(function(window) {

  var Slider = function() {};



  Slider.prototype.init = function(element, opts) {

    this.element = element;

    this.structure = this.structure(element);

    this.current_x = 0;

    this.current_y = 0;

    this.hooks = {};



    this.opts = jQuery.extend({

      next: undefined, 

      previous: undefined, 

      limit_left: false,

      limit_right: false, 

      use_margin: false,

      init: undefined

    }, opts);

    

    var self = this;

    if (this.opts.next) {

      this.opts.next.bind('click', function() {

        var previous = self.current_x;

        self.current_x = self.limitXBounds(self.nextPageX(self.current_x));

        if (self.current_x !== previous) {

          self.update(self.current_x, true);

          self.runHook('move', self);

        }



        return false;

      });

    }



    if (this.opts.previous) {

      this.opts.previous.bind('click', function() {

        var previous = self.current_x;

        self.current_x = self.limitXBounds(self.previousPageX(self.current_x));

        if (self.current_x !== previous) {

          self.update(self.current_x, true);

          self.runHook('move', self);

        }



        return false;

      });

    }



    if (this.opts.init !== undefined) {

      this.opts.init(this); 

    }

  };



  Slider.prototype.structure = function(element) {

    var structure = {};

    var first = element.find('.item').eq(0);



    structure.item_count = element.find('.item').size();

    //structure.item_width = parseInt(first.width());
    //structure.item_width = parseInt(jQuery(first).css('width'));
    structure.item_width = 940;
    structure.item_height = parseInt(first.height());

    var margin_right = first.css('marginRight');

    structure.item_spacing = (margin_right !== undefined) ? parseInt(margin_right.replace('px', '')) : 0;

    structure.container_width = (structure.item_spacing + structure.item_width);



    return structure;

  };



  Slider.prototype.subscribe = function(hook, fn) {

    if (this.hooks[hook] === undefined) {

      this.hooks[hook] = [];

    }

    this.hooks[hook].push(fn);

  };



  Slider.prototype.runHook = function(hook) {

    if (this.hooks[hook] !== undefined) {

      var args = Array().slice.call(arguments);

      var self = this;

      this.hooks[hook].forEach(function(fn) {

        fn.apply(self, args.slice(1));

      });

    }

  };



  Slider.prototype.page = function(current_x) {

    return Math.abs(Math.round(current_x / this.structure.container_width));

  };



  Slider.prototype.nearestPageX = function(current_x) {

    return Math.round(current_x / this.structure.container_width) * this.structure.container_width;

  };



  Slider.prototype.pageX = function(index) {

    var flip = (this.opts.reverse) ? 1 : -1;

    return flip * index * this.structure.container_width;

  };



  Slider.prototype.nextPageX = function(current_x) {

    if (this.page(current_x) + 1 <= this.structure.item_count - 1) {

      current_x = current_x - this.structure.container_width;

    } else {
        current_x = 0;
    }

    return current_x;

  };



  Slider.prototype.previousPageX = function(current_x) {
    if (this.page(current_x) >= 0) {

      current_x = current_x + this.structure.container_width;
      
      if (current_x > 0) {
        current_x = - this.structure.container_width * (this.structure.item_count - 1);
      }
    }

    return current_x;

  };



  Slider.prototype.limitXBounds = function(current_x) {

    var total_width = this.structure.container_width * this.structure.item_count;

    if (this.opts.reverse) {

      current_x = (current_x > total_width - this.structure.container_width) ? total_width - this.structure.container_width : current_x;

      current_x = (current_x < 0) ? 0 : current_x;

    } else {

      current_x = (current_x < -total_width + this.structure.container_width) ? -total_width + this.structure.container_width : current_x;

      current_x = (current_x > 0) ? 0 : current_x;

    }



    if ((this.current_x - current_x > 0 && this.opts.limit_right) || 

        (this.current_x - current_x < 0 && this.opts.limit_left)) {

      current_x = this.current_x;

    }

    return current_x;

  };



  Slider.prototype.update = function(current_x) {

    var self = this;

    this.element.animate({'margin-left': current_x + 'px'}).queue(function() {

      self.runHook('transition_end', self);

      jQuery(this).dequeue();

    });

    this.runHook('update', this);

  };





  var TouchSlider = function() {};

  TouchSlider.prototype = new Slider();

  TouchSlider.superobject = Slider.prototype;



  TouchSlider.prototype.init = function(element, structure, opts) {

    TouchSlider.superobject.init.call(this, element, structure, opts);



    this.gesturing = false;

    element[0].addEventListener('touchstart', this, false);

    element[0].addEventListener('webkitTransitionEnd', this, false);

  };



  TouchSlider.prototype.beforeMove = function() {

    this.element.css({'-webkit-transition-duration': '0s'});

    this.element.css({'-webkit-transition-property': 'none'});

  };



  TouchSlider.prototype.beforeUpdate = function() {

    this.element.css({'-webkit-transition-duration': '0.4s'});

    if (this.opts.use_margin) {

      this.element.css({'-webkit-transition-property': 'margin-left'});

    } else {

      this.element.css({'-webkit-transition-property': '-webkit-transform'});

    }

  };



  TouchSlider.prototype.update = function(current_x, opts) {

    var opts = jQuery.extend({animate: true, call_hook: true}, opts);

    if (opts.animate) { this.beforeUpdate(); }



    if (this.opts.use_margin) {

      this.element.css({'margin-left': current_x + 'px'}); 

    } else {

      this.element.css({'-webkit-transform': 'translate3d(' + current_x + 'px, 0, 0)'}); 

    }

    

    if (opts.call_hook) { this.runHook('update', this); }

  };



  TouchSlider.prototype.handleEvent = function(e) {

    this[e.type](e);

  };



  TouchSlider.prototype.click = function(e) {

    if (this.moved) { e.preventDefault(); }

    this.element[0].removeEventListener('click', this, false);

    return false;

  };



  TouchSlider.prototype.touchstart = function(e) {

    this.current_target = e.currentTarget;

    this.start_x = e.touches[0].pageX - this.current_x;

    this.start_y = e.touches[0].pageY - this.current_y;

    this.moved = false;



    window.addEventListener('gesturestart', this, false);

    window.addEventListener('gestureend', this, false);

    window.addEventListener('touchmove', this, false);

    window.addEventListener('touchend', this, false);

    this.element[0].addEventListener('click', this, false);



    this.beforeMove();



    this.runHook('start', this);



    return false;

  };



  TouchSlider.prototype.touchmove = function(e) {

    if (this.gesturing) {

      return false;

    }



    if (!this.moved) {

      var delta_y = e.touches[0].pageY - this.start_y;

      var delta_x = e.touches[0].pageX - this.start_x;

      if (Math.abs(delta_y) < 15) {

        e.preventDefault();

      }



      this.runHook('first_move', this);

    }



    this.moved = true;

    this.last_x = this.current_x;

    this.last_move_time = new Date();



    this.current_x = this.limitXBounds(e.touches[0].pageX - this.start_x);



    this.update(this.current_x);

    this.runHook('move', this);



    return false;

  };



  TouchSlider.prototype.touchend = function(e) {

    window.removeEventListener('gesturestart', this, false);

    window.removeEventListener('gestureend', this, false);

    window.removeEventListener('touchmove', this, false);

    window.removeEventListener('touchend', this, false);



    if (this.moved) {

      var dx = this.current_x - this.last_x;

      var dt = (new Date()) - this.last_move_time + 1; 

      

      var tossed_x = this.limitXBounds(this.current_x + dx * 100 / dt);

      this.current_x = this.nearestPageX(tossed_x);



      this.update(this.current_x);

      this.runHook('move', this);

    } else {

      this.runHook('end_no_move', this);

    }



    this.current_target = undefined;



    return false;  

  };



  TouchSlider.prototype.webkitTransitionEnd = function(e) {

    this.runHook('transition_end', this);

  };



  TouchSlider.prototype.gesturestart = function(e) { this.gesturing = true; };

  TouchSlider.prototype.gestureend = function(e) { this.gesturing = false; };



  Merkley.Slider = Slider;

  Merkley.TouchSlider = TouchSlider;

})(window);