chrome/browser/resources/bookmarks/command_manager.js

// Copyright 2017 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.

/**
 * @fileoverview Element which shows context menus and handles keyboard
 * shortcuts.
 */
import 'chrome://resources/cr_elements/cr_action_menu/cr_action_menu.m.js';
import 'chrome://resources/cr_elements/cr_button/cr_button.m.js';
import 'chrome://resources/cr_elements/cr_lazy_render/cr_lazy_render.m.js';
import 'chrome://resources/cr_elements/shared_vars_css.m.js';
import 'chrome://resources/polymer/v3_0/iron-a11y-keys-behavior/iron-a11y-keys-behavior.js';
import './edit_dialog.js';
import './shared_style.js';
import './strings.m.js';

import {getToastManager} from 'chrome://resources/cr_elements/cr_toast/cr_toast_manager.m.js';
import {assert, assertNotReached} from 'chrome://resources/js/assert.m.js';
import {isMac} from 'chrome://resources/js/cr.m.js';
import {KeyboardShortcutList} from 'chrome://resources/js/cr/ui/keyboard_shortcut_list.m.js';
import {loadTimeData} from 'chrome://resources/js/load_time_data.m.js';
import {PluralStringProxyImpl} from 'chrome://resources/js/plural_string_proxy.js';
import {IronA11yAnnouncer} from 'chrome://resources/polymer/v3_0/iron-a11y-announcer/iron-a11y-announcer.js';
import {afterNextRender, flush, html, Polymer} from 'chrome://resources/polymer/v3_0/polymer/polymer_bundled.min.js';

import {deselectItems, selectAll, selectFolder} from './actions.js';
import {highlightUpdatedItems, trackUpdatedItems} from './api_listener.js';
import {BrowserProxy} from './browser_proxy.js';
import {Command, IncognitoAvailability, MenuSource, OPEN_CONFIRMATION_LIMIT, ROOT_NODE_ID} from './constants.js';
import {DialogFocusManager} from './dialog_focus_manager.js';
import {StoreClient} from './store_client.js';
import {BookmarkNode} from './types.js';
import {canEditNode, canReorderChildren, getDisplayedList} from './util.js';

export const CommandManager = Polymer({
  is: 'bookmarks-command-manager',

  _template: html`{__html_template__}`,

  behaviors: [
    StoreClient,
  ],

  properties: {
    /** @private {!Array<Command>} */
    menuCommands_: {
      type: Array,
      computed: 'computeMenuCommands_(menuSource_)',
    },

    /** @private {Set<string>} */
    menuIds_: Object,

    /**
     * Indicates where the context menu was opened from. Will be NONE if
     * menu is not open, indicating that commands are from keyboard shortcuts
     * or elsewhere in the UI.
     * @private {MenuSource}
     */
    menuSource_: {
      type: Number,
      value: MenuSource.NONE,
    },

    /** @private */
    canPaste_: Boolean,

    /** @private */
    globalCanEdit_: Boolean,
  },

  /** @private {?Function} */
  confirmOpenCallback_: null,

  attached() {
    assert(CommandManager.instance_ === null);
    CommandManager.instance_ = this;

    /** @private {!BrowserProxy} */
    this.browserProxy_ = BrowserProxy.getInstance();

    this.watch('globalCanEdit_', state => state.prefs.canEdit);
    this.updateFromStore();

    /** @private {!Map<Command, KeyboardShortcutList>} */
    this.shortcuts_ = new Map();

    this.addShortcut_(Command.EDIT, 'F2', 'Enter');
    this.addShortcut_(Command.DELETE, 'Delete', 'Delete Backspace');

    this.addShortcut_(Command.OPEN, 'Enter', 'Meta|o');
    this.addShortcut_(Command.OPEN_NEW_TAB, 'Ctrl|Enter', 'Meta|Enter');
    this.addShortcut_(Command.OPEN_NEW_WINDOW, 'Shift|Enter');

    // Note: the undo shortcut is also defined in bookmarks_ui.cc
    // TODO(b/893033): de-duplicate shortcut by moving all shortcut
    // definitions from JS to C++.
    this.addShortcut_(Command.UNDO, 'Ctrl|z', 'Meta|z');
    this.addShortcut_(Command.REDO, 'Ctrl|y Ctrl|Shift|Z', 'Meta|Shift|Z');

    this.addShortcut_(Command.SELECT_ALL, 'Ctrl|a', 'Meta|a');
    this.addShortcut_(Command.DESELECT_ALL, 'Escape');

    this.addShortcut_(Command.CUT, 'Ctrl|x', 'Meta|x');
    this.addShortcut_(Command.COPY, 'Ctrl|c', 'Meta|c');
    this.addShortcut_(Command.PASTE, 'Ctrl|v', 'Meta|v');

    /** @private {!Map<string, Function>} */
    this.boundListeners_ = new Map();

    const addDocumentListener = (eventName, handler) => {
      assert(!this.boundListeners_.has(eventName));
      const boundListener = handler.bind(this);
      this.boundListeners_.set(eventName, boundListener);
      document.addEventListener(eventName, boundListener);
    };
    addDocumentListener('open-command-menu', this.onOpenCommandMenu_);
    addDocumentListener('keydown', this.onKeydown_);

    const addDocumentListenerForCommand = (eventName, command) => {
      addDocumentListener(eventName, (e) => {
        if (e.path[0].tagName === 'INPUT') {
          return;
        }

        const items = this.getState().selection.items;
        if (this.canExecute(command, items)) {
          this.handle(command, items);
        }
      });
    };
    addDocumentListenerForCommand('command-undo', Command.UNDO);
    addDocumentListenerForCommand('cut', Command.CUT);
    addDocumentListenerForCommand('copy', Command.COPY);
    addDocumentListenerForCommand('paste', Command.PASTE);

    afterNextRender(this, function() {
      IronA11yAnnouncer.requestAvailability();
    });
  },

  detached() {
    CommandManager.instance_ = null;
    this.boundListeners_.forEach(
        (handler, eventName) =>
            document.removeEventListener(eventName, handler));
  },

  /**
   * Display the command context menu at (|x|, |y|) in window coordinates.
   * Commands will execute on |items| if given, or on the currently selected
   * items.
   * @param {number} x
   * @param {number} y
   * @param {MenuSource} source
   * @param {Set<string>=} items
   */
  openCommandMenuAtPosition(x, y, source, items) {
    this.menuSource_ = source;
    this.menuIds_ = items || this.getState().selection.items;

    const dropdown =
        /** @type {!CrActionMenuElement} */ (this.$.dropdown.get());
    // Ensure that the menu is fully rendered before trying to position it.
    flush();
    DialogFocusManager.getInstance().showDialog(
        dropdown.getDialog(), function() {
          dropdown.showAtPosition({top: y, left: x});
        });
  },

  /**
   * Display the command context menu positioned to cover the |target|
   * element. Commands will execute on the currently selected items.
   * @param {!Element} target
   * @param {MenuSource} source
   */
  openCommandMenuAtElement(target, source) {
    this.menuSource_ = source;
    this.menuIds_ = this.getState().selection.items;

    const dropdown =
        /** @type {!CrActionMenuElement} */ (this.$.dropdown.get());
    // Ensure that the menu is fully rendered before trying to position it.
    flush();
    DialogFocusManager.getInstance().showDialog(
        dropdown.getDialog(), function() {
          dropdown.showAt(target);
        });
  },

  closeCommandMenu() {
    this.menuIds_ = new Set();
    this.menuSource_ = MenuSource.NONE;
    /** @type {!CrActionMenuElement} */ (this.$.dropdown.get()).close();
  },

  ////////////////////////////////////////////////////////////////////////////
  // Command handlers:

  /**
   * Determine if the |command| can be executed with the given |itemIds|.
   * Commands which appear in the context menu should be implemented
   * separately using `isCommandVisible_` and `isCommandEnabled_`.
   * @param {Command} command
   * @param {!Set<string>} itemIds
   * @return {boolean}
   */
  canExecute(command, itemIds) {
    const state = this.getState();
    switch (command) {
      case Command.OPEN:
        return itemIds.size > 0;
      case Command.UNDO:
      case Command.REDO:
        return this.globalCanEdit_;
      case Command.SELECT_ALL:
      case Command.DESELECT_ALL:
        return true;
      case Command.COPY:
        return itemIds.size > 0;
      case Command.CUT:
        return itemIds.size > 0 &&
            !this.containsMatchingNode_(itemIds, function(node) {
              return !canEditNode(state, node.id);
            });
      case Command.PASTE:
        return state.search.term === '' &&
            canReorderChildren(state, state.selectedFolder);
      default:
        return this.isCommandVisible_(command, itemIds) &&
            this.isCommandEnabled_(command, itemIds);
    }
  },

  /**
   * @param {Command} command
   * @param {!Set<string>} itemIds
   * @return {boolean} True if the command should be visible in the context
   *     menu.
   */
  isCommandVisible_(command, itemIds) {
    switch (command) {
      case Command.EDIT:
        return itemIds.size === 1 && this.globalCanEdit_;
      case Command.PASTE:
        return this.globalCanEdit_;
      case Command.CUT:
      case Command.COPY:
        return itemIds.size >= 1 && this.globalCanEdit_;
      case Command.COPY_URL:
        return this.isSingleBookmark_(itemIds);
      case Command.DELETE:
        return itemIds.size > 0 && this.globalCanEdit_;
      case Command.SHOW_IN_FOLDER:
        return this.menuSource_ === MenuSource.ITEM && itemIds.size === 1 &&
            this.getState().search.term !== '' &&
            !this.containsMatchingNode_(itemIds, function(node) {
              return !node.parentId || node.parentId === ROOT_NODE_ID;
            });
      case Command.OPEN_NEW_TAB:
      case Command.OPEN_NEW_WINDOW:
      case Command.OPEN_INCOGNITO:
        return itemIds.size > 0;
      case Command.ADD_BOOKMARK:
      case Command.ADD_FOLDER:
      case Command.SORT:
      case Command.EXPORT:
      case Command.IMPORT:
      case Command.HELP_CENTER:
        return true;
    }
    return assert(false);
  },

  /**
   * @param {Command} command
   * @param {!Set<string>} itemIds
   * @return {boolean} True if the command should be clickable in the context
   *     menu.
   */
  isCommandEnabled_(command, itemIds) {
    const state = this.getState();
    switch (command) {
      case Command.EDIT:
      case Command.DELETE:
        return !this.containsMatchingNode_(itemIds, function(node) {
          return !canEditNode(state, node.id);
        });
      case Command.OPEN_NEW_TAB:
      case Command.OPEN_NEW_WINDOW:
        return this.expandUrls_(itemIds).length > 0;
      case Command.OPEN_INCOGNITO:
        return this.expandUrls_(itemIds).length > 0 &&
            state.prefs.incognitoAvailability !==
            IncognitoAvailability.DISABLED;
      case Command.SORT:
        return this.canChangeList_() &&
            state.nodes[state.selectedFolder].children.length > 1;
      case Command.ADD_BOOKMARK:
      case Command.ADD_FOLDER:
        return this.canChangeList_();
      case Command.IMPORT:
        return this.globalCanEdit_;
      case Command.PASTE:
        return this.canPaste_;
      default:
        return true;
    }
  },

  /**
   * Returns whether the currently displayed bookmarks list can be changed.
   * @private
   * @return {boolean}
   */
  canChangeList_() {
    const state = this.getState();
    return state.search.term === '' &&
        canReorderChildren(state, state.selectedFolder);
  },

  /**
   * @param {Command} command
   * @param {!Set<string>} itemIds
   */
  handle(command, itemIds) {
    const state = this.getState();
    switch (command) {
      case Command.EDIT: {
        const id = Array.from(itemIds)[0];
        /** @type {!BookmarksEditDialogElement} */ (this.$.editDialog.get())
            .showEditDialog(state.nodes[id]);
        break;
      }
      case Command.COPY_URL:
      case Command.COPY: {
        const idList = Array.from(itemIds);
        chrome.bookmarkManagerPrivate.copy(idList, () => {
          let labelPromise;
          if (command === Command.COPY_URL) {
            labelPromise =
                Promise.resolve(loadTimeData.getString('toastUrlCopied'));
          } else if (idList.length === 1) {
            labelPromise =
                Promise.resolve(loadTimeData.getString('toastItemCopied'));
          } else {
            labelPromise = PluralStringProxyImpl.getInstance().getPluralString(
                'toastItemsCopied', idList.length);
          }

          this.showTitleToast_(
              labelPromise, state.nodes[idList[0]].title, false);
        });
        break;
      }
      case Command.SHOW_IN_FOLDER: {
        const id = Array.from(itemIds)[0];
        this.dispatch(
            selectFolder(assert(state.nodes[id].parentId), state.nodes));
        DialogFocusManager.getInstance().clearFocus();
        this.fire('highlight-items', [id]);
        break;
      }
      case Command.DELETE: {
        const idList = Array.from(this.minimizeDeletionSet_(itemIds));
        const title = state.nodes[idList[0]].title;
        let labelPromise;

        if (idList.length === 1) {
          labelPromise =
              Promise.resolve(loadTimeData.getString('toastItemDeleted'));
        } else {
          labelPromise = PluralStringProxyImpl.getInstance().getPluralString(
              'toastItemsDeleted', idList.length);
        }

        chrome.bookmarkManagerPrivate.removeTrees(idList, () => {
          this.showTitleToast_(labelPromise, title, true);
        });
        break;
      }
      case Command.UNDO:
        chrome.bookmarkManagerPrivate.undo();
        getToastManager().hide();
        break;
      case Command.REDO:
        chrome.bookmarkManagerPrivate.redo();
        break;
      case Command.OPEN_NEW_TAB:
      case Command.OPEN_NEW_WINDOW:
      case Command.OPEN_INCOGNITO:
        this.openUrls_(this.expandUrls_(itemIds), command);
        break;
      case Command.OPEN:
        if (this.isFolder_(itemIds)) {
          const folderId = Array.from(itemIds)[0];
          this.dispatch(selectFolder(folderId, state.nodes));
        } else {
          this.openUrls_(this.expandUrls_(itemIds), command);
        }
        break;
      case Command.SELECT_ALL:
        const displayedIds = getDisplayedList(state);
        this.dispatch(selectAll(displayedIds, state));
        break;
      case Command.DESELECT_ALL:
        this.dispatch(deselectItems());
        IronA11yAnnouncer.requestAvailability();
        this.fire('iron-announce', {
          text: loadTimeData.getString('itemsUnselected'),
        });
        break;
      case Command.CUT:
        chrome.bookmarkManagerPrivate.cut(Array.from(itemIds));
        break;
      case Command.PASTE:
        const selectedFolder = state.selectedFolder;
        const selectedItems = state.selection.items;
        trackUpdatedItems();
        chrome.bookmarkManagerPrivate.paste(
            selectedFolder, Array.from(selectedItems), highlightUpdatedItems);
        break;
      case Command.SORT:
        chrome.bookmarkManagerPrivate.sortChildren(
            assert(state.selectedFolder));
        getToastManager().querySelector('dom-if').if = true;
        getToastManager().show(loadTimeData.getString('toastFolderSorted'));
        break;
      case Command.ADD_BOOKMARK:
        /** @type {!BookmarksEditDialogElement} */ (this.$.editDialog.get())
            .showAddDialog(false, assert(state.selectedFolder));
        break;
      case Command.ADD_FOLDER:
        /** @type {!BookmarksEditDialogElement} */ (this.$.editDialog.get())
            .showAddDialog(true, assert(state.selectedFolder));
        break;
      case Command.IMPORT:
        chrome.bookmarks.import();
        break;
      case Command.EXPORT:
        chrome.bookmarks.export();
        break;
      case Command.HELP_CENTER:
        window.open('https://support.google.com/chrome/?p=bookmarks');
        break;
      default:
        assert(false);
    }
    this.recordCommandHistogram_(
        itemIds, 'BookmarkManager.CommandExecuted', command);
  },

  /**
   * @param {!Event} e
   * @param {!Set<string>} itemIds
   * @return {boolean} True if the event was handled, triggering a keyboard
   *     shortcut.
   */
  handleKeyEvent(e, itemIds) {
    for (const commandTuple of this.shortcuts_) {
      const command = /** @type {Command} */ (commandTuple[0]);
      const shortcut =
          /** @type {KeyboardShortcutList} */ (commandTuple[1]);
      if (shortcut.matchesEvent(e) && this.canExecute(command, itemIds)) {
        this.handle(command, itemIds);

        e.stopPropagation();
        e.preventDefault();
        return true;
      }
    }

    return false;
  },

  ////////////////////////////////////////////////////////////////////////////
  // Private functions:

  /**
   * Register a keyboard shortcut for a command.
   * @param {Command} command Command that the shortcut will trigger.
   * @param {string} shortcut Keyboard shortcut, using the syntax of
   *     cr/ui/command.js.
   * @param {string=} macShortcut If set, enables a replacement shortcut for
   *     Mac.
   */
  addShortcut_(command, shortcut, macShortcut) {
    shortcut = (isMac && macShortcut) ? macShortcut : shortcut;
    this.shortcuts_.set(command, new KeyboardShortcutList(shortcut));
  },

  /**
   * Minimize the set of |itemIds| by removing any node which has an ancestor
   * node already in the set. This ensures that instead of trying to delete
   * both a node and its descendant, we will only try to delete the topmost
   * node, preventing an error in the bookmarkManagerPrivate.removeTrees API
   * call.
   * @param {!Set<string>} itemIds
   * @return {!Set<string>}
   */
  minimizeDeletionSet_(itemIds) {
    const minimizedSet = new Set();
    const nodes = this.getState().nodes;
    itemIds.forEach(function(itemId) {
      let currentId = itemId;
      while (currentId !== ROOT_NODE_ID) {
        currentId = assert(nodes[currentId].parentId);
        if (itemIds.has(currentId)) {
          return;
        }
      }
      minimizedSet.add(itemId);
    });
    return minimizedSet;
  },

  /**
   * Open the given |urls| in response to a |command|. May show a confirmation
   * dialog before opening large numbers of URLs.
   * @param {!Array<string>} urls
   * @param {Command} command
   * @private
   */
  openUrls_(urls, command) {
    assert(
        command === Command.OPEN || command === Command.OPEN_NEW_TAB ||
        command === Command.OPEN_NEW_WINDOW ||
        command === Command.OPEN_INCOGNITO);

    if (urls.length === 0) {
      return;
    }

    const openUrlsCallback = function() {
      const incognito = command === Command.OPEN_INCOGNITO;
      if (command === Command.OPEN_NEW_WINDOW || incognito) {
        chrome.windows.create({url: urls, incognito: incognito});
      } else {
        if (command === Command.OPEN) {
          chrome.tabs.create({url: urls.shift(), active: true});
        }
        urls.forEach(function(url) {
          chrome.tabs.create({url: url, active: false});
        });
      }
    };

    if (urls.length <= OPEN_CONFIRMATION_LIMIT) {
      openUrlsCallback();
      return;
    }

    this.confirmOpenCallback_ = openUrlsCallback;
    const dialog = this.$.openDialog.get();
    dialog.querySelector('[slot=body]').textContent =
        loadTimeData.getStringF('openDialogBody', urls.length);

    DialogFocusManager.getInstance().showDialog(this.$.openDialog.get());
  },

  /**
   * Returns all URLs in the given set of nodes and their immediate children.
   * Note that these will be ordered by insertion order into the |itemIds|
   * set, and that it is possible to duplicate a URL by passing in both the
   * parent ID and child ID.
   * @param {!Set<string>} itemIds
   * @return {!Array<string>}
   * @private
   */
  expandUrls_(itemIds) {
    const urls = [];
    const nodes = this.getState().nodes;

    itemIds.forEach(function(id) {
      const node = nodes[id];
      if (node.url) {
        urls.push(node.url);
      } else {
        node.children.forEach(function(childId) {
          const childNode = nodes[childId];
          if (childNode.url) {
            urls.push(childNode.url);
          }
        });
      }
    });

    return urls;
  },

  /**
   * @param {!Set<string>} itemIds
   * @param {function(BookmarkNode):boolean} predicate
   * @return {boolean} True if any node in |itemIds| returns true for
   *     |predicate|.
   */
  containsMatchingNode_(itemIds, predicate) {
    const nodes = this.getState().nodes;

    return Array.from(itemIds).some(function(id) {
      return predicate(nodes[id]);
    });
  },

  /**
   * @param {!Set<string>} itemIds
   * @return {boolean} True if |itemIds| is a single bookmark (non-folder)
   *     node.
   * @private
   */
  isSingleBookmark_(itemIds) {
    return itemIds.size === 1 &&
        this.containsMatchingNode_(itemIds, function(node) {
          return !!node.url;
        });
  },

  /**
   * @param {!Set<string>} itemIds
   * @return {boolean}
   * @private
   */
  isFolder_(itemIds) {
    return itemIds.size === 1 &&
        this.containsMatchingNode_(itemIds, node => !node.url);
  },

  /**
   * @param {Command} command
   * @return {string}
   * @private
   */
  getCommandLabel_(command) {
    // Handle non-pluralized strings first.
    let label = null;
    switch (command) {
      case Command.EDIT:
        if (this.menuIds_.size !== 1) {
          return '';
        }

        const id = Array.from(this.menuIds_)[0];
        const itemUrl = this.getState().nodes[id].url;
        label = itemUrl ? 'menuEdit' : 'menuRename';
        break;
      case Command.CUT:
        label = 'menuCut';
        break;
      case Command.COPY:
        label = 'menuCopy';
        break;
      case Command.COPY_URL:
        label = 'menuCopyURL';
        break;
      case Command.PASTE:
        label = 'menuPaste';
        break;
      case Command.DELETE:
        label = 'menuDelete';
        break;
      case Command.SHOW_IN_FOLDER:
        label = 'menuShowInFolder';
        break;
      case Command.SORT:
        label = 'menuSort';
        break;
      case Command.ADD_BOOKMARK:
        label = 'menuAddBookmark';
        break;
      case Command.ADD_FOLDER:
        label = 'menuAddFolder';
        break;
      case Command.IMPORT:
        label = 'menuImport';
        break;
      case Command.EXPORT:
        label = 'menuExport';
        break;
      case Command.HELP_CENTER:
        label = 'menuHelpCenter';
        break;
    }
    if (label !== null) {
      return loadTimeData.getString(assert(label));
    }

    // Handle pluralized strings.
    switch (command) {
      case Command.OPEN_NEW_TAB:
        return this.getPluralizedOpenAllString_(
            'menuOpenAllNewTab', 'menuOpenNewTab',
            'menuOpenAllNewTabWithCount');
      case Command.OPEN_NEW_WINDOW:
        return this.getPluralizedOpenAllString_(
            'menuOpenAllNewWindow', 'menuOpenNewWindow',
            'menuOpenAllNewWindowWithCount');
      case Command.OPEN_INCOGNITO:
        return this.getPluralizedOpenAllString_(
            'menuOpenAllIncognito', 'menuOpenIncognito',
            'menuOpenAllIncognitoWithCount');
    }

    assertNotReached();
    return '';
  },

  /**
   * @param {string} case0 String ID for the case of zero URLs.
   * @param {string} case1 String ID for the case of 1 URL.
   * @param {string} caseOther String ID for string that includes the URL count.
   * @return {string}
   * @private
   */
  getPluralizedOpenAllString_(case0, case1, caseOther) {
    const multipleNodes = this.menuIds_.size > 1 ||
        this.containsMatchingNode_(this.menuIds_, node => !node.url);

    const urls = this.expandUrls_(this.menuIds_);
    if (urls.length === 0) {
      return loadTimeData.getStringF(case0, urls.length);
    }

    if (urls.length === 1 && !multipleNodes) {
      return loadTimeData.getString(case1);
    }

    return loadTimeData.getStringF(caseOther, urls.length);
  },

  /**
   * @param {Command} command
   * @return {string}
   * @private
   */
  getCommandSublabel_(command) {
    const multipleNodes = this.menuIds_.size > 1 ||
        this.containsMatchingNode_(this.menuIds_, function(node) {
          return !node.url;
        });
    switch (command) {
      case Command.OPEN_NEW_TAB:
        const urls = this.expandUrls_(this.menuIds_);
        return multipleNodes && urls.length > 0 ? String(urls.length) : '';
      default:
        return '';
    }
  },

  /** @private */
  computeMenuCommands_() {
    switch (this.menuSource_) {
      case MenuSource.ITEM:
      case MenuSource.TREE:
        return [
          Command.EDIT,
          Command.SHOW_IN_FOLDER,
          Command.DELETE,
          // <hr>
          Command.CUT,
          Command.COPY,
          Command.COPY_URL,
          Command.PASTE,
          // <hr>
          Command.OPEN_NEW_TAB,
          Command.OPEN_NEW_WINDOW,
          Command.OPEN_INCOGNITO,
        ];
      case MenuSource.TOOLBAR:
        return [
          Command.SORT,
          // <hr>
          Command.ADD_BOOKMARK,
          Command.ADD_FOLDER,
          // <hr>
          Command.IMPORT,
          Command.EXPORT,
          // <hr>
          Command.HELP_CENTER,
        ];
      case MenuSource.LIST:
        return [
          Command.ADD_BOOKMARK,
          Command.ADD_FOLDER,
        ];
      case MenuSource.NONE:
        return [];
    }
    assert(false);
  },

  /**
   * @param {Command} command
   * @param {!Set<string>} itemIds
   * @return {boolean}
   * @private
   */
  showDividerAfter_(command, itemIds) {
    switch (command) {
      case Command.SORT:
      case Command.ADD_FOLDER:
      case Command.EXPORT:
        return this.menuSource_ === MenuSource.TOOLBAR;
      case Command.DELETE:
        return this.globalCanEdit_;
      case Command.PASTE:
        return this.globalCanEdit_ || this.isSingleBookmark_(itemIds);
    }
    return false;
  },

  /**
   * @param {!Set<string>} itemIds
   * @param {string} histogram
   * @param {number} command
   * @private
   */
  recordCommandHistogram_(itemIds, histogram, command) {
    if (command === Command.OPEN) {
      command =
          this.isFolder_(itemIds) ? Command.OPEN_FOLDER : Command.OPEN_BOOKMARK;
    }

    this.browserProxy_.recordInHistogram(histogram, command, Command.MAX_VALUE);
  },

  /**
   * Show a toast with a bookmark |title| inserted into a label, with the
   * title ellipsised if necessary.
   * @param {!Promise<string>} labelPromise Promise which resolves with the
   *    label for the toast.
   * @param {string} title Bookmark title to insert.
   * @param {boolean} canUndo If true, shows an undo button in the toast.
   * @private
   */
  showTitleToast_: async function(labelPromise, title, canUndo) {
    const label = await labelPromise;
    const pieces =
        loadTimeData.getSubstitutedStringPieces(label, title).map(function(p) {
          // Make the bookmark name collapsible.
          p.collapsible = !!p.arg;
          return p;
        });
    getToastManager().querySelector('dom-if').if = canUndo;
    getToastManager().showForStringPieces(pieces);
  },

  /**
   * @param {number} targetId
   * @private
   */
  updateCanPaste_(targetId) {
    return new Promise(resolve => {
      chrome.bookmarkManagerPrivate.canPaste(`${targetId}`, result => {
        this.canPaste_ = result;
        resolve();
      });
    });
  },

  ////////////////////////////////////////////////////////////////////////////
  // Event handlers:

  /**
   * @param {Event} e
   * @private
   */
  onOpenCommandMenu_: async function(e) {
    await this.updateCanPaste_(e.detail.source);
    if (e.detail.targetElement) {
      this.openCommandMenuAtElement(e.detail.targetElement, e.detail.source);
    } else {
      this.openCommandMenuAtPosition(e.detail.x, e.detail.y, e.detail.source);
    }
    this.browserProxy_.recordInHistogram(
        'BookmarkManager.CommandMenuOpened', e.detail.source,
        MenuSource.NUM_VALUES);
  },

  /**
   * @param {Event} e
   * @private
   */
  onCommandClick_(e) {
    this.handle(
        /** @type {Command} */ (
            Number(e.currentTarget.getAttribute('command'))),
        assert(this.menuIds_));
    this.closeCommandMenu();
  },

  /**
   * @param {!Event} e
   * @private
   */
  onKeydown_(e) {
    const path = e.composedPath();
    if (path[0].tagName === 'INPUT') {
      return;
    }
    if ((e.target === document.body ||
         path.some(el => el.tagName === 'BOOKMARKS-TOOLBAR')) &&
        !DialogFocusManager.getInstance().hasOpenDialog()) {
      this.handleKeyEvent(e, this.getState().selection.items);
    }
  },

  /**
   * Close the menu on mousedown so clicks can propagate to the underlying UI.
   * This allows the user to right click the list while a context menu is
   * showing and get another context menu.
   * @param {Event} e
   * @private
   */
  onMenuMousedown_(e) {
    if (e.path[0].tagName !== 'DIALOG') {
      return;
    }

    this.closeCommandMenu();
  },

  /** @private */
  onOpenCancelTap_() {
    this.$.openDialog.get().cancel();
  },

  /** @private */
  onOpenConfirmTap_() {
    this.confirmOpenCallback_();
    this.$.openDialog.get().close();
  },
});

/** @private {CommandManager} */
CommandManager.instance_ = null;

/** @return {!CommandManager} */
CommandManager.getInstance = function() {
  return assert(CommandManager.instance_);
};