<?php
/*
 * $RCSfile: GalleryEventHelper_simple.class,v $
 *
 * Gallery - a web based photo album viewer and editor
 * Copyright (C) 2000-2005 Bharat Mediratta
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
 */
/**
 * @version $Revision: 1.16 $ $Date: 2005/08/23 03:49:04 $
 * @package GalleryCore
 * @author Bharat Mediratta <bharat@menalto.com>
 */

/**
 * Helper class for GalleryItems
 *
 * @package GalleryCore
 * @subpackage Helpers
 * @abstract
 */
class GalleryEventHelper_simple {

    /**
     * Get the static event listeners registry
     *
     * @return array
     * @access private
     * @staticvar array $eventListeners The event listener table
     * @static
     */
    function &_getEventListeners() {
	static $eventListeners = array();
	return $eventListeners;
    }

    /**
     * Create a new event with the given name
     * @static
     */
    function newEvent($eventName) {
	GalleryCoreApi::relativeRequireOnce('modules/core/classes/GalleryEvent.class');
	$event = new GalleryEvent();
	$event->setEventName($eventName);
	return $event;
    }

    /**
     * Register an event listener
     *
     * @param string the name of the event (eg "GalleryEntity::save")
     * @param object GalleryEventListener instance
     * @param boolean (optional) if true, disable event listener during unit tests
     * @static
     */
    function registerEventListener($eventName, &$listener, $disableForUnitTests=false) {
	if ($disableForUnitTests && class_exists('GalleryTestCase')) {
	    return;
	}

	$eventListeners =& GalleryEventHelper_simple::_getEventListeners();
	if (empty($eventListeners[$eventName])) {
	    $eventListeners[$eventName] = array();
	}

	$eventListeners[$eventName][] =& $listener;
    }

    /**
     * Deliver an event to anybody listening
     *
     * @param object a GalleryEvent
     * @return array object GalleryStatus a status code
     *               array data returned from listeners, if any
     * @static
     */
    function postEvent($event) {
	static $allListenersRegistered;
	if (!isset($allListenersRegistered)) {
	    list ($ret, $moduleStatus) = GalleryCoreApi::fetchPluginStatus('module');
	    if ($ret->isError()) {
		return array($ret->wrap(__FILE__, __LINE__), null);
	    }

	    foreach ($moduleStatus as $moduleId => $status) {
		if (!empty($status['active'])) {
		    if (in_array('registerEventListeners', explode('|', $status['callbacks']))) {
			/*
			 * Ignore version mismatches when loading the module, since we don't want
			 * event propagation during the upgrader to lead to the plugin framework
			 * deactivating plugins, which will in turn post more events.  All we want
			 * to do is to ignore plugins that are not current, which we'll do below.
			 */
			list ($ret, $module) =
			    GalleryCoreApi::loadPlugin('module', $moduleId, true);
			if ($ret->isError()) {
			    return array($ret->wrap(__FILE__, __LINE__), null);
			}

			if (!GalleryCoreApi::isPluginCompatibleWithApis($module)) {
			    continue;
			}

			$module->registerEventListeners();
		    }
		}
	    }

	    $allListenersRegistered = true;
	}

	$eventListeners =& GalleryEventHelper_simple::_getEventListeners();

	$result = array();
	if (!empty($eventListeners[$event->getEventName()])) {
	    $listeners = $eventListeners[$event->getEventName()];
	    for ($i = 0; $i < count($listeners); $i++) {
		list ($ret, $data) = $listeners[$i]->handleEvent($event);
		if ($ret->isError()) {
		    return array($ret->wrap(__FILE__, __LINE__), null);
		}
		if (isset($data)) {
		    $result[] = $data;
		}
	    }
	}

	return array(GalleryStatus::success(), $result);
    }
}
?>