/*
 * $.ui.swipable
 *
 * http://code.google.com/p/jquery-ui-swipable/
 * version 0.1.1 (2010/09/08)
 * Copyright (c) 2010 Takeshi Takatsudo (takazudo[at]gmail.com)
 * MIT license
 *
=============================================================================
 depends on
-----------------------------------------------------------------------------
 * jQuery 1.4.2
 * jQuery UI 1.8.2
 * jQuery UI Widget 1.8.2
 *
=============================================================================
 how to use
-----------------------------------------------------------------------------
 * // setup
 * 
 * $('#someUl').swipable();
 * 
 * // you can can bind iPhone,iPad swipe evnets
 * 
 * $('#someUl').bind('swipe.right', fn);
 * $('#someUl').bind('swipe.left', fn);
 * $('#someUl').bind('swipe.top', fn);
 * $('#someUl').bind('swipe.bottom', fn);
 * 
 */
(function($){ // start $=jQuery encapsulation
    
    $.widget('ui.swipable', {
        options: {
            preventDefault: true,
            distance: 150 // px distance to occur esw
        },
        _sleeping: false,
        _startX: null,
        _startY: null,
        _currentX: null,
        _currentY: null,
        _create: function(){
            if(!('ontouchstart' in document.documentElement)){
                return this;
            }
            this.widgetEventPrefix = 'swipe.';
            this._eventify();
            return this;
        },
        _eventify: function(){
            var e = this.element.get(0);
            e.addEventListener('touchstart',  $.proxy(this._touchStartHandler, this), false);
            e.addEventListener('touchmove',   $.proxy(this._touchMoveHandler, this), false);
            e.addEventListener('touchend',    $.proxy(this._touchEndHandler, this), false);
            e.addEventListener('touchcancel', $.proxy(this._touchCancelHandler, this), false);
            return this;
        },
        _evalSwipes: function(){
            var x = this._currentX;
            var y = this._currentY;
            var startX = this._startX;
            var startY = this._startY;
            var d = this.options.distance;
            ((x-startX)>d) && this._swipeRight();
            ((startX-x)>d) && this._swipeLeft();
            ((y-startY)>d) && this._swipeBottom();
            ((startY-y)>d) && this._swipeTop();
        },
        _awake: function(){
            this._sleeping = false;
            return this;
        },
        _sleep: function(){
            this._sleeping = true;
            return this;
        },
        _swipeTop: function(){
            this._sleep();
            this._trigger('top')
            return this;
        },
        _swipeRight: function(){
            this._sleep();
            this._trigger('right')
            return this;
        },
        _swipeBottom: function(){
            this._sleep();
            this._trigger('bottom')
            return this;
        },
        _swipeLeft: function(){
            this._sleep();
            this._trigger('left')
            return this;
        },
        _setStartTouch: function(touch){
            this._startX = touch.pageX;
            this._startY = touch.pageY;
            return this;
        },
        _setCurrentTouch: function(touch){
            this._currentX = touch.pageX;
            this._currentY = touch.pageY;
        },
        _touchStartHandler: function(event){
            var touches = event.touches;
            if(touches.length>1){
                return;
            }
            var touch = touches[0];
            this._setStartTouch(touch);
        },
        _touchMoveHandler: function(event){
            var touch = event.touches[0];
            this._setCurrentTouch(touch);
            !this._sleeping && this._evalSwipes();
            this.options.preventDefault && event.preventDefault();
        },
        _touchEndHandler: function(event){
            this._awake();
        },
        _touchCancelHandler: function(event){
            this._awake();
        }
    });

})(jQuery); // end $=jQuery encapsulation