/*

* 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 4187 2007-12-16 17:15:27Z joern.zaefferer $
*
*/

/**

* 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 three 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.
*          
* 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
* 
* @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 = "{}";

                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 undefined;
                        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;
                }

                if ( data.indexOf( '{' ) <0 )
                data = "{" + data + "}";

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

                $.data( elem, settings.single, data );
                return data;
        }
}

});

/**

* 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 containing settings to override the defaults
* @type jQuery
* @cat Plugins/Metadata
*/

$.fn.metadata = function( opts ){

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

};

})(jQuery);