#!/usr/bin/env ruby
# typed: strict
# frozen_string_literal: true

require "webrick"
require "fileutils"
require_relative "parse_formulas"
require_relative "build_site"

# Simple development server for the homebrew tap documentation
# Module for handling file watching and change detection
module FileWatcher
  def start_file_watcher
    Thread.new do
      last_mtime = max_mtime
      rebuild_pending = false
      watched_files = watched_files_count

      puts "👀 Watching #{watched_files} files for changes..."

      loop do
        sleep 1
        current_mtime = max_mtime

        next if should_skip_rebuild?(current_mtime, last_mtime, rebuild_pending)

        rebuild_pending = true
        handle_file_change(last_mtime)
        last_mtime = perform_rebuild_with_debounce
        rebuild_pending = false
        puts "✅ Rebuild complete"
      rescue => e
        puts "⚠️  File watcher error: #{e.message}"
        puts "📍 Backtrace: #{e.backtrace.first(3).join(", ")}"
        rebuild_pending = false
        sleep 2
        puts "🔄 File watcher continuing..."
      end
    end
  end

  def watched_files_count
    all_watched_files.count { |file| !File.directory?(file) }
  end

  def find_changed_file(since_mtime)
    all_watched_files.find do |file|
      File.exist?(file) && !File.directory?(file) && File.mtime(file) > since_mtime
    end
  end

  def all_watched_files
    [
      formula_files,
      theme_files,
      template_files,
      style_and_script_files,
      asset_files,
      build_script_files,
      config_files,
    ].flatten.compact.uniq
  end

  def max_mtime
    all_watched_files
      .select { |file| File.exist?(file) && !File.directory?(file) }
      .map { |file| File.mtime(file) }
      .max || Time.at(0)
  end

  private

  def should_skip_rebuild?(current_mtime, last_mtime, rebuild_pending)
    current_mtime <= last_mtime || rebuild_pending
  end

  def handle_file_change(last_mtime)
    changed_file = find_changed_file(last_mtime)
    puts "📝 Changed: #{changed_file}" if changed_file
    puts "🔄 Rebuilding in 1 second..."
  end

  def perform_rebuild_with_debounce
    sleep 1 # Debounce: wait for additional changes
    final_mtime = max_mtime
    puts "🔨 Building site..."
    build_site
    final_mtime
  end

  def formula_files
    Dir.glob(File.expand_path("../Formula/**/*.rb", __dir__))
  end

  def theme_files
    Dir.glob(File.expand_path("../theme/**/*", __dir__))
  end

  def template_files
    [
      Dir.glob(File.expand_path("../theme/*.erb", __dir__)),
      Dir.glob(File.expand_path("../theme/_*.erb", __dir__)),
      Dir.glob(File.expand_path("../theme/*.html.erb", __dir__)),
      Dir.glob(File.expand_path("../theme/_*.html.erb", __dir__)),
    ].flatten
  end

  def style_and_script_files
    [
      Dir.glob(File.expand_path("../theme/*.css", __dir__)),
      Dir.glob(File.expand_path("../theme/*.js", __dir__)),
    ].flatten
  end

  def asset_files
    Dir.glob(File.expand_path("../theme/assets/**/*", __dir__))
  end

  def build_script_files
    [
      File.expand_path("../scripts/parse_formulas.rb", __dir__),
      File.expand_path("../scripts/build_site.rb", __dir__),
    ]
  end

  def config_files
    [File.expand_path("../Makefile", __dir__)]
  end
end

# Development server with file watching for homebrew tap documentation
class DevServer
  include FileWatcher

  def self.serve(port: 4000, host: "localhost")
    new(port: port, host: host).start
  end

  def initialize(port: 4000, host: "localhost")
    @port = port
    @host = host
    @site_dir = File.expand_path("../docs", __dir__)
    @docs_dir = File.expand_path("../docs", __dir__)
  end

  def start
    puts "🔄 Building site..."
    build_site

    puts "🚀 Starting development server..."
    puts "📍 Server address: http://#{@host}:#{@port}"
    puts "📁 Serving from: #{@site_dir}"
    puts "💡 Press Ctrl+C to stop"

    start_server
  end

  private

  def build_site
    # Generate formulae data
    FormulaParser.run

    # Build static site
    SiteBuilder.build
  end

  def start_server
    server = WEBrick::HTTPServer.new(
      Port:         @port,
      Host:         @host,
      DocumentRoot: @site_dir,
      Logger:       WEBrick::Log.new($stderr, WEBrick::Log::INFO),
      AccessLog:    [[
        $stderr,
        WEBrick::AccessLog::COMBINED_LOG_FORMAT,
      ]],
    )

    # Handle Ctrl+C gracefully
    trap("INT") do
      puts "\n👋 Stopping server..."
      server.shutdown
    end

    # Add custom mime types if needed
    server.config[:MimeTypes]["json"] = "application/json"

    # Add auto-rebuild on file changes (simple polling)
    start_file_watcher

    server.start
  end
end

# Command line interface
if __FILE__ == $PROGRAM_NAME
  # Check for --list-watched flag
  if ARGV.include?("--list-watched")
    server = DevServer.new
    files = server.all_watched_files.select { |f| File.exist?(f) && !File.directory?(f) }
    puts "📋 Watching #{files.count} files:"
    files.sort.each { |f| puts "  - #{f.sub("#{File.expand_path("..", __dir__)}/", "")}" }
    exit 0
  end

  port = ARGV[0]&.to_i || 4000
  host = ARGV[1] || "localhost"

  DevServer.serve(port: port, host: host)
end