class EventLogSubscriber

final class EventLogSubscriber implements EventSubscriberInterface {
  
  /**
   * The name of the log file to write to.
   *
   * @var string
   */
  public const LOG_FILE_NAME = 'package_manager_test_event.log';
  
  /**
   * Excludes the log file from Package Manager operations.
   *
   * @param \Drupal\package_manager\Event\CollectPathsToExcludeEvent $event
   *   The event being handled.
   */
  public function excludeLogFile(CollectPathsToExcludeEvent $event) : void {
    $event->addPathsRelativeToProjectRoot([
      self::LOG_FILE_NAME,
    ]);
  }
  
  /**
   * Logs all events in the stage life cycle.
   *
   * @param \Drupal\package_manager\Event\SandboxEvent $event
   *   The event object.
   */
  public function logEventInfo(SandboxEvent $event) : void {
    $log_file = \Drupal::service(PathLocator::class)->getProjectRoot() . '/' . self::LOG_FILE_NAME;
    if (file_exists($log_file)) {
      $log_data = file_get_contents($log_file);
      $log_data = json_decode($log_data, TRUE, flags: JSON_THROW_ON_ERROR);
    }
    else {
      $log_data = [];
    }
    $log_data[] = [
      'event' => $event::class,
      'stage' => $event->sandboxManager::class,
    ];
    file_put_contents($log_file, json_encode($log_data, JSON_UNESCAPED_SLASHES));
  }
  
  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() : array {
    // This subscriber should run before every other validator, because the
    // purpose of this subscriber is to log all dispatched events.
    // @see \Drupal\package_manager\Validator\BaseRequirementsFulfilledValidator
    // @see \Drupal\package_manager\Validator\BaseRequirementValidatorTrait
    // @see \Drupal\package_manager\Validator\EnvironmentSupportValidator
    return [
      CollectPathsToExcludeEvent::class => [
        'excludeLogFile',
      ],
      PreCreateEvent::class => [
        'logEventInfo',
        PHP_INT_MAX,
      ],
      PostCreateEvent::class => [
        'logEventInfo',
        PHP_INT_MAX,
      ],
      PreRequireEvent::class => [
        'logEventInfo',
        PHP_INT_MAX,
      ],
      PostRequireEvent::class => [
        'logEventInfo',
        PHP_INT_MAX,
      ],
      PreApplyEvent::class => [
        'logEventInfo',
        PHP_INT_MAX,
      ],
      PostApplyEvent::class => [
        'logEventInfo',
        PHP_INT_MAX,
      ],
    ];
  }

}