/**
* AnimatedScroll.js v1.1.5
* Smooth, animated document scroll to a specific element, supporting native jQuery UI easings.
* https://github.com/yevhentiurin/animatedscrolljs
*
* By Yevhen Tiurin <yevhentiurin@gmail.com>, Mikhail Semakhin <mike.semakhin@gmail.com>, Carlo Alberto Ferraris <cafxx@cafxx.strayorange.com>
* Licensed under the LGPL Version 3 license.
* http://www.gnu.org/licenses/lgpl.txt
*
* Date: December 2, 2013
**/

(function($) 
{
  //***************************
  $.animatedScroll = 
  {
    animateOptions: {},
    offsetFromTarget: 
    {
      left: "50%",
      top: "50%"
    }
  };

  //***************************
  $.fn.animatedScroll = function(animateOptions, offsetFromTarget) 
  {
    animateOptions = $.extend({}, $.animatedScroll.animateOptions, animateOptions);
    offsetFromTarget = $.extend({}, $.animatedScroll.offsetFromTarget, offsetFromTarget);

    AnimatedScroll(this.get(0), animateOptions, offsetFromTarget);

    return this;
  };

  //***************************
  function AnimatedScroll(element, animateOptions, offsetFromTarget)
  {
    var $element,
      viewportWidth, viewportHeight, targetWidth, targetHeight, 
      documentWidth, documentHeight, targetLeft, targetTop,
      animateLeft, animateTop, offsetLeft, offsetTop,
      animateStep, animateComplete,
      $viewportDetectElement;

    $viewportDetectElement = $('<div style="visibility:hidden;position:fixed;width:100%;height:100%" />').appendTo(document.body);
    viewportWidth = $viewportDetectElement.width();
    viewportHeight = $viewportDetectElement.height();
    $viewportDetectElement.remove();
    
    targetWidth = $(element).outerWidth();
    targetHeight = $(element).outerHeight();
    documentWidth = $(document).width();
    documentHeight = $(document).height();
    targetLeft = $(element).offset().left;
    targetTop = $(element).offset().top;

    function parseOffsetValue(targetValue, offsetValue)
    {
      var parsedOffsetValue = parseInt(offsetValue);

      if (isNaN(parsedOffsetValue))
        return 0;

      if (offsetValue.indexOf !== undefined)
      {
          if (offsetValue.indexOf("%") > -1)
          {
            return (targetValue * parsedOffsetValue / 100);
          }
      };

      return parsedOffsetValue; 
    };

    offsetLeft = parseOffsetValue(targetWidth, offsetFromTarget.left);
    offsetTop = parseOffsetValue(targetHeight, offsetFromTarget.top);
    
    animateLeft = targetLeft + offsetLeft - (viewportWidth / 2);
    animateLeft = animateLeft < 0 ? 0 : (animateLeft + viewportWidth > documentWidth ? documentWidth - viewportWidth : animateLeft);
    animateTop = targetTop + offsetTop - (viewportHeight / 2);
    animateTop = animateTop < 0 ? 0 : (animateTop + viewportHeight > documentHeight ? documentHeight - viewportHeight : animateTop);

    animateStep = animateOptions.step;
    animateComplete = animateOptions.complete;

    animateOptions = $.extend({}, animateOptions, 
      {
        step: function(now, tween)
        {
          tween.elem.scrollIntoView(true);
          
          if (typeof animateStep == "function")
          {
            animateStep.apply(this, arguments);
          };
        },
        complete: function()
        {
          this.scrollIntoView(true);
          $(this).remove();

          if (typeof animateComplete == "function")
          {
            animateComplete.apply(this, arguments);
          };
        }
      }
    );

    $("<div/>")
      .css(
        {
          visibility: 'hidden',
          position: "absolute", 
          width: viewportWidth, 
          height: viewportHeight, 
          left: $(window).scrollLeft(),
          top: $(window).scrollTop()
        }
      )
      .appendTo(document.body)
      .animate({left: animateLeft, top: animateTop}, animateOptions);
  };

})(jQuery);