/* ***** BEGIN LICENSE BLOCK *****
 * Distributed under the BSD license:
 *
 * Copyright (c) 2010, Ajax.org B.V.
 * 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 Ajax.org B.V. 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 AJAX.ORG B.V. 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.
 *
 * ***** END LICENSE BLOCK ***** */

define(function(require, exports, module) {
"use strict";

var EventEmitter = {};

EventEmitter._emit =
EventEmitter._dispatchEvent = function(eventName, e) {
    this._eventRegistry = this._eventRegistry || {};
    this._defaultHandlers = this._defaultHandlers || {};

    var listeners = this._eventRegistry[eventName] || [];
    var defaultHandler = this._defaultHandlers[eventName];
    if (!listeners.length && !defaultHandler)
        return;

    if (typeof e != "object" || !e)
        e = {};

    if (!e.type)
        e.type = eventName;
    
    if (!e.stopPropagation) {
        e.stopPropagation = function() {
            this.propagationStopped = true;
        };
    }
    
    if (!e.preventDefault) {
        e.preventDefault = function() {
            this.defaultPrevented = true;
        };
    }

    for (var i=0; i<listeners.length; i++) {
        listeners[i](e);
        if (e.propagationStopped)
            break;
    }
    
    if (defaultHandler && !e.defaultPrevented)
        return defaultHandler(e);
};

EventEmitter.setDefaultHandler = function(eventName, callback) {
    this._defaultHandlers = this._defaultHandlers || {};
    
    if (this._defaultHandlers[eventName])
        throw new Error("The default handler for '" + eventName + "' is already set");
        
    this._defaultHandlers[eventName] = callback;
};

EventEmitter.on =
EventEmitter.addEventListener = function(eventName, callback) {
    this._eventRegistry = this._eventRegistry || {};

    var listeners = this._eventRegistry[eventName];
    if (!listeners)
        listeners = this._eventRegistry[eventName] = [];

    if (listeners.indexOf(callback) == -1)
        listeners.push(callback);
};

EventEmitter.removeListener =
EventEmitter.removeEventListener = function(eventName, callback) {
    this._eventRegistry = this._eventRegistry || {};

    var listeners = this._eventRegistry[eventName];
    if (!listeners)
        return;

    var index = listeners.indexOf(callback);
    if (index !== -1)
        listeners.splice(index, 1);
};

EventEmitter.removeAllListeners = function(eventName) {
    if (this._eventRegistry) this._eventRegistry[eventName] = [];
};

exports.EventEmitter = EventEmitter;

});