#!/usr/bin/env bash
# tmux-aware Claude profile helper
# Works in bash/zsh. No external deps except optional fzf and tmux.

set -euo pipefail

# Optional: set a directory to copy as a template when new profiles are created.
# Default: if ~/.claude exists it will be copied; otherwise create an empty dir.
CLAUDE_TEMPLATE_DIR="${CLAUDE_TEMPLATE_DIR:-}"

bin_exists() { command -v "$1" >/dev/null 2>&1; }

tmux_session_name() {
  if [[ -n "${TMUX:-}" ]] && bin_exists tmux; then
    tmux display-message -p '#S'
  else
    printf ''
  fi
}

sanitize_session() {
  # lowercase, spaces->-, keep alnum . _ : -
  printf '%s' "$1" \
    | tr '[:upper:] ' '[:lower:]-' \
    | tr -cd '[:alnum:]._:-'
}

profile_dir_for_session() {
  local s="$1"
  case "$s" in
    ""|"default"|"personal"|"main") printf '%s\n' "$HOME/.claude" ;;
    *) printf '%s\n' "$HOME/.claude-$(sanitize_session "$s")" ;;
  esac
}

ensure_profile_dir() {
  local dir="$1"
  if [[ -d "$dir" ]]; then
    return 0
  fi

  mkdir -p "$dir"
  # Copy from template if provided, else from ~/.claude if present
  local from="${CLAUDE_TEMPLATE_DIR:-}"
  if [[ -z "$from" && -d "$HOME/.claude" ]]; then
    from="$HOME/.claude"
  fi
  if [[ -n "$from" && -d "$from" ]]; then
    # Copy only if empty
    if [[ -z "$(ls -A "$dir")" ]]; then
      cp -a "$from"/. "$dir"/
    fi
  fi
}

run_claude_with_profile() {
  local dir="$1"; shift || true
  if ! bin_exists claude; then
    printf 'claude-tmux: "claude" binary not found in PATH\n' >&2
    exit 127
  fi
  ensure_profile_dir "$dir"
  CLAUDE_CONFIG_DIR="$dir" command claude "$@"
}

fzf_pick_session() {
  local list new_label sel
  if ! bin_exists tmux; then
    printf 'claude-tmux: tmux not installed\n' >&2
    return 1
  fi
  new_label="[new session]"
  # Gather sessions, newest first
  list="$(tmux list-sessions -F '#{session_last_attached} #{session_name}' 2>/dev/null \
           | sort -rn | awk '{ $1=""; sub(/^ /,""); print }')"
  if bin_exists fzf; then
    sel="$(printf '%s\n%s\n' "$new_label" "$list" | fzf --prompt='tmux session > ' --height=40% --reverse)"
  else
    printf '%s\n%s\n' "$new_label" "$list"
    printf 'Pick a session (type exact name or "%s"): ' "$new_label" >&2
    read -r sel
  fi
  printf '%s' "$sel"
}

create_and_launch_in_session() {
  local name="$1" dir cmd
  dir="$(profile_dir_for_session "$name")"
  ensure_profile_dir "$dir"

  # Start a session running Claude with the session’s profile
  cmd="CLAUDE_CONFIG_DIR='${dir}' claude"
  if tmux has-session -t "$name" 2>/dev/null; then
    # Session exists: send keys and attach
    tmux send-keys -t "$name" "$cmd" C-m
    exec tmux attach -t "$name"
  else
    exec tmux new-session -s "$name" "$cmd"
  fi
}

attach_and_launch_in_existing_session() {
  local name="$1" dir cmd
  dir="$(profile_dir_for_session "$name")"
  ensure_profile_dir "$dir"
  cmd="CLAUDE_CONFIG_DIR='${dir}' claude"
  tmux send-keys -t "$name" "$cmd" C-m
  exec tmux attach -t "$name"
}

# Subcommands:
#   ensure <session>         ensure profile dir exists for session
#   dir <session>            print profile dir for session
#   run [args...]            run claude for current tmux session (inside tmux)
#   pick                     fzf picker to choose or create a session and launch claude
#   hook-ensure #{session_name}   for tmux hooks
case "${1:-}" in
  ensure)
    shift; sess="${1:-}"
    if [[ -z "$sess" ]]; then printf 'usage: claude-tmux ensure <session>\n' >&2; exit 2; fi
    ensure_profile_dir "$(profile_dir_for_session "$sess")"
    ;;
  dir)
    shift; sess="${1:-}"
    if [[ -z "$sess" ]]; then printf 'usage: claude-tmux dir <session>\n' >&2; exit 2; fi
    profile_dir_for_session "$sess"
    ;;
  run)
    shift
    sess="$(tmux_session_name)"
    if [[ -z "$sess" ]]; then
      printf 'claude-tmux: not inside tmux. Use "claude-tmux pick" or run inside a session.\n' >&2
      exit 2
    fi
    run_claude_with_profile "$(profile_dir_for_session "$sess")" "$@"
    ;;
  pick)
    shift
    sel="$(fzf_pick_session)"
    if [[ -z "$sel" ]]; then exit 130; fi
    if [[ "$sel" == "[new session]" ]]; then
      printf 'New tmux session name: ' >&2
      read -r newname
      if [[ -z "$newname" ]]; then printf 'Empty name. Aborting.\n' >&2; exit 2; fi
      create_and_launch_in_session "$newname"
    else
      attach_and_launch_in_existing_session "$sel"
    fi
    ;;
  hook-ensure)
    # For tmux hooks like session-created / session-renamed
    shift
    sess="${1:-}"
    if [[ -n "$sess" ]]; then
      ensure_profile_dir "$(profile_dir_for_session "$sess")"
    fi
    ;;
  *)
    cat <<'EOF'
claude-tmux: tmux-aware Claude profile helper

Usage:
  claude-tmux run                 Run Claude for the current tmux session
  claude-tmux pick                Pick or create a tmux session with fzf, launch Claude, attach
  claude-tmux ensure <session>    Ensure a Claude profile exists for <session>
  claude-tmux dir <session>       Print the Claude profile dir for <session>
  claude-tmux hook-ensure <name>  For tmux hooks (session-created / session-renamed)

Env:
  CLAUDE_TEMPLATE_DIR             Directory to copy into new profiles (optional)
EOF
    ;;
esac