<?php
// $Id$

/**
 * @file
 *   Drush bot commands.
 */

/**
 * Implementation of hook_drush_command().
 *
 */
function bot_drush_command() {
  $items = array();

  $items['bot start'] = array(
    'callback' => 'drush_bot_start',
    'description' => "Starts the bot.",
  );

  $items['bot stop'] = array(
    'callback' => 'drush_bot_stop',
    'description' => "Stops the bot.",
  );

  $items['bot status'] = array(
    'callback' => 'drush_bot_status',
    'description' => "Show status of the bot.",
  );

  $items['bot restart'] = array(
    'callback' => 'drush_bot_restart',
    'description' => "Restarts the bot.",
  );

  return $items;
}

/**
 * Implementation of hook_drush_help().
 */
function bot_drush_help($section) {
  switch ($section) {
    case 'drush:bot start':
      return dt("Starts the bot.");

    case 'drush:bot stop':
      return dt("Stops the bot.");

    case 'drush:bot status':
      return dt("Show bot status.");

    case 'drush:bot restart':
      return dt("Restarts the bot.");
  }
}

/**
 * Command callback. Starts the bot, if not already running.
 */
function drush_bot_start() {
  $botname = variable_get('bot_nickname', '');
  if (_drush_bot_is_running()) {
    drush_log("Bot ($botname) is already running.", "failed");
    return;
  }

  declare(ticks = 1);
  $pid = pcntl_fork();
  if ($pid == -1) {
    drush_log("Unable to fork.", "failed");
    return;
  }
  else if ($pid) {
    // parent: $pid is my child's pid
    // get the pidfile and write the child's pid
    $site_root = drush_get_context('DRUSH_DRUPAL_SITE_ROOT');
    $pidfile   = "$site_root/bot.pid";
    $file      = fopen($pidfile, "w");
    if ($file === FALSE) {
      drush_log("Can't open pid file $pidfile.", "error");
      exit();
    }
    fwrite($file, $pid);
    fclose($file);
    return;
  }
  // child
  else {}

  // detatch from the controlling terminal
  if (posix_setsid() == -1) {
    drush("could not detach from terminal", "failed");
    return;
  }

  // setup signal handlers
  /*
  pcntl_signal(SIGTERM, "_drush_bot_sig_handler");
  pcntl_signal(SIGHUP, "_drush_bot_sig_handler");
  */


  //perform child task
  $path_to_drupal = drush_get_context('DRUSH_DRUPAL_ROOT');
  $path_to_bot    = drupal_get_path('module', 'bot');
  $url            = drush_get_context('DRUSH_URI');
  $args           = array(
    "$path_to_drupal/$path_to_bot/bot_start.php",
    "--root", $path_to_drupal,
    "--url", $url,
  );
  drush_log("Starting bot: $botname.", "success");
  $result = pcntl_exec("/usr/bin/php", $args);
  //NOTE: returns FALSE on failure... don't return on success
  drush_log("No no no, failure.", "failed");
  exit();
}

/**
 * Command callback. Stops the bot, if running.
 */
function drush_bot_stop() {
  $botname = variable_get('bot_nickname', '');
  if (!_drush_bot_is_running()) {
    drush_log("Bot ($botname) is not running.", "failed");
    return;
  }

  // get the pidfile
  $site_root = drush_get_context('DRUSH_DRUPAL_SITE_ROOT');
  $pidfile = "$site_root/bot.pid";

  // get the pid
  $file = fopen($pidfile, "r");
  $pid = fread($file, 6);
  fclose($file);

  // kill the process & delete pidfile
  posix_kill($pid, SIGKILL);
  unlink($pidfile);

  // message
  drush_log("Stopping bot: $botname.", "success");
}

/**
 * Command callback. Prints out current bot status.
 *
 */
function drush_bot_status() {
  $botname = variable_get('bot_nickname', '');
  if (_drush_bot_is_running()) {
    drush_log("Bot ($botname) is running.", "ok");
  }
  else {
    drush_log("Bot ($botname) is not running.", "ok");
  }
}

/**
 * Command callback. Restarts the bot.
 */
function drush_bot_restart() {
  drush_bot_stop();
  drush_bot_start();
}


////////////////////////////////////////////////////////////////////////////////
// BOT HELPER FUNCTIONS

/**
 * Tells if the bot is currently running.
 *
 * This function checks if a pidfile exists. If not it is assumed the bot is not
 * running. If the pidfile exists it checks if the process is running. If
 * pidfile exists and process is not running, it removes the pidfile.
 */
function _drush_bot_is_running() {
  // does pidfile exist?
  $site_root = drush_get_context('DRUSH_DRUPAL_SITE_ROOT');
  $pidfile = "$site_root/bot.pid";
  if (!file_exists($pidfile)) {
    return FALSE;
  }

  // get the process pid
  $file = fopen($pidfile, "r");
  $pid = fread($file, 6);
  fclose($file);

  // is the process alive?
  $cmd = "ps $pid";
  exec($cmd, $output, $result);
  if (count($output) >= 2) {
    //the process is alive
    return TRUE;
  }

  // the process is dead. let's remove the pidfile
  unlink($pidfile);

  return FALSE;
}


/*
 * Signal handler for the bot process
 *
 * This function is a callback invoked for the pcntl registered signals at 
 * _drush_bot_start()
 */

/*
function _drush_bot_sig_handler($signo) {
  switch ($signo) {
    case SIGTERM:
      // handle shutdown tasks
      drush_print("SIGTERM");
      exit;
      break;
    case SIGHUP:
      drush_print("SIGHUP");
      // handle restart tasks
      break;
    default:
      // handle all other signals
      drush_print("Other signal");
  }
}
*/