;(function($, window, undefined) {

  "use strict";

  /**
		 * Sticky Element constructor
		 * @param elm
		 * @param par
		 * @param options
		 * @constructor
		 * https://jsfiddle.net/aKuHs/show/
		 */
  var Sticky = function(elm, par, options) {
    this.element = elm;
    this.parent = par;
    this._frozen = false;
    this.options = $.extend({
      animate: false,
      useFixed: true,
      animTime: 300
    }, options);
    this.init();
  };

  Sticky.prototype.init = function() {
    this.element.addClass("sticky-scroll");
    this.update();
  };

  Sticky.prototype.update = function() {
    //This will handle any resizing of the container the sticky scroll is in and update the boundaries if necessary
    this.setBoundaries();
    this.moveIt();
  };

  Sticky.prototype.moveIt = function() {
    // This will decide whether to move the stickied item
    var scrollTop = $(window).scrollTop();
    var height = this.element.outerHeight(true);
    var realStop = this._stop - height;
    var width = this.element.innerWidth();

    if (this._parentHeight - this._offset > height && !this._frozen) {
      if (scrollTop >= this._start && scrollTop <= realStop) {
        if(this.options.useFixed){
          this.element.addClass('go');
          this.element.css({'position':'fixed', 'width': width,'top':0,'left':this.element.offset().left});
        } else {
          this.updateOffset(scrollTop - this._start);
        }
      } else {
        this.element.removeClass('go');
        this.element.css({'position':'relative','left':0});
        if (scrollTop < this._start) {
          this.updateOffset(0);
        } else if (scrollTop > realStop) {
          this.updateOffset(this._parentHeight - height - this._offset);
        }
      }
    }
  };

  Sticky.prototype.setBoundaries = function() {
    // This will set the boundaries the stickied item can move between and it's left position
    this._offset = this.element.position().top;
    this._start = this.parent.offset().top + this._offset;
    this._parentHeight = this.parent.outerHeight();
    this._stop = this._start + this._parentHeight - this._offset;
  };

  /**
		 * Update Stickied Element's offset
		 * @param yOffset
		 */
  Sticky.prototype.updateOffset = function(yOffset) {
    if (!this._lastPosition !== yOffset) {
      // This moves the item
      if (this.animate) {
        this.element.stop().animate({
          'top': yOffset
        }, this.animTime);
      } else {
        this.element.css('top', yOffset);
      }
      this._lastPosition = yOffset;
    }
  };

  Sticky.prototype.toggleFreeze = function() {
    // This will freeze the stickied item in place wherever it is
    this._frozen = !this._frozen;
  };

  $.fn.sticky = function(par, options) {
    var method, args, ret = false;
    if (typeof options === "string") {
      args = [].slice.call(arguments, 0);
    }

    this.each(function() {
      var self = $(this);
      var parent = par;
      if (parent) {
        parent = self.parent().closest(parent);
      } else {
        parent = self.parent();
      }
      parent.css({'position':'relative'}); // Set parent position to relative
      self.css({'position':'relative'}); // Set item position to relative
      var instance = self.data("stickyInstance");

      if (instance && options) {
        if (typeof options === "object") {
          ret = $.extend(instance.options, options);
        } else if (options === "options") {
          ret = instance.options;
        } else if (typeof instance[options] === "function") {
          ret = instance[options].apply(instance, args.slice(1));
        } else {
          throw new Error("Sticky Element has no option/method named " + method);
        }
      } else {
        instance = new Sticky(self, parent, options || {});
        self.data("stickyInstance", instance);
        $.fn.sticky._instances.push(instance);
      }
    });
    return ret || this;
  };

  $.fn.sticky._instances = [];

  $(window).on({
    'resize': function(e) {
      // Update the position/offset changed on resize and move
      $.each($.fn.sticky._instances, function() {
        this.update();
      });
    },
    'scroll': function() {
      // Move all those suckers on scroll
      $.each($.fn.sticky._instances, function() {
        if (!this._frozen) {
          this.moveIt();
        }
      });
    }
  });
}(jQuery, window));