// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

base.exportTo('ui', function() {

  /**
   * Helper function for creating new element for define.
   */
  function createElementHelper(tagName, opt_bag) {
    // Allow passing in ownerDocument to create in a different document.
    var doc;
    if (opt_bag && opt_bag.ownerDocument)
      doc = opt_bag.ownerDocument;

    return doc.createElement(tagName);
  }

  /**
   * Creates the constructor for a UI element class.
   *
   * Usage:
   * <pre>
   * var List = base.ui.define('list');
   * List.prototype = {
   *   __proto__: HTMLUListElement.prototype,
   *   decorate: function() {
   *     ...
   *   },
   *   ...
   * };
   * </pre>
   *
   * @param {string|Function} tagNameOrFunction The tagName or
   *     function to use for newly created elements. If this is a function it
   *     needs to return a new element when called.
   * @return {function(Object=):Element} The constructor function which takes
   *     an optional property bag. The function also has a static
   *     {@code decorate} method added to it.
   */
  function define(tagNameOrFunction) {
    var createFunction, tagName;
    if (typeof tagNameOrFunction == 'function') {
      createFunction = tagNameOrFunction;
      tagName = '';
    } else {
      createFunction = createElementHelper;
      tagName = tagNameOrFunction;
    }

    /**
     * Creates a new UI element constructor.
     * @param {Object=} opt_propertyBag Optional bag of properties to set on the
     *     object after created. The property {@code ownerDocument} is special
     *     cased and it allows you to create the element in a different
     *     document than the default.
     * @constructor
     */
    function f(opt_propertyBag) {
      var el = createFunction(tagName, opt_propertyBag);
      f.decorate(el);
      for (var propertyName in opt_propertyBag) {
        el[propertyName] = opt_propertyBag[propertyName];
      }
      return el;
    }

    /**
     * Decorates an element as a UI element class.
     * @param {!Element} el The element to decorate.
     */
    f.decorate = function(el) {
      el.__proto__ = f.prototype;
      el.decorate();
    };

    return f;
  }

  return {
    define: define
  };
});