<?php

final class PhabricatorTaskmasterDaemon extends PhabricatorDaemon {

  protected function run() {
    do {
      PhabricatorCaches::destroyRequestCache();

      $tasks = id(new PhabricatorWorkerLeaseQuery())
        ->setLimit(1)
        ->execute();

      if ($tasks) {
        $this->willBeginWork();

        foreach ($tasks as $task) {
          $id = $task->getID();
          $class = $task->getTaskClass();

          $this->log(pht('Working on task %d (%s)...', $id, $class));

          $task = $task->executeTask();
          $ex = $task->getExecutionException();
          if ($ex) {
            if ($ex instanceof PhabricatorWorkerPermanentFailureException) {
              // NOTE: Make sure these reach the daemon log, even when not
              // running in verbose mode. See T12803 for discussion.
              $log_exception = new Exception(
                pht(
                  'Task "%s" encountered a permanent failure and was '.
                  'cancelled.',
                  $id),
                0,
                $ex);
              phlog($log_exception);
            } else if ($ex instanceof PhabricatorWorkerYieldException) {
              $this->log(pht('Task %s yielded.', $id));
            } else {
              $this->log(pht('Task %d failed!', $id));
              throw new Exception(
                pht('Error while executing Task ID %d.', $id),
                0,
                $ex);
            }
          } else {
            $this->log(pht('Task %s complete! Moved to archive.', $id));
          }
        }

        $sleep = 0;
      } else {

        if ($this->getIdleDuration() > 15) {
          $hibernate_duration = phutil_units('3 minutes in seconds');
          if ($this->shouldHibernate($hibernate_duration)) {
            break;
          }
        }

        // When there's no work, sleep for one second. The pool will
        // autoscale down if we're continuously idle for an extended period
        // of time.
        $this->willBeginIdle();
        $sleep = 1;
      }

      $this->sleep($sleep);
    } while (!$this->shouldExit());
  }

}