// Copyright 2010 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/**
 * @fileoverview Similar to {@link goog.ui.FlatButtonRenderer},
 * but underlines text instead of adds borders.
 *
 * For accessibility reasons, it is best to use this with a goog.ui.Button
 * instead of an A element for links that perform actions in the page.  Links
 * that have an href and open a new page can and should remain as A elements.
 *
 * @author robbyw@google.com (Robby Walker)
 */

goog.provide('goog.ui.LinkButtonRenderer');

goog.require('goog.ui.Button');
goog.require('goog.ui.FlatButtonRenderer');
goog.require('goog.ui.registry');



/**
 * Link renderer for {@link goog.ui.Button}s.  Link buttons can contain
 * almost arbitrary HTML content, will flow like inline elements, but can be
 * styled like block-level elements.
 * @constructor
 * @extends {goog.ui.FlatButtonRenderer}
 */
goog.ui.LinkButtonRenderer = function() {
  goog.ui.FlatButtonRenderer.call(this);
};
goog.inherits(goog.ui.LinkButtonRenderer, goog.ui.FlatButtonRenderer);
goog.addSingletonGetter(goog.ui.LinkButtonRenderer);


/**
 * Default CSS class to be applied to the root element of components rendered
 * by this renderer.
 * @type {string}
 */
goog.ui.LinkButtonRenderer.CSS_CLASS = goog.getCssName('goog-link-button');


/** @override */
goog.ui.LinkButtonRenderer.prototype.getCssClass = function() {
  return goog.ui.LinkButtonRenderer.CSS_CLASS;
};


// Register a decorator factory function for Link Buttons.
goog.ui.registry.setDecoratorByClassName(
    goog.ui.LinkButtonRenderer.CSS_CLASS, function() {
      // Uses goog.ui.Button, but with LinkButtonRenderer.
      return new goog.ui.Button(null, goog.ui.LinkButtonRenderer.getInstance());
    });
