/**
 * jquery plugin to obtain touch gestures from iphone, ipod touch and ipad, should also work with android mobile phones (not tested yet!)
 * common usage: wipe images (left and right to show the previous or next image)
 * 
 * @author andreas waltl, netcu internetagentur (http://www.netcu.de)
 * @version 1.1.1 (9th december 2010) - fix bug (older ie's had problems)
 * @version 1.1 (1st september 2010) - support wipe up and wipe down
 * @version 1.0 (15th july 2010)
 */
(function($) { 
   $.fn.touchwipe = function(settings) {
     var config = {
    		min_move_x: 20,
    		min_move_y: 20,
 		wipeleft: function() { },
 		wiperight: function() { },
 		wipeup: function() { },
 		wipedown: function() { },
		preventdefaultevents: true
	 };
     
     if (settings) $.extend(config, settings);
 
     this.each(function() {
    	 var startx;
    	 var starty;
	 var ismoving = false;

    	 function canceltouch() {
    		 this.removeeventlistener('touchmove', ontouchmove);
    		 startx = null;
    		 ismoving = false;
    	 }	
    	 
    	 function ontouchmove(e) {
		var x = e.touches[0].pagex;
		var y = e.touches[0].pagey;
		var dx = startx - x;
		var dy = starty - y;
    		if(config.preventdefaultevents) { // prevent horizontal swiping only
			if(e.touches[0].pagex !== startx && math.abs(dy) <= 5){
				e.preventdefault();
			}    			
    		 }
    		 if(ismoving) {
	    		 
	    		 if(math.abs(dx) >= config.min_move_x) {
	    			canceltouch();
	    			if(dx > 0) {
	    				config.wipeleft();
	    			}
	    			else {
	    				config.wiperight();
	    			}
	    		 }
	    		 else if(math.abs(dy) >= config.min_move_y) {
		    			canceltouch();
		    			if(dy > 0) {
		    				config.wipedown();
		    			}
		    			else {
		    				config.wipeup();
		    			}
		    		 }
    		 }
    	 }
    	 
    	 function ontouchstart(e)
    	 {
    		 if (e.touches.length == 1) {
    			 startx = e.touches[0].pagex;
    			 starty = e.touches[0].pagey;
    			 ismoving = true;
    			 this.addeventlistener('touchmove', ontouchmove, false);
    		 }
    	 }    	 
    	 if ('ontouchstart' in document.documentelement) {
    		 this.addeventlistener('touchstart', ontouchstart, false);
    	 }
     });
 
     return this;
   };
 
 })(jquery);