<?php

namespace Symfony\Foundation\Debug;

use Symfony\Foundation\EventDispatcher as BaseEventDispatcher;
use Symfony\Components\EventDispatcher\EventDispatcherInterface;
use Symfony\Components\EventDispatcher\Event;
use Symfony\Foundation\LoggerInterface;
use Symfony\Components\DependencyInjection\ContainerInterface;

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien.potencier@symfony-project.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * EventDispatcher extends the original EventDispatcher class to add some debugging tools.
 *
 * @package    Symfony
 * @subpackage Foundation
 * @author     Fabien Potencier <fabien.potencier@symfony-project.com>
 */
class EventDispatcher extends BaseEventDispatcher
{
  protected $logger;

  /**
   * Constructor.
   *
   * @param LoggerInterface $logger A LoggerInterface instance
   */
  public function __construct(ContainerInterface $container, LoggerInterface $logger = null)
  {
    $this->logger = $logger;

    parent::__construct($container);
  }

  /**
   * Notifies all listeners of a given event.
   *
   * @param Event $event A Event instance
   *
   * @return Event The Event instance
   */
  public function notify(Event $event)
  {
    foreach ($this->getListeners($event->getName()) as $listener)
    {
      if (null !== $this->logger)
      {
        $this->logger->debug(sprintf('Notifying event "%s" to listener "%s"', $event->getName(), $this->listenerToString($listener)));
      }

      call_user_func($listener, $event);
    }

    return $event;
  }

  /**
   * Notifies all listeners of a given event until one returns a non null value.
   *
   * @param  Event $event A Event instance
   *
   * @return Event The Event instance
   */
  public function notifyUntil(Event $event)
  {
    foreach ($this->getListeners($event->getName()) as $listener)
    {
      if (null !== $this->logger)
      {
        $this->logger->debug(sprintf('Notifying (until) event "%s" to listener "%s"', $event->getName(), $this->listenerToString($listener)));
      }

      if (call_user_func($listener, $event))
      {
        if (null !== $this->logger)
        {
          $this->logger->debug(sprintf('Listener "%s" processed the event "%s"', $this->listenerToString($listener), $event->getName()));
        }

        $event->setProcessed(true);
        break;
      }
    }

    return $event;
  }

  /**
   * Filters a value by calling all listeners of a given event.
   *
   * @param  Event  $event   A Event instance
   * @param  mixed    $value   The value to be filtered
   *
   * @return Event The Event instance
   */
  public function filter(Event $event, $value)
  {
    foreach ($this->getListeners($event->getName()) as $listener)
    {
      if (null !== $this->logger)
      {
        $this->logger->debug(sprintf('Notifying (filter) event "%s" to listener "%s"', $event->getName(), $this->listenerToString($listener)));
      }

      $value = call_user_func($listener, $event, $value);
    }

    $event->setReturnValue($value);

    return $event;
  }

  protected function listenerToString($listener)
  {
    if (is_object($listener) && $listener instanceof \Closure)
    {
      return 'Closure';
    }

    if (is_string($listener))
    {
      return $listener;
    }

    if (is_array($listener))
    {
      return sprintf('(%s, %s)', is_object($listener[0]) ? get_class($listener[0]) : $listener[0], $listener[1]);
    }
  }
}