<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_EventManager

 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

require_once 'Zend/EventManager/EventManager.php';

require_once 'Zend/EventManager/SharedEventCollection.php';

/**

 * Shared/contextual EventManager

 *

 * Allows attaching to EMs composed by other classes without having an instance first.

 * The assumption is that the SharedEventManager will be injected into EventManager 

 * instances, and then queried for additional listeners when triggering an event.

 *

 * @category   Zend

 * @package    Zend_EventManager

 * @copyright  Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_EventManager_SharedEventManager implements Zend_EventManager_SharedEventCollection

{

    /**

     * Identifiers with event connections

     * @var array

     */

    protected $identifiers = array();

    /**

     * Attach a listener to an event

     *

     * Allows attaching a callback to an event offerred by one or more 

     * identifying components. As an example, the following connects to the 

     * "getAll" event of both an AbstractResource and EntityResource:

     *

     * <code>

     * SharedEventManager::getInstance()->connect(

     *     array('My\Resource\AbstractResource', 'My\Resource\EntityResource'),

     *     'getOne',

     *     function ($e) use ($cache) {

     *         if (!$id = $e->getParam('id', false)) {

     *             return;

     *         }

     *         if (!$data = $cache->load(get_class($resource) . '::getOne::' . $id )) {

     *             return;

     *         }

     *         return $data;

     *     }

     * );

     * </code>

     * 

     * @param  string|array $id Identifier(s) for event emitting component(s)

     * @param  string $event 

     * @param  callback $callback PHP Callback

     * @param  int $priority Priority at which listener should execute

     * @return void

     */

    public function attach($id, $event, $callback, $priority = 1)

    {

        $ids = (array) $id;

        foreach ($ids as $id) {

            if (!array_key_exists($id, $this->identifiers)) {

                $this->identifiers[$id] = new Zend_EventManager_EventManager();

            }

            $this->identifiers[$id]->attach($event, $callback, $priority);

        }

    }

    /**

     * Detach a listener from an event offered by a given resource

     * 

     * @param  string|int $id

     * @param  Zend_Stdlib_CallbackHandler $listener 

     * @return bool Returns true if event and listener found, and unsubscribed; returns false if either event or listener not found

     */

    public function detach($id, Zend_Stdlib_CallbackHandler $listener)

    {

        if (!array_key_exists($id, $this->identifiers)) {

            return false;

        }

        return $this->identifiers[$id]->detach($listener);

    }

    /**

     * Retrieve all registered events for a given resource

     * 

     * @param  string|int $id

     * @return array

     */

    public function getEvents($id)

    {

        if (!array_key_exists($id, $this->identifiers)) {

            return false;

        }

        return $this->identifiers[$id]->getEvents();

    }

    /**

     * Retrieve all listeners for a given identifier and event

     * 

     * @param  string|int $id

     * @param  string|int $event 

     * @return false|Zend_Stdlib_PriorityQueue

     */

    public function getListeners($id, $event)

    {

        if (!array_key_exists($id, $this->identifiers)) {

            return false;

        }

        return $this->identifiers[$id]->getListeners($event);

    }

    /**

     * Clear all listeners for a given identifier, optionally for a specific event

     * 

     * @param  string|int $id 

     * @param  null|string $event 

     * @return bool

     */

    public function clearListeners($id, $event = null)

    {

        if (!array_key_exists($id, $this->identifiers)) {

            return false;

        }

        if (null === $event) {

            unset($this->identifiers[$id]);

            return true;

        }

        return $this->identifiers[$id]->clearListeners($event);

    }

}