/*

 * Metadata - jQuery plugin for parsing metadata from elements

 *

 * Copyright (c) 2006 John Resig, Yehuda Katz, J�örn Zaefferer, Paul McLanahan

 *

 * Dual licensed under the MIT and GPL licenses:

 *   http://www.opensource.org/licenses/mit-license.php

 *   http://www.gnu.org/licenses/gpl.html

 *

 * Revision: $Id: jquery.metadata.js 3640 2007-10-11 18:34:38Z pmclanahan $

 *

 */



/**

 * Sets the type of metadata to use. Metadata is encoded in JSON, and each property

 * in the JSON will become a property of the element itself.

 *

 * There are four supported types of metadata storage:

 *

 *   attr:  Inside an attribute. The name parameter indicates *which* attribute.

 *          

 *   class: Inside the class attribute, wrapped in curly braces: { }

 *   

 *   elem:  Inside a child element (e.g. a script tag). The

 *          name parameter indicates *which* element.

 *   html5: Values are stored in data-* attributes.

 *          

 * The metadata for an element is loaded the first time the element is accessed via jQuery.

 *

 * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements

 * matched by expr, then redefine the metadata type and run another $(expr) for other elements.

 * 

 * @name $.metadata.setType

 *

 * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>

 * @before $.metadata.setType("class")

 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

 * @desc Reads metadata from the class attribute

 * 

 * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>

 * @before $.metadata.setType("attr", "data")

 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

 * @desc Reads metadata from a "data" attribute

 * 

 * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>

 * @before $.metadata.setType("elem", "script")

 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

 * @desc Reads metadata from a nested script element

 * 

 * @example <p id="one" class="some_class" data-item_id="1" data-item_label="Label">This is a p</p>

 * @before $.metadata.setType("html5")

 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

 * @desc Reads metadata from a series of data-* attributes

 *

 * @param String type The encoding type

 * @param String name The name of the attribute to be used to get metadata (optional)

 * @cat Plugins/Metadata

 * @descr Sets the type of encoding to be used when loading metadata for the first time

 * @type undefined

 * @see metadata()

 */



(function($) {



$.extend({

  metadata : {

    defaults : {

      type: 'class',

      name: 'metadata',

      cre: /({.*})/,

      single: 'metadata'

    },

    setType: function( type, name ){

      this.defaults.type = type;

      this.defaults.name = name;

    },

    get: function( elem, opts ){

      var settings = $.extend({},this.defaults,opts);

      // check for empty string in single property

      if ( !settings.single.length ) settings.single = 'metadata';

      

      var data = $.data(elem, settings.single);

      // returned cached data if it already exists

      if ( data ) return data;

      

      data = "{}";

      

      var getData = function(data) {

        if(typeof data != "string") return data;

        

        if( data.indexOf('{') < 0 ) {

          data = eval("(" + data + ")");

        }

      }

      

      var getObject = function(data) {

        if(typeof data != "string") return data;

        

        data = eval("(" + data + ")");

        return data;

      }

      

      if ( settings.type == "html5" ) {

        var object = {};

        $( elem.attributes ).each(function() {

          var name = this.nodeName;

          if(name.match(/^data-/)) name = name.replace(/^data-/, '');

          else return true;

          object[name] = getObject(this.nodeValue);

        });

      } else {

        if ( settings.type == "class" ) {

          var m = settings.cre.exec( elem.className );

          if ( m )

            data = m[1];

        } else if ( settings.type == "elem" ) {

          if( !elem.getElementsByTagName ) return;

          var e = elem.getElementsByTagName(settings.name);

          if ( e.length )

            data = $.trim(e[0].innerHTML);

        } else if ( elem.getAttribute != undefined ) {

          var attr = elem.getAttribute( settings.name );

          if ( attr )

            data = attr;

        }

        object = getObject(data.indexOf("{") < 0 ? "{" + data + "}" : data);

      }

      

      $.data( elem, settings.single, object );

      return object;

    }

  }

});



/**

 * Returns the metadata object for the first member of the jQuery object.

 *

 * @name metadata

 * @descr Returns element's metadata object

 * @param Object opts An object contianing settings to override the defaults

 * @type jQuery

 * @cat Plugins/Metadata

 */

$.fn.metadata = function( opts ){

  return $.metadata.get( this[0], opts );

};



})(jQuery);