/*
 * 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 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);