/**
 * Base class for objects that dispatches events.
 * @class EventTarget
 * @constructor
 */
var EventTarget = function () {

};

module.exports = EventTarget;

EventTarget.prototype = {
    constructor: EventTarget,

    /**
     * Add an event listener
     * @method addEventListener
     * @param  {String} type
     * @param  {Function} listener
     * @return {EventTarget} The self object, for chainability.
     */
    addEventListener: function ( type, listener ) {
        if ( this._listeners === undefined ){ this._listeners = {}; }
        var listeners = this._listeners;
        if ( listeners[ type ] === undefined ) {
            listeners[ type ] = [];
        }
        if ( listeners[ type ].indexOf( listener ) === - 1 ) {
            listeners[ type ].push( listener );
        }
        return this;
    },

    /**
     * Check if an event listener is added
     * @method hasEventListener
     * @param  {String} type
     * @param  {Function} listener
     * @return {Boolean}
     */
    hasEventListener: function ( type, listener ) {
        if ( this._listeners === undefined ){ return false; }
        var listeners = this._listeners;
        if ( listeners[ type ] !== undefined && listeners[ type ].indexOf( listener ) !== - 1 ) {
            return true;
        }
        return false;
    },

    /**
     * Remove an event listener
     * @method removeEventListener
     * @param  {String} type
     * @param  {Function} listener
     * @return {EventTarget} The self object, for chainability.
     */
    removeEventListener: function ( type, listener ) {
        if ( this._listeners === undefined ){ return this; }
        var listeners = this._listeners;
        if ( listeners[type] === undefined ){ return this; }
        var index = listeners[ type ].indexOf( listener );
        if ( index !== - 1 ) {
            listeners[ type ].splice( index, 1 );
        }
        return this;
    },

    /**
     * Emit an event.
     * @method dispatchEvent
     * @param  {Object} event
     * @param  {String} event.type
     * @return {EventTarget} The self object, for chainability.
     */
    dispatchEvent: function ( event ) {
        if ( this._listeners === undefined ){ return this; }
        var listeners = this._listeners;
        var listenerArray = listeners[ event.type ];
        if ( listenerArray !== undefined ) {
            event.target = this;
            for ( var i = 0, l = listenerArray.length; i < l; i ++ ) {
                listenerArray[ i ].call( this, event );
            }
        }
        return this;
    }
};