(function($){
  var touch = {}, touchTimeout;

  function parentIfText(node){
    return 'tagName' in node ? node : node.parentNode;
  }

  function swipeDirection(x1, x2, y1, y2){
    var xDelta = Math.abs(x1 - x2), yDelta = Math.abs(y1 - y2);
    if (xDelta >= yDelta) {
      return (x1 - x2 > 0 ? 'Left' : 'Right');
    } else {
      return (y1 - y2 > 0 ? 'Up' : 'Down');
    }
  }

  $(document).ready(function(){
    $(document.body).bind('touchstart', function(e){
      var now = Date.now(), delta = now - (touch.last || now);
      touch.target = parentIfText(e.touches[0].target);
      touchTimeout && clearTimeout(touchTimeout);
      touch.x1 = e.touches[0].pageX;
      touch.y1 = e.touches[0].pageY;
      if (delta > 0 && delta <= 250) touch.isDoubleTap = true;
      touch.last = now;
    }).bind('touchmove', function(e){
      touch.x2 = e.touches[0].pageX;
      touch.y2 = e.touches[0].pageY;
    }).bind('touchend', function(e){
      if (touch.isDoubleTap) {
        $(touch.target).trigger('doubleTap');
        touch = {};
      } else if (touch.x2 > 0 || touch.y2 > 0) {
        (Math.abs(touch.x1 - touch.x2) > 30 || Math.abs(touch.y1 - touch.y2) > 30)  &&
          $(touch.target).trigger('swipe') &&
          $(touch.target).trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)));
        touch.x1 = touch.x2 = touch.y1 = touch.y2 = touch.last = 0;
      } else if ('last' in touch) {
        touchTimeout = setTimeout(function(){
          touchTimeout = null;
          $(touch.target).trigger('tap')
          touch = {};
        }, 250);
      }
    }).bind('touchcancel', function(){ touch = {} });
  });

  ['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown', 'doubleTap', 'tap'].forEach(function(m){
    $.fn[m] = function(callback){ return this.bind(m, callback) }
  });
})(Zepto);