	// Get current memory usage
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+	currentMemory := int64(m.Alloc)
+
+	bp.mu.Lock()
+	defer bp.mu.Unlock()
+
+	bp.lastMemoryCheck = time.Now()
+
+	// Check if we're over the memory limit
+	if currentMemory > bp.maxMemoryUsage {
+		if !bp.memoryWarningLogged {
+			logrus.Warnf("Memory usage (%d bytes) exceeds limit (%d bytes), applying back-pressure",
+				currentMemory, bp.maxMemoryUsage)
+			bp.memoryWarningLogged = true
+		}
+		return true
+	}
+
+	// Reset warning flag if we're back under the limit
+	if bp.memoryWarningLogged && currentMemory < bp.maxMemoryUsage*8/10 { // 80% of limit
+		logrus.Infof("Memory usage normalized (%d bytes), removing back-pressure", currentMemory)
+		bp.memoryWarningLogged = false
+	}
+
+	return false
+}
+
+// ApplyBackpressure applies back-pressure by triggering garbage collection and adding delay.
+func (bp *BackpressureManager) ApplyBackpressure(ctx context.Context) {
+	if !bp.enabled {
+		return
+	}
+
+	// Force garbage collection to free up memory
+	runtime.GC()
+
+	// Add a small delay to allow memory to be freed
+	select {
+	case <-ctx.Done():
+		return
+	case <-time.After(10 * time.Millisecond):
+		// Small delay to allow GC to complete
+	}
+
+	// Log memory usage after GC
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+	logrus.Debugf("Applied back-pressure: memory after GC = %d bytes", m.Alloc)
+}
+
+// GetStats returns current back-pressure statistics.
+func (bp *BackpressureManager) GetStats() BackpressureStats {
+	bp.mu.RLock()
+	defer bp.mu.RUnlock()
+
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	return BackpressureStats{
+		Enabled:             bp.enabled,
+		FilesProcessed:      atomic.LoadInt64(&bp.filesProcessed),
+		CurrentMemoryUsage:  int64(m.Alloc),
+		MaxMemoryUsage:      bp.maxMemoryUsage,
+		MemoryWarningActive: bp.memoryWarningLogged,
+		LastMemoryCheck:     bp.lastMemoryCheck,
+		MaxPendingFiles:     bp.maxPendingFiles,
+		MaxPendingWrites:    bp.maxPendingWrites,
+	}
+}
+
+// BackpressureStats represents back-pressure manager statistics.
+type BackpressureStats struct {
+	Enabled             bool      `json:"enabled"`
+	FilesProcessed      int64     `json:"files_processed"`
+	CurrentMemoryUsage  int64     `json:"current_memory_usage"`
+	MaxMemoryUsage      int64     `json:"max_memory_usage"`
+	MemoryWarningActive bool      `json:"memory_warning_active"`
+	LastMemoryCheck     time.Time `json:"last_memory_check"`
+	MaxPendingFiles     int       `json:"max_pending_files"`
+	MaxPendingWrites    int       `json:"max_pending_writes"`
+}
+
+// WaitForChannelSpace waits for space in channels if they're getting full.
+func (bp *BackpressureManager) WaitForChannelSpace(ctx context.Context, fileCh chan string, writeCh chan WriteRequest) {
+	if !bp.enabled {
+		return
+	}
+
+	// Check if file channel is getting full (>90% capacity)
+	if len(fileCh) > bp.maxPendingFiles*9/10 {
+		logrus.Debugf("File channel is %d%% full, waiting for space", len(fileCh)*100/bp.maxPendingFiles)
+
+		// Wait a bit for the channel to drain
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(5 * time.Millisecond):
+		}
+	}
+
+	// Check if write channel is getting full (>90% capacity)
+	if len(writeCh) > bp.maxPendingWrites*9/10 {
+		logrus.Debugf("Write channel is %d%% full, waiting for space", len(writeCh)*100/bp.maxPendingWrites)
+
+		// Wait a bit for the channel to drain
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(5 * time.Millisecond):
+		}
+	}
+}
+
+// LogBackpressureInfo logs back-pressure configuration and status.
+func (bp *BackpressureManager) LogBackpressureInfo() {
+	if bp.enabled {
+		logrus.Infof("Back-pressure enabled: maxMemory=%dMB, fileBuffer=%d, writeBuffer=%d, checkInterval=%d",
+			bp.maxMemoryUsage/1024/1024, bp.maxPendingFiles, bp.maxPendingWrites, bp.memoryCheckInterval)
+	} else {
+		logrus.Info("Back-pressure disabled")
+	}
+}

fileproc/cache.go

@@ -0,0 +1,127 @@
+package fileproc
+
+// getNormalizedExtension efficiently extracts and normalizes the file extension with caching.
+func (r *FileTypeRegistry) getNormalizedExtension(filename string) string {
+	// Try cache first (read lock)
+	r.cacheMutex.RLock()
+	if ext, exists := r.extCache[filename]; exists {
+		r.cacheMutex.RUnlock()
+		return ext
+	}
+	r.cacheMutex.RUnlock()
+
+	// Compute normalized extension
+	ext := normalizeExtension(filename)
+
+	// Cache the result (write lock)
+	r.cacheMutex.Lock()
+	// Check cache size and clean if needed
+	if len(r.extCache) >= r.maxCacheSize*2 {
+		r.clearExtCache()
+		r.stats.CacheEvictions++
+	}
+	r.extCache[filename] = ext
+	r.cacheMutex.Unlock()
+
+	return ext
+}
+
+// getFileTypeResult gets cached file type detection result or computes it.
+func (r *FileTypeRegistry) getFileTypeResult(filename string) FileTypeResult {
+	ext := r.getNormalizedExtension(filename)
+
+	// Update statistics
+	r.updateStats(func() {
+		r.stats.TotalLookups++
+	})
+
+	// Try cache first (read lock)
+	r.cacheMutex.RLock()
+	if result, exists := r.resultCache[ext]; exists {
+		r.cacheMutex.RUnlock()
+		r.updateStats(func() {
+			r.stats.CacheHits++
+		})
+		return result
+	}
+	r.cacheMutex.RUnlock()
+
+	// Cache miss
+	r.updateStats(func() {
+		r.stats.CacheMisses++
+	})
+
+	// Compute result
+	result := FileTypeResult{
+		Extension: ext,
+		IsImage:   r.imageExts[ext],
+		IsBinary:  r.binaryExts[ext],
+		Language:  r.languageMap[ext],
+	}
+
+	// Handle special cases for binary detection (like .DS_Store)
+	if !result.IsBinary && isSpecialFile(filename, r.binaryExts) {
+		result.IsBinary = true
+	}
+
+	// Cache the result (write lock)
+	r.cacheMutex.Lock()
+	if len(r.resultCache) >= r.maxCacheSize {
+		r.clearResultCache()
+		r.stats.CacheEvictions++
+	}
+	r.resultCache[ext] = result
+	r.cacheMutex.Unlock()
+
+	return result
+}
+
+// clearExtCache clears half of the extension cache (LRU-like behavior).
+func (r *FileTypeRegistry) clearExtCache() {
+	r.clearCache(&r.extCache, r.maxCacheSize)
+}
+
+// clearResultCache clears half of the result cache.
+func (r *FileTypeRegistry) clearResultCache() {
+	newCache := make(map[string]FileTypeResult, r.maxCacheSize)
+	count := 0
+	for k, v := range r.resultCache {
+		if count >= r.maxCacheSize/2 {
+			break
+		}
+		newCache[k] = v
+		count++
+	}
+	r.resultCache = newCache
+}
+
+// clearCache is a generic cache clearing function.
+func (r *FileTypeRegistry) clearCache(cache *map[string]string, maxSize int) {
+	newCache := make(map[string]string, maxSize)
+	count := 0
+	for k, v := range *cache {
+		if count >= maxSize/2 {
+			break
+		}
+		newCache[k] = v
+		count++
+	}
+	*cache = newCache
+}
+
+// invalidateCache clears both caches when the registry is modified.
+func (r *FileTypeRegistry) invalidateCache() {
+	r.cacheMutex.Lock()
+	defer r.cacheMutex.Unlock()
+
+	r.extCache = make(map[string]string, r.maxCacheSize)
+	r.resultCache = make(map[string]FileTypeResult, r.maxCacheSize)
+	r.stats.CacheEvictions++
+}
+
+// updateStats safely updates statistics.
+func (r *FileTypeRegistry) updateStats(fn func()) {
+	r.cacheMutex.Lock()
+	fn()
+	r.cacheMutex.Unlock()
+}

fileproc/collector.go

@@ -4,6 +4,6 @@ package fileproc
 // CollectFiles scans the given root directory using the default walker (ProdWalker)
 // and returns a slice of file paths.
 func CollectFiles(root string) ([]string, error) {
-	var w Walker = ProdWalker{}
+	w := NewProdWalker()
 	return w.Walk(root)
 }

fileproc/collector_test.go

@@ -1,8 +1,10 @@
-package fileproc
+package fileproc_test
 
 import (
 	"os"
 	"testing"
+
+	"github.com/ivuorinen/gibidify/fileproc"
 )
 
 func TestCollectFilesWithFakeWalker(t *testing.T) {
@@ -11,7 +13,7 @@ func TestCollectFilesWithFakeWalker(t *testing.T) {
 		"/path/to/file1.txt",
 		"/path/to/file2.go",
 	}
-	fake := FakeWalker{
+	fake := fileproc.FakeWalker{
 		Files: expectedFiles,
 		Err:   nil,
 	}
@@ -35,7 +37,7 @@ func TestCollectFilesWithFakeWalker(t *testing.T) {
 
 func TestCollectFilesError(t *testing.T) {
 	// Fake walker returns an error.
-	fake := FakeWalker{
+	fake := fileproc.FakeWalker{
 		Files: nil,
 		Err:   os.ErrNotExist,
 	}

fileproc/config.go

@@ -0,0 +1,40 @@
+package fileproc
+
+import "strings"
+
+// ApplyCustomExtensions applies custom extensions from configuration.
+func (r *FileTypeRegistry) ApplyCustomExtensions(customImages, customBinary []string, customLanguages map[string]string) {
+	// Add custom image extensions
+	r.addExtensions(customImages, r.AddImageExtension)
+
+	// Add custom binary extensions
+	r.addExtensions(customBinary, r.AddBinaryExtension)
+
+	// Add custom language mappings
+	for ext, lang := range customLanguages {
+		if ext != "" && lang != "" {
+			r.AddLanguageMapping(strings.ToLower(ext), lang)
+		}
+	}
+}
+
+// addExtensions is a helper to add multiple extensions.
+func (r *FileTypeRegistry) addExtensions(extensions []string, adder func(string)) {
+	for _, ext := range extensions {
+		if ext != "" {
+			adder(strings.ToLower(ext))
+		}
+	}
+}
+
+// ConfigureFromSettings applies configuration settings to the registry.
+// This function is called from main.go after config is loaded to avoid circular imports.
+func ConfigureFromSettings(
+	customImages, customBinary []string,
+	customLanguages map[string]string,
+	disabledImages, disabledBinary, disabledLanguages []string,
+) {
+	registry := GetDefaultRegistry()
+	registry.ApplyCustomExtensions(customImages, customBinary, customLanguages)
+	registry.DisableExtensions(disabledImages, disabledBinary, disabledLanguages)
+}

fileproc/detection.go

@@ -0,0 +1,99 @@
+package fileproc
+
+import "strings"
+
+// Package-level detection functions
+
+// IsImage checks if the file extension indicates an image file.
+func IsImage(filename string) bool {
+	return getRegistry().IsImage(filename)
+}
+
+// IsBinary checks if the file extension indicates a binary file.
+func IsBinary(filename string) bool {
+	return getRegistry().IsBinary(filename)
+}
+
+// GetLanguage returns the language identifier for the given filename based on its extension.
+func GetLanguage(filename string) string {
+	return getRegistry().GetLanguage(filename)
+}
+
+// Registry methods for detection
+
+// IsImage checks if the file extension indicates an image file.
+func (r *FileTypeRegistry) IsImage(filename string) bool {
+	result := r.getFileTypeResult(filename)
+	return result.IsImage
+}
+
+// IsBinary checks if the file extension indicates a binary file.
+func (r *FileTypeRegistry) IsBinary(filename string) bool {
+	result := r.getFileTypeResult(filename)
+	return result.IsBinary
+}
+
+// GetLanguage returns the language identifier for the given filename based on its extension.
+func (r *FileTypeRegistry) GetLanguage(filename string) string {
+	if len(filename) < minExtensionLength {
+		return ""
+	}
+	result := r.getFileTypeResult(filename)
+	return result.Language
+}
+
+// Extension management methods
+
+// AddImageExtension adds a new image extension to the registry.
+func (r *FileTypeRegistry) AddImageExtension(ext string) {
+	r.addExtension(ext, r.imageExts)
+}
+
+// AddBinaryExtension adds a new binary extension to the registry.
+func (r *FileTypeRegistry) AddBinaryExtension(ext string) {
+	r.addExtension(ext, r.binaryExts)
+}
+
+// AddLanguageMapping adds a new language mapping to the registry.
+func (r *FileTypeRegistry) AddLanguageMapping(ext, language string) {
+	r.languageMap[strings.ToLower(ext)] = language
+	r.invalidateCache()
+}
+
+// addExtension is a helper to add extensions to a map.
+func (r *FileTypeRegistry) addExtension(ext string, target map[string]bool) {
+	target[strings.ToLower(ext)] = true
+	r.invalidateCache()
+}
+
+// removeExtension is a helper to remove extensions from a map.
+func (r *FileTypeRegistry) removeExtension(ext string, target map[string]bool) {
+	delete(target, strings.ToLower(ext))
+}
+
+// DisableExtensions removes specified extensions from the registry.
+func (r *FileTypeRegistry) DisableExtensions(disabledImages, disabledBinary, disabledLanguages []string) {
+	// Disable image extensions
+	for _, ext := range disabledImages {
+		if ext != "" {
+			r.removeExtension(ext, r.imageExts)
+		}
+	}
+
+	// Disable binary extensions
+	for _, ext := range disabledBinary {
+		if ext != "" {
+			r.removeExtension(ext, r.binaryExts)
+		}
+	}
+
+	// Disable language extensions
+	for _, ext := range disabledLanguages {
+		if ext != "" {
+			delete(r.languageMap, strings.ToLower(ext))
+		}
+	}
+
+	// Invalidate cache after all modifications
+	r.invalidateCache()
+}

fileproc/extensions.go

@@ -0,0 +1,161 @@
+package fileproc
+
+// getImageExtensions returns the default image file extensions.
+func getImageExtensions() map[string]bool {
+	return map[string]bool{
+		".png":  true,
+		".jpg":  true,
+		".jpeg": true,
+		".gif":  true,
+		".bmp":  true,
+		".tiff": true,
+		".tif":  true,
+		".svg":  true,
+		".webp": true,
+		".ico":  true,
+	}
+}
+
+// getBinaryExtensions returns the default binary file extensions.
+func getBinaryExtensions() map[string]bool {
+	return map[string]bool{
+		// Executables and libraries
+		".exe":   true,
+		".dll":   true,
+		".so":    true,
+		".dylib": true,
+		".bin":   true,
+		".o":     true,
+		".a":     true,
+		".lib":   true,
+
+		// Compiled bytecode
+		".jar":   true,
+		".class": true,
+		".pyc":   true,
+		".pyo":   true,
+
+		// Data files
+		".dat":      true,
+		".db":       true,
+		".sqlite":   true,
+		".ds_store": true,
+
+		// Documents
+		".pdf": true,
+
+		// Archives
+		".zip": true,
+		".tar": true,
+		".gz":  true,
+		".bz2": true,
+		".xz":  true,
+		".7z":  true,
+		".rar": true,
+
+		// Fonts
+		".ttf":   true,
+		".otf":   true,
+		".woff":  true,
+		".woff2": true,
+
+		// Media files
+		".mp3":  true,
+		".mp4":  true,
+		".avi":  true,
+		".mov":  true,
+		".wmv":  true,
+		".flv":  true,
+		".webm": true,
+		".ogg":  true,
+		".wav":  true,
+		".flac": true,
+	}
+}
+
+// getLanguageMap returns the default language mappings.
+func getLanguageMap() map[string]string {
+	return map[string]string{
+		// Systems programming
+		".go":  "go",
+		".c":   "c",
+		".cpp": "cpp",
+		".h":   "c",
+		".hpp": "cpp",
+		".rs":  "rust",
+
+		// Scripting languages
+		".py":  "python",
+		".rb":  "ruby",
+		".pl":  "perl",
+		".lua": "lua",
+		".php": "php",
+
+		// Web technologies
+		".js":   "javascript",
+		".ts":   "typescript",
+		".jsx":  "javascript",
+		".tsx":  "typescript",
+		".html": "html",
+		".htm":  "html",
+		".css":  "css",
+		".scss": "scss",
+		".sass": "sass",
+		".less": "less",
+		".vue":  "vue",
+
+		// JVM languages
+		".java":  "java",
+		".scala": "scala",
+		".kt":    "kotlin",
+		".clj":   "clojure",
+
+		// .NET languages
+		".cs": "csharp",
+		".vb": "vbnet",
+		".fs": "fsharp",
+
+		// Apple platforms
+		".swift": "swift",
+		".m":     "objc",
+		".mm":    "objcpp",
+
+		// Shell scripts
+		".sh":   "bash",
+		".bash": "bash",
+		".zsh":  "zsh",
+		".fish": "fish",
+		".ps1":  "powershell",
+		".bat":  "batch",
+		".cmd":  "batch",
+
+		// Data formats
+		".json": "json",
+		".yaml": "yaml",
+		".yml":  "yaml",
+		".toml": "toml",
+		".xml":  "xml",
+		".sql":  "sql",
+
+		// Documentation
+		".md":  "markdown",
+		".rst": "rst",
+		".tex": "latex",
+
+		// Functional languages
+		".hs":  "haskell",
+		".ml":  "ocaml",
+		".mli": "ocaml",
+		".elm": "elm",
+		".ex":  "elixir",
+		".exs": "elixir",
+		".erl": "erlang",
+		".hrl": "erlang",
+
+		// Other languages
+		".r":    "r",
+		".dart": "dart",
+		".nim":  "nim",
+		".nims": "nim",
+	}
+}

fileproc/fake_walker.go

@@ -3,12 +3,12 @@ package fileproc
 
 // FakeWalker implements Walker for testing purposes.
 type FakeWalker struct {
-	Files []string
 	Err   error
+	Files []string
 }
 
 // Walk returns predetermined file paths or an error, depending on FakeWalker's configuration.
-func (fw FakeWalker) Walk(root string) ([]string, error) {
+func (fw FakeWalker) Walk(_ string) ([]string, error) {
 	if fw.Err != nil {
 		return nil, fw.Err
 	}

fileproc/file_filters.go

@@ -0,0 +1,55 @@
+package fileproc
+
+import (
+	"os"
+
+	"github.com/ivuorinen/gibidify/config"
+)
+
+// FileFilter defines filtering criteria for files and directories.
+type FileFilter struct {
+	ignoredDirs []string
+	sizeLimit   int64
+}
+
+// NewFileFilter creates a new file filter with current configuration.
+func NewFileFilter() *FileFilter {
+	return &FileFilter{
+		ignoredDirs: config.GetIgnoredDirectories(),
+		sizeLimit:   config.GetFileSizeLimit(),
+	}
+}
+
+// shouldSkipEntry determines if an entry should be skipped based on ignore rules and filters.
+func (f *FileFilter) shouldSkipEntry(entry os.DirEntry, fullPath string, rules []ignoreRule) bool {
+	if entry.IsDir() {
+		return f.shouldSkipDirectory(entry)
+	}
+
+	if f.shouldSkipFile(entry, fullPath) {
+		return true
+	}
+
+	return matchesIgnoreRules(fullPath, rules)
+}
+
+// shouldSkipDirectory checks if a directory should be skipped based on the ignored directories list.
+func (f *FileFilter) shouldSkipDirectory(entry os.DirEntry) bool {
+	for _, d := range f.ignoredDirs {
+		if entry.Name() == d {
+			return true
+		}
+	}
+	return false
+}
+
+// shouldSkipFile checks if a file should be skipped based on size limit and file type.
+func (f *FileFilter) shouldSkipFile(entry os.DirEntry, fullPath string) bool {
+	// Check if file exceeds the configured size limit.
+	if info, err := entry.Info(); err == nil && info.Size() > f.sizeLimit {
+		return true
+	}
+
+	// Apply the default filter to ignore binary and image files.
+	return IsBinary(fullPath) || IsImage(fullPath)
+}

fileproc/filetypes_concurrency_test.go

@@ -0,0 +1,105 @@
+package fileproc
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+)
+
+// TestFileTypeRegistry_ThreadSafety tests thread safety of the FileTypeRegistry.
+func TestFileTypeRegistry_ThreadSafety(t *testing.T) {
+	const numGoroutines = 100
+	const numOperationsPerGoroutine = 100
+
+	var wg sync.WaitGroup
+
+	// Test concurrent read operations
+	t.Run("ConcurrentReads", func(t *testing.T) {
+		for i := 0; i < numGoroutines; i++ {
+			wg.Add(1)
+			go func(id int) {
+				defer wg.Done()
+				registry := GetDefaultRegistry()
+
+				for j := 0; j < numOperationsPerGoroutine; j++ {
+					// Test various file detection operations
+					_ = registry.IsImage("test.png")
+					_ = registry.IsBinary("test.exe")
+					_ = registry.GetLanguage("test.go")
+
+					// Test global functions too
+					_ = IsImage("image.jpg")
+					_ = IsBinary("binary.dll")
+					_ = GetLanguage("script.py")
+				}
+			}(i)
+		}
+		wg.Wait()
+	})
+
+	// Test concurrent registry access (singleton creation)
+	t.Run("ConcurrentRegistryAccess", func(t *testing.T) {
+		// Reset the registry to test concurrent initialization
+		// Note: This is not safe in a real application, but needed for testing
+		registryOnce = sync.Once{}
+		registry = nil
+
+		registries := make([]*FileTypeRegistry, numGoroutines)
+
+		for i := 0; i < numGoroutines; i++ {
+			wg.Add(1)
+			go func(id int) {
+				defer wg.Done()
+				registries[id] = GetDefaultRegistry()
+			}(i)
+		}
+		wg.Wait()
+
+		// Verify all goroutines got the same registry instance
+		firstRegistry := registries[0]
+		for i := 1; i < numGoroutines; i++ {
+			if registries[i] != firstRegistry {
+				t.Errorf("Registry %d is different from registry 0", i)
+			}
+		}
+	})
+
+	// Test concurrent modifications on separate registry instances
+	t.Run("ConcurrentModifications", func(t *testing.T) {
+		// Create separate registry instances for each goroutine to test modification thread safety
+		for i := 0; i < numGoroutines; i++ {
+			wg.Add(1)
+			go func(id int) {
+				defer wg.Done()
+
+				// Create a new registry instance for this goroutine
+				registry := &FileTypeRegistry{
+					imageExts:   make(map[string]bool),
+					binaryExts:  make(map[string]bool),
+					languageMap: make(map[string]string),
+				}
+
+				for j := 0; j < numOperationsPerGoroutine; j++ {
+					// Add unique extensions for this goroutine
+					extSuffix := fmt.Sprintf("_%d_%d", id, j)
+
+					registry.AddImageExtension(".img" + extSuffix)
+					registry.AddBinaryExtension(".bin" + extSuffix)
+					registry.AddLanguageMapping(".lang"+extSuffix, "lang"+extSuffix)
+
+					// Verify the additions worked
+					if !registry.IsImage("test.img" + extSuffix) {
+						t.Errorf("Failed to add image extension .img%s", extSuffix)
+					}
+					if !registry.IsBinary("test.bin" + extSuffix) {
+						t.Errorf("Failed to add binary extension .bin%s", extSuffix)
+					}
+					if registry.GetLanguage("test.lang"+extSuffix) != "lang"+extSuffix {
+						t.Errorf("Failed to add language mapping .lang%s", extSuffix)
+					}
+				}
+			}(i)
+		}
+		wg.Wait()
+	})
+}

fileproc/filetypes_config_test.go

@@ -0,0 +1,258 @@
+package fileproc
+
+import (
+	"sync"
+	"testing"
+)
+
+// TestFileTypeRegistry_Configuration tests the configuration functionality.
+func TestFileTypeRegistry_Configuration(t *testing.T) {
+	// Create a new registry instance for testing
+	registry := &FileTypeRegistry{
+		imageExts:   make(map[string]bool),
+		binaryExts:  make(map[string]bool),
+		languageMap: make(map[string]string),
+	}
+
+	// Test ApplyCustomExtensions
+	t.Run("ApplyCustomExtensions", func(t *testing.T) {
+		customImages := []string{".webp", ".avif", ".heic"}
+		customBinary := []string{".custom", ".mybin"}
+		customLanguages := map[string]string{
+			".zig":  "zig",
+			".odin": "odin",
+			".v":    "vlang",
+		}
+
+		registry.ApplyCustomExtensions(customImages, customBinary, customLanguages)
+
+		// Test custom image extensions
+		for _, ext := range customImages {
+			if !registry.IsImage("test" + ext) {
+				t.Errorf("Expected %s to be recognized as image", ext)
+			}
+		}
+
+		// Test custom binary extensions
+		for _, ext := range customBinary {
+			if !registry.IsBinary("test" + ext) {
+				t.Errorf("Expected %s to be recognized as binary", ext)
+			}
+		}
+
+		// Test custom language mappings
+		for ext, expectedLang := range customLanguages {
+			if lang := registry.GetLanguage("test" + ext); lang != expectedLang {
+				t.Errorf("Expected %s to map to %s, got %s", ext, expectedLang, lang)
+			}
+		}
+	})
+
+	// Test DisableExtensions
+	t.Run("DisableExtensions", func(t *testing.T) {
+		// Add some extensions first
+		registry.AddImageExtension(".png")
+		registry.AddImageExtension(".jpg")
+		registry.AddBinaryExtension(".exe")
+		registry.AddBinaryExtension(".dll")
+		registry.AddLanguageMapping(".go", "go")
+		registry.AddLanguageMapping(".py", "python")
+
+		// Verify they work
+		if !registry.IsImage("test.png") {
+			t.Error("Expected .png to be image before disabling")
+		}
+		if !registry.IsBinary("test.exe") {
+			t.Error("Expected .exe to be binary before disabling")
+		}
+		if registry.GetLanguage("test.go") != "go" {
+			t.Error("Expected .go to map to go before disabling")
+		}
+
+		// Disable some extensions
+		disabledImages := []string{".png"}
+		disabledBinary := []string{".exe"}
+		disabledLanguages := []string{".go"}
+
+		registry.DisableExtensions(disabledImages, disabledBinary, disabledLanguages)
+
+		// Test that disabled extensions no longer work
+		if registry.IsImage("test.png") {
+			t.Error("Expected .png to not be image after disabling")
+		}
+		if registry.IsBinary("test.exe") {
+			t.Error("Expected .exe to not be binary after disabling")
+		}
+		if registry.GetLanguage("test.go") != "" {
+			t.Error("Expected .go to not map to language after disabling")
+		}
+
+		// Test that non-disabled extensions still work
+		if !registry.IsImage("test.jpg") {
+			t.Error("Expected .jpg to still be image after disabling .png")
+		}
+		if !registry.IsBinary("test.dll") {
+			t.Error("Expected .dll to still be binary after disabling .exe")
+		}
+		if registry.GetLanguage("test.py") != "python" {
+			t.Error("Expected .py to still map to python after disabling .go")
+		}
+	})
+
+	// Test empty values handling
+	t.Run("EmptyValuesHandling", func(t *testing.T) {
+		registry := &FileTypeRegistry{
+			imageExts:   make(map[string]bool),
+			binaryExts:  make(map[string]bool),
+			languageMap: make(map[string]string),
+		}
+
+		// Test with empty values
+		customImages := []string{"", ".valid", ""}
+		customBinary := []string{"", ".valid"}
+		customLanguages := map[string]string{
+			"":       "invalid",
+			".valid": "",
+			".good":  "good",
+		}
+
+		registry.ApplyCustomExtensions(customImages, customBinary, customLanguages)
+
+		// Only valid entries should be added
+		if registry.IsImage("test.") {
+			t.Error("Expected empty extension to not be added as image")
+		}
+		if !registry.IsImage("test.valid") {
+			t.Error("Expected .valid to be added as image")
+		}
+		if registry.IsBinary("test.") {
+			t.Error("Expected empty extension to not be added as binary")
+		}
+		if !registry.IsBinary("test.valid") {
+			t.Error("Expected .valid to be added as binary")
+		}
+		if registry.GetLanguage("test.") != "" {
+			t.Error("Expected empty extension to not be added as language")
+		}
+		if registry.GetLanguage("test.valid") != "" {
+			t.Error("Expected .valid with empty language to not be added")
+		}
+		if registry.GetLanguage("test.good") != "good" {
+			t.Error("Expected .good to map to good")
+		}
+	})
+
+	// Test case insensitive handling
+	t.Run("CaseInsensitiveHandling", func(t *testing.T) {
+		registry := &FileTypeRegistry{
+			imageExts:   make(map[string]bool),
+			binaryExts:  make(map[string]bool),
+			languageMap: make(map[string]string),
+		}
+
+		customImages := []string{".WEBP", ".Avif"}
+		customBinary := []string{".CUSTOM", ".MyBin"}
+		customLanguages := map[string]string{
+			".ZIG":  "zig",
+			".Odin": "odin",
+		}
+
+		registry.ApplyCustomExtensions(customImages, customBinary, customLanguages)
+
+		// Test that both upper and lower case work
+		if !registry.IsImage("test.webp") {
+			t.Error("Expected .webp (lowercase) to work after adding .WEBP")
+		}
+		if !registry.IsImage("test.WEBP") {
+			t.Error("Expected .WEBP (uppercase) to work")
+		}
+		if !registry.IsBinary("test.custom") {
+			t.Error("Expected .custom (lowercase) to work after adding .CUSTOM")
+		}
+		if !registry.IsBinary("test.CUSTOM") {
+			t.Error("Expected .CUSTOM (uppercase) to work")
+		}
+		if registry.GetLanguage("test.zig") != "zig" {
+			t.Error("Expected .zig (lowercase) to work after adding .ZIG")
+		}
+		if registry.GetLanguage("test.ZIG") != "zig" {
+			t.Error("Expected .ZIG (uppercase) to work")
+		}
+	})
+}
+
+// TestConfigureFromSettings tests the global configuration function.
+func TestConfigureFromSettings(t *testing.T) {
+	// Reset registry to ensure clean state
+	registryOnce = sync.Once{}
+	registry = nil
+
+	// Test configuration application
+	customImages := []string{".webp", ".avif"}
+	customBinary := []string{".custom"}
+	customLanguages := map[string]string{".zig": "zig"}
+	disabledImages := []string{".gif"}   // Disable default extension
+	disabledBinary := []string{".exe"}   // Disable default extension
+	disabledLanguages := []string{".rb"} // Disable default extension
+
+	ConfigureFromSettings(
+		customImages,
+		customBinary,
+		customLanguages,
+		disabledImages,
+		disabledBinary,
+		disabledLanguages,
+	)
+
+	// Test that custom extensions work
+	if !IsImage("test.webp") {
+		t.Error("Expected custom image extension .webp to work")
+	}
+	if !IsBinary("test.custom") {
+		t.Error("Expected custom binary extension .custom to work")
+	}
+	if GetLanguage("test.zig") != "zig" {
+		t.Error("Expected custom language .zig to work")
+	}
+
+	// Test that disabled extensions don't work
+	if IsImage("test.gif") {
+		t.Error("Expected disabled image extension .gif to not work")
+	}
+	if IsBinary("test.exe") {
+		t.Error("Expected disabled binary extension .exe to not work")
+	}
+	if GetLanguage("test.rb") != "" {
+		t.Error("Expected disabled language extension .rb to not work")
+	}
+
+	// Test that non-disabled defaults still work
+	if !IsImage("test.png") {
+		t.Error("Expected non-disabled image extension .png to still work")
+	}
+	if !IsBinary("test.dll") {
+		t.Error("Expected non-disabled binary extension .dll to still work")
+	}
+	if GetLanguage("test.go") != "go" {
+		t.Error("Expected non-disabled language extension .go to still work")
+	}
+
+	// Test multiple calls don't override previous configuration
+	ConfigureFromSettings(
+		[]string{".extra"},
+		[]string{},
+		map[string]string{},
+		[]string{},
+		[]string{},
+		[]string{},
+	)
+
+	// Previous configuration should still work
+	if !IsImage("test.webp") {
+		t.Error("Expected previous configuration to persist")
+	}
+	// New configuration should also work
+	if !IsImage("test.extra") {
+		t.Error("Expected new configuration to be applied")
+	}
+}

fileproc/filetypes_detection_test.go

@@ -0,0 +1,226 @@
+package fileproc
+
+import (
+	"testing"
+)
+
+// TestFileTypeRegistry_LanguageDetection tests the language detection functionality.
+func TestFileTypeRegistry_LanguageDetection(t *testing.T) {
+	registry := GetDefaultRegistry()
+
+	tests := []struct {
+		filename string
+		expected string
+	}{
+		// Programming languages
+		{"main.go", "go"},
+		{"script.py", "python"},
+		{"app.js", "javascript"},
+		{"component.tsx", "typescript"},
+		{"service.ts", "typescript"},
+		{"App.java", "java"},
+		{"program.c", "c"},
+		{"program.cpp", "cpp"},
+		{"header.h", "c"},
+		{"header.hpp", "cpp"},
+		{"main.rs", "rust"},
+		{"script.rb", "ruby"},
+		{"index.php", "php"},
+		{"app.swift", "swift"},
+		{"MainActivity.kt", "kotlin"},
+		{"Main.scala", "scala"},
+		{"analysis.r", "r"},
+		{"ViewController.m", "objc"},
+		{"ViewController.mm", "objcpp"},
+		{"Program.cs", "csharp"},
+		{"Module.vb", "vbnet"},
+		{"program.fs", "fsharp"},
+		{"script.lua", "lua"},
+		{"script.pl", "perl"},
+
+		// Shell scripts
+		{"script.sh", "bash"},
+		{"script.bash", "bash"},
+		{"script.zsh", "zsh"},
+		{"script.fish", "fish"},
+		{"script.ps1", "powershell"},
+		{"script.bat", "batch"},
+		{"script.cmd", "batch"},
+
+		// Data and markup
+		{"query.sql", "sql"},
+		{"index.html", "html"},
+		{"page.htm", "html"},
+		{"data.xml", "xml"},
+		{"style.css", "css"},
+		{"style.scss", "scss"},
+		{"style.sass", "sass"},
+		{"style.less", "less"},
+		{"config.json", "json"},
+		{"config.yaml", "yaml"},
+		{"config.yml", "yaml"},
+		{"data.toml", "toml"},
+		{"page.md", "markdown"},
+		{"readme.markdown", ""},
+		{"doc.rst", "rst"},
+		{"book.tex", "latex"},
+
+		// Configuration files
+		{"Dockerfile", ""},
+		{"Makefile", ""},
+		{"GNUmakefile", ""},
+
+		// Case sensitivity tests
+		{"MAIN.GO", "go"},
+		{"SCRIPT.PY", "python"},
+		{"APP.JS", "javascript"},
+
+		// Unknown extensions
+		{"unknown.xyz", ""},
+		{"file.unknown", ""},
+		{"noextension", ""},
+		{"", ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.filename, func(t *testing.T) {
+			result := registry.GetLanguage(tt.filename)
+			if result != tt.expected {
+				t.Errorf("GetLanguage(%q) = %q, expected %q", tt.filename, result, tt.expected)
+			}
+		})
+	}
+}
+
+// TestFileTypeRegistry_ImageDetection tests the image detection functionality.
+func TestFileTypeRegistry_ImageDetection(t *testing.T) {
+	registry := GetDefaultRegistry()
+
+	tests := []struct {
+		filename string
+		expected bool
+	}{
+		// Common image formats
+		{"photo.png", true},
+		{"image.jpg", true},
+		{"picture.jpeg", true},
+		{"animation.gif", true},
+		{"bitmap.bmp", true},
+		{"image.tiff", true},
+		{"scan.tif", true},
+		{"vector.svg", true},
+		{"modern.webp", true},
+		{"favicon.ico", true},
+
+		// Case sensitivity tests
+		{"PHOTO.PNG", true},
+		{"IMAGE.JPG", true},
+		{"PICTURE.JPEG", true},
+
+		// Non-image files
+		{"document.txt", false},
+		{"script.js", false},
+		{"data.json", false},
+		{"archive.zip", false},
+		{"executable.exe", false},
+
+		// Edge cases
+		{"", false},              // Empty filename
+		{"image", false},         // No extension
+		{".png", true},           // Just extension
+		{"file.png.bak", false},  // Multiple extensions
+		{"image.unknown", false}, // Unknown extension
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.filename, func(t *testing.T) {
+			result := registry.IsImage(tt.filename)
+			if result != tt.expected {
+				t.Errorf("IsImage(%q) = %t, expected %t", tt.filename, result, tt.expected)
+			}
+		})
+	}
+}
+
+// TestFileTypeRegistry_BinaryDetection tests the binary detection functionality.
+func TestFileTypeRegistry_BinaryDetection(t *testing.T) {
+	registry := GetDefaultRegistry()
+
+	tests := []struct {
+		filename string
+		expected bool
+	}{
+		// Executable files
+		{"program.exe", true},
+		{"library.dll", true},
+		{"libfoo.so", true},
+		{"framework.dylib", true},
+		{"data.bin", true},
+
+		// Object and library files
+		{"object.o", true},
+		{"archive.a", true},
+		{"library.lib", true},
+		{"application.jar", true},
+		{"bytecode.class", true},
+		{"compiled.pyc", true},
+		{"optimized.pyo", true},
+
+		// System files
+		{".DS_Store", true},
+
+		// Document files (treated as binary)
+		{"document.pdf", true},
+
+		// Archive files
+		{"archive.zip", true},
+		{"backup.tar", true},
+		{"compressed.gz", true},
+		{"data.bz2", true},
+		{"package.xz", true},
+		{"archive.7z", true},
+		{"backup.rar", true},
+
+		// Font files
+		{"font.ttf", true},
+		{"font.otf", true},
+		{"font.woff", true},
+		{"font.woff2", true},
+
+		// Media files (video/audio)
+		{"video.mp4", true},
+		{"movie.avi", true},
+		{"clip.mov", true},
+		{"song.mp3", true},
+		{"audio.wav", true},
+		{"music.flac", true},
+
+		// Case sensitivity tests
+		{"PROGRAM.EXE", true},
+		{"LIBRARY.DLL", true},
+		{"ARCHIVE.ZIP", true},
+
+		// Non-binary files
+		{"document.txt", false},
+		{"script.py", false},
+		{"config.json", false},
+		{"style.css", false},
+		{"page.html", false},
+
+		// Edge cases
+		{"", false},              // Empty filename
+		{"binary", false},        // No extension
+		{".exe", true},           // Just extension
+		{"file.exe.txt", false},  // Multiple extensions
+		{"file.unknown", false},  // Unknown extension
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.filename, func(t *testing.T) {
+			result := registry.IsBinary(tt.filename)
+			if result != tt.expected {
+				t.Errorf("IsBinary(%q) = %t, expected %t", tt.filename, result, tt.expected)
+			}
+		})
+	}
+}

fileproc/filetypes_edge_cases_test.go

@@ -0,0 +1,128 @@
+package fileproc
+
+import (
+	"testing"
+)
+
+// TestFileTypeRegistry_EdgeCases tests edge cases and boundary conditions.
+func TestFileTypeRegistry_EdgeCases(t *testing.T) {
+	registry := GetDefaultRegistry()
+
+	// Test various edge cases for filename handling
+	edgeCases := []struct {
+		name     string
+		filename string
+		desc     string
+	}{
+		{"empty", "", "empty filename"},
+		{"single_char", "a", "single character filename"},
+		{"just_dot", ".", "just a dot"},
+		{"double_dot", "..", "double dot"},
+		{"hidden_file", ".hidden", "hidden file"},
+		{"hidden_with_ext", ".hidden.txt", "hidden file with extension"},
+		{"multiple_dots", "file.tar.gz", "multiple extensions"},
+		{"trailing_dot", "file.", "trailing dot"},
+		{"unicode", "файл.txt", "unicode filename"},
+		{"spaces", "my file.txt", "filename with spaces"},
+		{"special_chars", "file@#$.txt", "filename with special characters"},
+		{"very_long", "very_long_filename_with_many_characters_in_it.extension", "very long filename"},
+		{"no_basename", ".gitignore", "dotfile with no basename"},
+		{"case_mixed", "FiLe.ExT", "mixed case"},
+	}
+
+	for _, tc := range edgeCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// These should not panic
+			_ = registry.IsImage(tc.filename)
+			_ = registry.IsBinary(tc.filename)
+			_ = registry.GetLanguage(tc.filename)
+
+			// Global functions should also not panic
+			_ = IsImage(tc.filename)
+			_ = IsBinary(tc.filename)
+			_ = GetLanguage(tc.filename)
+		})
+	}
+}
+
+// TestFileTypeRegistry_MinimumExtensionLength tests the minimum extension length requirement.
+func TestFileTypeRegistry_MinimumExtensionLength(t *testing.T) {
+	registry := GetDefaultRegistry()
+
+	tests := []struct {
+		filename string
+		expected string
+	}{
+		{"", ""},            // Empty filename
+		{"a", ""},           // Single character (less than minExtensionLength)
+		{"ab", ""},          // Two characters, no extension
+		{"a.b", ""},         // Extension too short, but filename too short anyway
+		{"ab.c", "c"},       // Valid: filename >= minExtensionLength and .c is valid extension
+		{"a.go", "go"},      // Valid extension
+		{"ab.py", "python"}, // Valid extension
+		{"a.unknown", ""},   // Valid length but unknown extension
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.filename, func(t *testing.T) {
+			result := registry.GetLanguage(tt.filename)
+			if result != tt.expected {
+				t.Errorf("GetLanguage(%q) = %q, expected %q", tt.filename, result, tt.expected)
+			}
+		})
+	}
+}
+
+// Benchmark tests for performance validation
+func BenchmarkFileTypeRegistry_IsImage(b *testing.B) {
+	registry := GetDefaultRegistry()
+	filename := "test.png"
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = registry.IsImage(filename)
+	}
+}
+
+func BenchmarkFileTypeRegistry_IsBinary(b *testing.B) {
+	registry := GetDefaultRegistry()
+	filename := "test.exe"
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = registry.IsBinary(filename)
+	}
+}
+
+func BenchmarkFileTypeRegistry_GetLanguage(b *testing.B) {
+	registry := GetDefaultRegistry()
+	filename := "test.go"
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = registry.GetLanguage(filename)
+	}
+}
+
+func BenchmarkFileTypeRegistry_GlobalFunctions(b *testing.B) {
+	filename := "test.go"
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = IsImage(filename)
+		_ = IsBinary(filename)
+		_ = GetLanguage(filename)
+	}
+}
+
+func BenchmarkFileTypeRegistry_ConcurrentAccess(b *testing.B) {
+	filename := "test.go"
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			_ = IsImage(filename)
+			_ = IsBinary(filename)
+			_ = GetLanguage(filename)
+		}
+	})
+}

fileproc/filetypes_registry_test.go

@@ -0,0 +1,137 @@
+package fileproc
+
+import (
+	"testing"
+)
+
+// TestFileTypeRegistry_ModificationMethods tests the modification methods of FileTypeRegistry.
+func TestFileTypeRegistry_ModificationMethods(t *testing.T) {
+	// Create a new registry instance for testing
+	registry := &FileTypeRegistry{
+		imageExts:   make(map[string]bool),
+		binaryExts:  make(map[string]bool),
+		languageMap: make(map[string]string),
+	}
+
+	// Test AddImageExtension
+	t.Run("AddImageExtension", func(t *testing.T) {
+		// Add a new image extension
+		registry.AddImageExtension(".webp")
+		if !registry.IsImage("test.webp") {
+			t.Errorf("Expected .webp to be recognized as image after adding")
+		}
+
+		// Test case insensitive addition
+		registry.AddImageExtension(".AVIF")
+		if !registry.IsImage("test.avif") {
+			t.Errorf("Expected .avif to be recognized as image after adding .AVIF")
+		}
+		if !registry.IsImage("test.AVIF") {
+			t.Errorf("Expected .AVIF to be recognized as image")
+		}
+
+		// Test with dot prefix
+		registry.AddImageExtension("heic")
+		if registry.IsImage("test.heic") {
+			t.Errorf("Expected extension without dot to not work")
+		}
+
+		// Test with proper dot prefix
+		registry.AddImageExtension(".heic")
+		if !registry.IsImage("test.heic") {
+			t.Errorf("Expected .heic to be recognized as image")
+		}
+	})
+
+	// Test AddBinaryExtension
+	t.Run("AddBinaryExtension", func(t *testing.T) {
+		// Add a new binary extension
+		registry.AddBinaryExtension(".custom")
+		if !registry.IsBinary("file.custom") {
+			t.Errorf("Expected .custom to be recognized as binary after adding")
+		}
+
+		// Test case insensitive addition
+		registry.AddBinaryExtension(".SPECIAL")
+		if !registry.IsBinary("file.special") {
+			t.Errorf("Expected .special to be recognized as binary after adding .SPECIAL")
+		}
+		if !registry.IsBinary("file.SPECIAL") {
+			t.Errorf("Expected .SPECIAL to be recognized as binary")
+		}
+
+		// Test with dot prefix
+		registry.AddBinaryExtension("bin")
+		if registry.IsBinary("file.bin") {
+			t.Errorf("Expected extension without dot to not work")
+		}
+
+		// Test with proper dot prefix
+		registry.AddBinaryExtension(".bin")
+		if !registry.IsBinary("file.bin") {
+			t.Errorf("Expected .bin to be recognized as binary")
+		}
+	})
+
+	// Test AddLanguageMapping
+	t.Run("AddLanguageMapping", func(t *testing.T) {
+		// Add a new language mapping
+		registry.AddLanguageMapping(".xyz", "CustomLang")
+		if lang := registry.GetLanguage("file.xyz"); lang != "CustomLang" {
+			t.Errorf("Expected CustomLang, got %s", lang)
+		}
+
+		// Test case insensitive addition
+		registry.AddLanguageMapping(".ABC", "UpperLang")
+		if lang := registry.GetLanguage("file.abc"); lang != "UpperLang" {
+			t.Errorf("Expected UpperLang, got %s", lang)
+		}
+		if lang := registry.GetLanguage("file.ABC"); lang != "UpperLang" {
+			t.Errorf("Expected UpperLang for uppercase, got %s", lang)
+		}
+
+		// Test with dot prefix
+		registry.AddLanguageMapping("nolang", "NoLang")
+		if lang := registry.GetLanguage("file.nolang"); lang == "NoLang" {
+			t.Errorf("Expected extension without dot to not work")
+		}
+
+		// Test with proper dot prefix
+		registry.AddLanguageMapping(".nolang", "NoLang")
+		if lang := registry.GetLanguage("file.nolang"); lang != "NoLang" {
+			t.Errorf("Expected NoLang, got %s", lang)
+		}
+
+		// Test overriding existing mapping
+		registry.AddLanguageMapping(".xyz", "NewCustomLang")
+		if lang := registry.GetLanguage("file.xyz"); lang != "NewCustomLang" {
+			t.Errorf("Expected NewCustomLang after override, got %s", lang)
+		}
+	})
+}
+
+// TestFileTypeRegistry_DefaultRegistryConsistency tests default registry behavior.
+func TestFileTypeRegistry_DefaultRegistryConsistency(t *testing.T) {
+	registry := GetDefaultRegistry()
+
+	// Test that registry methods work consistently
+	if !registry.IsImage("test.png") {
+		t.Error("Expected .png to be recognized as image")
+	}
+	if !registry.IsBinary("test.exe") {
+		t.Error("Expected .exe to be recognized as binary")
+	}
+	if lang := registry.GetLanguage("test.go"); lang != "go" {
+		t.Errorf("Expected go, got %s", lang)
+	}
+
+	// Test that multiple calls return consistent results
+	for i := 0; i < 5; i++ {
+		if !registry.IsImage("test.jpg") {
+			t.Errorf("Iteration %d: Expected .jpg to be recognized as image", i)
+		}
+		if registry.IsBinary("test.txt") {
+			t.Errorf("Iteration %d: Expected .txt to not be recognized as binary", i)
+		}
+	}
+}

fileproc/formats.go

@@ -0,0 +1,28 @@
+package fileproc
+
+// FileData represents a single file's path and content.
+type FileData struct {
+	Path     string `json:"path"     yaml:"path"`
+	Content  string `json:"content"  yaml:"content"`
+	Language string `json:"language" yaml:"language"`
+}
+
+// OutputData represents the full output structure.
+type OutputData struct {
+	Prefix string     `json:"prefix,omitempty" yaml:"prefix,omitempty"`
+	Suffix string     `json:"suffix,omitempty" yaml:"suffix,omitempty"`
+	Files  []FileData `json:"files"            yaml:"files"`
+}
+
+// FormatWriter defines the interface for format-specific writers.
+type FormatWriter interface {
+	Start(prefix, suffix string) error
+	WriteFile(req WriteRequest) error
+	Close() error
+}
+
+// detectLanguage tries to infer the code block language from the file extension.
+func detectLanguage(filePath string) string {
+	registry := GetDefaultRegistry()
+	return registry.GetLanguage(filePath)
+}

fileproc/ignore_rules.go

@@ -0,0 +1,66 @@
+package fileproc
+
+import (
+	"os"
+	"path/filepath"
+
+	ignore "github.com/sabhiram/go-gitignore"
+)
+
+// ignoreRule holds an ignore matcher along with the base directory where it was loaded.
+type ignoreRule struct {
+	gi   *ignore.GitIgnore
+	base string
+}
+
+// loadIgnoreRules loads ignore rules from the current directory and combines them with parent rules.
+func loadIgnoreRules(currentDir string, parentRules []ignoreRule) []ignoreRule {
+	// Pre-allocate for parent rules plus possible .gitignore and .ignore
+	const expectedIgnoreFiles = 2
+	rules := make([]ignoreRule, 0, len(parentRules)+expectedIgnoreFiles)
+	rules = append(rules, parentRules...)
+
+	// Check for .gitignore and .ignore files in the current directory.
+	for _, fileName := range []string{".gitignore", ".ignore"} {
+		if rule := tryLoadIgnoreFile(currentDir, fileName); rule != nil {
+			rules = append(rules, *rule)
+		}
+	}
+
+	return rules
+}
+
+// tryLoadIgnoreFile attempts to load an ignore file from the given directory.
+func tryLoadIgnoreFile(dir, fileName string) *ignoreRule {
+	ignorePath := filepath.Join(dir, fileName)
+	if info, err := os.Stat(ignorePath); err == nil && !info.IsDir() {
+		if gi, err := ignore.CompileIgnoreFile(ignorePath); err == nil {
+			return &ignoreRule{
+				base: dir,
+				gi:   gi,
+			}
+		}
+	}
+	return nil
+}
+
+// matchesIgnoreRules checks if a path matches any of the ignore rules.
+func matchesIgnoreRules(fullPath string, rules []ignoreRule) bool {
+	for _, rule := range rules {
+		if matchesRule(fullPath, rule) {
+			return true
+		}
+	}
+	return false
+}
+
+// matchesRule checks if a path matches a specific ignore rule.
+func matchesRule(fullPath string, rule ignoreRule) bool {
+	// Compute the path relative to the base where the ignore rule was defined.
+	rel, err := filepath.Rel(rule.base, fullPath)
+	if err != nil {
+		return false
+	}
+	// If the rule matches, skip this entry.
+	return rule.gi.MatchesPath(rel)
+}

fileproc/json_writer.go

@@ -0,0 +1,158 @@
+package fileproc
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// JSONWriter handles JSON format output with streaming support.
+type JSONWriter struct {
+	outFile   *os.File
+	firstFile bool
+}
+
+// NewJSONWriter creates a new JSON writer.
+func NewJSONWriter(outFile *os.File) *JSONWriter {
+	return &JSONWriter{
+		outFile:   outFile,
+		firstFile: true,
+	}
+}
+
+// Start writes the JSON header.
+func (w *JSONWriter) Start(prefix, suffix string) error {
+	// Start JSON structure
+	if _, err := w.outFile.WriteString(`{"prefix":"`); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON start")
+	}
+
+	// Write escaped prefix
+	escapedPrefix := utils.EscapeForJSON(prefix)
+	if err := utils.WriteWithErrorWrap(w.outFile, escapedPrefix, "failed to write JSON prefix", ""); err != nil {
+		return err
+	}
+
+	if _, err := w.outFile.WriteString(`","suffix":"`); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON middle")
+	}
+
+	// Write escaped suffix
+	escapedSuffix := utils.EscapeForJSON(suffix)
+	if err := utils.WriteWithErrorWrap(w.outFile, escapedSuffix, "failed to write JSON suffix", ""); err != nil {
+		return err
+	}
+
+	if _, err := w.outFile.WriteString(`","files":[`); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON files start")
+	}
+
+	return nil
+}
+
+// WriteFile writes a file entry in JSON format.
+func (w *JSONWriter) WriteFile(req WriteRequest) error {
+	if !w.firstFile {
+		if _, err := w.outFile.WriteString(","); err != nil {
+			return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON separator")
+		}
+	}
+	w.firstFile = false
+
+	if req.IsStream {
+		return w.writeStreaming(req)
+	}
+	return w.writeInline(req)
+}
+
+// Close writes the JSON footer.
+func (w *JSONWriter) Close() error {
+	// Close JSON structure
+	if _, err := w.outFile.WriteString("]}"); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON end")
+	}
+	return nil
+}
+
+// writeStreaming writes a large file as JSON in streaming chunks.
+func (w *JSONWriter) writeStreaming(req WriteRequest) error {
+	defer utils.SafeCloseReader(req.Reader, req.Path)
+
+	language := detectLanguage(req.Path)
+
+	// Write file start
+	escapedPath := utils.EscapeForJSON(req.Path)
+	if _, err := fmt.Fprintf(w.outFile, `{"path":"%s","language":"%s","content":"`, escapedPath, language); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON file start").WithFilePath(req.Path)
+	}
+
+	// Stream content with JSON escaping
+	if err := w.streamJSONContent(req.Reader, req.Path); err != nil {
+		return err
+	}
+
+	// Write file end
+	if _, err := w.outFile.WriteString(`"}`); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON file end").WithFilePath(req.Path)
+	}
+
+	return nil
+}
+
+// writeInline writes a small file directly as JSON.
+func (w *JSONWriter) writeInline(req WriteRequest) error {
+	language := detectLanguage(req.Path)
+	fileData := FileData{
+		Path:     req.Path,
+		Content:  req.Content,
+		Language: language,
+	}
+
+	encoded, err := json.Marshal(fileData)
+	if err != nil {
+		return utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingEncode, "failed to marshal JSON").WithFilePath(req.Path)
+	}
+
+	if _, err := w.outFile.Write(encoded); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write JSON file").WithFilePath(req.Path)
+	}
+	return nil
+}
+
+// streamJSONContent streams content with JSON escaping.
+func (w *JSONWriter) streamJSONContent(reader io.Reader, path string) error {
+	return utils.StreamContent(reader, w.outFile, StreamChunkSize, path, func(chunk []byte) []byte {
+		escaped := utils.EscapeForJSON(string(chunk))
+		return []byte(escaped)
+	})
+}
+
+
+
+// startJSONWriter handles JSON format output with streaming support.
+func startJSONWriter(outFile *os.File, writeCh <-chan WriteRequest, done chan<- struct{}, prefix, suffix string) {
+	defer close(done)
+
+	writer := NewJSONWriter(outFile)
+
+	// Start writing
+	if err := writer.Start(prefix, suffix); err != nil {
+		utils.LogError("Failed to write JSON start", err)
+		return
+	}
+
+	// Process files
+	for req := range writeCh {
+		if err := writer.WriteFile(req); err != nil {
+			utils.LogError("Failed to write JSON file", err)
+		}
+	}
+
+	// Close writer
+	if err := writer.Close(); err != nil {
+		utils.LogError("Failed to write JSON end", err)
+	}
+}

fileproc/markdown_writer.go

@@ -0,0 +1,139 @@
+package fileproc
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// MarkdownWriter handles markdown format output with streaming support.
+type MarkdownWriter struct {
+	outFile *os.File
+}
+
+// NewMarkdownWriter creates a new markdown writer.
+func NewMarkdownWriter(outFile *os.File) *MarkdownWriter {
+	return &MarkdownWriter{outFile: outFile}
+}
+
+// Start writes the markdown header.
+func (w *MarkdownWriter) Start(prefix, suffix string) error {
+	if prefix != "" {
+		if _, err := fmt.Fprintf(w.outFile, "# %s\n\n", prefix); err != nil {
+			return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write prefix")
+		}
+	}
+	return nil
+}
+
+// WriteFile writes a file entry in markdown format.
+func (w *MarkdownWriter) WriteFile(req WriteRequest) error {
+	if req.IsStream {
+		return w.writeStreaming(req)
+	}
+	return w.writeInline(req)
+}
+
+// Close writes the markdown footer.
+func (w *MarkdownWriter) Close(suffix string) error {
+	if suffix != "" {
+		if _, err := fmt.Fprintf(w.outFile, "\n# %s\n", suffix); err != nil {
+			return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write suffix")
+		}
+	}
+	return nil
+}
+
+// writeStreaming writes a large file in streaming chunks.
+func (w *MarkdownWriter) writeStreaming(req WriteRequest) error {
+	defer w.closeReader(req.Reader, req.Path)
+
+	language := detectLanguage(req.Path)
+
+	// Write file header
+	if _, err := fmt.Fprintf(w.outFile, "## File: `%s`\n```%s\n", req.Path, language); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write file header").WithFilePath(req.Path)
+	}
+
+	// Stream file content in chunks
+	if err := w.streamContent(req.Reader, req.Path); err != nil {
+		return err
+	}
+
+	// Write file footer
+	if _, err := w.outFile.WriteString("\n```\n\n"); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write file footer").WithFilePath(req.Path)
+	}
+
+	return nil
+}
+
+// writeInline writes a small file directly from content.
+func (w *MarkdownWriter) writeInline(req WriteRequest) error {
+	language := detectLanguage(req.Path)
+	formatted := fmt.Sprintf("## File: `%s`\n```%s\n%s\n```\n\n", req.Path, language, req.Content)
+
+	if _, err := w.outFile.WriteString(formatted); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write inline content").WithFilePath(req.Path)
+	}
+	return nil
+}
+
+// streamContent streams file content in chunks.
+func (w *MarkdownWriter) streamContent(reader io.Reader, path string) error {
+	buf := make([]byte, StreamChunkSize)
+	for {
+		n, err := reader.Read(buf)
+		if n > 0 {
+			if _, writeErr := w.outFile.Write(buf[:n]); writeErr != nil {
+				return utils.WrapError(writeErr, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write chunk").WithFilePath(path)
+			}
+		}
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIORead, "failed to read chunk").WithFilePath(path)
+		}
+	}
+	return nil
+}
+
+// closeReader safely closes a reader if it implements io.Closer.
+func (w *MarkdownWriter) closeReader(reader io.Reader, path string) {
+	if closer, ok := reader.(io.Closer); ok {
+		if err := closer.Close(); err != nil {
+			utils.LogError(
+				"Failed to close file reader",
+				utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOClose, "failed to close file reader").WithFilePath(path),
+			)
+		}
+	}
+}
+
+// startMarkdownWriter handles markdown format output with streaming support.
+func startMarkdownWriter(outFile *os.File, writeCh <-chan WriteRequest, done chan<- struct{}, prefix, suffix string) {
+	defer close(done)
+
+	writer := NewMarkdownWriter(outFile)
+
+	// Start writing
+	if err := writer.Start(prefix, suffix); err != nil {
+		utils.LogError("Failed to write markdown prefix", err)
+		return
+	}
+
+	// Process files
+	for req := range writeCh {
+		if err := writer.WriteFile(req); err != nil {
+			utils.LogError("Failed to write markdown file", err)
+		}
+	}
+
+	// Close writer
+	if err := writer.Close(suffix); err != nil {
+		utils.LogError("Failed to write markdown suffix", err)
+	}
+}

fileproc/processor.go

@@ -2,35 +2,308 @@
 package fileproc
 
 import (
+	"context"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
+	"strings"
+	"time"
 
 	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+const (
+	// StreamChunkSize is the size of chunks when streaming large files (64KB).
+	StreamChunkSize = 65536
+	// StreamThreshold is the file size above which we use streaming (1MB).
+	StreamThreshold = 1048576
+	// MaxMemoryBuffer is the maximum memory to use for buffering content (10MB).
+	MaxMemoryBuffer = 10485760
 )
 
 // WriteRequest represents the content to be written.
 type WriteRequest struct {
-	Path    string
-	Content string
+	Path     string
+	Content  string
+	IsStream bool
+	Reader   io.Reader
+}
+
+// FileProcessor handles file processing operations.
+type FileProcessor struct {
+	rootPath        string
+	sizeLimit       int64
+	resourceMonitor *ResourceMonitor
+}
+
+// NewFileProcessor creates a new file processor.
+func NewFileProcessor(rootPath string) *FileProcessor {
+	return &FileProcessor{
+		rootPath:        rootPath,
+		sizeLimit:       config.GetFileSizeLimit(),
+		resourceMonitor: NewResourceMonitor(),
+	}
+}
+
+// NewFileProcessorWithMonitor creates a new file processor with a shared resource monitor.
+func NewFileProcessorWithMonitor(rootPath string, monitor *ResourceMonitor) *FileProcessor {
+	return &FileProcessor{
+		rootPath:        rootPath,
+		sizeLimit:       config.GetFileSizeLimit(),
+		resourceMonitor: monitor,
+	}
 }
 
 // ProcessFile reads the file at filePath and sends a formatted output to outCh.
+// It automatically chooses between loading the entire file or streaming based on file size.
 func ProcessFile(filePath string, outCh chan<- WriteRequest, rootPath string) {
-	content, err := os.ReadFile(filePath)
-	if err != nil {
-		logrus.Errorf("Failed to read file %s: %v", filePath, err)
+	processor := NewFileProcessor(rootPath)
+	ctx := context.Background()
+	processor.ProcessWithContext(ctx, filePath, outCh)
+}
+
+// ProcessFileWithMonitor processes a file using a shared resource monitor.
+func ProcessFileWithMonitor(ctx context.Context, filePath string, outCh chan<- WriteRequest, rootPath string, monitor *ResourceMonitor) {
+	processor := NewFileProcessorWithMonitor(rootPath, monitor)
+	processor.ProcessWithContext(ctx, filePath, outCh)
+}
+
+// Process handles file processing with the configured settings.
+func (p *FileProcessor) Process(filePath string, outCh chan<- WriteRequest) {
+	ctx := context.Background()
+	p.ProcessWithContext(ctx, filePath, outCh)
+}
+
+// ProcessWithContext handles file processing with context and resource monitoring.
+func (p *FileProcessor) ProcessWithContext(ctx context.Context, filePath string, outCh chan<- WriteRequest) {
+	// Create file processing context with timeout
+	fileCtx, fileCancel := p.resourceMonitor.CreateFileProcessingContext(ctx)
+	defer fileCancel()
+
+	// Wait for rate limiting
+	if err := p.resourceMonitor.WaitForRateLimit(fileCtx); err != nil {
+		if err == context.DeadlineExceeded {
+			utils.LogErrorf(
+				utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "file processing timeout during rate limiting", filePath, nil),
+				"File processing timeout during rate limiting: %s", filePath,
+			)
+		}
 		return
 	}
 
-	// Compute path relative to rootPath, so /a/b/c/d.c becomes c/d.c
-	relPath, err := filepath.Rel(rootPath, filePath)
+	// Validate file and check resource limits
+	fileInfo, err := p.validateFileWithLimits(fileCtx, filePath)
 	if err != nil {
-		// Fallback if something unexpected happens
-		relPath = filePath
+		return // Error already logged
 	}
 
-	// Format: separator, then relative path, then content
-	formatted := fmt.Sprintf("\n---\n%s\n%s\n", relPath, string(content))
-	outCh <- WriteRequest{Path: relPath, Content: formatted}
+	// Acquire read slot for concurrent processing
+	if err := p.resourceMonitor.AcquireReadSlot(fileCtx); err != nil {
+		if err == context.DeadlineExceeded {
+			utils.LogErrorf(
+				utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "file processing timeout waiting for read slot", filePath, nil),
+				"File processing timeout waiting for read slot: %s", filePath,
+			)
+		}
+		return
+	}
+	defer p.resourceMonitor.ReleaseReadSlot()
+
+	// Check hard memory limits before processing
+	if err := p.resourceMonitor.CheckHardMemoryLimit(); err != nil {
+		utils.LogErrorf(err, "Hard memory limit check failed for file: %s", filePath)
+		return
+	}
+
+	// Get relative path
+	relPath := p.getRelativePath(filePath)
+
+	// Process file with timeout
+	processStart := time.Now()
+	defer func() {
+		// Record successful processing
+		p.resourceMonitor.RecordFileProcessed(fileInfo.Size())
+		logrus.Debugf("File processed in %v: %s", time.Since(processStart), filePath)
+	}()
+
+	// Choose processing strategy based on file size
+	if fileInfo.Size() <= StreamThreshold {
+		p.processInMemoryWithContext(fileCtx, filePath, relPath, outCh)
+	} else {
+		p.processStreamingWithContext(fileCtx, filePath, relPath, outCh)
+	}
+}
+
+
+// validateFileWithLimits checks if the file can be processed with resource limits.
+func (p *FileProcessor) validateFileWithLimits(ctx context.Context, filePath string) (os.FileInfo, error) {
+	// Check context cancellation
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	default:
+	}
+
+	fileInfo, err := os.Stat(filePath)
+	if err != nil {
+		structErr := utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSAccess, "failed to stat file").WithFilePath(filePath)
+		utils.LogErrorf(structErr, "Failed to stat file %s", filePath)
+		return nil, err
+	}
+
+	// Check traditional size limit
+	if fileInfo.Size() > p.sizeLimit {
+		context := map[string]interface{}{
+			"file_size":  fileInfo.Size(),
+			"size_limit": p.sizeLimit,
+		}
+		utils.LogErrorf(
+			utils.NewStructuredError(
+				utils.ErrorTypeValidation,
+				utils.CodeValidationSize,
+				fmt.Sprintf("file size (%d bytes) exceeds limit (%d bytes)", fileInfo.Size(), p.sizeLimit),
+				filePath,
+				context,
+			),
+			"Skipping large file %s", filePath,
+		)
+		return nil, fmt.Errorf("file too large")
+	}
+
+	// Check resource limits
+	if err := p.resourceMonitor.ValidateFileProcessing(filePath, fileInfo.Size()); err != nil {
+		utils.LogErrorf(err, "Resource limit validation failed for file: %s", filePath)
+		return nil, err
+	}
+
+	return fileInfo, nil
+}
+
+// getRelativePath computes the path relative to rootPath.
+func (p *FileProcessor) getRelativePath(filePath string) string {
+	relPath, err := filepath.Rel(p.rootPath, filePath)
+	if err != nil {
+		return filePath // Fallback
+	}
+	return relPath
+}
+
+
+// processInMemoryWithContext loads the entire file into memory with context awareness.
+func (p *FileProcessor) processInMemoryWithContext(ctx context.Context, filePath, relPath string, outCh chan<- WriteRequest) {
+	// Check context before reading
+	select {
+	case <-ctx.Done():
+		utils.LogErrorf(
+			utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "file processing cancelled", filePath, nil),
+			"File processing cancelled: %s", filePath,
+		)
+		return
+	default:
+	}
+
+	content, err := os.ReadFile(filePath) // #nosec G304 - filePath is validated by walker
+	if err != nil {
+		structErr := utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingFileRead, "failed to read file").WithFilePath(filePath)
+		utils.LogErrorf(structErr, "Failed to read file %s", filePath)
+		return
+	}
+
+	// Check context again after reading
+	select {
+	case <-ctx.Done():
+		utils.LogErrorf(
+			utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "file processing cancelled after read", filePath, nil),
+			"File processing cancelled after read: %s", filePath,
+		)
+		return
+	default:
+	}
+
+	// Try to send the result, but respect context cancellation
+	select {
+	case <-ctx.Done():
+		utils.LogErrorf(
+			utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "file processing cancelled before output", filePath, nil),
+			"File processing cancelled before output: %s", filePath,
+		)
+		return
+	case outCh <- WriteRequest{
+		Path:     relPath,
+		Content:  p.formatContent(relPath, string(content)),
+		IsStream: false,
+	}:
+	}
+}
+
+
+// processStreamingWithContext creates a streaming reader for large files with context awareness.
+func (p *FileProcessor) processStreamingWithContext(ctx context.Context, filePath, relPath string, outCh chan<- WriteRequest) {
+	// Check context before creating reader
+	select {
+	case <-ctx.Done():
+		utils.LogErrorf(
+			utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "streaming processing cancelled", filePath, nil),
+			"Streaming processing cancelled: %s", filePath,
+		)
+		return
+	default:
+	}
+
+	reader := p.createStreamReaderWithContext(ctx, filePath, relPath)
+	if reader == nil {
+		return // Error already logged
+	}
+
+	// Try to send the result, but respect context cancellation
+	select {
+	case <-ctx.Done():
+		utils.LogErrorf(
+			utils.NewStructuredError(utils.ErrorTypeValidation, utils.CodeResourceLimitTimeout, "streaming processing cancelled before output", filePath, nil),
+			"Streaming processing cancelled before output: %s", filePath,
+		)
+		return
+	case outCh <- WriteRequest{
+		Path:     relPath,
+		Content:  "", // Empty since content is in Reader
+		IsStream: true,
+		Reader:   reader,
+	}:
+	}
+}
+
+
+// createStreamReaderWithContext creates a reader that combines header and file content with context awareness.
+func (p *FileProcessor) createStreamReaderWithContext(ctx context.Context, filePath, relPath string) io.Reader {
+	// Check context before opening file
+	select {
+	case <-ctx.Done():
+		return nil
+	default:
+	}
+
+	file, err := os.Open(filePath) // #nosec G304 - filePath is validated by walker
+	if err != nil {
+		structErr := utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingFileRead, "failed to open file for streaming").WithFilePath(filePath)
+		utils.LogErrorf(structErr, "Failed to open file for streaming %s", filePath)
+		return nil
+	}
+	// Note: file will be closed by the writer
+
+	header := p.formatHeader(relPath)
+	return io.MultiReader(header, file)
+}
+
+// formatContent formats the file content with header.
+func (p *FileProcessor) formatContent(relPath, content string) string {
+	return fmt.Sprintf("\n---\n%s\n%s\n", relPath, content)
+}
+
+// formatHeader creates a reader for the file header.
+func (p *FileProcessor) formatHeader(relPath string) io.Reader {
+	return strings.NewReader(fmt.Sprintf("\n---\n%s\n", relPath))
 }

fileproc/processor_test.go

@@ -1,15 +1,20 @@
-package fileproc
+package fileproc_test
 
 import (
 	"os"
 	"strings"
 	"sync"
 	"testing"
+
+	"github.com/ivuorinen/gibidify/fileproc"
+	"github.com/ivuorinen/gibidify/testutil"
 )
 
 func TestProcessFile(t *testing.T) {
+	// Reset and load default config to ensure proper file size limits
+	testutil.ResetViperConfig(t, "")
 	// Create a temporary file with known content.
-	tmpFile, err := os.CreateTemp("", "testfile")
+	tmpFile, err := os.CreateTemp(t.TempDir(), "testfile")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -30,12 +35,12 @@ func TestProcessFile(t *testing.T) {
 		return
 	}
 
-	ch := make(chan WriteRequest, 1)
+	ch := make(chan fileproc.WriteRequest, 1)
 	var wg sync.WaitGroup
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
-		ProcessFile(tmpFile.Name(), ch, "")
+		fileproc.ProcessFile(tmpFile.Name(), ch, "")
 	}()
 	wg.Wait()
 	close(ch)

fileproc/registry.go

@@ -0,0 +1,107 @@
+// Package fileproc provides file processing utilities.
+package fileproc
+
+import (
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+const minExtensionLength = 2
+
+var (
+	registry     *FileTypeRegistry
+	registryOnce sync.Once
+)
+
+// FileTypeRegistry manages file type detection and classification.
+type FileTypeRegistry struct {
+	imageExts   map[string]bool
+	binaryExts  map[string]bool
+	languageMap map[string]string
+
+	// Cache for frequent lookups to avoid repeated string operations
+	extCache     map[string]string         // filename -> normalized extension
+	resultCache  map[string]FileTypeResult // extension -> cached result
+	cacheMutex   sync.RWMutex
+	maxCacheSize int
+
+	// Performance statistics
+	stats RegistryStats
+}
+
+// RegistryStats tracks performance metrics for the registry.
+type RegistryStats struct {
+	TotalLookups   uint64
+	CacheHits      uint64
+	CacheMisses    uint64
+	CacheEvictions uint64
+}
+
+// FileTypeResult represents cached file type detection results.
+type FileTypeResult struct {
+	IsImage   bool
+	IsBinary  bool
+	Language  string
+	Extension string
+}
+
+// initRegistry initializes the default file type registry with common extensions.
+func initRegistry() *FileTypeRegistry {
+	return &FileTypeRegistry{
+		imageExts:    getImageExtensions(),
+		binaryExts:   getBinaryExtensions(),
+		languageMap:  getLanguageMap(),
+		extCache:     make(map[string]string, 1000),        // Cache for extension normalization
+		resultCache:  make(map[string]FileTypeResult, 500), // Cache for type results
+		maxCacheSize: 500,
+	}
+}
+
+// getRegistry returns the singleton file type registry, creating it if necessary.
+func getRegistry() *FileTypeRegistry {
+	registryOnce.Do(func() {
+		registry = initRegistry()
+	})
+	return registry
+}
+
+// GetDefaultRegistry returns the default file type registry.
+func GetDefaultRegistry() *FileTypeRegistry {
+	return getRegistry()
+}
+
+// GetStats returns a copy of the current registry statistics.
+func (r *FileTypeRegistry) GetStats() RegistryStats {
+	r.cacheMutex.RLock()
+	defer r.cacheMutex.RUnlock()
+	return r.stats
+}
+
+// GetCacheInfo returns current cache size information.
+func (r *FileTypeRegistry) GetCacheInfo() (extCacheSize, resultCacheSize, maxCacheSize int) {
+	r.cacheMutex.RLock()
+	defer r.cacheMutex.RUnlock()
+	return len(r.extCache), len(r.resultCache), r.maxCacheSize
+}
+
+// ResetRegistryForTesting resets the registry to its initial state.
+// This function should only be used in tests.
+func ResetRegistryForTesting() {
+	registryOnce = sync.Once{}
+	registry = nil
+}
+
+// normalizeExtension extracts and normalizes the file extension.
+func normalizeExtension(filename string) string {
+	return strings.ToLower(filepath.Ext(filename))
+}
+
+// isSpecialFile checks if the filename matches special cases like .DS_Store.
+func isSpecialFile(filename string, extensions map[string]bool) bool {
+	if filepath.Ext(filename) == "" {
+		basename := strings.ToLower(filepath.Base(filename))
+		return extensions[basename]
+	}
+	return false
+}

fileproc/resource_monitor_concurrency.go

@@ -0,0 +1,59 @@
+package fileproc
+
+import (
+	"context"
+	"sync/atomic"
+	"time"
+)
+
+// AcquireReadSlot attempts to acquire a slot for concurrent file reading.
+func (rm *ResourceMonitor) AcquireReadSlot(ctx context.Context) error {
+	if !rm.enabled {
+		return nil
+	}
+
+	// Wait for available read slot
+	for {
+		currentReads := atomic.LoadInt64(&rm.concurrentReads)
+		if currentReads < int64(rm.maxConcurrentReads) {
+			if atomic.CompareAndSwapInt64(&rm.concurrentReads, currentReads, currentReads+1) {
+				break
+			}
+			// CAS failed, retry
+			continue
+		}
+
+		// Wait and retry
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-time.After(time.Millisecond):
+			// Continue loop
+		}
+	}
+
+	return nil
+}
+
+// ReleaseReadSlot releases a concurrent reading slot.
+func (rm *ResourceMonitor) ReleaseReadSlot() {
+	if rm.enabled {
+		atomic.AddInt64(&rm.concurrentReads, -1)
+	}
+}
+
+// CreateFileProcessingContext creates a context with file processing timeout.
+func (rm *ResourceMonitor) CreateFileProcessingContext(parent context.Context) (context.Context, context.CancelFunc) {
+	if !rm.enabled || rm.fileProcessingTimeout <= 0 {
+		return parent, func() {}
+	}
+	return context.WithTimeout(parent, rm.fileProcessingTimeout)
+}
+
+// CreateOverallProcessingContext creates a context with overall processing timeout.
+func (rm *ResourceMonitor) CreateOverallProcessingContext(parent context.Context) (context.Context, context.CancelFunc) {
+	if !rm.enabled || rm.overallTimeout <= 0 {
+		return parent, func() {}
+	}
+	return context.WithTimeout(parent, rm.overallTimeout)
+}

fileproc/resource_monitor_concurrency_test.go

@@ -0,0 +1,95 @@
+package fileproc
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+func TestResourceMonitor_ConcurrentReadsLimit(t *testing.T) {
+	testutil.ResetViperConfig(t, "")
+
+	// Set a low concurrent reads limit for testing
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.maxConcurrentReads", 2)
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel()
+
+	// First read slot should succeed
+	err := rm.AcquireReadSlot(ctx)
+	if err != nil {
+		t.Errorf("Expected no error for first read slot, got %v", err)
+	}
+
+	// Second read slot should succeed
+	err = rm.AcquireReadSlot(ctx)
+	if err != nil {
+		t.Errorf("Expected no error for second read slot, got %v", err)
+	}
+
+	// Third read slot should timeout (context deadline exceeded)
+	err = rm.AcquireReadSlot(ctx)
+	if err == nil {
+		t.Error("Expected timeout error for third read slot, got nil")
+	}
+
+	// Release one slot and try again
+	rm.ReleaseReadSlot()
+	
+	// Create new context for the next attempt
+	ctx2, cancel2 := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	defer cancel2()
+	
+	err = rm.AcquireReadSlot(ctx2)
+	if err != nil {
+		t.Errorf("Expected no error after releasing a slot, got %v", err)
+	}
+
+	// Clean up remaining slots
+	rm.ReleaseReadSlot()
+	rm.ReleaseReadSlot()
+}
+
+func TestResourceMonitor_TimeoutContexts(t *testing.T) {
+	testutil.ResetViperConfig(t, "")
+
+	// Set short timeouts for testing
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.fileProcessingTimeoutSec", 1) // 1 second
+	viper.Set("resourceLimits.overallTimeoutSec", 2)        // 2 seconds
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	parentCtx := context.Background()
+
+	// Test file processing context
+	fileCtx, fileCancel := rm.CreateFileProcessingContext(parentCtx)
+	defer fileCancel()
+
+	deadline, ok := fileCtx.Deadline()
+	if !ok {
+		t.Error("Expected file processing context to have a deadline")
+	} else if time.Until(deadline) > time.Second+100*time.Millisecond {
+		t.Error("File processing timeout appears to be too long")
+	}
+
+	// Test overall processing context
+	overallCtx, overallCancel := rm.CreateOverallProcessingContext(parentCtx)
+	defer overallCancel()
+
+	deadline, ok = overallCtx.Deadline()
+	if !ok {
+		t.Error("Expected overall processing context to have a deadline")
+	} else if time.Until(deadline) > 2*time.Second+100*time.Millisecond {
+		t.Error("Overall processing timeout appears to be too long")
+	}
+}

fileproc/resource_monitor_integration_test.go

@@ -0,0 +1,81 @@
+package fileproc
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+func TestResourceMonitor_Integration(t *testing.T) {
+	// Create temporary test directory
+	tempDir := t.TempDir()
+
+	// Create test files
+	testFiles := []string{"test1.txt", "test2.txt", "test3.txt"}
+	for _, filename := range testFiles {
+		testutil.CreateTestFile(t, tempDir, filename, []byte("test content"))
+	}
+
+	testutil.ResetViperConfig(t, "")
+
+	// Configure resource limits
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.maxFiles", 5)
+	viper.Set("resourceLimits.maxTotalSize", 1024*1024) // 1MB
+	viper.Set("resourceLimits.fileProcessingTimeoutSec", 10)
+	viper.Set("resourceLimits.maxConcurrentReads", 3)
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	ctx := context.Background()
+
+	// Test file processing workflow
+	for _, filename := range testFiles {
+		filePath := filepath.Join(tempDir, filename)
+		fileInfo, err := os.Stat(filePath)
+		if err != nil {
+			t.Fatalf("Failed to stat test file %s: %v", filePath, err)
+		}
+
+		// Validate file can be processed
+		err = rm.ValidateFileProcessing(filePath, fileInfo.Size())
+		if err != nil {
+			t.Errorf("Failed to validate file %s: %v", filePath, err)
+			continue
+		}
+
+		// Acquire read slot
+		err = rm.AcquireReadSlot(ctx)
+		if err != nil {
+			t.Errorf("Failed to acquire read slot for %s: %v", filePath, err)
+			continue
+		}
+
+		// Check memory limits
+		err = rm.CheckHardMemoryLimit()
+		if err != nil {
+			t.Errorf("Memory limit check failed for %s: %v", filePath, err)
+		}
+
+		// Record processing
+		rm.RecordFileProcessed(fileInfo.Size())
+
+		// Release read slot
+		rm.ReleaseReadSlot()
+	}
+
+	// Verify final metrics
+	metrics := rm.GetMetrics()
+	if metrics.FilesProcessed != int64(len(testFiles)) {
+		t.Errorf("Expected %d files processed, got %d", len(testFiles), metrics.FilesProcessed)
+	}
+
+	// Test resource limit logging
+	rm.LogResourceInfo()
+}

fileproc/resource_monitor_metrics.go

@@ -0,0 +1,79 @@
+package fileproc
+
+import (
+	"runtime"
+	"sync/atomic"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+// RecordFileProcessed records that a file has been successfully processed.
+func (rm *ResourceMonitor) RecordFileProcessed(fileSize int64) {
+	if rm.enabled {
+		atomic.AddInt64(&rm.filesProcessed, 1)
+		atomic.AddInt64(&rm.totalSizeProcessed, fileSize)
+	}
+}
+
+// GetMetrics returns current resource usage metrics.
+func (rm *ResourceMonitor) GetMetrics() ResourceMetrics {
+	if !rm.enableResourceMon {
+		return ResourceMetrics{}
+	}
+
+	rm.mu.RLock()
+	defer rm.mu.RUnlock()
+
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	filesProcessed := atomic.LoadInt64(&rm.filesProcessed)
+	totalSize := atomic.LoadInt64(&rm.totalSizeProcessed)
+	duration := time.Since(rm.startTime)
+
+	avgFileSize := float64(0)
+	if filesProcessed > 0 {
+		avgFileSize = float64(totalSize) / float64(filesProcessed)
+	}
+
+	processingRate := float64(0)
+	if duration.Seconds() > 0 {
+		processingRate = float64(filesProcessed) / duration.Seconds()
+	}
+
+	// Collect violations
+	violations := make([]string, 0, len(rm.violationLogged))
+	for violation := range rm.violationLogged {
+		violations = append(violations, violation)
+	}
+
+	return ResourceMetrics{
+		FilesProcessed:      filesProcessed,
+		TotalSizeProcessed:  totalSize,
+		ConcurrentReads:     atomic.LoadInt64(&rm.concurrentReads),
+		ProcessingDuration:  duration,
+		AverageFileSize:     avgFileSize,
+		ProcessingRate:      processingRate,
+		MemoryUsageMB:       int64(m.Alloc) / 1024 / 1024,
+		MaxMemoryUsageMB:    int64(rm.hardMemoryLimitMB),
+		ViolationsDetected:  violations,
+		DegradationActive:   rm.degradationActive,
+		EmergencyStopActive: rm.emergencyStopRequested,
+		LastUpdated:         time.Now(),
+	}
+}
+
+// LogResourceInfo logs current resource limit configuration.
+func (rm *ResourceMonitor) LogResourceInfo() {
+	if rm.enabled {
+		logrus.Infof("Resource limits enabled: maxFiles=%d, maxTotalSize=%dMB, fileTimeout=%ds, overallTimeout=%ds",
+			rm.maxFiles, rm.maxTotalSize/1024/1024, int(rm.fileProcessingTimeout.Seconds()), int(rm.overallTimeout.Seconds()))
+		logrus.Infof("Resource limits: maxConcurrentReads=%d, rateLimitFPS=%d, hardMemoryMB=%d",
+			rm.maxConcurrentReads, rm.rateLimitFilesPerSec, rm.hardMemoryLimitMB)
+		logrus.Infof("Resource features: gracefulDegradation=%v, monitoring=%v",
+			rm.enableGracefulDegr, rm.enableResourceMon)
+	} else {
+		logrus.Info("Resource limits disabled")
+	}
+}

fileproc/resource_monitor_metrics_test.go

@@ -0,0 +1,49 @@
+package fileproc
+
+import (
+	"testing"
+	"time"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+func TestResourceMonitor_Metrics(t *testing.T) {
+	testutil.ResetViperConfig(t, "")
+
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.enableResourceMonitoring", true)
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	// Process some files to generate metrics
+	rm.RecordFileProcessed(1000)
+	rm.RecordFileProcessed(2000)
+	rm.RecordFileProcessed(500)
+
+	metrics := rm.GetMetrics()
+
+	// Verify metrics
+	if metrics.FilesProcessed != 3 {
+		t.Errorf("Expected 3 files processed, got %d", metrics.FilesProcessed)
+	}
+
+	if metrics.TotalSizeProcessed != 3500 {
+		t.Errorf("Expected total size 3500, got %d", metrics.TotalSizeProcessed)
+	}
+
+	expectedAvgSize := float64(3500) / float64(3)
+	if metrics.AverageFileSize != expectedAvgSize {
+		t.Errorf("Expected average file size %.2f, got %.2f", expectedAvgSize, metrics.AverageFileSize)
+	}
+
+	if metrics.ProcessingRate <= 0 {
+		t.Error("Expected positive processing rate")
+	}
+
+	if !metrics.LastUpdated.After(time.Now().Add(-time.Second)) {
+		t.Error("Expected recent LastUpdated timestamp")
+	}
+}

fileproc/resource_monitor_rate_limiting.go

@@ -0,0 +1,36 @@
+package fileproc
+
+import (
+	"context"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+// WaitForRateLimit waits for rate limiting if enabled.
+func (rm *ResourceMonitor) WaitForRateLimit(ctx context.Context) error {
+	if !rm.enabled || rm.rateLimitFilesPerSec <= 0 {
+		return nil
+	}
+
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-rm.rateLimitChan:
+		return nil
+	case <-time.After(time.Second): // Fallback timeout
+		logrus.Warn("Rate limiting timeout exceeded, continuing without rate limit")
+		return nil
+	}
+}
+
+// rateLimiterRefill refills the rate limiting channel periodically.
+func (rm *ResourceMonitor) rateLimiterRefill() {
+	for range rm.rateLimiter.C {
+		select {
+		case rm.rateLimitChan <- struct{}{}:
+		default:
+			// Channel is full, skip
+		}
+	}
+}

fileproc/resource_monitor_rate_limiting_test.go

@@ -0,0 +1,40 @@
+package fileproc
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+func TestResourceMonitor_RateLimiting(t *testing.T) {
+	testutil.ResetViperConfig(t, "")
+
+	// Enable rate limiting with a low rate for testing
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.rateLimitFilesPerSec", 5) // 5 files per second
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	defer cancel()
+
+	// First few requests should succeed quickly
+	start := time.Now()
+	for i := 0; i < 3; i++ {
+		err := rm.WaitForRateLimit(ctx)
+		if err != nil {
+			t.Errorf("Expected no error for rate limit wait %d, got %v", i, err)
+		}
+	}
+
+	// Should have taken some time due to rate limiting
+	duration := time.Since(start)
+	if duration < 200*time.Millisecond {
+		t.Logf("Rate limiting may not be working as expected, took only %v", duration)
+	}
+}

fileproc/resource_monitor_state.go

@@ -0,0 +1,22 @@
+package fileproc
+
+// IsEmergencyStopActive returns whether emergency stop is active.
+func (rm *ResourceMonitor) IsEmergencyStopActive() bool {
+	rm.mu.RLock()
+	defer rm.mu.RUnlock()
+	return rm.emergencyStopRequested
+}
+
+// IsDegradationActive returns whether degradation mode is active.
+func (rm *ResourceMonitor) IsDegradationActive() bool {
+	rm.mu.RLock()
+	defer rm.mu.RUnlock()
+	return rm.degradationActive
+}
+
+// Close cleans up the resource monitor.
+func (rm *ResourceMonitor) Close() {
+	if rm.rateLimiter != nil {
+		rm.rateLimiter.Stop()
+	}
+}

fileproc/resource_monitor_types.go

@@ -0,0 +1,108 @@
+package fileproc
+
+import (
+	"sync"
+	"time"
+
+	"github.com/ivuorinen/gibidify/config"
+)
+
+// ResourceMonitor monitors resource usage and enforces limits to prevent DoS attacks.
+type ResourceMonitor struct {
+	enabled               bool
+	maxFiles              int
+	maxTotalSize          int64
+	fileProcessingTimeout time.Duration
+	overallTimeout        time.Duration
+	maxConcurrentReads    int
+	rateLimitFilesPerSec  int
+	hardMemoryLimitMB     int
+	enableGracefulDegr    bool
+	enableResourceMon     bool
+
+	// Current state tracking
+	filesProcessed       int64
+	totalSizeProcessed   int64
+	concurrentReads      int64
+	startTime            time.Time
+	lastRateLimitCheck   time.Time
+	hardMemoryLimitBytes int64
+
+	// Rate limiting
+	rateLimiter   *time.Ticker
+	rateLimitChan chan struct{}
+
+	// Synchronization
+	mu                     sync.RWMutex
+	violationLogged        map[string]bool
+	degradationActive      bool
+	emergencyStopRequested bool
+}
+
+// ResourceMetrics holds comprehensive resource usage metrics.
+type ResourceMetrics struct {
+	FilesProcessed      int64         `json:"files_processed"`
+	TotalSizeProcessed  int64         `json:"total_size_processed"`
+	ConcurrentReads     int64         `json:"concurrent_reads"`
+	ProcessingDuration  time.Duration `json:"processing_duration"`
+	AverageFileSize     float64       `json:"average_file_size"`
+	ProcessingRate      float64       `json:"processing_rate_files_per_sec"`
+	MemoryUsageMB       int64         `json:"memory_usage_mb"`
+	MaxMemoryUsageMB    int64         `json:"max_memory_usage_mb"`
+	ViolationsDetected  []string      `json:"violations_detected"`
+	DegradationActive   bool          `json:"degradation_active"`
+	EmergencyStopActive bool          `json:"emergency_stop_active"`
+	LastUpdated         time.Time     `json:"last_updated"`
+}
+
+// ResourceViolation represents a detected resource limit violation.
+type ResourceViolation struct {
+	Type      string                 `json:"type"`
+	Message   string                 `json:"message"`
+	Current   interface{}            `json:"current"`
+	Limit     interface{}            `json:"limit"`
+	Timestamp time.Time              `json:"timestamp"`
+	Context   map[string]interface{} `json:"context"`
+}
+
+// NewResourceMonitor creates a new resource monitor with configuration.
+func NewResourceMonitor() *ResourceMonitor {
+	rm := &ResourceMonitor{
+		enabled:               config.GetResourceLimitsEnabled(),
+		maxFiles:              config.GetMaxFiles(),
+		maxTotalSize:          config.GetMaxTotalSize(),
+		fileProcessingTimeout: time.Duration(config.GetFileProcessingTimeoutSec()) * time.Second,
+		overallTimeout:        time.Duration(config.GetOverallTimeoutSec()) * time.Second,
+		maxConcurrentReads:    config.GetMaxConcurrentReads(),
+		rateLimitFilesPerSec:  config.GetRateLimitFilesPerSec(),
+		hardMemoryLimitMB:     config.GetHardMemoryLimitMB(),
+		enableGracefulDegr:    config.GetEnableGracefulDegradation(),
+		enableResourceMon:     config.GetEnableResourceMonitoring(),
+		startTime:             time.Now(),
+		lastRateLimitCheck:    time.Now(),
+		violationLogged:       make(map[string]bool),
+		hardMemoryLimitBytes:  int64(config.GetHardMemoryLimitMB()) * 1024 * 1024,
+	}
+
+	// Initialize rate limiter if rate limiting is enabled
+	if rm.enabled && rm.rateLimitFilesPerSec > 0 {
+		interval := time.Second / time.Duration(rm.rateLimitFilesPerSec)
+		rm.rateLimiter = time.NewTicker(interval)
+		rm.rateLimitChan = make(chan struct{}, rm.rateLimitFilesPerSec)
+
+		// Pre-fill the rate limit channel
+		for i := 0; i < rm.rateLimitFilesPerSec; i++ {
+			select {
+			case rm.rateLimitChan <- struct{}{}:
+			default:
+				goto rateLimitFull
+			}
+		}
+	rateLimitFull:
+
+		// Start rate limiter refill goroutine  
+		go rm.rateLimiterRefill()
+	}
+
+	return rm
+}

fileproc/resource_monitor_types_test.go

@@ -0,0 +1,74 @@
+package fileproc
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/config"
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+func TestResourceMonitor_NewResourceMonitor(t *testing.T) {
+	// Reset viper for clean test state
+	testutil.ResetViperConfig(t, "")
+
+	rm := NewResourceMonitor()
+	if rm == nil {
+		t.Fatal("NewResourceMonitor() returned nil")
+	}
+
+	// Test default values are set correctly
+	if !rm.enabled {
+		t.Error("Expected resource monitor to be enabled by default")
+	}
+
+	if rm.maxFiles != config.DefaultMaxFiles {
+		t.Errorf("Expected maxFiles to be %d, got %d", config.DefaultMaxFiles, rm.maxFiles)
+	}
+
+	if rm.maxTotalSize != config.DefaultMaxTotalSize {
+		t.Errorf("Expected maxTotalSize to be %d, got %d", config.DefaultMaxTotalSize, rm.maxTotalSize)
+	}
+
+	if rm.fileProcessingTimeout != time.Duration(config.DefaultFileProcessingTimeoutSec)*time.Second {
+		t.Errorf("Expected fileProcessingTimeout to be %v, got %v", 
+			time.Duration(config.DefaultFileProcessingTimeoutSec)*time.Second, rm.fileProcessingTimeout)
+	}
+
+	// Clean up
+	rm.Close()
+}
+
+func TestResourceMonitor_DisabledResourceLimits(t *testing.T) {
+	// Reset viper for clean test state
+	testutil.ResetViperConfig(t, "")
+
+	// Set resource limits disabled
+	viper.Set("resourceLimits.enabled", false)
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	// Test that validation passes when disabled
+	err := rm.ValidateFileProcessing("/tmp/test.txt", 1000)
+	if err != nil {
+		t.Errorf("Expected no error when resource limits disabled, got %v", err)
+	}
+
+	// Test that read slot acquisition works when disabled
+	ctx := context.Background()
+	err = rm.AcquireReadSlot(ctx)
+	if err != nil {
+		t.Errorf("Expected no error when acquiring read slot with disabled limits, got %v", err)
+	}
+	rm.ReleaseReadSlot()
+
+	// Test that rate limiting is bypassed when disabled
+	err = rm.WaitForRateLimit(ctx)
+	if err != nil {
+		t.Errorf("Expected no error when rate limiting disabled, got %v", err)
+	}
+}

fileproc/resource_monitor_validation.go

@@ -0,0 +1,148 @@
+package fileproc
+
+import (
+	"runtime"
+	"sync/atomic"
+	"time"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// ValidateFileProcessing checks if a file can be processed based on resource limits.
+func (rm *ResourceMonitor) ValidateFileProcessing(filePath string, fileSize int64) error {
+	if !rm.enabled {
+		return nil
+	}
+
+	rm.mu.RLock()
+	defer rm.mu.RUnlock()
+
+	// Check if emergency stop is active
+	if rm.emergencyStopRequested {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeResourceLimitMemory,
+			"processing stopped due to emergency memory condition",
+			filePath,
+			map[string]interface{}{
+				"emergency_stop_active": true,
+			},
+		)
+	}
+
+	// Check file count limit
+	currentFiles := atomic.LoadInt64(&rm.filesProcessed)
+	if int(currentFiles) >= rm.maxFiles {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeResourceLimitFiles,
+			"maximum file count limit exceeded",
+			filePath,
+			map[string]interface{}{
+				"current_files": currentFiles,
+				"max_files":     rm.maxFiles,
+			},
+		)
+	}
+
+	// Check total size limit
+	currentTotalSize := atomic.LoadInt64(&rm.totalSizeProcessed)
+	if currentTotalSize+fileSize > rm.maxTotalSize {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeResourceLimitTotalSize,
+			"maximum total size limit would be exceeded",
+			filePath,
+			map[string]interface{}{
+				"current_total_size": currentTotalSize,
+				"file_size":          fileSize,
+				"max_total_size":     rm.maxTotalSize,
+			},
+		)
+	}
+
+	// Check overall timeout
+	if time.Since(rm.startTime) > rm.overallTimeout {
+		return utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeResourceLimitTimeout,
+			"overall processing timeout exceeded",
+			filePath,
+			map[string]interface{}{
+				"processing_duration": time.Since(rm.startTime),
+				"overall_timeout":     rm.overallTimeout,
+			},
+		)
+	}
+
+	return nil
+}
+
+// CheckHardMemoryLimit checks if hard memory limit is exceeded and takes action.
+func (rm *ResourceMonitor) CheckHardMemoryLimit() error {
+	if !rm.enabled || rm.hardMemoryLimitMB <= 0 {
+		return nil
+	}
+
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+	currentMemory := int64(m.Alloc)
+
+	if currentMemory > rm.hardMemoryLimitBytes {
+		rm.mu.Lock()
+		defer rm.mu.Unlock()
+
+		// Log violation if not already logged
+		violationKey := "hard_memory_limit"
+		if !rm.violationLogged[violationKey] {
+			logrus.Errorf("Hard memory limit exceeded: %dMB > %dMB",
+				currentMemory/1024/1024, rm.hardMemoryLimitMB)
+			rm.violationLogged[violationKey] = true
+		}
+
+		if rm.enableGracefulDegr {
+			// Force garbage collection
+			runtime.GC()
+
+			// Check again after GC
+			runtime.ReadMemStats(&m)
+			currentMemory = int64(m.Alloc)
+
+			if currentMemory > rm.hardMemoryLimitBytes {
+				// Still over limit, activate emergency stop
+				rm.emergencyStopRequested = true
+				return utils.NewStructuredError(
+					utils.ErrorTypeValidation,
+					utils.CodeResourceLimitMemory,
+					"hard memory limit exceeded, emergency stop activated",
+					"",
+					map[string]interface{}{
+						"current_memory_mb": currentMemory / 1024 / 1024,
+						"limit_mb":          rm.hardMemoryLimitMB,
+						"emergency_stop":    true,
+					},
+				)
+			} else {
+				// Memory freed by GC, continue with degradation
+				rm.degradationActive = true
+				logrus.Info("Memory freed by garbage collection, continuing with degradation mode")
+			}
+		} else {
+			// No graceful degradation, hard stop
+			return utils.NewStructuredError(
+				utils.ErrorTypeValidation,
+				utils.CodeResourceLimitMemory,
+				"hard memory limit exceeded",
+				"",
+				map[string]interface{}{
+					"current_memory_mb": currentMemory / 1024 / 1024,
+					"limit_mb":          rm.hardMemoryLimitMB,
+				},
+			)
+		}
+	}
+
+	return nil
+}

fileproc/resource_monitor_validation_test.go

@@ -0,0 +1,88 @@
+package fileproc
+
+import (
+	"testing"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/testutil"
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+func TestResourceMonitor_FileCountLimit(t *testing.T) {
+	testutil.ResetViperConfig(t, "")
+
+	// Set a very low file count limit for testing
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.maxFiles", 2)
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	// First file should pass
+	err := rm.ValidateFileProcessing("/tmp/file1.txt", 100)
+	if err != nil {
+		t.Errorf("Expected no error for first file, got %v", err)
+	}
+	rm.RecordFileProcessed(100)
+
+	// Second file should pass
+	err = rm.ValidateFileProcessing("/tmp/file2.txt", 100)
+	if err != nil {
+		t.Errorf("Expected no error for second file, got %v", err)
+	}
+	rm.RecordFileProcessed(100)
+
+	// Third file should fail
+	err = rm.ValidateFileProcessing("/tmp/file3.txt", 100)
+	if err == nil {
+		t.Error("Expected error for third file (exceeds limit), got nil")
+	}
+
+	// Verify it's the correct error type
+	structErr, ok := err.(*utils.StructuredError)
+	if !ok {
+		t.Errorf("Expected StructuredError, got %T", err)
+	} else if structErr.Code != utils.CodeResourceLimitFiles {
+		t.Errorf("Expected error code %s, got %s", utils.CodeResourceLimitFiles, structErr.Code)
+	}
+}
+
+func TestResourceMonitor_TotalSizeLimit(t *testing.T) {
+	testutil.ResetViperConfig(t, "")
+
+	// Set a low total size limit for testing (1KB)
+	viper.Set("resourceLimits.enabled", true)
+	viper.Set("resourceLimits.maxTotalSize", 1024)
+
+	rm := NewResourceMonitor()
+	defer rm.Close()
+
+	// First small file should pass
+	err := rm.ValidateFileProcessing("/tmp/small.txt", 500)
+	if err != nil {
+		t.Errorf("Expected no error for small file, got %v", err)
+	}
+	rm.RecordFileProcessed(500)
+
+	// Second small file should pass
+	err = rm.ValidateFileProcessing("/tmp/small2.txt", 400)
+	if err != nil {
+		t.Errorf("Expected no error for second small file, got %v", err)
+	}
+	rm.RecordFileProcessed(400)
+
+	// Large file that would exceed limit should fail
+	err = rm.ValidateFileProcessing("/tmp/large.txt", 200)
+	if err == nil {
+		t.Error("Expected error for file that would exceed size limit, got nil")
+	}
+
+	// Verify it's the correct error type
+	structErr, ok := err.(*utils.StructuredError)
+	if !ok {
+		t.Errorf("Expected StructuredError, got %T", err)
+	} else if structErr.Code != utils.CodeResourceLimitTotalSize {
+		t.Errorf("Expected error code %s, got %s", utils.CodeResourceLimitTotalSize, structErr.Code)
+	}
+}

fileproc/walker.go

@@ -4,10 +4,8 @@ package fileproc
 import (
 	"os"
 	"path/filepath"
-	"strings"
 
-	"github.com/ivuorinen/gibidify/config"
-	ignore "github.com/sabhiram/go-gitignore"
+	"github.com/ivuorinen/gibidify/utils"
 )
 
 // Walker defines an interface for scanning directories.
@@ -18,22 +16,25 @@ type Walker interface {
 // ProdWalker implements Walker using a custom directory walker that
 // respects .gitignore and .ignore files, configuration-defined ignore directories,
 // and ignores binary and image files by default.
-type ProdWalker struct{}
+type ProdWalker struct {
+	filter *FileFilter
+}
 
-// ignoreRule holds an ignore matcher along with the base directory where it was loaded.
-type ignoreRule struct {
-	base string
-	gi   *ignore.GitIgnore
+// NewProdWalker creates a new production walker with current configuration.
+func NewProdWalker() *ProdWalker {
+	return &ProdWalker{
+		filter: NewFileFilter(),
+	}
 }
 
 // Walk scans the given root directory recursively and returns a slice of file paths
 // that are not ignored based on .gitignore/.ignore files, the configuration, or the default binary/image filter.
-func (pw ProdWalker) Walk(root string) ([]string, error) {
-	absRoot, err := filepath.Abs(root)
+func (w *ProdWalker) Walk(root string) ([]string, error) {
+	absRoot, err := utils.GetAbsolutePath(root)
 	if err != nil {
-		return nil, err
+		return nil, utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSPathResolution, "failed to resolve root path").WithFilePath(root)
 	}
-	return walkDir(absRoot, absRoot, []ignoreRule{})
+	return w.walkDir(absRoot, []ignoreRule{})
 }
 
 // walkDir recursively walks the directory tree starting at currentDir.
@@ -41,122 +42,34 @@ func (pw ProdWalker) Walk(root string) ([]string, error) {
 // appends the corresponding rules to the inherited list. Each file/directory is
 // then checked against the accumulated ignore rules, the configuration's list of ignored directories,
 // and a default filter that ignores binary and image files.
-func walkDir(root string, currentDir string, parentRules []ignoreRule) ([]string, error) {
+func (w *ProdWalker) walkDir(currentDir string, parentRules []ignoreRule) ([]string, error) {
 	var results []string
 
 	entries, err := os.ReadDir(currentDir)
 	if err != nil {
-		return nil, err
+		return nil, utils.WrapError(err, utils.ErrorTypeFileSystem, utils.CodeFSAccess, "failed to read directory").WithFilePath(currentDir)
 	}
 
-	// Start with the parent's ignore rules.
-	rules := make([]ignoreRule, len(parentRules))
-	copy(rules, parentRules)
-
-	// Check for .gitignore and .ignore files in the current directory.
-	for _, fileName := range []string{".gitignore", ".ignore"} {
-		ignorePath := filepath.Join(currentDir, fileName)
-		if info, err := os.Stat(ignorePath); err == nil && !info.IsDir() {
-			gi, err := ignore.CompileIgnoreFile(ignorePath)
-			if err == nil {
-				rules = append(rules, ignoreRule{
-					base: currentDir,
-					gi:   gi,
-				})
-			}
-		}
-	}
-
-	// Get the list of directories to ignore from configuration.
-	ignoredDirs := config.GetIgnoredDirectories()
-	sizeLimit := config.GetFileSizeLimit() // e.g., 5242880 for 5 MB
+	rules := loadIgnoreRules(currentDir, parentRules)
 
 	for _, entry := range entries {
 		fullPath := filepath.Join(currentDir, entry.Name())
 
-		// For directories, check if its name is in the config ignore list.
-		if entry.IsDir() {
-			for _, d := range ignoredDirs {
-				if entry.Name() == d {
-					// Skip this directory entirely.
-					goto SkipEntry
-				}
-			}
-		} else {
-			// Check if file exceeds the configured size limit.
-			info, err := entry.Info()
-			if err == nil && info.Size() > sizeLimit {
-				goto SkipEntry
-			}
-
-			// For files, apply the default filter to ignore binary and image files.
-			if isBinaryOrImage(fullPath) {
-				goto SkipEntry
-			}
+		if w.filter.shouldSkipEntry(entry, fullPath, rules) {
+			continue
 		}
 
-		// Check accumulated ignore rules.
-		for _, rule := range rules {
-			// Compute the path relative to the base where the ignore rule was defined.
-			rel, err := filepath.Rel(rule.base, fullPath)
-			if err != nil {
-				continue
-			}
-			// If the rule matches, skip this entry.
-			if rule.gi.MatchesPath(rel) {
-				goto SkipEntry
-			}
-		}
-
-		// If not ignored, then process the entry.
+		// Process entry
 		if entry.IsDir() {
-			subFiles, err := walkDir(root, fullPath, rules)
+			subFiles, err := w.walkDir(fullPath, rules)
 			if err != nil {
-				return nil, err
+				return nil, utils.WrapError(err, utils.ErrorTypeProcessing, utils.CodeProcessingTraversal, "failed to traverse subdirectory").WithFilePath(fullPath)
 			}
 			results = append(results, subFiles...)
 		} else {
 			results = append(results, fullPath)
 		}
-	SkipEntry:
-		continue
 	}
 
 	return results, nil
 }
-
-// isBinaryOrImage checks if a file should be considered binary or an image based on its extension.
-// The check is case-insensitive.
-func isBinaryOrImage(filePath string) bool {
-	ext := strings.ToLower(filepath.Ext(filePath))
-	// Common image file extensions.
-	imageExtensions := map[string]bool{
-		".png":  true,
-		".jpg":  true,
-		".jpeg": true,
-		".gif":  true,
-		".bmp":  true,
-		".tiff": true,
-		".ico":  true,
-		".svg":  true,
-		".webp": true,
-	}
-	// Common binary file extensions.
-	binaryExtensions := map[string]bool{
-		".exe":      true,
-		".dll":      true,
-		".so":       true,
-		".bin":      true,
-		".dat":      true,
-		".zip":      true,
-		".tar":      true,
-		".gz":       true,
-		".7z":       true,
-		".rar":      true,
-		".DS_Store": true,
-	}
-	if imageExtensions[ext] || binaryExtensions[ext] {
-		return true
-	}
-	return false
-}

fileproc/walker_test.go

@@ -0,0 +1,103 @@
+package fileproc_test
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/fileproc"
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+func TestProdWalkerWithIgnore(t *testing.T) {
+	// Create a temporary directory structure.
+	rootDir := t.TempDir()
+
+	subDir := testutil.CreateTestDirectory(t, rootDir, "vendor")
+
+	// Write sample files
+	testutil.CreateTestFiles(t, rootDir, []testutil.FileSpec{
+		{Name: "file1.go", Content: "content"},
+		{Name: "file2.txt", Content: "content"},
+	})
+	testutil.CreateTestFile(t, subDir, "file_in_vendor.txt", []byte("content")) // should be ignored
+
+	// .gitignore that ignores *.txt and itself
+	gitignoreContent := `*.txt
+.gitignore
+`
+	testutil.CreateTestFile(t, rootDir, ".gitignore", []byte(gitignoreContent))
+
+	// Initialize config to ignore "vendor" directory
+	testutil.ResetViperConfig(t, "")
+	viper.Set("ignoreDirectories", []string{"vendor"})
+
+	// Run walker
+	w := fileproc.NewProdWalker()
+	found, err := w.Walk(rootDir)
+	testutil.MustSucceed(t, err, "walking directory")
+
+	// We expect only file1.go to appear
+	if len(found) != 1 {
+		t.Errorf("Expected 1 file to pass filters, got %d: %v", len(found), found)
+	}
+	if len(found) == 1 && filepath.Base(found[0]) != "file1.go" {
+		t.Errorf("Expected file1.go, got %s", found[0])
+	}
+}
+
+func TestProdWalkerBinaryCheck(t *testing.T) {
+	rootDir := t.TempDir()
+
+	// Create test files
+	testutil.CreateTestFiles(t, rootDir, []testutil.FileSpec{
+		{Name: "somefile.exe", Content: "fake-binary-content"},
+		{Name: "keep.go", Content: "package main"},
+	})
+
+	// Reset and load default config
+	testutil.ResetViperConfig(t, "")
+
+	// Reset FileTypeRegistry to ensure clean state
+	fileproc.ResetRegistryForTesting()
+
+	// Run walker
+	w := fileproc.NewProdWalker()
+	found, err := w.Walk(rootDir)
+	testutil.MustSucceed(t, err, "walking directory")
+
+	// Only "keep.go" should be returned
+	if len(found) != 1 {
+		t.Errorf("Expected 1 file, got %d: %v", len(found), found)
+	}
+	if len(found) == 1 && filepath.Base(found[0]) != "keep.go" {
+		t.Errorf("Expected keep.go in results, got %s", found[0])
+	}
+}
+
+func TestProdWalkerSizeLimit(t *testing.T) {
+	rootDir := t.TempDir()
+
+	// Create test files
+	largeFileData := make([]byte, 6*1024*1024) // 6 MB
+	testutil.CreateTestFile(t, rootDir, "largefile.txt", largeFileData)
+	testutil.CreateTestFile(t, rootDir, "smallfile.go", []byte("package main"))
+
+	// Reset and load default config, which sets size limit to 5 MB
+	testutil.ResetViperConfig(t, "")
+
+	w := fileproc.NewProdWalker()
+	found, err := w.Walk(rootDir)
+	if err != nil {
+		t.Fatalf("Walk returned error: %v", err)
+	}
+
+	// We should only get the small file
+	if len(found) != 1 {
+		t.Errorf("Expected 1 file under size limit, got %d", len(found))
+	}
+	if len(found) == 1 && filepath.Base(found[0]) != "smallfile.go" {
+		t.Errorf("Expected smallfile.go, got %s", found[0])
+	}
+}

fileproc/writer.go

@@ -1,94 +1,34 @@
+// Package fileproc provides a writer for the output of the file processor.
 package fileproc
 
 import (
-	"encoding/json"
 	"fmt"
 	"os"
 
-	"github.com/sirupsen/logrus"
-	"gopkg.in/yaml.v3"
+	"github.com/ivuorinen/gibidify/utils"
 )
 
-// FileData represents a single file's path and content.
-type FileData struct {
-	Path    string `json:"path" yaml:"path"`
-	Content string `json:"content" yaml:"content"`
-}
-
-// OutputData represents the full output structure.
-type OutputData struct {
-	Prefix string     `json:"prefix,omitempty" yaml:"prefix,omitempty"`
-	Files  []FileData `json:"files" yaml:"files"`
-	Suffix string     `json:"suffix,omitempty" yaml:"suffix,omitempty"`
-}
-
-// StartWriter writes the output in the specified format.
-func StartWriter(outFile *os.File, writeCh <-chan WriteRequest, done chan<- struct{}, format string, prefix, suffix string) {
-	var files []FileData
-
-	// Read from channel until closed
-	for req := range writeCh {
-		files = append(files, FileData{Path: req.Path, Content: req.Content})
-	}
-
-	// Create output struct
-	output := OutputData{Prefix: prefix, Files: files, Suffix: suffix}
-
-	// Serialize based on format
-	var outputData []byte
-	var err error
-
+// StartWriter writes the output in the specified format with memory optimization.
+func StartWriter(outFile *os.File, writeCh <-chan WriteRequest, done chan<- struct{}, format, prefix, suffix string) {
 	switch format {
-	case "json":
-		outputData, err = json.MarshalIndent(output, "", "  ")
-	case "yaml":
-		outputData, err = yaml.Marshal(output)
 	case "markdown":
-		outputData = []byte(formatMarkdown(output))
+		startMarkdownWriter(outFile, writeCh, done, prefix, suffix)
+	case "json":
+		startJSONWriter(outFile, writeCh, done, prefix, suffix)
+	case "yaml":
+		startYAMLWriter(outFile, writeCh, done, prefix, suffix)
 	default:
-		err = fmt.Errorf("unsupported format: %s", format)
-	}
-
-	if err != nil {
-		logrus.Errorf("Error encoding output: %v", err)
+		context := map[string]interface{}{
+			"format": format,
+		}
+		err := utils.NewStructuredError(
+			utils.ErrorTypeValidation,
+			utils.CodeValidationFormat,
+			fmt.Sprintf("unsupported format: %s", format),
+			"",
+			context,
+		)
+		utils.LogError("Failed to encode output", err)
 		close(done)
-		return
-	}
-
-	// Write to file
-	if _, err := outFile.Write(outputData); err != nil {
-		logrus.Errorf("Error writing to file: %v", err)
-	}
-
-	close(done)
-}
-
-func formatMarkdown(output OutputData) string {
-	markdown := "# " + output.Prefix + "\n\n"
-
-	for _, file := range output.Files {
-		markdown += fmt.Sprintf("## File: `%s`\n```%s\n%s\n```\n\n", file.Path, detectLanguage(file.Path), file.Content)
-	}
-
-	markdown += "# " + output.Suffix
-	return markdown
-}
-
-// detectLanguage tries to infer code block language from file extension.
-func detectLanguage(filename string) string {
-	if len(filename) < 3 {
-		return ""
-	}
-	switch {
-	case len(filename) >= 3 && filename[len(filename)-3:] == ".go":
-		return "go"
-	case len(filename) >= 3 && filename[len(filename)-3:] == ".py":
-		return "python"
-	case len(filename) >= 2 && filename[len(filename)-2:] == ".c":
-		return "c"
-	case len(filename) >= 3 && filename[len(filename)-3:] == ".js":
-		return "javascript"
-	default:
-		return ""
 	}
 }

fileproc/writer_test.go

@@ -1,45 +1,127 @@
-package fileproc
+package fileproc_test
 
 import (
 	"encoding/json"
 	"os"
+	"strings"
+	"sync"
 	"testing"
+
+	"gopkg.in/yaml.v3"
+
+	"github.com/ivuorinen/gibidify/fileproc"
 )
 
-func TestStartWriter_JSONOutput(t *testing.T) {
-	outFile, err := os.CreateTemp("", "output.json")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer func(name string) {
-		err := os.Remove(name)
-		if err != nil {
-			t.Fatal(err)
-		}
-	}(outFile.Name())
-
-	writeCh := make(chan WriteRequest)
-	done := make(chan struct{})
-
-	go StartWriter(outFile, writeCh, done, "json", "Prefix", "Suffix")
-
-	writeCh <- WriteRequest{Path: "file1.go", Content: "package main"}
-	writeCh <- WriteRequest{Path: "file2.py", Content: "def hello(): print('Hello')"}
-
-	close(writeCh)
-	<-done
-
-	data, err := os.ReadFile(outFile.Name())
-	if err != nil {
-		t.Fatal(err)
+func TestStartWriter_Formats(t *testing.T) {
+	// Define table-driven test cases
+	tests := []struct {
+		name        string
+		format      string
+		expectError bool
+	}{
+		{"JSON format", "json", false},
+		{"YAML format", "yaml", false},
+		{"Markdown format", "markdown", false},
+		{"Invalid format", "invalid", true},
 	}
 
-	var output OutputData
-	if err := json.Unmarshal(data, &output); err != nil {
-		t.Fatalf("JSON output is invalid: %v", err)
-	}
-
-	if len(output.Files) != 2 {
-		t.Errorf("Expected 2 files, got %d", len(output.Files))
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			data := runWriterTest(t, tc.format)
+			if tc.expectError {
+				verifyErrorOutput(t, data)
+			} else {
+				verifyValidOutput(t, data, tc.format)
+				verifyPrefixSuffix(t, data)
+			}
+		})
+	}
+}
+
+// runWriterTest executes the writer with the given format and returns the output data.
+func runWriterTest(t *testing.T, format string) []byte {
+	t.Helper()
+	outFile, err := os.CreateTemp(t.TempDir(), "gibidify_test_output")
+	if err != nil {
+		t.Fatalf("Failed to create temp file: %v", err)
+	}
+	defer func() {
+		if closeErr := outFile.Close(); closeErr != nil {
+			t.Errorf("close temp file: %v", closeErr)
+		}
+		if removeErr := os.Remove(outFile.Name()); removeErr != nil {
+			t.Errorf("remove temp file: %v", removeErr)
+		}
+	}()
+
+	// Prepare channels
+	writeCh := make(chan fileproc.WriteRequest, 2)
+	doneCh := make(chan struct{})
+
+	// Write a couple of sample requests
+	writeCh <- fileproc.WriteRequest{Path: "sample.go", Content: "package main"}
+	writeCh <- fileproc.WriteRequest{Path: "example.py", Content: "def foo(): pass"}
+	close(writeCh)
+
+	// Start the writer
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		fileproc.StartWriter(outFile, writeCh, doneCh, format, "PREFIX", "SUFFIX")
+	}()
+
+	// Wait until writer signals completion
+	wg.Wait()
+	<-doneCh // make sure all writes finished
+
+	// Read output
+	data, err := os.ReadFile(outFile.Name())
+	if err != nil {
+		t.Fatalf("Error reading output file: %v", err)
+	}
+
+	return data
+}
+
+// verifyErrorOutput checks that error cases produce no output.
+func verifyErrorOutput(t *testing.T, data []byte) {
+	t.Helper()
+	if len(data) != 0 {
+		t.Errorf("Expected no output for invalid format, got:\n%s", data)
+	}
+}
+
+// verifyValidOutput checks format-specific output validity.
+func verifyValidOutput(t *testing.T, data []byte, format string) {
+	t.Helper()
+	content := string(data)
+	switch format {
+	case "json":
+		var outStruct fileproc.OutputData
+		if err := json.Unmarshal(data, &outStruct); err != nil {
+			t.Errorf("JSON unmarshal failed: %v", err)
+		}
+	case "yaml":
+		var outStruct fileproc.OutputData
+		if err := yaml.Unmarshal(data, &outStruct); err != nil {
+			t.Errorf("YAML unmarshal failed: %v", err)
+		}
+	case "markdown":
+		if !strings.Contains(content, "```") {
+			t.Error("Expected markdown code fences not found")
+		}
+	}
+}
+
+// verifyPrefixSuffix checks that output contains expected prefix and suffix.
+func verifyPrefixSuffix(t *testing.T, data []byte) {
+	t.Helper()
+	content := string(data)
+	if !strings.Contains(content, "PREFIX") {
+		t.Errorf("Missing prefix in output: %s", data)
+	}
+	if !strings.Contains(content, "SUFFIX") {
+		t.Errorf("Missing suffix in output: %s", data)
 	}
 }

fileproc/yaml_writer.go

@@ -0,0 +1,148 @@
+package fileproc
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/ivuorinen/gibidify/utils"
+)
+
+// YAMLWriter handles YAML format output with streaming support.
+type YAMLWriter struct {
+	outFile *os.File
+}
+
+// NewYAMLWriter creates a new YAML writer.
+func NewYAMLWriter(outFile *os.File) *YAMLWriter {
+	return &YAMLWriter{outFile: outFile}
+}
+
+// Start writes the YAML header.
+func (w *YAMLWriter) Start(prefix, suffix string) error {
+	// Write YAML header
+	if _, err := fmt.Fprintf(w.outFile, "prefix: %s\nsuffix: %s\nfiles:\n", yamlQuoteString(prefix), yamlQuoteString(suffix)); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write YAML header")
+	}
+	return nil
+}
+
+// WriteFile writes a file entry in YAML format.
+func (w *YAMLWriter) WriteFile(req WriteRequest) error {
+	if req.IsStream {
+		return w.writeStreaming(req)
+	}
+	return w.writeInline(req)
+}
+
+// Close writes the YAML footer (no footer needed for YAML).
+func (w *YAMLWriter) Close() error {
+	return nil
+}
+
+// writeStreaming writes a large file as YAML in streaming chunks.
+func (w *YAMLWriter) writeStreaming(req WriteRequest) error {
+	defer w.closeReader(req.Reader, req.Path)
+
+	language := detectLanguage(req.Path)
+
+	// Write YAML file entry start
+	if _, err := fmt.Fprintf(w.outFile, "  - path: %s\n    language: %s\n    content: |\n", yamlQuoteString(req.Path), language); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write YAML file start").WithFilePath(req.Path)
+	}
+
+	// Stream content with YAML indentation
+	return w.streamYAMLContent(req.Reader, req.Path)
+}
+
+// writeInline writes a small file directly as YAML.
+func (w *YAMLWriter) writeInline(req WriteRequest) error {
+	language := detectLanguage(req.Path)
+	fileData := FileData{
+		Path:     req.Path,
+		Content:  req.Content,
+		Language: language,
+	}
+
+	// Write YAML entry
+	if _, err := fmt.Fprintf(w.outFile, "  - path: %s\n    language: %s\n    content: |\n", yamlQuoteString(fileData.Path), fileData.Language); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write YAML entry start").WithFilePath(req.Path)
+	}
+
+	// Write indented content
+	lines := strings.Split(fileData.Content, "\n")
+	for _, line := range lines {
+		if _, err := fmt.Fprintf(w.outFile, "      %s\n", line); err != nil {
+			return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write YAML content line").WithFilePath(req.Path)
+		}
+	}
+
+	return nil
+}
+
+// streamYAMLContent streams content with YAML indentation.
+func (w *YAMLWriter) streamYAMLContent(reader io.Reader, path string) error {
+	scanner := bufio.NewScanner(reader)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if _, err := fmt.Fprintf(w.outFile, "      %s\n", line); err != nil {
+			return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOWrite, "failed to write YAML line").WithFilePath(path)
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIORead, "failed to scan YAML content").WithFilePath(path)
+	}
+	return nil
+}
+
+// closeReader safely closes a reader if it implements io.Closer.
+func (w *YAMLWriter) closeReader(reader io.Reader, path string) {
+	if closer, ok := reader.(io.Closer); ok {
+		if err := closer.Close(); err != nil {
+			utils.LogError(
+				"Failed to close file reader",
+				utils.WrapError(err, utils.ErrorTypeIO, utils.CodeIOClose, "failed to close file reader").WithFilePath(path),
+			)
+		}
+	}
+}
+
+// yamlQuoteString quotes a string for YAML output if needed.
+func yamlQuoteString(s string) string {
+	if s == "" {
+		return `""`
+	}
+	// Simple YAML quoting - use double quotes if string contains special characters
+	if strings.ContainsAny(s, "\n\r\t:\"'\\") {
+		return fmt.Sprintf(`"%s"`, strings.ReplaceAll(s, `"`, `\"`))
+	}
+	return s
+}
+
+// startYAMLWriter handles YAML format output with streaming support.
+func startYAMLWriter(outFile *os.File, writeCh <-chan WriteRequest, done chan<- struct{}, prefix, suffix string) {
+	defer close(done)
+
+	writer := NewYAMLWriter(outFile)
+
+	// Start writing
+	if err := writer.Start(prefix, suffix); err != nil {
+		utils.LogError("Failed to write YAML header", err)
+		return
+	}
+
+	// Process files
+	for req := range writeCh {
+		if err := writer.WriteFile(req); err != nil {
+			utils.LogError("Failed to write YAML file", err)
+		}
+	}
+
+	// Close writer
+	if err := writer.Close(); err != nil {
+		utils.LogError("Failed to write YAML end", err)
+	}
+}

go.mod

@@ -1,33 +1,32 @@
 module github.com/ivuorinen/gibidify
 
-go 1.23
+go 1.24.1
 
 require (
+	github.com/fatih/color v1.18.0
 	github.com/sabhiram/go-gitignore v0.0.0-20210923224102-525f6e181f06
+	github.com/schollz/progressbar/v3 v3.18.0
 	github.com/sirupsen/logrus v1.9.3
-	github.com/spf13/viper v1.19.0
+	github.com/spf13/viper v1.20.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
-	github.com/fsnotify/fsnotify v1.7.0 // indirect
-	github.com/hashicorp/hcl v1.0.0 // indirect
-	github.com/magiconair/properties v1.8.7 // indirect
-	github.com/mitchellh/mapstructure v1.5.0 // indirect
-	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
-	github.com/sagikazarmark/locafero v0.4.0 // indirect
-	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
+	github.com/fsnotify/fsnotify v1.8.0 // indirect
+	github.com/go-viper/mapstructure/v2 v2.2.1 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db // indirect
+	github.com/pelletier/go-toml/v2 v2.2.3 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/sagikazarmark/locafero v0.8.0 // indirect
 	github.com/sourcegraph/conc v0.3.0 // indirect
-	github.com/spf13/afero v1.11.0 // indirect
-	github.com/spf13/cast v1.6.0 // indirect
-	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/spf13/afero v1.14.0 // indirect
+	github.com/spf13/cast v1.7.1 // indirect
+	github.com/spf13/pflag v1.0.6 // indirect
 	github.com/subosito/gotenv v1.6.0 // indirect
-	go.uber.org/atomic v1.9.0 // indirect
-	go.uber.org/multierr v1.9.0 // indirect
-	golang.org/x/crypto v0.31.0 // indirect
-	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
-	golang.org/x/net v0.33.0 // indirect
-	golang.org/x/sys v0.29.0 // indirect
-	golang.org/x/text v0.21.0 // indirect
-	gopkg.in/ini.v1 v1.67.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/sys v0.31.0 // indirect
+	golang.org/x/term v0.28.0 // indirect
+	golang.org/x/text v0.23.0 // indirect
 )

go.sum

@@ -1,86 +1,78 @@
+github.com/chengxilo/virtualterm v1.0.4 h1:Z6IpERbRVlfB8WkOmtbHiDbBANU7cimRIof7mk9/PwM=
+github.com/chengxilo/virtualterm v1.0.4/go.mod h1:DyxxBZz/x1iqJjFxTFcr6/x+jSpqN0iwWCOK1q10rlY=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
-github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
+github.com/fatih/color v1.18.0/go.mod h1:4FelSpRwEGDpQ12mAdzqdOukCy4u8WUtOY6lkT/6HfU=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
-github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
-github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
-github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
+github.com/fsnotify/fsnotify v1.8.0 h1:dAwr6QBTBZIkG8roQaJjGof0pp0EeF+tNV7YBP3F/8M=
+github.com/fsnotify/fsnotify v1.8.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
+github.com/go-viper/mapstructure/v2 v2.2.1 h1:ZAaOCxANMuZx5RCeg0mBdEZk7DZasvvZIxtHqx8aGss=
+github.com/go-viper/mapstructure/v2 v2.2.1/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
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 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
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integration_test.go

@@ -1,120 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"strings"
-	"testing"
-	"time"
-)
-
-// TestIntegrationFullCLI simulates a full run of the CLI application using adaptive concurrency.
-func TestIntegrationFullCLI(t *testing.T) {
-	// Create a temporary source directory and populate it with test files.
-	srcDir, err := ioutil.TempDir("", "gibidify_src")
-	if err != nil {
-		t.Fatalf("Failed to create temp source directory: %v", err)
-	}
-	defer os.RemoveAll(srcDir)
-
-	// Create two test files.
-	file1 := filepath.Join(srcDir, "file1.txt")
-	if err := ioutil.WriteFile(file1, []byte("Hello World"), 0644); err != nil {
-		t.Fatalf("Failed to write file1: %v", err)
-	}
-	file2 := filepath.Join(srcDir, "file2.go")
-	if err := ioutil.WriteFile(file2, []byte("package main\nfunc main() {}"), 0644); err != nil {
-		t.Fatalf("Failed to write file2: %v", err)
-	}
-
-	// Create a temporary output file.
-	outFile, err := ioutil.TempFile("", "gibidify_output.txt")
-	if err != nil {
-		t.Fatalf("Failed to create temp output file: %v", err)
-	}
-	outFilePath := outFile.Name()
-	outFile.Close()
-	defer os.Remove(outFilePath)
-
-	// Set up CLI arguments.
-	os.Args = []string{
-		"gibidify",
-		"-source", srcDir,
-		"-destination", outFilePath,
-		"-prefix", "PREFIX",
-		"-suffix", "SUFFIX",
-		"-concurrency", "2", // For testing, set concurrency to 2.
-	}
-
-	// Run the application with a background context.
-	ctx := context.Background()
-	if err := Run(ctx); err != nil {
-		t.Fatalf("Run failed: %v", err)
-	}
-
-	// Verify the output file contains the expected prefix, file contents, and suffix.
-	data, err := ioutil.ReadFile(outFilePath)
-	if err != nil {
-		t.Fatalf("Failed to read output file: %v", err)
-	}
-	output := string(data)
-	if !strings.Contains(output, "PREFIX") {
-		t.Error("Output missing prefix")
-	}
-	if !strings.Contains(output, "Hello World") {
-		t.Error("Output missing content from file1.txt")
-	}
-	if !strings.Contains(output, "SUFFIX") {
-		t.Error("Output missing suffix")
-	}
-}
-
-// TestIntegrationCancellation verifies that the application correctly cancels processing when the context times out.
-func TestIntegrationCancellation(t *testing.T) {
-	// Create a temporary source directory with many files to simulate a long-running process.
-	srcDir, err := ioutil.TempDir("", "gibidify_src_long")
-	if err != nil {
-		t.Fatalf("Failed to create temp source directory: %v", err)
-	}
-	defer os.RemoveAll(srcDir)
-
-	// Create a large number of small files.
-	for i := 0; i < 1000; i++ {
-		filePath := filepath.Join(srcDir, fmt.Sprintf("file%d.txt", i))
-		if err := ioutil.WriteFile(filePath, []byte("Content"), 0644); err != nil {
-			t.Fatalf("Failed to write %s: %v", filePath, err)
-		}
-	}
-
-	// Create a temporary output file.
-	outFile, err := ioutil.TempFile("", "gibidify_output.txt")
-	if err != nil {
-		t.Fatalf("Failed to create temp output file: %v", err)
-	}
-	outFilePath := outFile.Name()
-	outFile.Close()
-	defer os.Remove(outFilePath)
-
-	// Set up CLI arguments.
-	os.Args = []string{
-		"gibidify",
-		"-source", srcDir,
-		"-destination", outFilePath,
-		"-prefix", "PREFIX",
-		"-suffix", "SUFFIX",
-		"-concurrency", "2",
-	}
-
-	// Create a context with a very short timeout to force cancellation.
-	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Millisecond)
-	defer cancel()
-
-	// Run the application; we expect an error due to cancellation.
-	err = Run(ctx)
-	if err == nil {
-		t.Error("Expected Run to fail due to cancellation, but it succeeded")
-	}
-}

kics.config

@@ -0,0 +1,4 @@
+# vim: ft=yaml
+
+log-level: WARN
+exclude-severities: 'info,low'

main.go

@@ -4,139 +4,46 @@ package main
 
 import (
 	"context"
-	"flag"
-	"fmt"
 	"os"
-	"path/filepath"
-	"runtime"
-	"sync"
 
-	"github.com/ivuorinen/gibidify/config"
-	"github.com/ivuorinen/gibidify/fileproc"
 	"github.com/sirupsen/logrus"
+
+	"github.com/ivuorinen/gibidify/cli"
+	"github.com/ivuorinen/gibidify/config"
 )
 
-var (
-	sourceDir   string
-	destination string
-	prefix      string
-	suffix      string
-	concurrency int
-	format      string
-)
+func main() {
+	// Initialize UI for error handling
+	ui := cli.NewUIManager()
+	errorFormatter := cli.NewErrorFormatter(ui)
 
-func init() {
-	flag.StringVar(&sourceDir, "source", "", "Source directory to scan recursively")
-	flag.StringVar(&destination, "destination", "", "Output file to write aggregated code")
-	flag.StringVar(&prefix, "prefix", "", "Text to add at the beginning of the output file")
-	flag.StringVar(&suffix, "suffix", "", "Text to add at the end of the output file")
-	flag.StringVar(&format, "format", "json", "Output format (json, markdown, yaml)")
-	flag.IntVar(&concurrency, "concurrency", runtime.NumCPU(), "Number of concurrent workers (default: number of CPU cores)")
+	// In production, use a background context.
+	if err := run(context.Background()); err != nil {
+		// Handle errors with better formatting and suggestions
+		if cli.IsUserError(err) {
+			errorFormatter.FormatError(err)
+			os.Exit(1)
+		} else {
+			// System errors still go to logrus for debugging
+			logrus.Errorf("System error: %v", err)
+			ui.PrintError("An unexpected error occurred. Please check the logs.")
+			os.Exit(2)
+		}
+	}
 }
 
 // Run executes the main logic of the CLI application using the provided context.
-func Run(ctx context.Context) error {
-	flag.Parse()
-
-	// We need at least a source directory
-	if sourceDir == "" {
-		return fmt.Errorf("usage: gibidify -source <source_directory> [--destination <output_file>] [--format=json|yaml|markdown] ")
-	}
-
-	// If destination is not specified, auto-generate it using the base name of sourceDir + "." + format
-	if destination == "" {
-		absRoot, err := filepath.Abs(sourceDir)
-		if err != nil {
-			return fmt.Errorf("failed to get absolute path for %s: %w", sourceDir, err)
-		}
-		baseName := filepath.Base(absRoot)
-		// If sourceDir ends with a slash, baseName might be "." so handle that case as needed
-		if baseName == "." || baseName == "" {
-			baseName = "output"
-		}
-		destination = baseName + "." + format
+func run(ctx context.Context) error {
+	// Parse CLI flags
+	flags, err := cli.ParseFlags()
+	if err != nil {
+		return err
 	}
 
+	// Load configuration
 	config.LoadConfig()
 
-	logrus.Infof("Starting gibidify. Format: %s, Source: %s, Destination: %s, Workers: %d", format, sourceDir, destination, concurrency)
-
-	// Collect files
-	files, err := fileproc.CollectFiles(sourceDir)
-	if err != nil {
-		return fmt.Errorf("error collecting files: %w", err)
-	}
-	logrus.Infof("Found %d files to process", len(files))
-
-	// Open output file
-	outFile, err := os.Create(destination)
-	if err != nil {
-		return fmt.Errorf("failed to create output file %s: %w", destination, err)
-	}
-	defer func(outFile *os.File) {
-		if err := outFile.Close(); err != nil {
-			logrus.Errorf("Error closing output file: %v", err)
-		}
-	}(outFile)
-
-	// Create channels
-	fileCh := make(chan string)
-	writeCh := make(chan fileproc.WriteRequest)
-	writerDone := make(chan struct{})
-
-	// Start writer goroutine
-	go fileproc.StartWriter(outFile, writeCh, writerDone, format, prefix, suffix)
-
-	var wg sync.WaitGroup
-
-	// Start worker goroutines with context cancellation
-	for i := 0; i < concurrency; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-			for {
-				select {
-				case <-ctx.Done():
-					return
-				case filePath, ok := <-fileCh:
-					if !ok {
-						return
-					}
-					// Pass sourceDir to ProcessFile so it knows the 'root'
-					absRoot, err := filepath.Abs(sourceDir)
-					if err != nil {
-						logrus.Errorf("Failed to get absolute path for %s: %v", sourceDir, err)
-						return
-					}
-					fileproc.ProcessFile(filePath, writeCh, absRoot)
-				}
-			}
-		}()
-	}
-
-	// Feed files to worker pool while checking for cancellation
-	for _, fp := range files {
-		select {
-		case <-ctx.Done():
-			close(fileCh)
-			return ctx.Err()
-		case fileCh <- fp:
-		}
-	}
-	close(fileCh)
-
-	wg.Wait()
-	close(writeCh)
-	<-writerDone
-
-	logrus.Infof("Processing completed. Output saved to %s", destination)
-	return nil
-}
-
-func main() {
-	// In production, use a background context.
-	if err := Run(context.Background()); err != nil {
-		fmt.Println("Error:", err)
-		os.Exit(1)
-	}
+	// Create and run processor
+	processor := cli.NewProcessor(flags)
+	return processor.Process(ctx)
 }

main_test.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/ivuorinen/gibidify/testutil"
+)
+
+const (
+	testFileCount = 1000
+)
+
+// TestIntegrationFullCLI simulates a full run of the CLI application using adaptive concurrency.
+func TestIntegrationFullCLI(t *testing.T) {
+	srcDir := setupTestFiles(t)
+	outFilePath := setupOutputFile(t)
+	setupCLIArgs(srcDir, outFilePath)
+
+	// Run the application with a background context.
+	ctx := t.Context()
+	if runErr := run(ctx); runErr != nil {
+		t.Fatalf("Run failed: %v", runErr)
+	}
+
+	verifyOutput(t, outFilePath)
+}
+
+// setupTestFiles creates test files and returns the source directory.
+func setupTestFiles(t *testing.T) string {
+	t.Helper()
+	srcDir := t.TempDir()
+
+	// Create two test files.
+	testutil.CreateTestFiles(t, srcDir, []testutil.FileSpec{
+		{Name: "file1.txt", Content: "Hello World"},
+		{Name: "file2.go", Content: "package main\nfunc main() {}"},
+	})
+
+	return srcDir
+}
+
+// setupOutputFile creates a temporary output file and returns its path.
+func setupOutputFile(t *testing.T) string {
+	t.Helper()
+	outFile, outFilePath := testutil.CreateTempOutputFile(t, "gibidify_output.txt")
+	testutil.CloseFile(t, outFile)
+
+	return outFilePath
+}
+
+// setupCLIArgs configures the CLI arguments for testing.
+func setupCLIArgs(srcDir, outFilePath string) {
+	testutil.SetupCLIArgs(srcDir, outFilePath, "PREFIX", "SUFFIX", 2)
+}
+
+// verifyOutput checks that the output file contains expected content.
+func verifyOutput(t *testing.T, outFilePath string) {
+	t.Helper()
+	data, err := os.ReadFile(outFilePath)
+	if err != nil {
+		t.Fatalf("Failed to read output file: %v", err)
+	}
+	output := string(data)
+	testutil.VerifyContentContains(t, output, []string{"PREFIX", "Hello World", "SUFFIX"})
+}
+
+// TestIntegrationCancellation verifies that the application correctly cancels processing when the context times out.
+func TestIntegrationCancellation(t *testing.T) {
+	// Create a temporary source directory with many files to simulate a long-running process.
+	srcDir := t.TempDir()
+
+	// Create a large number of small files.
+	for i := range testFileCount {
+		fileName := fmt.Sprintf("file%d.txt", i)
+		testutil.CreateTestFile(t, srcDir, fileName, []byte("Content"))
+	}
+
+	// Create a temporary output file.
+	outFile, outFilePath := testutil.CreateTempOutputFile(t, "gibidify_output.txt")
+	testutil.CloseFile(t, outFile)
+	defer func() {
+		if removeErr := os.Remove(outFilePath); removeErr != nil {
+			t.Fatalf("cleanup output file: %v", removeErr)
+		}
+	}()
+
+	// Set up CLI arguments.
+	testutil.SetupCLIArgs(srcDir, outFilePath, "PREFIX", "SUFFIX", 2)
+
+	// Create a context with a very short timeout to force cancellation.
+	ctx, cancel := context.WithTimeout(
+		t.Context(),
+		1*time.Millisecond,
+	)
+	defer cancel()
+
+	// Run the application; we expect an error due to cancellation.
+	runErr := run(ctx)
+	if runErr == nil {
+		t.Error("Expected Run to fail due to cancellation, but it succeeded")
+	}
+}

scripts/help.txt

@@ -0,0 +1,25 @@
+Available targets:
+  install-tools  - Install required linting and development tools
+  lint          - Run all linters (Go, Makefile, shell, YAML)
+  lint-fix      - Run linters with auto-fix enabled
+  lint-verbose  - Run linters with verbose output
+  test          - Run tests
+  coverage      - Run tests with coverage
+  build         - Build the application
+  clean         - Clean build artifacts
+  all           - Run lint, test, and build
+
+Security targets:
+  security      - Run comprehensive security scan
+  security-full - Run full security analysis with all tools
+  vuln-check    - Check for dependency vulnerabilities
+
+Benchmark targets:
+  build-benchmark        - Build the benchmark binary
+  benchmark              - Run all benchmarks
+  benchmark-collection   - Run file collection benchmarks
+  benchmark-processing   - Run file processing benchmarks
+  benchmark-concurrency  - Run concurrency benchmarks
+  benchmark-format       - Run format benchmarks
+
+Run 'make <target>' to execute a specific target.

scripts/lint.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+set -e
+
+echo "Running golangci-lint..."
+golangci-lint run ./...
+
+echo "Running checkmake..."
+checkmake --config=.checkmake Makefile
+
+echo "Running shfmt check..."
+shfmt -d .
+
+echo "Running yamllint..."
+yamllint -c .yamllint .

scripts/security-scan.sh

@@ -0,0 +1,426 @@
+#!/bin/bash
+set -euo pipefail
+
+# Security Scanning Script for gibidify
+# This script runs comprehensive security checks locally and in CI
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+
+cd "$PROJECT_ROOT"
+
+echo "🔒 Starting comprehensive security scan for gibidify..."
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+BLUE='\033[0;34m'
+NC='\033[0m' # No Color
+
+# Function to print status
+print_status() {
+	echo -e "${BLUE}[INFO]${NC} $1"
+}
+
+print_warning() {
+	echo -e "${YELLOW}[WARN]${NC} $1"
+}
+
+print_error() {
+	echo -e "${RED}[ERROR]${NC} $1"
+}
+
+print_success() {
+	echo -e "${GREEN}[SUCCESS]${NC} $1"
+}
+
+# Check if required tools are installed
+check_dependencies() {
+	print_status "Checking security scanning dependencies..."
+
+	local missing_tools=()
+
+	if ! command -v go &>/dev/null; then
+		missing_tools+=("go")
+	fi
+
+	if ! command -v golangci-lint &>/dev/null; then
+		print_warning "golangci-lint not found, installing..."
+		go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
+	fi
+
+	if ! command -v gosec &>/dev/null; then
+		print_warning "gosec not found, installing..."
+		go install github.com/securecodewarrior/gosec/v2/cmd/gosec@latest
+	fi
+
+	if ! command -v govulncheck &>/dev/null; then
+		print_warning "govulncheck not found, installing..."
+		go install golang.org/x/vuln/cmd/govulncheck@latest
+	fi
+
+	if ! command -v checkmake &>/dev/null; then
+		print_warning "checkmake not found, installing..."
+		go install github.com/mrtazz/checkmake/cmd/checkmake@latest
+	fi
+
+	if ! command -v shfmt &>/dev/null; then
+		print_warning "shfmt not found, installing..."
+		go install mvdan.cc/sh/v3/cmd/shfmt@latest
+	fi
+
+	if ! command -v yamllint &>/dev/null; then
+		print_warning "yamllint not found, installing..."
+		go install github.com/excilsploft/yamllint@latest
+	fi
+
+	if [ ${#missing_tools[@]} -ne 0 ]; then
+		print_error "Missing required tools: ${missing_tools[*]}"
+		print_error "Please install the missing tools and try again."
+		exit 1
+	fi
+
+	print_success "All dependencies are available"
+}
+
+# Run gosec security scanner
+run_gosec() {
+	print_status "Running gosec security scanner..."
+
+	if gosec -fmt=json -out=gosec-report.json -stdout -verbose=text ./...; then
+		print_success "gosec scan completed successfully"
+	else
+		print_error "gosec found security issues!"
+		if [ -f "gosec-report.json" ]; then
+			echo "Detailed report saved to gosec-report.json"
+		fi
+		return 1
+	fi
+}
+
+# Run vulnerability check
+run_govulncheck() {
+	print_status "Running govulncheck for dependency vulnerabilities..."
+
+	if govulncheck -json ./... >govulncheck-report.json 2>&1; then
+		print_success "No known vulnerabilities found in dependencies"
+	else
+		if grep -q '"finding"' govulncheck-report.json 2>/dev/null; then
+			print_error "Vulnerabilities found in dependencies!"
+			echo "Detailed report saved to govulncheck-report.json"
+			return 1
+		else
+			print_success "No vulnerabilities found"
+		fi
+	fi
+}
+
+# Run enhanced golangci-lint with security focus
+run_security_lint() {
+	print_status "Running security-focused linting..."
+
+	local security_linters="gosec,gocritic,bodyclose,rowserrcheck,misspell,unconvert,unparam,unused,errcheck,ineffassign,staticcheck"
+
+	if golangci-lint run --enable="$security_linters" --timeout=5m; then
+		print_success "Security linting passed"
+	else
+		print_error "Security linting found issues!"
+		return 1
+	fi
+}
+
+# Check for potential secrets
+check_secrets() {
+	print_status "Scanning for potential secrets and sensitive data..."
+
+	local secrets_found=false
+
+	# Common secret patterns
+	local patterns=(
+		"password\s*[:=]\s*['\"][^'\"]{3,}['\"]"
+		"secret\s*[:=]\s*['\"][^'\"]{3,}['\"]"
+		"key\s*[:=]\s*['\"][^'\"]{8,}['\"]"
+		"token\s*[:=]\s*['\"][^'\"]{8,}['\"]"
+		"api_?key\s*[:=]\s*['\"][^'\"]{8,}['\"]"
+		"aws_?access_?key"
+		"aws_?secret"
+		"AKIA[0-9A-Z]{16}" # AWS Access Key pattern
+		"github_?token"
+		"private_?key"
+	)
+
+	for pattern in "${patterns[@]}"; do
+		if grep -r -i -E "$pattern" --include="*.go" . 2>/dev/null; then
+			print_warning "Potential secret pattern found: $pattern"
+			secrets_found=true
+		fi
+	done
+
+	# Check git history for secrets (last 10 commits)
+	if git log --oneline -10 | grep -i -E "(password|secret|key|token)" >/dev/null 2>&1; then
+		print_warning "Potential secrets mentioned in recent commit messages"
+		secrets_found=true
+	fi
+
+	if [ "$secrets_found" = true ]; then
+		print_warning "Potential secrets detected. Please review manually."
+		return 1
+	else
+		print_success "No obvious secrets detected"
+	fi
+}
+
+# Check for hardcoded network addresses
+check_hardcoded_addresses() {
+	print_status "Checking for hardcoded network addresses..."
+
+	local addresses_found=false
+
+	# Look for IP addresses (excluding common safe ones)
+	if grep -r -E "([0-9]{1,3}\.){3}[0-9]{1,3}" --include="*.go" . |
+		grep -v -E "(127\.0\.0\.1|0\.0\.0\.0|255\.255\.255\.255|localhost)" >/dev/null 2>&1; then
+		print_warning "Hardcoded IP addresses found:"
+		grep -r -E "([0-9]{1,3}\.){3}[0-9]{1,3}" --include="*.go" . |
+			grep -v -E "(127\.0\.0\.1|0\.0\.0\.0|255\.255\.255\.255|localhost)" || true
+		addresses_found=true
+	fi
+
+	# Look for URLs (excluding documentation examples)
+	if grep -r -E "https?://[^/\s]+" --include="*.go" . |
+		grep -v -E "(example\.com|localhost|127\.0\.0\.1|\$\{)" >/dev/null 2>&1; then
+		print_warning "Hardcoded URLs found:"
+		grep -r -E "https?://[^/\s]+" --include="*.go" . |
+			grep -v -E "(example\.com|localhost|127\.0\.0\.1|\$\{)" || true
+		addresses_found=true
+	fi
+
+	if [ "$addresses_found" = true ]; then
+		print_warning "Hardcoded network addresses detected. Please review."
+		return 1
+	else
+		print_success "No hardcoded network addresses found"
+	fi
+}
+
+# Check Docker security (if Dockerfile exists)
+check_docker_security() {
+	if [ -f "Dockerfile" ]; then
+		print_status "Checking Docker security..."
+
+		# Basic Dockerfile security checks
+		local docker_issues=false
+
+		if grep -q "^USER root" Dockerfile; then
+			print_warning "Dockerfile runs as root user"
+			docker_issues=true
+		fi
+
+		if ! grep -q "^USER " Dockerfile; then
+			print_warning "Dockerfile doesn't specify a non-root user"
+			docker_issues=true
+		fi
+
+		if grep -q "RUN.*wget\|RUN.*curl" Dockerfile && ! grep -q "rm.*wget\|rm.*curl" Dockerfile; then
+			print_warning "Dockerfile may leave curl/wget installed"
+			docker_issues=true
+		fi
+
+		if [ "$docker_issues" = true ]; then
+			print_warning "Docker security issues detected"
+			return 1
+		else
+			print_success "Docker security check passed"
+		fi
+	else
+		print_status "No Dockerfile found, skipping Docker security check"
+	fi
+}
+
+# Check file permissions
+check_file_permissions() {
+	print_status "Checking file permissions..."
+
+	local perm_issues=false
+
+	# Check for overly permissive files
+	if find . -type f -perm /o+w -not -path "./.git/*" | grep -q .; then
+		print_warning "World-writable files found:"
+		find . -type f -perm /o+w -not -path "./.git/*" || true
+		perm_issues=true
+	fi
+
+	# Check for executable files that shouldn't be
+	if find . -type f -name "*.go" -perm /a+x | grep -q .; then
+		print_warning "Executable Go files found (should not be executable):"
+		find . -type f -name "*.go" -perm /a+x || true
+		perm_issues=true
+	fi
+
+	if [ "$perm_issues" = true ]; then
+		print_warning "File permission issues detected"
+		return 1
+	else
+		print_success "File permissions check passed"
+	fi
+}
+
+# Check Makefile with checkmake
+check_makefile() {
+	if [ -f "Makefile" ]; then
+		print_status "Checking Makefile with checkmake..."
+
+		if checkmake --config=.checkmake Makefile; then
+			print_success "Makefile check passed"
+		else
+			print_error "Makefile issues detected!"
+			return 1
+		fi
+	else
+		print_status "No Makefile found, skipping checkmake"
+	fi
+}
+
+# Check shell scripts with shfmt
+check_shell_scripts() {
+	print_status "Checking shell script formatting..."
+
+	if find . -name "*.sh" -type f | head -1 | grep -q .; then
+		if shfmt -d .; then
+			print_success "Shell script formatting check passed"
+		else
+			print_error "Shell script formatting issues detected!"
+			return 1
+		fi
+	else
+		print_status "No shell scripts found, skipping shfmt check"
+	fi
+}
+
+# Check YAML files
+check_yaml_files() {
+	print_status "Checking YAML files..."
+
+	if find . -name "*.yml" -o -name "*.yaml" -type f | head -1 | grep -q .; then
+		if yamllint -c .yamllint .; then
+			print_success "YAML files check passed"
+		else
+			print_error "YAML file issues detected!"
+			return 1
+		fi
+	else
+		print_status "No YAML files found, skipping yamllint check"
+	fi
+}
+
+# Generate security report
+generate_report() {
+	print_status "Generating security scan report..."
+
+	local report_file="security-report.md"
+
+	cat >"$report_file" <<EOF
+# Security Scan Report
+
+**Generated:** $(date)
+**Project:** gibidify
+**Scan Type:** Comprehensive Security Analysis
+
+## Scan Results
+
+### Security Tools Used
+- gosec (Go security analyzer)
+- govulncheck (Vulnerability database checker)
+- golangci-lint (Static analysis with security linters)
+- checkmake (Makefile linting)
+- shfmt (Shell script formatting)
+- yamllint (YAML file validation)
+- Custom secret detection
+- Custom network address detection
+- Docker security checks
+- File permission checks
+
+### Files Generated
+- \`gosec-report.json\` - Detailed gosec security findings
+- \`govulncheck-report.json\` - Dependency vulnerability report
+
+### Recommendations
+1. Review all security findings in the generated reports
+2. Address any HIGH or MEDIUM severity issues immediately
+3. Consider implementing additional security measures for LOW severity issues
+4. Regularly update dependencies to patch known vulnerabilities
+5. Run security scans before each release
+
+### Next Steps
+- Fix any identified vulnerabilities
+- Update security scanning in CI/CD pipeline
+- Consider adding security testing to the test suite
+- Review and update security documentation
+
+---
+*This report was generated automatically by the gibidify security scanning script.*
+EOF
+
+	print_success "Security report generated: $report_file"
+}
+
+# Main execution
+main() {
+	echo "🔒 gibidify Security Scanner"
+	echo "=========================="
+	echo
+
+	local exit_code=0
+
+	check_dependencies
+	echo
+
+	# Run all security checks
+	run_gosec || exit_code=1
+	echo
+
+	run_govulncheck || exit_code=1
+	echo
+
+	run_security_lint || exit_code=1
+	echo
+
+	check_secrets || exit_code=1
+	echo
+
+	check_hardcoded_addresses || exit_code=1
+	echo
+
+	check_docker_security || exit_code=1
+	echo
+
+	check_file_permissions || exit_code=1
+	echo
+
+	check_makefile || exit_code=1
+	echo
+
+	check_shell_scripts || exit_code=1
+	echo
+
+	check_yaml_files || exit_code=1
+	echo
+
+	generate_report
+	echo
+
+	if [ $exit_code -eq 0 ]; then
+		print_success "🎉 All security checks passed!"
+	else
+		print_error "❌ Security issues detected. Please review the reports and fix identified issues."
+		print_status "Generated reports:"
+		print_status "- gosec-report.json (if exists)"
+		print_status "- govulncheck-report.json (if exists)"
+		print_status "- security-report.md"
+	fi
+
+	exit $exit_code
+}
+
+# Run main function
+main "$@"

testutil/concurrency_test.go

@@ -0,0 +1,86 @@
+package testutil
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// Test thread safety of functions that might be called concurrently
+func TestConcurrentOperations(t *testing.T) {
+	tempDir := t.TempDir()
+	done := make(chan bool)
+
+	// Test concurrent file creation
+	for i := 0; i < 5; i++ {
+		go func(n int) {
+			CreateTestFile(t, tempDir, string(rune('a'+n))+".txt", []byte("content"))
+			done <- true
+		}(i)
+	}
+
+	// Test concurrent directory creation
+	for i := 0; i < 5; i++ {
+		go func(n int) {
+			CreateTestDirectory(t, tempDir, "dir"+string(rune('0'+n)))
+			done <- true
+		}(i)
+	}
+
+	// Wait for all goroutines
+	for i := 0; i < 10; i++ {
+		<-done
+	}
+}
+
+// Benchmarks
+func BenchmarkCreateTestFile(b *testing.B) {
+	tempDir := b.TempDir()
+	content := []byte("benchmark content")
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		// Use a unique filename for each iteration to avoid conflicts
+		filename := "bench" + string(rune(i%26+'a')) + ".txt"
+		filePath := filepath.Join(tempDir, filename)
+		if err := os.WriteFile(filePath, content, FilePermission); err != nil {
+			b.Fatalf("Failed to write file: %v", err)
+		}
+	}
+}
+
+func BenchmarkCreateTestFiles(b *testing.B) {
+	tempDir := b.TempDir()
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		// Create specs with unique names for each iteration
+		specs := []FileSpec{
+			{Name: "file1_" + string(rune(i%26+'a')) + ".txt", Content: "content1"},
+			{Name: "file2_" + string(rune(i%26+'a')) + ".txt", Content: "content2"},
+			{Name: "file3_" + string(rune(i%26+'a')) + ".txt", Content: "content3"},
+		}
+
+		for _, spec := range specs {
+			filePath := filepath.Join(tempDir, spec.Name)
+			if err := os.WriteFile(filePath, []byte(spec.Content), FilePermission); err != nil {
+				b.Fatalf("Failed to write file: %v", err)
+			}
+		}
+	}
+}
+
+func BenchmarkVerifyContentContains(b *testing.B) {
+	content := strings.Repeat("test content with various words ", 100)
+	expected := []string{"test", "content", "various", "words"}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		// We can't use the actual function in benchmark since it needs testing.T
+		// So we'll benchmark the core logic
+		for _, exp := range expected {
+			_ = strings.Contains(content, exp)
+		}
+	}
+}

testutil/config_test.go

@@ -0,0 +1,132 @@
+package testutil
+
+import (
+	"os"
+	"testing"
+
+	"github.com/spf13/viper"
+)
+
+func TestResetViperConfig(t *testing.T) {
+	tests := []struct {
+		name       string
+		configPath string
+		preSetup   func()
+		verify     func(t *testing.T)
+	}{
+		{
+			name:       "reset with empty config path",
+			configPath: "",
+			preSetup: func() {
+				viper.Set("test.key", "value")
+			},
+			verify: func(t *testing.T) {
+				if viper.IsSet("test.key") {
+					t.Error("Viper config not reset properly")
+				}
+			},
+		},
+		{
+			name:       "reset with config path",
+			configPath: t.TempDir(),
+			preSetup: func() {
+				viper.Set("test.key", "value")
+			},
+			verify: func(t *testing.T) {
+				if viper.IsSet("test.key") {
+					t.Error("Viper config not reset properly")
+				}
+				// Verify config path was added
+				paths := viper.ConfigFileUsed()
+				if paths == "" {
+					// This is expected as no config file exists
+					return
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tt.preSetup()
+			ResetViperConfig(t, tt.configPath)
+			tt.verify(t)
+		})
+	}
+}
+
+func TestSetupCLIArgs(t *testing.T) {
+	// Save original args
+	originalArgs := os.Args
+	defer func() {
+		os.Args = originalArgs
+	}()
+
+	tests := []struct {
+		name        string
+		srcDir      string
+		outFile     string
+		prefix      string
+		suffix      string
+		concurrency int
+		wantLen     int
+	}{
+		{
+			name:        "basic CLI args",
+			srcDir:      "/src",
+			outFile:     "/out.txt",
+			prefix:      "PREFIX",
+			suffix:      "SUFFIX",
+			concurrency: 4,
+			wantLen:     11,
+		},
+		{
+			name:        "empty strings",
+			srcDir:      "",
+			outFile:     "",
+			prefix:      "",
+			suffix:      "",
+			concurrency: 1,
+			wantLen:     11,
+		},
+		{
+			name:        "special characters in args",
+			srcDir:      "/path with spaces/src",
+			outFile:     "/path/to/output file.txt",
+			prefix:      "Prefix with\nnewline",
+			suffix:      "Suffix with\ttab",
+			concurrency: 8,
+			wantLen:     11,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			SetupCLIArgs(tt.srcDir, tt.outFile, tt.prefix, tt.suffix, tt.concurrency)
+
+			if len(os.Args) != tt.wantLen {
+				t.Errorf("os.Args length = %d, want %d", len(os.Args), tt.wantLen)
+			}
+
+			// Verify specific args
+			if os.Args[0] != "gibidify" {
+				t.Errorf("Program name = %s, want gibidify", os.Args[0])
+			}
+			if os.Args[2] != tt.srcDir {
+				t.Errorf("Source dir = %s, want %s", os.Args[2], tt.srcDir)
+			}
+			if os.Args[4] != tt.outFile {
+				t.Errorf("Output file = %s, want %s", os.Args[4], tt.outFile)
+			}
+			if os.Args[6] != tt.prefix {
+				t.Errorf("Prefix = %s, want %s", os.Args[6], tt.prefix)
+			}
+			if os.Args[8] != tt.suffix {
+				t.Errorf("Suffix = %s, want %s", os.Args[8], tt.suffix)
+			}
+			if os.Args[10] != string(rune(tt.concurrency+'0')) {
+				t.Errorf("Concurrency = %s, want %d", os.Args[10], tt.concurrency)
+			}
+		})
+	}
+}

testutil/file_creation_test.go

@@ -0,0 +1,286 @@
+package testutil
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestCreateTestFile(t *testing.T) {
+	tests := []struct {
+		name     string
+		dir      string
+		filename string
+		content  []byte
+		wantErr  bool
+	}{
+		{
+			name:     "create simple test file",
+			filename: "test.txt",
+			content:  []byte("hello world"),
+			wantErr:  false,
+		},
+		{
+			name:     "create file with empty content",
+			filename: "empty.txt",
+			content:  []byte{},
+			wantErr:  false,
+		},
+		{
+			name:     "create file with binary content",
+			filename: "binary.bin",
+			content:  []byte{0x00, 0xFF, 0x42},
+			wantErr:  false,
+		},
+		{
+			name:     "create file with subdirectory",
+			filename: "subdir/test.txt",
+			content:  []byte("nested file"),
+			wantErr:  false,
+		},
+		{
+			name:     "create file with special characters",
+			filename: "special-file_123.go",
+			content:  []byte("package main"),
+			wantErr:  false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Use a temporary directory for each test
+			tempDir := t.TempDir()
+			if tt.dir == "" {
+				tt.dir = tempDir
+			}
+
+			// Create subdirectory if needed
+			if strings.Contains(tt.filename, "/") {
+				subdir := filepath.Join(tt.dir, filepath.Dir(tt.filename))
+				if err := os.MkdirAll(subdir, DirPermission); err != nil {
+					t.Fatalf("Failed to create subdirectory: %v", err)
+				}
+			}
+
+			// Test CreateTestFile
+			filePath := CreateTestFile(t, tt.dir, tt.filename, tt.content)
+
+			// Verify file exists
+			info, err := os.Stat(filePath)
+			if err != nil {
+				t.Fatalf("Created file does not exist: %v", err)
+			}
+
+			// Verify it's a regular file
+			if !info.Mode().IsRegular() {
+				t.Errorf("Created path is not a regular file")
+			}
+
+			// Verify permissions
+			if info.Mode().Perm() != FilePermission {
+				t.Errorf("File permissions = %v, want %v", info.Mode().Perm(), FilePermission)
+			}
+
+			// Verify content
+			readContent, err := os.ReadFile(filePath)
+			if err != nil {
+				t.Fatalf("Failed to read created file: %v", err)
+			}
+			if string(readContent) != string(tt.content) {
+				t.Errorf("File content = %q, want %q", readContent, tt.content)
+			}
+		})
+	}
+}
+
+func TestCreateTempOutputFile(t *testing.T) {
+	tests := []struct {
+		name    string
+		pattern string
+	}{
+		{
+			name:    "simple pattern",
+			pattern: "output-*.txt",
+		},
+		{
+			name:    "pattern with prefix only",
+			pattern: "test-",
+		},
+		{
+			name:    "pattern with suffix only",
+			pattern: "*.json",
+		},
+		{
+			name:    "empty pattern",
+			pattern: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			file, path := CreateTempOutputFile(t, tt.pattern)
+			defer CloseFile(t, file)
+
+			// Verify file exists
+			info, err := os.Stat(path)
+			if err != nil {
+				t.Fatalf("Temp file does not exist: %v", err)
+			}
+
+			// Verify it's a regular file
+			if !info.Mode().IsRegular() {
+				t.Errorf("Created path is not a regular file")
+			}
+
+			// Verify we can write to it
+			testContent := []byte("test content")
+			if _, err := file.Write(testContent); err != nil {
+				t.Errorf("Failed to write to temp file: %v", err)
+			}
+
+			// Verify the path is in a temp directory (any temp directory)
+			if !strings.Contains(path, os.TempDir()) {
+				t.Errorf("Temp file not in temp directory: %s", path)
+			}
+		})
+	}
+}
+
+func TestCreateTestDirectory(t *testing.T) {
+	tests := []struct {
+		name   string
+		parent string
+		dir    string
+	}{
+		{
+			name: "simple directory",
+			dir:  "testdir",
+		},
+		{
+			name: "directory with special characters",
+			dir:  "test-dir_123",
+		},
+		{
+			name: "nested directory name",
+			dir:  "nested/dir",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tempDir := t.TempDir()
+			if tt.parent == "" {
+				tt.parent = tempDir
+			}
+
+			// For nested directories, create parent first
+			if strings.Contains(tt.dir, "/") {
+				parentPath := filepath.Join(tt.parent, filepath.Dir(tt.dir))
+				if err := os.MkdirAll(parentPath, DirPermission); err != nil {
+					t.Fatalf("Failed to create parent directory: %v", err)
+				}
+				tt.dir = filepath.Base(tt.dir)
+				tt.parent = parentPath
+			}
+
+			dirPath := CreateTestDirectory(t, tt.parent, tt.dir)
+
+			// Verify directory exists
+			info, err := os.Stat(dirPath)
+			if err != nil {
+				t.Fatalf("Created directory does not exist: %v", err)
+			}
+
+			// Verify it's a directory
+			if !info.IsDir() {
+				t.Errorf("Created path is not a directory")
+			}
+
+			// Verify permissions
+			if info.Mode().Perm() != DirPermission {
+				t.Errorf("Directory permissions = %v, want %v", info.Mode().Perm(), DirPermission)
+			}
+
+			// Verify we can create files in it
+			testFile := filepath.Join(dirPath, "test.txt")
+			if err := os.WriteFile(testFile, []byte("test"), FilePermission); err != nil {
+				t.Errorf("Cannot create file in directory: %v", err)
+			}
+		})
+	}
+}
+
+func TestCreateTestFiles(t *testing.T) {
+	tests := []struct {
+		name      string
+		fileSpecs []FileSpec
+		wantCount int
+	}{
+		{
+			name: "create multiple files",
+			fileSpecs: []FileSpec{
+				{Name: "file1.txt", Content: "content1"},
+				{Name: "file2.go", Content: "package main"},
+				{Name: "file3.json", Content: `{"key": "value"}`},
+			},
+			wantCount: 3,
+		},
+		{
+			name: "create files with subdirectories",
+			fileSpecs: []FileSpec{
+				{Name: "src/main.go", Content: "package main"},
+				{Name: "test/test.go", Content: "package test"},
+			},
+			wantCount: 2,
+		},
+		{
+			name:      "empty file specs",
+			fileSpecs: []FileSpec{},
+			wantCount: 0,
+		},
+		{
+			name: "files with empty content",
+			fileSpecs: []FileSpec{
+				{Name: "empty1.txt", Content: ""},
+				{Name: "empty2.txt", Content: ""},
+			},
+			wantCount: 2,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			rootDir := t.TempDir()
+
+			// Create necessary subdirectories
+			for _, spec := range tt.fileSpecs {
+				if strings.Contains(spec.Name, "/") {
+					subdir := filepath.Join(rootDir, filepath.Dir(spec.Name))
+					if err := os.MkdirAll(subdir, DirPermission); err != nil {
+						t.Fatalf("Failed to create subdirectory: %v", err)
+					}
+				}
+			}
+
+			createdFiles := CreateTestFiles(t, rootDir, tt.fileSpecs)
+
+			// Verify count
+			if len(createdFiles) != tt.wantCount {
+				t.Errorf("Created %d files, want %d", len(createdFiles), tt.wantCount)
+			}
+
+			// Verify each file
+			for i, filePath := range createdFiles {
+				content, err := os.ReadFile(filePath)
+				if err != nil {
+					t.Errorf("Failed to read file %s: %v", filePath, err)
+					continue
+				}
+				if string(content) != tt.fileSpecs[i].Content {
+					t.Errorf("File %s content = %q, want %q", filePath, content, tt.fileSpecs[i].Content)
+				}
+			}
+		})
+	}
+}

testutil/testutil.go

@@ -0,0 +1,117 @@
+// Package testutil provides common testing utilities and helper functions.
+package testutil
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/spf13/viper"
+
+	"github.com/ivuorinen/gibidify/config"
+)
+
+const (
+	// FilePermission is the default file permission for test files.
+	FilePermission = 0o644
+	// DirPermission is the default directory permission for test directories.
+	DirPermission = 0o755
+)
+
+// CreateTestFile creates a test file with the given content and returns its path.
+func CreateTestFile(t *testing.T, dir, filename string, content []byte) string {
+	t.Helper()
+	filePath := filepath.Join(dir, filename)
+	if err := os.WriteFile(filePath, content, FilePermission); err != nil {
+		t.Fatalf("Failed to write file %s: %v", filePath, err)
+	}
+	return filePath
+}
+
+// CreateTempOutputFile creates a temporary output file and returns the file handle and path.
+func CreateTempOutputFile(t *testing.T, pattern string) (file *os.File, path string) {
+	t.Helper()
+	outFile, err := os.CreateTemp(t.TempDir(), pattern)
+	if err != nil {
+		t.Fatalf("Failed to create temp output file: %v", err)
+	}
+	path = outFile.Name()
+	return outFile, path
+}
+
+// CreateTestDirectory creates a test directory and returns its path.
+func CreateTestDirectory(t *testing.T, parent, name string) string {
+	t.Helper()
+	dirPath := filepath.Join(parent, name)
+	if err := os.Mkdir(dirPath, DirPermission); err != nil {
+		t.Fatalf("Failed to create directory %s: %v", dirPath, err)
+	}
+	return dirPath
+}
+
+// FileSpec represents a file specification for creating test files.
+type FileSpec struct {
+	Name    string
+	Content string
+}
+
+// CreateTestFiles creates multiple test files from specifications.
+func CreateTestFiles(t *testing.T, rootDir string, fileSpecs []FileSpec) []string {
+	t.Helper()
+	createdFiles := make([]string, 0, len(fileSpecs))
+	for _, spec := range fileSpecs {
+		filePath := CreateTestFile(t, rootDir, spec.Name, []byte(spec.Content))
+		createdFiles = append(createdFiles, filePath)
+	}
+	return createdFiles
+}
+
+// ResetViperConfig resets Viper configuration and optionally sets a config path.
+func ResetViperConfig(t *testing.T, configPath string) {
+	t.Helper()
+	viper.Reset()
+	if configPath != "" {
+		viper.AddConfigPath(configPath)
+	}
+	config.LoadConfig()
+}
+
+// SetupCLIArgs configures os.Args for CLI testing.
+func SetupCLIArgs(srcDir, outFilePath, prefix, suffix string, concurrency int) {
+	os.Args = []string{
+		"gibidify",
+		"-source", srcDir,
+		"-destination", outFilePath,
+		"-prefix", prefix,
+		"-suffix", suffix,
+		"-concurrency", strconv.Itoa(concurrency),
+	}
+}
+
+// VerifyContentContains checks that content contains all expected substrings.
+func VerifyContentContains(t *testing.T, content string, expectedSubstrings []string) {
+	t.Helper()
+	for _, expected := range expectedSubstrings {
+		if !strings.Contains(content, expected) {
+			t.Errorf("Content missing expected substring: %s", expected)
+		}
+	}
+}
+
+// MustSucceed fails the test if the error is not nil.
+func MustSucceed(t *testing.T, err error, operation string) {
+	t.Helper()
+	if err != nil {
+		t.Fatalf("Operation %s failed: %v", operation, err)
+	}
+}
+
+// CloseFile closes a file and reports errors to the test.
+func CloseFile(t *testing.T, file *os.File) {
+	t.Helper()
+	if err := file.Close(); err != nil {
+		t.Errorf("Failed to close file: %v", err)
+	}
+}

testutil/verification_test.go

@@ -0,0 +1,107 @@
+package testutil
+
+import (
+	"errors"
+	"os"
+	"testing"
+)
+
+func TestVerifyContentContains(t *testing.T) {
+	// Test successful verification
+	t.Run("all substrings present", func(t *testing.T) {
+		content := "This is a test file with multiple lines"
+		VerifyContentContains(t, content, []string{"test file", "multiple lines"})
+		// If we get here, the test passed
+	})
+
+	// Test empty expected substrings
+	t.Run("empty expected substrings", func(t *testing.T) {
+		content := "Any content"
+		VerifyContentContains(t, content, []string{})
+		// Should pass with no expected strings
+	})
+
+	// For failure cases, we'll test indirectly by verifying behavior
+	t.Run("verify error reporting", func(t *testing.T) {
+		// We can't easily test the failure case directly since it calls t.Errorf
+		// But we can at least verify the function doesn't panic
+		defer func() {
+			if r := recover(); r != nil {
+				t.Errorf("VerifyContentContains panicked: %v", r)
+			}
+		}()
+
+		// This would normally fail but we're just checking it doesn't panic
+		content := "test"
+		expected := []string{"not found"}
+		// Create a sub-test that we expect to fail
+		t.Run("expected_failure", func(t *testing.T) {
+			t.Skip("Skipping actual failure test")
+			VerifyContentContains(t, content, expected)
+		})
+	})
+}
+
+func TestMustSucceed(t *testing.T) {
+	// Test with nil error (should succeed)
+	t.Run("nil error", func(t *testing.T) {
+		MustSucceed(t, nil, "successful operation")
+		// If we get here, the test passed
+	})
+
+	// Test error behavior without causing test failure
+	t.Run("verify error handling", func(t *testing.T) {
+		// We can't test the failure case directly since it calls t.Fatalf
+		// But we can verify the function exists and is callable
+		defer func() {
+			if r := recover(); r != nil {
+				t.Errorf("MustSucceed panicked: %v", r)
+			}
+		}()
+
+		// Create a sub-test that we expect to fail
+		t.Run("expected_failure", func(t *testing.T) {
+			t.Skip("Skipping actual failure test")
+			MustSucceed(t, errors.New("test error"), "failed operation")
+		})
+	})
+}
+
+func TestCloseFile(t *testing.T) {
+	// Test closing a normal file
+	t.Run("close normal file", func(t *testing.T) {
+		file, err := os.CreateTemp(t.TempDir(), "test")
+		if err != nil {
+			t.Fatalf("Failed to create test file: %v", err)
+		}
+
+		CloseFile(t, file)
+
+		// Verify file is closed by trying to write to it
+		_, writeErr := file.Write([]byte("test"))
+		if writeErr == nil {
+			t.Error("Expected write to fail on closed file")
+		}
+	})
+
+	// Test that CloseFile doesn't panic on already closed files
+	// Note: We can't easily test the error case without causing test failure
+	// since CloseFile calls t.Errorf, which is the expected behavior
+	t.Run("verify CloseFile function exists and is callable", func(t *testing.T) {
+		// This test just verifies the function signature and basic functionality
+		// The error case is tested in integration tests where failures are expected
+		file, err := os.CreateTemp(t.TempDir(), "test")
+		if err != nil {
+			t.Fatalf("Failed to create test file: %v", err)
+		}
+
+		// Test normal case - file should close successfully
+		CloseFile(t, file)
+
+		// Verify file is closed
+		_, writeErr := file.Write([]byte("test"))
+		if writeErr == nil {
+			t.Error("Expected write to fail on closed file")
+		}
+	})
+}

utils/errors.go

@@ -0,0 +1,240 @@
+// Package utils provides common utility functions.
+package utils
+
+import (
+	"fmt"
+
+	"github.com/sirupsen/logrus"
+)
+
+// ErrorType represents the category of error.
+type ErrorType int
+
+const (
+	// ErrorTypeUnknown represents an unknown error type.
+	ErrorTypeUnknown ErrorType = iota
+	// ErrorTypeCLI represents command-line interface errors.
+	ErrorTypeCLI
+	// ErrorTypeFileSystem represents file system operation errors.
+	ErrorTypeFileSystem
+	// ErrorTypeProcessing represents file processing errors.
+	ErrorTypeProcessing
+	// ErrorTypeConfiguration represents configuration errors.
+	ErrorTypeConfiguration
+	// ErrorTypeIO represents input/output errors.
+	ErrorTypeIO
+	// ErrorTypeValidation represents validation errors.
+	ErrorTypeValidation
+)
+
+// String returns the string representation of the error type.
+func (e ErrorType) String() string {
+	switch e {
+	case ErrorTypeCLI:
+		return "CLI"
+	case ErrorTypeFileSystem:
+		return "FileSystem"
+	case ErrorTypeProcessing:
+		return "Processing"
+	case ErrorTypeConfiguration:
+		return "Configuration"
+	case ErrorTypeIO:
+		return "IO"
+	case ErrorTypeValidation:
+		return "Validation"
+	default:
+		return "Unknown"
+	}
+}
+
+// StructuredError represents a structured error with type, code, and context.
+type StructuredError struct {
+	Type     ErrorType
+	Code     string
+	Message  string
+	Cause    error
+	Context  map[string]any
+	FilePath string
+	Line     int
+}
+
+// Error implements the error interface.
+func (e *StructuredError) Error() string {
+	if e.Cause != nil {
+		return fmt.Sprintf("%s [%s]: %s: %v", e.Type, e.Code, e.Message, e.Cause)
+	}
+	return fmt.Sprintf("%s [%s]: %s", e.Type, e.Code, e.Message)
+}
+
+// Unwrap returns the underlying cause error.
+func (e *StructuredError) Unwrap() error {
+	return e.Cause
+}
+
+// WithContext adds context information to the error.
+func (e *StructuredError) WithContext(key string, value any) *StructuredError {
+	if e.Context == nil {
+		e.Context = make(map[string]any)
+	}
+	e.Context[key] = value
+	return e
+}
+
+// WithFilePath adds file path information to the error.
+func (e *StructuredError) WithFilePath(filePath string) *StructuredError {
+	e.FilePath = filePath
+	return e
+}
+
+// WithLine adds line number information to the error.
+func (e *StructuredError) WithLine(line int) *StructuredError {
+	e.Line = line
+	return e
+}
+
+// NewStructuredError creates a new structured error.
+func NewStructuredError(errorType ErrorType, code, message, filePath string, context map[string]interface{}) *StructuredError {
+	return &StructuredError{
+		Type:     errorType,
+		Code:     code,
+		Message:  message,
+		FilePath: filePath,
+		Context:  context,
+	}
+}
+
+// NewStructuredErrorf creates a new structured error with formatted message.
+func NewStructuredErrorf(errorType ErrorType, code, format string, args ...any) *StructuredError {
+	return &StructuredError{
+		Type:    errorType,
+		Code:    code,
+		Message: fmt.Sprintf(format, args...),
+	}
+}
+
+// WrapError wraps an existing error with structured error information.
+func WrapError(err error, errorType ErrorType, code, message string) *StructuredError {
+	return &StructuredError{
+		Type:    errorType,
+		Code:    code,
+		Message: message,
+		Cause:   err,
+	}
+}
+
+// WrapErrorf wraps an existing error with formatted message.
+func WrapErrorf(err error, errorType ErrorType, code, format string, args ...any) *StructuredError {
+	return &StructuredError{
+		Type:    errorType,
+		Code:    code,
+		Message: fmt.Sprintf(format, args...),
+		Cause:   err,
+	}
+}
+
+// Common error codes for each type
+const (
+	// CLI Error Codes
+	CodeCLIMissingSource = "MISSING_SOURCE"
+	CodeCLIInvalidArgs   = "INVALID_ARGS"
+
+	// FileSystem Error Codes
+	CodeFSPathResolution = "PATH_RESOLUTION"
+	CodeFSPermission     = "PERMISSION_DENIED"
+	CodeFSNotFound       = "NOT_FOUND"
+	CodeFSAccess         = "ACCESS_DENIED"
+
+	// Processing Error Codes
+	CodeProcessingFileRead   = "FILE_READ"
+	CodeProcessingCollection = "COLLECTION"
+	CodeProcessingTraversal  = "TRAVERSAL"
+	CodeProcessingEncode     = "ENCODE"
+
+	// Configuration Error Codes
+	CodeConfigValidation = "VALIDATION"
+	CodeConfigMissing    = "MISSING"
+
+	// IO Error Codes
+	CodeIOFileCreate = "FILE_CREATE"
+	CodeIOFileWrite  = "FILE_WRITE"
+	CodeIOEncoding   = "ENCODING"
+	CodeIOWrite      = "WRITE"
+	CodeIORead       = "READ"
+	CodeIOClose      = "CLOSE"
+
+	// Validation Error Codes
+	CodeValidationFormat   = "FORMAT"
+	CodeValidationFileType = "FILE_TYPE"
+	CodeValidationSize     = "SIZE_LIMIT"
+	CodeValidationRequired = "REQUIRED"
+	CodeValidationPath     = "PATH_TRAVERSAL"
+
+	// Resource Limit Error Codes
+	CodeResourceLimitFiles       = "FILE_COUNT_LIMIT"
+	CodeResourceLimitTotalSize   = "TOTAL_SIZE_LIMIT"
+	CodeResourceLimitTimeout     = "TIMEOUT"
+	CodeResourceLimitMemory      = "MEMORY_LIMIT"
+	CodeResourceLimitConcurrency = "CONCURRENCY_LIMIT"
+	CodeResourceLimitRate        = "RATE_LIMIT"
+)
+
+// Predefined error constructors for common error scenarios
+
+// NewCLIMissingSourceError creates a CLI error for missing source argument.
+func NewCLIMissingSourceError() *StructuredError {
+	return NewStructuredError(ErrorTypeCLI, CodeCLIMissingSource, "usage: gibidify -source <source_directory> [--destination <output_file>] [--format=json|yaml|markdown]", "", nil)
+}
+
+// NewFileSystemError creates a file system error.
+func NewFileSystemError(code, message string) *StructuredError {
+	return NewStructuredError(ErrorTypeFileSystem, code, message, "", nil)
+}
+
+// NewProcessingError creates a processing error.
+func NewProcessingError(code, message string) *StructuredError {
+	return NewStructuredError(ErrorTypeProcessing, code, message, "", nil)
+}
+
+// NewIOError creates an IO error.
+func NewIOError(code, message string) *StructuredError {
+	return NewStructuredError(ErrorTypeIO, code, message, "", nil)
+}
+
+// NewValidationError creates a validation error.
+func NewValidationError(code, message string) *StructuredError {
+	return NewStructuredError(ErrorTypeValidation, code, message, "", nil)
+}
+
+// LogError logs an error with a consistent format if the error is not nil.
+// The operation parameter describes what was being attempted.
+// Additional context can be provided via the args parameter.
+func LogError(operation string, err error, args ...any) {
+	if err != nil {
+		msg := operation
+		if len(args) > 0 {
+			// Format the operation string with the provided arguments
+			msg = fmt.Sprintf(operation, args...)
+		}
+
+		// Check if it's a structured error and log with additional context
+		if structErr, ok := err.(*StructuredError); ok {
+			logrus.WithFields(logrus.Fields{
+				"error_type": structErr.Type.String(),
+				"error_code": structErr.Code,
+				"context":    structErr.Context,
+				"file_path":  structErr.FilePath,
+				"line":       structErr.Line,
+			}).Errorf("%s: %v", msg, err)
+		} else {
+			logrus.Errorf("%s: %v", msg, err)
+		}
+	}
+}
+
+// LogErrorf logs an error with a formatted message if the error is not nil.
+// This is a convenience wrapper around LogError for cases where formatting is needed.
+func LogErrorf(err error, format string, args ...any) {
+	if err != nil {
+		LogError(format, err, args...)
+	}
+}

utils/errors_test.go

@@ -0,0 +1,242 @@
+package utils
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/sirupsen/logrus"
+)
+
+// captureLogOutput captures logrus output for testing
+func captureLogOutput(f func()) string {
+	var buf bytes.Buffer
+	logrus.SetOutput(&buf)
+	defer logrus.SetOutput(logrus.StandardLogger().Out)
+	f()
+	return buf.String()
+}
+
+func TestLogError(t *testing.T) {
+	tests := []struct {
+		name      string
+		operation string
+		err       error
+		args      []any
+		wantLog   string
+		wantEmpty bool
+	}{
+		{
+			name:      "nil error should not log",
+			operation: "test operation",
+			err:       nil,
+			args:      nil,
+			wantEmpty: true,
+		},
+		{
+			name:      "basic error logging",
+			operation: "failed to read file",
+			err:       errors.New("permission denied"),
+			args:      nil,
+			wantLog:   "failed to read file: permission denied",
+		},
+		{
+			name:      "error with formatting args",
+			operation: "failed to process file %s",
+			err:       errors.New("file too large"),
+			args:      []any{"test.txt"},
+			wantLog:   "failed to process file test.txt: file too large",
+		},
+		{
+			name:      "error with multiple formatting args",
+			operation: "failed to copy from %s to %s",
+			err:       errors.New("disk full"),
+			args:      []any{"source.txt", "dest.txt"},
+			wantLog:   "failed to copy from source.txt to dest.txt: disk full",
+		},
+		{
+			name:      "wrapped error",
+			operation: "database operation failed",
+			err:       fmt.Errorf("connection error: %w", errors.New("timeout")),
+			args:      nil,
+			wantLog:   "database operation failed: connection error: timeout",
+		},
+		{
+			name:      "empty operation string",
+			operation: "",
+			err:       errors.New("some error"),
+			args:      nil,
+			wantLog:   ": some error",
+		},
+		{
+			name:      "operation with percentage sign",
+			operation: "processing 50% complete",
+			err:       errors.New("interrupted"),
+			args:      nil,
+			wantLog:   "processing 50% complete: interrupted",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			output := captureLogOutput(func() {
+				LogError(tt.operation, tt.err, tt.args...)
+			})
+
+			if tt.wantEmpty {
+				if output != "" {
+					t.Errorf("LogError() logged output when error was nil: %q", output)
+				}
+				return
+			}
+
+			if !strings.Contains(output, tt.wantLog) {
+				t.Errorf("LogError() output = %q, want to contain %q", output, tt.wantLog)
+			}
+
+			// Verify it's logged at ERROR level
+			if !strings.Contains(output, "level=error") {
+				t.Errorf("LogError() should log at ERROR level, got: %q", output)
+			}
+		})
+	}
+}
+
+func TestLogErrorf(t *testing.T) {
+	tests := []struct {
+		name      string
+		err       error
+		format    string
+		args      []any
+		wantLog   string
+		wantEmpty bool
+	}{
+		{
+			name:      "nil error should not log",
+			err:       nil,
+			format:    "operation %s failed",
+			args:      []any{"test"},
+			wantEmpty: true,
+		},
+		{
+			name:    "basic formatted error",
+			err:     errors.New("not found"),
+			format:  "file %s not found",
+			args:    []any{"config.yaml"},
+			wantLog: "file config.yaml not found: not found",
+		},
+		{
+			name:    "multiple format arguments",
+			err:     errors.New("invalid range"),
+			format:  "value %d is not between %d and %d",
+			args:    []any{150, 0, 100},
+			wantLog: "value 150 is not between 0 and 100: invalid range",
+		},
+		{
+			name:    "no format arguments",
+			err:     errors.New("generic error"),
+			format:  "operation failed",
+			args:    nil,
+			wantLog: "operation failed: generic error",
+		},
+		{
+			name:    "format with different types",
+			err:     errors.New("type mismatch"),
+			format:  "expected %s but got %d",
+			args:    []any{"string", 42},
+			wantLog: "expected string but got 42: type mismatch",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			output := captureLogOutput(func() {
+				LogErrorf(tt.err, tt.format, tt.args...)
+			})
+
+			if tt.wantEmpty {
+				if output != "" {
+					t.Errorf("LogErrorf() logged output when error was nil: %q", output)
+				}
+				return
+			}
+
+			if !strings.Contains(output, tt.wantLog) {
+				t.Errorf("LogErrorf() output = %q, want to contain %q", output, tt.wantLog)
+			}
+
+			// Verify it's logged at ERROR level
+			if !strings.Contains(output, "level=error") {
+				t.Errorf("LogErrorf() should log at ERROR level, got: %q", output)
+			}
+		})
+	}
+}
+
+func TestLogErrorConcurrency(t *testing.T) {
+	// Test that LogError is safe for concurrent use
+	done := make(chan bool)
+	for i := 0; i < 10; i++ {
+		go func(n int) {
+			LogError("concurrent operation", fmt.Errorf("error %d", n))
+			done <- true
+		}(i)
+	}
+
+	// Wait for all goroutines to complete
+	for i := 0; i < 10; i++ {
+		<-done
+	}
+}
+
+func TestLogErrorfConcurrency(t *testing.T) {
+	// Test that LogErrorf is safe for concurrent use
+	done := make(chan bool)
+	for i := 0; i < 10; i++ {
+		go func(n int) {
+			LogErrorf(fmt.Errorf("error %d", n), "concurrent operation %d", n)
+			done <- true
+		}(i)
+	}
+
+	// Wait for all goroutines to complete
+	for i := 0; i < 10; i++ {
+		<-done
+	}
+}
+
+// BenchmarkLogError benchmarks the LogError function
+func BenchmarkLogError(b *testing.B) {
+	err := errors.New("benchmark error")
+	// Disable output during benchmark
+	logrus.SetOutput(bytes.NewBuffer(nil))
+	defer logrus.SetOutput(logrus.StandardLogger().Out)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		LogError("benchmark operation", err)
+	}
+}
+
+// BenchmarkLogErrorf benchmarks the LogErrorf function
+func BenchmarkLogErrorf(b *testing.B) {
+	err := errors.New("benchmark error")
+	// Disable output during benchmark
+	logrus.SetOutput(bytes.NewBuffer(nil))
+	defer logrus.SetOutput(logrus.StandardLogger().Out)
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		LogErrorf(err, "benchmark operation %d", i)
+	}
+}
+
+// BenchmarkLogErrorNil benchmarks LogError with nil error (no-op case)
+func BenchmarkLogErrorNil(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		LogError("benchmark operation", nil)
+	}
+}

utils/paths.go

@@ -0,0 +1,167 @@
+// Package utils provides common utility functions.
+package utils
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// GetAbsolutePath returns the absolute path for the given path.
+// It wraps filepath.Abs with consistent error handling.
+func GetAbsolutePath(path string) (string, error) {
+	abs, err := filepath.Abs(path)
+	if err != nil {
+		return "", fmt.Errorf("failed to get absolute path for %s: %w", path, err)
+	}
+	return abs, nil
+}
+
+// GetBaseName returns the base name for the given path, handling special cases.
+func GetBaseName(absPath string) string {
+	baseName := filepath.Base(absPath)
+	if baseName == "." || baseName == "" {
+		return "output"
+	}
+	return baseName
+}
+
+// ValidateSourcePath validates a source directory path for security.
+// It ensures the path exists, is a directory, and doesn't contain path traversal attempts.
+func ValidateSourcePath(path string) error {
+	if path == "" {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationRequired, "source path is required", "", nil)
+	}
+
+	// Check for path traversal patterns before cleaning
+	if strings.Contains(path, "..") {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "path traversal attempt detected in source path", path, map[string]interface{}{
+			"original_path": path,
+		})
+	}
+
+	// Clean and get absolute path
+	cleaned := filepath.Clean(path)
+	abs, err := filepath.Abs(cleaned)
+	if err != nil {
+		return NewStructuredError(ErrorTypeFileSystem, CodeFSPathResolution, "cannot resolve source path", path, map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Get current working directory to ensure we're not escaping it for relative paths
+	if !filepath.IsAbs(path) {
+		cwd, err := os.Getwd()
+		if err != nil {
+			return NewStructuredError(ErrorTypeFileSystem, CodeFSPathResolution, "cannot get current working directory", path, map[string]interface{}{
+				"error": err.Error(),
+			})
+		}
+
+		// Ensure the resolved path is within or below the current working directory
+		cwdAbs, err := filepath.Abs(cwd)
+		if err != nil {
+			return NewStructuredError(ErrorTypeFileSystem, CodeFSPathResolution, "cannot resolve current working directory", path, map[string]interface{}{
+				"error": err.Error(),
+			})
+		}
+
+		// Check if the absolute path tries to escape the current working directory
+		if !strings.HasPrefix(abs, cwdAbs) {
+			return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "source path attempts to access directories outside current working directory", path, map[string]interface{}{
+				"resolved_path": abs,
+				"working_dir":   cwdAbs,
+			})
+		}
+	}
+
+	// Check if path exists and is a directory
+	info, err := os.Stat(cleaned)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return NewStructuredError(ErrorTypeFileSystem, CodeFSNotFound, "source directory does not exist", path, nil)
+		}
+		return NewStructuredError(ErrorTypeFileSystem, CodeFSAccess, "cannot access source directory", path, map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	if !info.IsDir() {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "source path must be a directory", path, map[string]interface{}{
+			"is_file": true,
+		})
+	}
+
+	return nil
+}
+
+// ValidateDestinationPath validates a destination file path for security.
+// It ensures the path doesn't contain path traversal attempts and the parent directory exists.
+func ValidateDestinationPath(path string) error {
+	if path == "" {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationRequired, "destination path is required", "", nil)
+	}
+
+	// Check for path traversal patterns before cleaning
+	if strings.Contains(path, "..") {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "path traversal attempt detected in destination path", path, map[string]interface{}{
+			"original_path": path,
+		})
+	}
+
+	// Clean and validate the path
+	cleaned := filepath.Clean(path)
+
+	// Get absolute path to ensure it's not trying to escape current working directory
+	abs, err := filepath.Abs(cleaned)
+	if err != nil {
+		return NewStructuredError(ErrorTypeFileSystem, CodeFSPathResolution, "cannot resolve destination path", path, map[string]interface{}{
+			"error": err.Error(),
+		})
+	}
+
+	// Ensure the destination is not a directory
+	if info, err := os.Stat(abs); err == nil && info.IsDir() {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "destination cannot be a directory", path, map[string]interface{}{
+			"is_directory": true,
+		})
+	}
+
+	// Check if parent directory exists and is writable
+	parentDir := filepath.Dir(abs)
+	if parentInfo, err := os.Stat(parentDir); err != nil {
+		if os.IsNotExist(err) {
+			return NewStructuredError(ErrorTypeFileSystem, CodeFSNotFound, "destination parent directory does not exist", path, map[string]interface{}{
+				"parent_dir": parentDir,
+			})
+		}
+		return NewStructuredError(ErrorTypeFileSystem, CodeFSAccess, "cannot access destination parent directory", path, map[string]interface{}{
+			"parent_dir": parentDir,
+			"error":      err.Error(),
+		})
+	} else if !parentInfo.IsDir() {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "destination parent is not a directory", path, map[string]interface{}{
+			"parent_dir": parentDir,
+		})
+	}
+
+	return nil
+}
+
+// ValidateConfigPath validates a configuration file path for security.
+// It ensures the path doesn't contain path traversal attempts.
+func ValidateConfigPath(path string) error {
+	if path == "" {
+		return nil // Empty path is allowed for config
+	}
+
+	// Check for path traversal patterns before cleaning
+	if strings.Contains(path, "..") {
+		return NewStructuredError(ErrorTypeValidation, CodeValidationPath, "path traversal attempt detected in config path", path, map[string]interface{}{
+			"original_path": path,
+		})
+	}
+
+	return nil
+}

utils/paths_test.go

@@ -0,0 +1,262 @@
+package utils
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestGetAbsolutePath(t *testing.T) {
+	// Get current working directory for tests
+	cwd, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("Failed to get current directory: %v", err)
+	}
+
+	tests := []struct {
+		name        string
+		path        string
+		wantPrefix  string
+		wantErr     bool
+		wantErrMsg  string
+		skipWindows bool
+	}{
+		{
+			name:       "absolute path unchanged",
+			path:       cwd,
+			wantPrefix: cwd,
+			wantErr:    false,
+		},
+		{
+			name:       "relative path current directory",
+			path:       ".",
+			wantPrefix: cwd,
+			wantErr:    false,
+		},
+		{
+			name:       "relative path parent directory",
+			path:       "..",
+			wantPrefix: filepath.Dir(cwd),
+			wantErr:    false,
+		},
+		{
+			name:       "relative path with file",
+			path:       "test.txt",
+			wantPrefix: filepath.Join(cwd, "test.txt"),
+			wantErr:    false,
+		},
+		{
+			name:       "relative path with subdirectory",
+			path:       "subdir/file.go",
+			wantPrefix: filepath.Join(cwd, "subdir", "file.go"),
+			wantErr:    false,
+		},
+		{
+			name:       "empty path",
+			path:       "",
+			wantPrefix: cwd,
+			wantErr:    false,
+		},
+		{
+			name:        "path with tilde",
+			path:        "~/test",
+			wantPrefix:  filepath.Join(cwd, "~", "test"),
+			wantErr:     false,
+			skipWindows: false,
+		},
+		{
+			name:       "path with multiple separators",
+			path:       "path//to///file",
+			wantPrefix: filepath.Join(cwd, "path", "to", "file"),
+			wantErr:    false,
+		},
+		{
+			name:       "path with trailing separator",
+			path:       "path/",
+			wantPrefix: filepath.Join(cwd, "path"),
+			wantErr:    false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.skipWindows && runtime.GOOS == "windows" {
+				t.Skip("Skipping test on Windows")
+			}
+
+			got, err := GetAbsolutePath(tt.path)
+
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("GetAbsolutePath() error = nil, wantErr %v", tt.wantErr)
+					return
+				}
+				if tt.wantErrMsg != "" && !strings.Contains(err.Error(), tt.wantErrMsg) {
+					t.Errorf("GetAbsolutePath() error = %v, want error containing %v", err, tt.wantErrMsg)
+				}
+				return
+			}
+
+			if err != nil {
+				t.Errorf("GetAbsolutePath() unexpected error = %v", err)
+				return
+			}
+
+			// Clean the expected path for comparison
+			wantClean := filepath.Clean(tt.wantPrefix)
+			gotClean := filepath.Clean(got)
+
+			if gotClean != wantClean {
+				t.Errorf("GetAbsolutePath() = %v, want %v", gotClean, wantClean)
+			}
+
+			// Verify the result is actually absolute
+			if !filepath.IsAbs(got) {
+				t.Errorf("GetAbsolutePath() returned non-absolute path: %v", got)
+			}
+		})
+	}
+}
+
+func TestGetAbsolutePathSpecialCases(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("Skipping Unix-specific tests on Windows")
+	}
+
+	tests := []struct {
+		name    string
+		setup   func() (string, func())
+		path    string
+		wantErr bool
+	}{
+		{
+			name: "symlink to directory",
+			setup: func() (string, func()) {
+				tmpDir := t.TempDir()
+				target := filepath.Join(tmpDir, "target")
+				link := filepath.Join(tmpDir, "link")
+
+				if err := os.Mkdir(target, 0o755); err != nil {
+					t.Fatalf("Failed to create target directory: %v", err)
+				}
+				if err := os.Symlink(target, link); err != nil {
+					t.Fatalf("Failed to create symlink: %v", err)
+				}
+
+				return link, func() {}
+			},
+			path:    "",
+			wantErr: false,
+		},
+		{
+			name: "broken symlink",
+			setup: func() (string, func()) {
+				tmpDir := t.TempDir()
+				link := filepath.Join(tmpDir, "broken_link")
+
+				if err := os.Symlink("/nonexistent/path", link); err != nil {
+					t.Fatalf("Failed to create broken symlink: %v", err)
+				}
+
+				return link, func() {}
+			},
+			path:    "",
+			wantErr: false, // filepath.Abs still works with broken symlinks
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			path, cleanup := tt.setup()
+			defer cleanup()
+
+			if tt.path == "" {
+				tt.path = path
+			}
+
+			got, err := GetAbsolutePath(tt.path)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("GetAbsolutePath() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			if err == nil && !filepath.IsAbs(got) {
+				t.Errorf("GetAbsolutePath() returned non-absolute path: %v", got)
+			}
+		})
+	}
+}
+
+func TestGetAbsolutePathConcurrency(t *testing.T) {
+	// Test that GetAbsolutePath is safe for concurrent use
+	paths := []string{".", "..", "test.go", "subdir/file.txt", "/tmp/test"}
+	done := make(chan bool)
+
+	for _, p := range paths {
+		go func(path string) {
+			_, _ = GetAbsolutePath(path)
+			done <- true
+		}(p)
+	}
+
+	// Wait for all goroutines to complete
+	for range paths {
+		<-done
+	}
+}
+
+func TestGetAbsolutePathErrorFormatting(t *testing.T) {
+	// This test verifies error message formatting
+	// We need to trigger an actual error from filepath.Abs
+	// On Unix systems, we can't easily trigger filepath.Abs errors
+	// so we'll just verify the error wrapping works correctly
+
+	// Create a test that would fail if filepath.Abs returns an error
+	path := "test/path"
+	got, err := GetAbsolutePath(path)
+	if err != nil {
+		// If we somehow get an error, verify it's properly formatted
+		if !strings.Contains(err.Error(), "failed to get absolute path for") {
+			t.Errorf("Error message format incorrect: %v", err)
+		}
+		if !strings.Contains(err.Error(), path) {
+			t.Errorf("Error message should contain original path: %v", err)
+		}
+	} else {
+		// Normal case - just verify we got a valid absolute path
+		if !filepath.IsAbs(got) {
+			t.Errorf("Expected absolute path, got: %v", got)
+		}
+	}
+}
+
+// BenchmarkGetAbsolutePath benchmarks the GetAbsolutePath function
+func BenchmarkGetAbsolutePath(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = GetAbsolutePath("test/path/file.go")
+	}
+}
+
+// BenchmarkGetAbsolutePathAbs benchmarks with already absolute path
+func BenchmarkGetAbsolutePathAbs(b *testing.B) {
+	absPath := "/home/user/test/file.go"
+	if runtime.GOOS == "windows" {
+		absPath = "C:\\Users\\test\\file.go"
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = GetAbsolutePath(absPath)
+	}
+}
+
+// BenchmarkGetAbsolutePathCurrent benchmarks with current directory
+func BenchmarkGetAbsolutePathCurrent(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, _ = GetAbsolutePath(".")
+	}
+}

utils/writers.go

@@ -0,0 +1,138 @@
+package utils
+
+import (
+	"encoding/json"
+	"io"
+	"strings"
+)
+
+// SafeCloseReader safely closes a reader if it implements io.Closer.
+// This eliminates the duplicated closeReader methods across all writers.
+func SafeCloseReader(reader io.Reader, path string) {
+	if closer, ok := reader.(io.Closer); ok {
+		if err := closer.Close(); err != nil {
+			LogError(
+				"Failed to close file reader",
+				WrapError(err, ErrorTypeIO, CodeIOClose, "failed to close file reader").WithFilePath(path),
+			)
+		}
+	}
+}
+
+// WriteWithErrorWrap performs file writing with consistent error handling.
+// This centralizes the common pattern of writing strings with error wrapping.
+func WriteWithErrorWrap(writer io.Writer, content, errorMsg, filePath string) error {
+	if _, err := writer.Write([]byte(content)); err != nil {
+		wrappedErr := WrapError(err, ErrorTypeIO, CodeIOWrite, errorMsg)
+		if filePath != "" {
+			wrappedErr = wrappedErr.WithFilePath(filePath)
+		}
+		return wrappedErr
+	}
+	return nil
+}
+
+// StreamContent provides a common streaming implementation with chunk processing.
+// This eliminates the similar streaming patterns across JSON and Markdown writers.
+func StreamContent(reader io.Reader, writer io.Writer, chunkSize int, filePath string, processChunk func([]byte) []byte) error {
+	buf := make([]byte, chunkSize)
+	for {
+		n, err := reader.Read(buf)
+		if n > 0 {
+			processed := buf[:n]
+			if processChunk != nil {
+				processed = processChunk(processed)
+			}
+			if _, writeErr := writer.Write(processed); writeErr != nil {
+				wrappedErr := WrapError(writeErr, ErrorTypeIO, CodeIOWrite, "failed to write content chunk")
+				if filePath != "" {
+					wrappedErr = wrappedErr.WithFilePath(filePath)
+				}
+				return wrappedErr
+			}
+		}
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			wrappedErr := WrapError(err, ErrorTypeIO, CodeIORead, "failed to read content chunk")
+			if filePath != "" {
+				wrappedErr = wrappedErr.WithFilePath(filePath)
+			}
+			return wrappedErr
+		}
+	}
+	return nil
+}
+
+// EscapeForJSON escapes content for JSON output using the standard library.
+// This replaces the custom escapeJSONString function with a more robust implementation.
+func EscapeForJSON(content string) string {
+	// Use the standard library's JSON marshaling for proper escaping
+	jsonBytes, _ := json.Marshal(content)
+	// Remove the surrounding quotes that json.Marshal adds
+	jsonStr := string(jsonBytes)
+	if len(jsonStr) >= 2 && jsonStr[0] == '"' && jsonStr[len(jsonStr)-1] == '"' {
+		return jsonStr[1 : len(jsonStr)-1]
+	}
+	return jsonStr
+}
+
+// EscapeForYAML quotes/escapes content for YAML output if needed.
+// This centralizes the YAML string quoting logic.
+func EscapeForYAML(content string) string {
+	// Quote if contains special characters, spaces, or starts with special chars
+	needsQuotes := strings.ContainsAny(content, " \t\n\r:{}[]|>-'\"\\") ||
+		strings.HasPrefix(content, "-") ||
+		strings.HasPrefix(content, "?") ||
+		strings.HasPrefix(content, ":") ||
+		content == "" ||
+		content == "true" || content == "false" ||
+		content == "null" || content == "~"
+
+	if needsQuotes {
+		// Use double quotes and escape internal quotes
+		escaped := strings.ReplaceAll(content, "\\", "\\\\")
+		escaped = strings.ReplaceAll(escaped, "\"", "\\\"")
+		return "\"" + escaped + "\""
+	}
+	return content
+}
+
+// StreamLines provides line-based streaming for YAML content.
+// This provides an alternative streaming approach for YAML writers.
+func StreamLines(reader io.Reader, writer io.Writer, filePath string, lineProcessor func(string) string) error {
+	// Read all content first (for small files this is fine)
+	content, err := io.ReadAll(reader)
+	if err != nil {
+		wrappedErr := WrapError(err, ErrorTypeIO, CodeIORead, "failed to read content for line processing")
+		if filePath != "" {
+			wrappedErr = wrappedErr.WithFilePath(filePath)
+		}
+		return wrappedErr
+	}
+
+	// Split into lines and process each
+	lines := strings.Split(string(content), "\n")
+	for i, line := range lines {
+		processedLine := line
+		if lineProcessor != nil {
+			processedLine = lineProcessor(line)
+		}
+		
+		// Write line with proper line ending (except for last empty line)
+		lineToWrite := processedLine
+		if i < len(lines)-1 || line != "" {
+			lineToWrite += "\n"
+		}
+		
+		if _, writeErr := writer.Write([]byte(lineToWrite)); writeErr != nil {
+			wrappedErr := WrapError(writeErr, ErrorTypeIO, CodeIOWrite, "failed to write processed line")
+			if filePath != "" {
+				wrappedErr = wrappedErr.WithFilePath(filePath)
+			}
+			return wrappedErr
+		}
+	}
+	return nil
+}