/**
 * 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) {
             if(config.preventDefaultEvents) {
                 e.preventDefault();
             }
             if(isMoving) {
                 var x = e.touches[0].pageX;
                 var y = e.touches[0].pageY;
                 var dx = startX - x;
                 var dy = startY - y;
                 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);