#!/usr/bin/env bash
#
# Credit to ThePrimeagen, Jess Archer
# See https://github.com/jessarcher/dotfiles/blob/master/scripts/t
#
# Tweaks by Ismo Vuorinen <https://github.com/ivuorinen> 2025
# vim: ft=bash ts=2 sw=2 et

# Set environment variables for configuration with defaults
T_ROOT="${T_ROOT:-$HOME/Code}"
DOTFILES="${DOTFILES:-$HOME/.dotfiles}"
T_MAX_DEPTH="${T_MAX_DEPTH:-3}"

# Function to print an error message and exit
error_exit()
{
  echo "Error: $1" >&2
  exit 1
}

# Validate that T_ROOT exists
if [[ ! -d "$T_ROOT" ]]; then
  error_exit "T_ROOT directory '$T_ROOT' does not exist."
fi

# Check for required dependencies
check_dependencies()
{
  local T_DEPS=(tmux fzf find)
  for cmd in "${T_DEPS[@]}"; do
    if ! command -v "$cmd" &> /dev/null; then
      error_exit "$cmd is not installed."
    fi
  done
}

check_dependencies

# Generate an array of '-not -path' rules for each exclusion pattern
# without using namerefs.
generate_exclude_rules()
{
  local result_var="$1"
  shift
  local arr=()
  for pattern in "$@"; do
    # Exclude both the directory and any subdirectories under it.
    arr+=(-not -path "*/${pattern}" -not -path "*/${pattern}/*")
  done
  # Use eval to assign the array to the variable whose name was passed.
  eval "$result_var=(\"\${arr[@]}\")"
}

get_directories()
{
  local exclude_patterns=(
    ".bzr" ".git" ".hg" ".idea" ".obsidian" ".run" ".svn" ".vscode"
    "build" "dist" "node_modules" "out" "target" "vendor"
  )
  local exclude_rules=()
  generate_exclude_rules exclude_rules "${exclude_patterns[@]}"

  local dirs
  # Use $'string' to correctly process escape sequences.
  dirs=$'# Directories\n'
  dirs+=$(
    find "$T_ROOT" \
      -maxdepth "$T_MAX_DEPTH" \
      -mindepth 1 \
      -type d \
      "${exclude_rules[@]}"
  )
  echo -e "$dirs"
}

check_tmux()
{
  if ! command -v tmux &> /dev/null; then
    error_exit "tmux is not installed."
  fi

  # Ensure tmux server is running
  if ! tmux info &> /dev/null; then
    tmux start-server
  fi
}

get_sessions()
{
  check_tmux

  T_TMUX_SESSIONS=$(tmux list-sessions -F "#{session_name}" 2> /dev/null)

  if [[ -z "$T_TMUX_SESSIONS" ]]; then
    echo ""
    return
  fi

  echo -e "# Sessions\n$T_TMUX_SESSIONS"
}

# Determine selection from command-line argument or interactive fzf menu
if [[ $# -eq 1 ]]; then
  selected="$1"
else
  # Combine sessions and directories for selection
  T_ITEMS="$(get_sessions | sort)
$(get_directories | sort)"

  # Use sort to order the entries and fzf for interactive selection
  selected=$(echo "$T_ITEMS" | fzf) || exit 0
fi

# Reject selection if it is a header line
[[ ${selected:0:1} == "#" ]] && error_exit "Header selected. Please choose a valid session or directory."

[[ -z "$selected" ]] && error_exit "No directory or session selected."

# Sanitize the session name
session_name=$(basename "$selected")
if [[ -z "$session_name" ]]; then
  session_name="$selected"
fi
# Remove dots since tmux dislikes them
session_name="${session_name//./}"

# Attempt to switch to an existing session
tmux switch-client -t "=$session_name" 2> /dev/null
active_session=$(tmux display-message -p -F '#{session_name}' 2> /dev/null)

if [[ "$active_session" == "$session_name" ]]; then
  exit 0
fi

# Create a new session (or attach to an existing one) based on the selection
if [ -z "$TMUX" ]; then
  # Not inside tmux: create (or attach to) the session and attach.
  tmux new-session -A -s "$session_name" -c "$selected"
else
  # Inside tmux: check if the target session exists.
  if tmux has-session -t "$session_name" 2> /dev/null; then
    # Session exists; switch to it.
    tmux switch-client -t "$session_name"
  else
    # Session does not exist; create it in detached mode and then switch.
    tmux new-session -d -s "$session_name" -c "$selected"
    tmux switch-client -t "$session_name"
  fi
fi