/home/edulekha/studygroup.edulekha.com/ow_plugins/slideshow/classes/event_handler.php
<?php

/**
 * This software is intended for use with Oxwall Free Community Software http://www.oxwall.org/ and is
 * licensed under The BSD license.

 * ---
 * Copyright (c) 2011, Oxwall Foundation
 * All rights reserved.

 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 *  - Redistributions of source code must retain the above copyright notice, this list of conditions and
 *  the following disclaimer.
 *
 *  - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
 *  the following disclaimer in the documentation and/or other materials provided with the distribution.
 *
 *  - Neither the name of the Oxwall Foundation nor the names of its contributors may be used to endorse or promote products
 *  derived from this software without specific prior written permission.

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * @author Egor Bulgakov <egor.bulgakov@gmail.com>
 * @package ow_plugins.slideshow.classes
 * @since 1.6.0
 */
class SLIDESHOW_CLASS_EventHandler
{
    /**
     * @var SLIDESHOW_CLASS_EventHandler
     */
    private static $classInstance;

    /**
     * @return SLIDESHOW_CLASS_EventHandler
     */
    public static function getInstance()
    {
        if ( self::$classInstance === null )
        {
            self::$classInstance = new self();
        }

        return self::$classInstance;
    }

    private function __construct() { }

    public function beforeWidgetPlaceDelete( OW_Event $event )
    {
        $params = $event->getParams();

        $class = $params['class'];

        if ( $class != 'SLIDESHOW_CMP_SlideshowWidget' )
        {
            return;
        }

        $uniqName = $params['uniqName'];

        $service = SLIDESHOW_BOL_Service::getInstance();
        $list = $service->getAllSlideList($uniqName);

        if ( $list )
        {
            foreach ( $list as $slide )
            {
                $service->addSlideToDeleteQueue($slide->id);
            }
        }
    }

    public function init()
    {
        $em = OW::getEventManager();

        $em->bind('widgets.before_place_delete', array($this, 'beforeWidgetPlaceDelete'));
    }
}