/*
* Metadata - jQuery plugin for parsing metadata from elements
*
* Copyright (c) 2006 John Resig, Yehuda Katz, Jörn Zaefferer
*
* Dual licensed under the MIT and GPL licenses:
*   http://www.opensource.org/licenses/mit-license.php
*   http://www.gnu.org/licenses/gpl.html
*
* Revision: $Id$
*
*/

/**
* 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 $.meta.setType
*
* @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>
* @before $.meta.setType("class")
* @after $("#one").data().item_id == 1; $("#one")[0].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 $.meta.setType("attr", "data")
* @after $("#one").data().item_id == 1; $("#one")[0].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 $.meta.setType("elem", "script")
* @after $("#one").data().item_id == 1; $("#one")[0].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 data()
*/

(function($) {
    // settings
    $.meta = {
        type: "class",
        name: "data",
        setType: function(type, name) {
            this.type = type;
            this.name = name;
        },
        cre: /({.*})/,
        single: 'data'
    };

    // reference to original setArray()
    var setArray = $.fn.setArray;

    // define new setArray()
    $.fn.setArray = function(arr) {
        return setArray.apply(this, arguments).each(function() {
            if (this.nodeType == 9 || $.isXMLDoc(this) || this.metaDone) return;

            var data = "{}";

            if ($.meta.type == "class") {
                var m = $.meta.cre.exec(this.className);
                if (m)
                    data = m[1];
            } else if ($.meta.type == "elem") {
                if (!this.getElementsByTagName) return;
                var e = this.getElementsByTagName($.meta.name);
                if (e.length)
                    data = $.trim(e[0].innerHTML);
            } else if (this.getAttribute != undefined) {
                var attr = this.getAttribute($.meta.name);
                if (attr)
                    data = attr;
            }

            if (!/^{/.test(data))
                data = "{" + data + "}";

            eval("data = " + data);

            if ($.meta.single)
                this[$.meta.single] = data;
            else
                $.extend(this, data);

            this.metaDone = true;
        });
    };

    /**
    * Returns the metadata object for the first member of the jQuery object.
    *
    * @name data
    * @descr Returns element's metadata object
    * @type jQuery
    * @cat Plugins/Metadata
    */
    $.fn.data = function() {
        return this[0][$.meta.single || "data"];
    };
})(jQuery);