text: // Copyright 2009 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 A customized MenuButton for selection of items among lists.
   * Menu contains 'select all' and 'select none' MenuItems for selecting all and
   * no items by default. Other MenuItems can be added by user.
   *
   * The checkbox content fires the action events associated with the 'select all'
   * and 'select none' menu items.
   *
   * @see ../demos/selectionmenubutton.html
   */
  
  goog.provide('goog.ui.SelectionMenuButton');
  goog.provide('goog.ui.SelectionMenuButton.SelectionState');
  
  goog.require('goog.dom.InputType');
  goog.require('goog.dom.TagName');
  goog.require('goog.events.EventType');
  goog.require('goog.style');
  goog.require('goog.ui.Component');
  goog.require('goog.ui.MenuButton');
  goog.require('goog.ui.MenuItem');
  goog.require('goog.ui.registry');
  
  
  
  /**
   * A selection menu button control.  Extends {@link goog.ui.MenuButton}.
   * Menu contains 'select all' and 'select none' MenuItems for selecting all and
   * no items by default. Other MenuItems can be added by user.
   *
   * The checkbox content fires the action events associated with the 'select all'
   * and 'select none' menu items.
   *
   * @param {goog.ui.ButtonRenderer=} opt_renderer Renderer used to render or
   *     decorate the menu button; defaults to {@link goog.ui.MenuButtonRenderer}.
   * @param {goog.ui.MenuItemRenderer=} opt_itemRenderer Optional menu item
   *     renderer.
   * @param {goog.dom.DomHelper=} opt_domHelper Optional DOM helper, used for
   *     document interaction.
   * @constructor
   * @extends {goog.ui.MenuButton}
   */
  goog.ui.SelectionMenuButton = function(
      opt_renderer, opt_itemRenderer, opt_domHelper) {
    goog.ui.MenuButton.call(this, null, null, opt_renderer, opt_domHelper);
    this.initialItemRenderer_ = opt_itemRenderer || null;
  };
  goog.inherits(goog.ui.SelectionMenuButton, goog.ui.MenuButton);
  goog.tagUnsealableClass(goog.ui.SelectionMenuButton);
  
  
  /**
   * Constants for menu action types.
   * @enum {number}
   */
  goog.ui.SelectionMenuButton.SelectionState = {
    ALL: 0,
    SOME: 1,
    NONE: 2
  };
  
  
  /**
   * Select button state
   * @type {goog.ui.SelectionMenuButton.SelectionState}
   * @protected
   */
  goog.ui.SelectionMenuButton.prototype.selectionState =
      goog.ui.SelectionMenuButton.SelectionState.NONE;
  
  
  /**
   * Item renderer used for the first 2 items, 'select all' and 'select none'.
   * @type {goog.ui.MenuItemRenderer}
   * @private
   */
  goog.ui.SelectionMenuButton.prototype.initialItemRenderer_;
  
  
  /**
   * Enables button and embedded checkbox.
   * @param {boolean} enable Whether to enable or disable the button.
   * @override
   */
  goog.ui.SelectionMenuButton.prototype.setEnabled = function(enable) {
    goog.ui.SelectionMenuButton.base(this, 'setEnabled', enable);
    this.setCheckboxEnabled(enable);
  };
  
  
  /**
   * Enables the embedded checkbox.
   * @param {boolean} enable Whether to enable or disable the checkbox.
   * @protected
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.ui.SelectionMenuButton.prototype.setCheckboxEnabled = function(enable) {
    this.getCheckboxElement().disabled = !enable;
  };
  
  
  /** @override */
  goog.ui.SelectionMenuButton.prototype.handleMouseDown = function(e) {
    if (!this.getDomHelper().contains(
            this.getCheckboxElement(),
            /** @type {Element} */ (e.target))) {
      goog.ui.SelectionMenuButton.superClass_.handleMouseDown.call(this, e);
    }
  };
  
  
  /**
   * Gets the checkbox element. Needed because if decorating html, getContent()
   * may include and comment/text elements in addition to the input element.
   * @return {Element} Checkbox.
   * @protected
   */
  goog.ui.SelectionMenuButton.prototype.getCheckboxElement = function() {
    var elements = this.getDomHelper().getElementsByTagNameAndClass(
        goog.dom.TagName.INPUT,
        goog.getCssName('goog-selectionmenubutton-checkbox'),
        this.getContentElement());
    return elements[0];
  };
  
  
  /**
   * Checkbox click handler.
   * @param {goog.events.BrowserEvent} e Checkbox click event.
   * @protected
   */
  goog.ui.SelectionMenuButton.prototype.handleCheckboxClick = function(e) {
    if (this.selectionState == goog.ui.SelectionMenuButton.SelectionState.NONE) {
      this.setSelectionState(goog.ui.SelectionMenuButton.SelectionState.ALL);
      if (this.getItemAt(0)) {
        this.getItemAt(0).dispatchEvent(  // 'All' item
            goog.ui.Component.EventType.ACTION);
      }
    } else {
      this.setSelectionState(goog.ui.SelectionMenuButton.SelectionState.NONE);
      if (this.getItemAt(1)) {
        this.getItemAt(1).dispatchEvent(  // 'None' item
            goog.ui.Component.EventType.ACTION);
      }
    }
  };
  
  
  /**
   * Menu action handler to update checkbox checked state.
   * @param {goog.events.Event} e Menu action event.
   * @private
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.ui.SelectionMenuButton.prototype.handleMenuAction_ = function(e) {
    if (e.target.getModel() == goog.ui.SelectionMenuButton.SelectionState.ALL) {
      this.setSelectionState(goog.ui.SelectionMenuButton.SelectionState.ALL);
    } else {
      this.setSelectionState(goog.ui.SelectionMenuButton.SelectionState.NONE);
    }
  };
  
  
  /**
   * Set up events related to the menu items.
   * @private
   */
  goog.ui.SelectionMenuButton.prototype.addMenuEvent_ = function() {
    if (this.getItemAt(0) && this.getItemAt(1)) {
      this.getHandler().listen(
          this.getMenu(), goog.ui.Component.EventType.ACTION,
          this.handleMenuAction_);
      this.getItemAt(0).setModel(goog.ui.SelectionMenuButton.SelectionState.ALL);
      this.getItemAt(1).setModel(goog.ui.SelectionMenuButton.SelectionState.NONE);
    }
  };
  
  
  /**
   * Set up events related to the checkbox.
   * @protected
   */
  goog.ui.SelectionMenuButton.prototype.addCheckboxEvent = function() {
    this.getHandler().listen(
        this.getCheckboxElement(), goog.events.EventType.CLICK,
        this.handleCheckboxClick);
  };
  
  
  /**
   * Adds the checkbox to the button, and adds 2 items to the menu corresponding
   * to 'select all' and 'select none'.
   * @override
   * @protected
   */
  goog.ui.SelectionMenuButton.prototype.createDom = function() {
    goog.ui.SelectionMenuButton.superClass_.createDom.call(this);
  
    this.createCheckbox();
  
    /** @desc Text for 'All' button, used to select all items in a list. */
    var MSG_SELECTIONMENUITEM_ALL = goog.getMsg('All');
    /** @desc Text for 'None' button, used to unselect all items in a list. */
    var MSG_SELECTIONMENUITEM_NONE = goog.getMsg('None');
  
    var itemAll = new goog.ui.MenuItem(
        MSG_SELECTIONMENUITEM_ALL, null, this.getDomHelper(),
        this.initialItemRenderer_);
    var itemNone = new goog.ui.MenuItem(
        MSG_SELECTIONMENUITEM_NONE, null, this.getDomHelper(),
        this.initialItemRenderer_);
    this.addItem(itemAll);
    this.addItem(itemNone);
  
    this.addCheckboxEvent();
    this.addMenuEvent_();
  };
  
  
  /**
   * Creates and adds the checkbox to the button.
   * @protected
   */
  goog.ui.SelectionMenuButton.prototype.createCheckbox = function() {
    var checkbox = this.getDomHelper().createElement(goog.dom.TagName.INPUT);
    checkbox.type = goog.dom.InputType.CHECKBOX;
    checkbox.className = goog.getCssName('goog-selectionmenubutton-checkbox');
    this.setContent(checkbox);
  };
  
  
  /** @override */
  goog.ui.SelectionMenuButton.prototype.decorateInternal = function(element) {
    goog.ui.SelectionMenuButton.superClass_.decorateInternal.call(this, element);
    this.addCheckboxEvent();
    this.addMenuEvent_();
  };
  
  
  /** @override */
  goog.ui.SelectionMenuButton.prototype.setMenu = function(menu) {
    goog.ui.SelectionMenuButton.superClass_.setMenu.call(this, menu);
    this.addMenuEvent_();
  };
  
  
  /**
   * Set selection state and update checkbox.
   * @param {goog.ui.SelectionMenuButton.SelectionState} state Selection state.
   * @suppress {strictMissingProperties} Part of the go/strict_warnings_migration
   */
  goog.ui.SelectionMenuButton.prototype.setSelectionState = function(state) {
    if (this.selectionState != state) {
      var checkbox = this.getCheckboxElement();
      if (state == goog.ui.SelectionMenuButton.SelectionState.ALL) {
        checkbox.checked = true;
        goog.style.setOpacity(checkbox, 1);
      } else if (state == goog.ui.SelectionMenuButton.SelectionState.SOME) {
        checkbox.checked = true;
        // TODO(user): Get UX help to style this
        goog.style.setOpacity(checkbox, 0.5);
      } else {  // NONE
        checkbox.checked = false;
        goog.style.setOpacity(checkbox, 1);
      }
      this.selectionState = state;
    }
  };
  
  
  /**
  * Get selection state.
  * @return {goog.ui.SelectionMenuButton.SelectionState} Selection state.
  */
  goog.ui.SelectionMenuButton.prototype.getSelectionState = function() {
    return this.selectionState;
  };
  
  
  // Register a decorator factory function for goog.ui.SelectionMenuButton.
  goog.ui.registry.setDecoratorByClassName(
      goog.getCssName('goog-selectionmenubutton-button'),
      function() { return new goog.ui.SelectionMenuButton(); });
  