#!/usr/bin/env bash
set -euo pipefail

SELF="$(realpath "$0")"
CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/tmux-sessionizer"
CONFIG_FILE="$CONFIG_DIR/sources.conf"

DEFAULT_SPECS=(
  "$HOME/src/github|2|2"
  "$HOME/src/aur|1|1"
  "$HOME/.config|0|1"
  "$HOME/.local/bin|0|0"
)

# --- Path shortening ---
# Shorten all but last 2 components: ~/src/github/user/repo → ~/s/g/user/repo
# Dotfile components keep the dot: .config → .c
_shorten_paths() {
  awk -v home="$HOME" '{
    p = $0
    if (index(p, home) == 1) p = "~" substr(p, length(home) + 1)
    n = split(p, parts, "/")
    result = ""
    for (i = 1; i <= n; i++) {
      if (i == 1) {
        result = parts[i]
      } else if (i <= n - 2) {
        if (substr(parts[i], 1, 1) == ".")
          result = result "/" substr(parts[i], 1, 2)
        else
          result = result "/" substr(parts[i], 1, 1)
      } else {
        result = result "/" parts[i]
      }
    }
    print $0 "\t" result
  }'
}

# --- Internal subcommands (called by fzf) ---

_preview() {
  local item="$1"
  if [[ "$item" == SESSION:* ]]; then
    local name="${item#SESSION:}"
    printf '\e[1;33mSession: %s\e[0m\n\n' "$name"
    tmux list-windows -t "$name" \
      -F '  #{window_index}: #{window_name}#{?window_active, (active),} — #{pane_current_command}' 2>/dev/null
  else
    if command -v eza >/dev/null 2>&1; then
      eza -la --icons --no-permissions --no-user --no-time "$item" 2>/dev/null
    elif command -v tree >/dev/null 2>&1; then
      tree -L 1 -a --noreport "$item" 2>/dev/null
    else
      ls -la "$item" 2>/dev/null
    fi
  fi
}

_kill_session() {
  local item="$1"
  if [[ "$item" == SESSION:* ]]; then
    local name="${item#SESSION:}"
    tmux kill-session -t "$name" 2>/dev/null || true
  fi
}

_rename_session() {
  local item="$1"
  if [[ "$item" != SESSION:* ]]; then
    echo "Not a session."
    read -r
    return
  fi
  local name="${item#SESSION:}"
  printf 'Rename session "%s" to: ' "$name"
  read -r new_name
  [[ -z "$new_name" ]] && return
  tmux rename-session -t "$name" "$new_name" 2>/dev/null
}

_load_specs() {
  if [[ -f "$CONFIG_FILE" ]]; then
    local found=false
    while IFS= read -r line; do
      line="${line%%#*}"
      [[ -z "${line// /}" ]] && continue
      line="${line//\~/$HOME}"
      local path min max
      IFS='|' read -r path min max <<< "$line"
      path="${path#"${path%%[![:space:]]*}"}"; path="${path%"${path##*[![:space:]]}"}"
      min="${min#"${min%%[![:space:]]*}"}"; min="${min%"${min##*[![:space:]]}"}"
      max="${max#"${max%%[![:space:]]*}"}"; max="${max%"${max##*[![:space:]]}"}"
      printf '%s|%s|%s\n' "$path" "$min" "$max"
      found=true
    done < "$CONFIG_FILE"
    $found && return
  fi
  printf '%s\n' "${DEFAULT_SPECS[@]}"
}

_list() {
  # Active tmux sessions (keyed with SESSION: prefix)
  while IFS='|' read -r name windows path; do
    [[ -z "$name" ]] && continue
    local short_path="$path"
    [[ "$short_path" == "$HOME"* ]] && short_path="~${short_path#"$HOME"}"
    printf 'SESSION:%s\t* %s (%s win) [%s]\n' "$name" "$name" "$windows" "$short_path"
  done < <(tmux list-sessions -F '#{session_name}|#{session_windows}|#{session_path}' 2>/dev/null || true)

  # Directories from config
  local use_fd=false
  command -v fd >/dev/null 2>&1 && use_fd=true

  while IFS='|' read -r path min max; do
    [[ -d "$path" ]] || continue
    if [[ "$min" -eq 0 && "$max" -eq 0 ]]; then
      printf '%s\n' "$path"
    elif $use_fd; then
      fd --type d --min-depth "$min" --max-depth "$max" . "$path" 2>/dev/null
    else
      find "$path" -mindepth "$min" -maxdepth "$max" -type d 2>/dev/null
    fi
  done < <(_load_specs) | sed 's:/$::' | sort -u | _shorten_paths
}

# Find existing session by working directory
_find_session_by_path() {
  local target="$1"
  tmux list-sessions -F '#{session_name}|#{session_path}' 2>/dev/null |
    awk -F'|' -v p="$target" '$2 == p { print $1; exit }'
}

# Route subcommands
case "${1:-}" in
  --preview)        shift; _preview "$1"; exit 0 ;;
  --kill-session)   shift; _kill_session "$1"; exit 0 ;;
  --rename-session) shift; _rename_session "$1"; exit 0 ;;
  --list)           _list; exit 0 ;;
esac

# --- Main ---

edit_mode=false

if [[ $# -eq 1 ]]; then
  selected="$1"
else
  selected=$(
    "$SELF" --list | fzf \
      --delimiter '\t' \
      --with-nth 2 \
      --header 'C-x:kill  C-e:editor  C-r:rename  ?:preview' \
      --preview "$SELF --preview {1}" \
      --preview-window 'top:33%' \
      --bind "ctrl-x:execute-silent($SELF --kill-session {1})+reload($SELF --list)" \
      --bind "ctrl-r:execute($SELF --rename-session {1})+reload($SELF --list)" \
      --bind "ctrl-e:become(printf 'EDIT\t%s' {1})" \
      --bind '?:toggle-preview'
  ) || true
fi

[[ -z "${selected:-}" ]] && exit 0

# Extract the key (full path or SESSION:name) from the tab-delimited line
selected_key="${selected%%	*}"

# Detect edit mode from ctrl-e
if [[ "$selected_key" == EDIT ]]; then
  edit_mode=true
  selected_key=$(cut -f2 <<< "$selected")
fi

# Handle active session vs directory
if [[ "$selected_key" == SESSION:* ]]; then
  selected_name="${selected_key#SESSION:}"
else
  selected="$selected_key"

  # Check for existing session by working directory first (supports renamed sessions)
  selected_name=$(_find_session_by_path "$selected")

  if [[ -z "$selected_name" ]]; then
    selected_name=$(basename "$selected" | tr -c '[:alnum:]' '_' | sed 's/^_*//;s/_*$//')
    [[ -z "$selected_name" ]] && selected_name="sess_$(date +%s)"

    if [[ -z "${TMUX:-}" ]] && ! tmux list-sessions &>/dev/null; then
      if $edit_mode; then
        exec tmux new-session -s "$selected_name" -c "$selected" "${EDITOR:-nvim}" .
      fi
      exec tmux new-session -s "$selected_name" -c "$selected"
    fi
    tmux new-session -ds "$selected_name" -c "$selected"
    tmux rename-window -t "$selected_name:" "shell"
  fi
fi

if $edit_mode; then
  tmux send-keys -t "$selected_name" "${EDITOR:-nvim} ." Enter
fi

if [[ -z "${TMUX:-}" ]]; then
  tmux attach -t "$selected_name"
else
  tmux switch-client -t "$selected_name"
fi