/**
 * @author Mat Groves http://matgroves.com/ @Doormat23
 */
 
/**
 * https://github.com/mrdoob/eventtarget.js/
 * THankS mr DOob!
 */

/**
 * Adds event emitter functionality to a class
 *
 * @class EventTarget
 * @example
 *      function MyEmitter() {
 *          PIXI.EventTarget.call(this); //mixes in event target stuff
 *      }
 *
 *      var em = new MyEmitter();
 *      em.emit({ type: 'eventName', data: 'some data' });
 */
PIXI.EventTarget = function () {

    /**
     * Holds all the listeners
     *
     * @property listeners
     * @type Object
     */
    var listeners = {};

    /**
     * Adds a listener for a specific event
     *
     * @method addEventListener
     * @param type {string} A string representing the event type to listen for.
     * @param listener {function} The callback function that will be fired when the event occurs
     */
    this.addEventListener = this.on = function ( type, listener ) {


        if ( listeners[ type ] === undefined ) {

            listeners[ type ] = [];

        }

        if ( listeners[ type ].indexOf( listener ) === - 1 ) {

            listeners[ type ].push( listener );
        }

    };

    /**
     * Fires the event, ie pretends that the event has happened
     *
     * @method dispatchEvent
     * @param event {Event} the event object
     */
    this.dispatchEvent = this.emit = function ( event ) {

        if ( !listeners[ event.type ] || !listeners[ event.type ].length ) {

            return;

        }

        for(var i = 0, l = listeners[ event.type ].length; i < l; i++) {

            listeners[ event.type ][ i ]( event );

        }

    };

    /**
     * Removes the specified listener that was assigned to the specified event type
     *
     * @method removeEventListener
     * @param type {string} A string representing the event type which will have its listener removed
     * @param listener {function} The callback function that was be fired when the event occured
     */
    this.removeEventListener = this.off = function ( type, listener ) {

        var index = listeners[ type ].indexOf( listener );

        if ( index !== - 1 ) {

            listeners[ type ].splice( index, 1 );

        }

    };

    /**
     * Removes all the listeners that were active for the specified event type
     *
     * @method removeAllEventListeners
     * @param type {string} A string representing the event type which will have all its listeners removed
     */
	this.removeAllEventListeners = function( type ) {
		var a = listeners[type];
		if (a)
			a.length = 0;
	};
};