<?php

/**
 * @file
 * job scheduler module.
 */

/**
 * Collects and returns scheduler info.
 *
 * @see hook_cron_job_scheduler_info()
 *
 * @param $name
 *   Name of the schedule
 * @return array
 *   Information for the schedule if $name, all the information if not
 */
function job_scheduler_info($name = NULL) {
  $info = &drupal_static(__FUNCTION__);
  if (!$info) {
    $info = module_invoke_all('cron_job_scheduler_info');
    drupal_alter('cron_job_scheduler_info', $info);
  }
  if ($name) {
    return isset($info[$name]) ? $info[$name] : NULL;
  }
  else {
    return $info;
  }
}

/**
 * Implements hook_cron().
 */
function job_scheduler_cron() {
  // Reschedule all jobs if requested.
  if (variable_get('job_scheduler_rebuild_all', FALSE)) {
    foreach (job_scheduler_info() as $name => $info) {
      job_scheduler_rebuild_scheduler($name, $info);
    }
    variable_set('job_scheduler_rebuild_all', FALSE);
    return;
  }

  // Reschedule stuck periodic jobs after one hour.
  db_update('job_schedule')
    ->fields(array(
      'scheduled' => 0,
    ))
    ->condition('scheduled', REQUEST_TIME - 3600, '<')
    ->condition('periodic', 1)
    ->execute();

  // Query and dispatch scheduled jobs.
  // Process a maximum of 200 jobs in a maximum of 30 seconds.
  $start = time();
  $total =
  $failed = 0;
  $jobs = db_select('job_schedule', NULL, array('fetch' => PDO::FETCH_ASSOC))
            ->fields('job_schedule')
            ->condition('scheduled', 0)
            ->condition('next', REQUEST_TIME, '<=')
            ->orderBy('next', 'ASC')
            ->range(0, 200)
            ->execute();
  foreach ($jobs as $job) {
    try {
      JobScheduler::get($job['name'])->dispatch($job);
    }
    catch (Exception $e) {
      watchdog('job_scheduler', $e->getMessage(), array(), WATCHDOG_ERROR);
      $failed++;
      // Drop jobs that have caused exceptions
      JobScheduler::get($job['name'])->remove($job);
    }
    $total++;
    if (time() > ($start + 30)) {
      break;
    }
  }

  // Leave a note on how much time we spent processing.
  watchdog('job_scheduler', 'Finished processing scheduled jobs (!time s, !total total, !failed failed).', array('!time' => format_interval(time() - $start), '!total' => $total, '!failed' => $failed));
}

/**
 * Implements hook_modules_enabled().
 */
function job_scheduler_modules_enabled($modules) {
  job_scheduler_rebuild_all();
}

/**
 * Implements hook_modules_disabled().
 */
function job_scheduler_modules_disabled($modules) {
  job_scheduler_rebuild_all();
}

/**
 * Rebuild scheduled information after enable/disable modules
 *
 * @todo What should we do about missing ones when disabling their module?
 */
function job_scheduler_rebuild_all() {
  variable_set('job_scheduler_rebuild_all', TRUE);
}

/**
 * Rebuild a single scheduler
 */
function job_scheduler_rebuild_scheduler($name, $info = NULL) {
  $info = $info ? $info : job_scheduler_info($name);
  if (!empty($info['jobs'])) {
    $scheduler = JobScheduler::get($name);
    foreach ($info['jobs'] as $job) {
      if (!$scheduler->check($job)) {
        $scheduler->set($job);
      }
    }
  }
}

/**
 * Implements hook_cron_queue_info().
 *
 * Provide queue worker information for jobs declared in
 * hook_cron_job_scheduler_info().
 */
function job_scheduler_cron_queue_info() {
  $queue = array();
  foreach (job_scheduler_info() as $name => $info) {
    if (!empty($info['jobs']) && !empty($info['queue name'])) {
      $queue[$info['queue name']] = array(
        'worker callback' => 'job_scheduler_cron_queue_worker',
        'time' => 60, // Some reasonable default as we don't know
      );
    }
  }
  return $queue;
}

/**
 * Execute job worker from queue
 *
 * Providing our own worker has the advantage that we can reschedule the job or take care of cleanup
 * Note that as we run the execute() action, the job won't be queued again this time.
 */
function job_scheduler_cron_queue_worker($job) {
  try {
    JobScheduler::get($job['name'])->execute($job);
  }
  catch (Exception $e) {
    watchdog('job_scheduler', $e->getMessage(), array(), WATCHDOG_ERROR);
    // Drop jobs that have caused exceptions
    JobScheduler::get($job['name'])->remove($job);
  }
}