/**
 * @depends jquery
 * @name jquery.scrollto
 * @package jquery-scrollto {@link http://www.balupton/projects/jquery-scrollto}
 */

/**
 * jQuery Aliaser
 */
(function($){

  /**
   * jQuery ScrollTo (balupton edition)
   * @version 1.0.1
   * @date August 31, 2010
   * @since 0.1.0, August 27, 2010
     * @package jquery-scrollto {@link http://www.balupton/projects/jquery-scrollto}
   * @author Benjamin "balupton" Lupton {@link http://www.balupton.com}
   * @copyright (c) 2010 Benjamin Arthur Lupton {@link http://www.balupton.com}
   * @license GNU Affero General Public License version 3 {@link http://www.gnu.org/licenses/agpl-3.0.html}
   */
  if ( !($.ScrollTo||false) ) {
    $.ScrollTo = {
      /**
       * The Default Configuration
       */
      config: {
        duration: 400,
        easing: 'swing',
        callback: undefined,
        durationMode: 'each',
        offset: 0,
      },

      /**
       * Configure ScrollTo
       */
      configure: function(options){
        var ScrollTo = $.ScrollTo;

        // Apply Options to Config
        $.extend(ScrollTo.config, options||{});

        // Chain
        return this;
      },

      /**
       * Perform the Scroll Animation for the Collections
       * We use $inline here, so we can determine the actual offset start for each overflow:scroll item
       * Each collection is for each overflow:scroll item
       */
      scroll: function(collections, config){
        var ScrollTo = $.ScrollTo;

        // Determine the Scroll
          var collection = collections.pop(),
          $container = collection.$container,
          $target = collection.$target;

        // Prepare the Inline Element of the Container
        var $inline = $('<span/>').css({
          'position': 'absolute',
          'top': '0px',
          'left': '0px'
        });
        var position = $container.css('position');

        // Insert the Inline Element of the Container
        $container.css('position','relative');
        $inline.appendTo($container);

        // Determine the Offsets
        var startOffset = $inline.offset().top,
          targetOffset = $target.offset().top,
          offsetDifference = targetOffset - startOffset + config.offset;

        // Reset the Inline Element of the Container
        $inline.remove();
        $container.css('position',position);

        // Prepare the callback
        var callback = function(event){
          // Check
          if ( collections.length === 0 ) {
            // Callback
            if ( typeof config.callback === 'function' ) {
              config.callback.apply(this,[event]);
            }
          }
          else {
            // Recurse
            ScrollTo.scroll(collections,config);
          }
          // Return true
          return true;
        };

        // Perform the Scroll
        $container.animate({
          'scrollTop': offsetDifference+'px'
        }, config.duration, config.easing, callback);

        // Return true
        return true;
      },

      /**
       * ScrollTo the Element using the Options
       */
      fn: function(options){
        var ScrollTo = $.ScrollTo;

        // Prepare
        var $target = $(this);
        if ( $target.length === 0 ) {
          // Chain
          return this;
        }

        // Fetch
        var $container = $target.parent(),
          collections = [];

        // Handle Options
        config = $.extend({},ScrollTo.config,options);

        // Cycle through the containers
        while ( $container.length === 1 && !$container.is('body') && !($container.get(0) === document) ) {
          // Check Container
          var container = $container.get(0);
          if ( $container.css('overflow-y') !== 'visible' && container.scrollHeight !== container.clientHeight ) {
            // Push the Collection
            collections.push({
              '$container': $container,
              '$target': $target
            });
            // Update the Target
            $target = $container;
          }
          // Update the Container
          $container = $container.parent();
        }

        // Add the final collection
        collections.push({
          '$container': $($.browser.msie ? 'html' : 'body'),
          '$target': $target
        });

        // Adjust the Config
        if ( config.durationMode === 'all' ) {
          config.duration /= collections.length;
        }

        // Handle
        ScrollTo.scroll(collections,config);

        // Chain
        return this;
      },

      /**
       * Construct
       */
      construct: function(options){
        var ScrollTo = $.ScrollTo;

        // Apply our jQuery Function
        $.fn.ScrollTo = ScrollTo.fn;

        // Apply our Options to the Default Config
        ScrollTo.config = $.extend(ScrollTo.config,options);

        // Chain
        return this;
      }
    };

    // Construct It
    $.ScrollTo.construct();
  }
  else {
    window.console.warn("$.ScrollTo has already been defined...");
  }

})(jQuery);