'use strict';

/**
 * status-watcher-hook/handler.js
 *
 * Spawns the Live Status v4 watcher-manager daemon on gateway startup.
 *
 * Events: ["gateway:startup"]
 *
 * Behavior:
 *   1. Check PID file — if watcher is already running, do nothing.
 *   2. If not running, spawn watcher-manager.js as a detached background process.
 *   3. The hook handler returns immediately; the daemon runs independently.
 */

/* eslint-disable no-console */

const fs = require('fs');
const path = require('path');
const { spawn } = require('child_process');

// PID file location (must match watcher-manager.js default)
const PID_FILE = process.env.PID_FILE || '/tmp/status-watcher.pid';

// Path to watcher-manager.js (relative to this hook file's location)
// Hook is in: workspace/hooks/status-watcher-hook/handler.js
// Watcher is in: workspace/projects/openclaw-live-status/src/watcher-manager.js
const WATCHER_PATH = path.resolve(
  __dirname,
  '../../projects/openclaw-live-status/src/watcher-manager.js',
);

/**
 * Check if a process is alive given its PID.
 * Returns true if process exists and is running.
 */
function isProcessRunning(pid) {
  try {
    process.kill(pid, 0);
    return true;
  } catch (_err) {
    return false;
  }
}

/**
 * Check if the watcher daemon is already running via PID file.
 * Returns true if running, false if not (or PID file stale/missing).
 */
function isWatcherRunning() {
  try {
    // eslint-disable-next-line security/detect-non-literal-fs-filename
    const pidStr = fs.readFileSync(PID_FILE, 'utf8').trim();
    const pid = parseInt(pidStr, 10);
    if (isNaN(pid) || pid <= 0) return false;
    return isProcessRunning(pid);
  } catch (_err) {
    // PID file missing or unreadable — watcher is not running
    return false;
  }
}

/**
 * Spawn the watcher daemon as a detached background process.
 * The parent (this hook handler) does not wait for it.
 */
function spawnWatcher() {
  if (!fs.existsSync(WATCHER_PATH)) {
    console.error('[status-watcher-hook] watcher-manager.js not found at:', WATCHER_PATH);
    console.error('[status-watcher-hook] Deploy the live-status project first: see install.sh');
    return;
  }

  console.log('[status-watcher-hook] Starting Live Status v4 watcher daemon...');

  const child = spawn(process.execPath, [WATCHER_PATH, 'start'], {
    detached: true,
    stdio: 'ignore',
    env: process.env,
  });

  child.unref();

  console.log(
    '[status-watcher-hook] Watcher daemon spawned (PID will be written to',
    PID_FILE + ')',
  );
}

/**
 * Hook entry point — called by OpenClaw on gateway:startup event.
 */
async function handle(_event) {
  if (isWatcherRunning()) {
    console.log('[status-watcher-hook] Watcher already running, skipping spawn.');
    return;
  }

  spawnWatcher();
}

// OpenClaw hook loader expects a default export
module.exports = handle;
module.exports.default = handle;