// 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.

/**
 * A command.
 * @interface
 */
var Command = function() {};

/**
 * Handles the execute event.
 * @param {!Event} event Command event.
 * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps.
 */
Command.prototype.execute = function(event, fileManager) {};

/**
 * Handles the can execute event.
 * @param {!Event} event Can execute event.
 * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps.
 */
Command.prototype.canExecute = function(event, fileManager) {};

/**
 * Utility for commands.
 */
var CommandUtil = {};

/**
 * Extracts entry on which command event was dispatched.
 *
 * @param {EventTarget} element Element which is the command event's target.
 * @return {Entry} Entry of the found node.
 */
CommandUtil.getCommandEntry = function(element) {
  var entries = CommandUtil.getCommandEntries(element);
  return entries.length === 0 ? null : entries[0];
};

/**
 * Extracts entries on which command event was dispatched.
 *
 * @param {EventTarget} element Element which is the command event's target.
 * @return {!Array<!Entry>} Entries of the found node.
 */
CommandUtil.getCommandEntries = function(element) {
  if (element instanceof DirectoryTree) {
    // element is a DirectoryTree.
    return element.selectedItem ? [element.selectedItem.entry] : [];
  } else if (element instanceof DirectoryItem ||
             element instanceof ShortcutItem) {
    // element are sub items in DirectoryTree.
    return element.entry ? [element.entry] : [];
  } else if (element instanceof cr.ui.List) {
    // element is a normal List (eg. the file list on the right panel).
    var entries = element.selectedItems;
    // Check if it is Entry or not by checking for toURL().
    return entries.some(function(entry) { return !('toURL' in entry); }) ?
        [] : entries;
  } else {
    return [];
  }
};

/**
 * Extracts a directory which contains entries on which command event was
 * dispatched.
 *
 * @param {EventTarget} element Element which is the command event's target.
 * @param {DirectoryModel} directoryModel
 * @return {DirectoryEntry|FilesAppEntry} The extracted parent entry.
 */
CommandUtil.getParentEntry = function(element, directoryModel) {
  if (element instanceof DirectoryTree) {
    if (!element.selectedItem)
      return null;
    var parentItem = element.selectedItem.parentItem;
    return parentItem ? parentItem.entry : null;
  } else if (element instanceof DirectoryItem ||
             element instanceof ShortcutItem) {
    return element.parentItem ? element.parentItem.entry : null;
  } else if (element instanceof cr.ui.List) {
    return directoryModel ? directoryModel.getCurrentDirEntry() : null;
  } else {
    return null;
  }
};

/**
 * @param {EventTarget} element
 * @param {!CommandHandlerDeps} fileManager
 * @return {VolumeInfo}
 */
CommandUtil.getElementVolumeInfo = function(element, fileManager) {
  if (element instanceof DirectoryTree && element.selectedItem)
    return CommandUtil.getElementVolumeInfo(element.selectedItem, fileManager);
  if (element instanceof VolumeItem)
    return element.volumeInfo;
  if (element instanceof ShortcutItem) {
    return element.entry && fileManager.volumeManager.getVolumeInfo(
        element.entry);
  }
  return null;
};

/**
 * @param {!CommandHandlerDeps} fileManager
 * @return {VolumeInfo}
 */
CommandUtil.getCurrentVolumeInfo = function(fileManager) {
  var currentDirEntry = fileManager.directoryModel.getCurrentDirEntry();
  return currentDirEntry ? fileManager.volumeManager.getVolumeInfo(
      currentDirEntry) : null;
};

/**
 * Obtains an entry from the give navigation model item.
 * @param {!NavigationModelItem} item Navigation model item.
 * @return {Entry} Related entry.
 * @private
 */
CommandUtil.getEntryFromNavigationModelItem_ = function(item) {
  switch (item.type) {
    case NavigationModelItemType.VOLUME:
      return /** @type {!NavigationModelVolumeItem} */ (
          item).volumeInfo.displayRoot;
    case NavigationModelItemType.SHORTCUT:
      return /** @type {!NavigationModelShortcutItem} */ (item).entry;
  }
  return null;
};

/**
 * Checks if command can be executed on drive.
 * @param {!Event} event Command event to mark.
 * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
 */
CommandUtil.canExecuteEnabledOnDriveOnly = function(event, fileManager) {
  event.canExecute = fileManager.directoryModel.isOnDrive();
};

/**
 * Sets the command as visible only when the current volume is drive and it's
 * running as a normal app, not as a modal dialog.
 * @param {!Event} event Command event to mark.
 * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
 */
CommandUtil.canExecuteVisibleOnDriveInNormalAppModeOnly = function(
    event, fileManager) {
  var enabled = fileManager.directoryModel.isOnDrive() &&
      !DialogType.isModal(fileManager.dialogType);
  event.canExecute = enabled;
  event.command.setHidden(!enabled);
};

/**
 * Sets as the command as always enabled.
 * @param {!Event} event Command event to mark.
 */
CommandUtil.canExecuteAlways = function(event) {
  event.canExecute = true;
};

/**
 * Sets the default handler for the commandId and prevents handling
 * the keydown events for this command. Not doing that breaks relationship
 * of original keyboard event and the command. WebKit would handle it
 * differently in some cases.
 * @param {Node} node to register command handler on.
 * @param {string} commandId Command id to respond to.
 */
CommandUtil.forceDefaultHandler = function(node, commandId) {
  var doc = node.ownerDocument;
  var command = /** @type {!cr.ui.Command} */ (
      doc.querySelector('command[id="' + commandId + '"]'));
  node.addEventListener('keydown', function(e) {
    if (command.matchesEvent(e)) {
      // Prevent cr.ui.CommandManager of handling it and leave it
      // for the default handler.
      e.stopPropagation();
    }
  });
  node.addEventListener('command', function(event) {
    if (event.command.id !== commandId)
      return;
    document.execCommand(event.command.id);
    event.cancelBubble = true;
  });
  node.addEventListener('canExecute', function(event) {
    if (event.command.id !== commandId)
      return;
    event.canExecute = document.queryCommandEnabled(event.command.id);
    event.command.setHidden(false);
  });
};

/**
 * Creates the volume switch command with index.
 * @param {number} index Volume index from 1 to 9.
 * @return {Command} Volume switch command.
 */
CommandUtil.createVolumeSwitchCommand = function(index) {
  return /** @type {Command} */ ({
    /**
     * @param {!Event} event Command event.
     * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
     */
    execute: function(event, fileManager) {
      fileManager.directoryTree.activateByIndex(index - 1);
    },
    /**
     * @param {!Event} event Command event.
     * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
     */
    canExecute: function(event, fileManager) {
      event.canExecute = index > 0 &&
          index <= fileManager.directoryTree.items.length;
    }
  });
};

/**
 * Returns a directory entry when only one entry is selected and it is
 * directory. Otherwise, returns null.
 * @param {FileSelection} selection Instance of FileSelection.
 * @return {?DirectoryEntry} Directory entry which is selected alone.
 */
CommandUtil.getOnlyOneSelectedDirectory = function(selection) {
  if (!selection)
    return null;
  if (selection.totalCount !== 1)
    return null;
  if (!selection.entries[0].isDirectory)
    return null;
  return /** @type {!DirectoryEntry} */(selection.entries[0]);
};

/**
 * Returns true if the given entry is the root entry of the volume.
 * @param {!VolumeManager} volumeManager
 * @param {(!Entry|!FakeEntry)} entry Entry or a fake entry.
 * @return {boolean} True if the entry is a root entry.
 */
CommandUtil.isRootEntry = function(volumeManager, entry) {
  if (!volumeManager || !entry)
    return false;

  var volumeInfo = volumeManager.getVolumeInfo(entry);
  return !!volumeInfo && volumeInfo.displayRoot === entry;
};

/**
 * Returns true if the given event was triggered by the selection menu button.
 * @event {!Event} event Command event.
 * @return {boolean} Ture if the event was triggered by the selection menu
 * button.
 */
CommandUtil.isFromSelectionMenu = function(event) {
  return event.target.id == 'selection-menu-button';
};

/**
 * If entry is fake/invalid/root, we don't show menu items for regular entries.
 * @param {!VolumeManager} volumeManager
 * @param {(!Entry|!FakeEntry)} entry Entry or a fake entry.
 * @return {boolean} True if we should show the menu items for regular entries.
 */
CommandUtil.shouldShowMenuItemsForEntry = function(volumeManager, entry) {
  // If the entry is fake entry, hide context menu entries.
  if (util.isFakeEntry(entry))
    return false;

  // If the entry is not a valid entry, hide context menu entries.
  if (!volumeManager || !volumeManager.getVolumeInfo(entry))
    return false;

  // If the entry is root entry of its volume (but not a team drive root), hide
  // context menu entries.
  if (CommandUtil.isRootEntry(volumeManager, entry) &&
      !util.isTeamDriveRoot(entry))
    return false;

  if (util.isTeamDrivesGrandRoot(entry))
    return false;

  return true;
};

/**
 * Returns whether all of the given entries have the given capability.
 *
 * @param {!Array<Entry>} entries List of entries to check capabilities for.
 * @param {!string} capability Name of the capability to check for.
 */
CommandUtil.hasCapability = function(entries, capability) {
  if (entries.length == 0) {
    return false;
  }

  // Check if the capability is true or undefined, but not false. A capability
  // can be undefined if the metadata is not fetched from the server yet (e.g.
  // if we create a new file in offline mode), or if there is a problem with the
  // cache and we don't have data yet. For this reason, we need to allow the
  // functionality even if it's not set.
  // TODO(crbug.com/849999): Store restrictions instead of capabilities.
  var metadata = fileManager.metadataModel.getCache(entries, [capability]);
  return metadata.length === entries.length &&
      metadata.every(item => item[capability] !== false);
};

/**
 * Handle of the command events.
 * @param {!CommandHandlerDeps} fileManager Classes |CommandHalder| depends.
 * @param {!FileSelectionHandler} selectionHandler
 * @constructor
 * @struct
 */
var CommandHandler = function(fileManager, selectionHandler) {
  /**
   * CommandHandlerDeps.
   * @type {!CommandHandlerDeps}
   * @private
   */
  this.fileManager_ = fileManager;

  /**
   * Command elements.
   * @type {Object<cr.ui.Command>}
   * @private
   */
  this.commands_ = {};

  // Decorate command tags in the document.
  var commands = fileManager.document.querySelectorAll('command');
  for (var i = 0; i < commands.length; i++) {
    cr.ui.Command.decorate(commands[i]);
    this.commands_[commands[i].id] = commands[i];
  }

  // Register events.
  fileManager.document.addEventListener('command', this.onCommand_.bind(this));
  fileManager.document.addEventListener(
      'canExecute', this.onCanExecute_.bind(this));
  fileManager.directoryModel.addEventListener(
      'directory-change', this.updateAvailability.bind(this));
  fileManager.volumeManager.addEventListener(
      'drive-connection-changed', this.updateAvailability.bind(this));
  selectionHandler.addEventListener(
      FileSelectionHandler.EventType.CHANGE_THROTTLED,
      this.updateAvailability.bind(this));
  fileManager.metadataModel.addEventListener(
      'update', this.updateAvailability.bind(this));

  chrome.commandLinePrivate.hasSwitch(
      'disable-zip-archiver-packer', function(disabled) {
        CommandHandler.IS_ZIP_ARCHIVER_PACKER_ENABLED_ = !disabled;
      });
};

/**
 * A flag that determines whether zip archiver - packer is enabled or no.
 * @type {boolean}
 * @private
 */
CommandHandler.IS_ZIP_ARCHIVER_PACKER_ENABLED_ = false;

/**
 * Supported disk file system types for renaming.
 * @type {!Array<!VolumeManagerCommon.FileSystemType>}
 * @const
 * @private
 */
CommandHandler.RENAME_DISK_FILE_SYSYTEM_SUPPORT_ = [
  VolumeManagerCommon.FileSystemType.EXFAT,
  VolumeManagerCommon.FileSystemType.VFAT
];

/**
 * Name of a command (for UMA).
 * @enum {string}
 * @const
 */
CommandHandler.MenuCommandsForUMA = {
  HELP: 'volume-help',
  DRIVE_HELP: 'volume-help-drive',
  DRIVE_BUY_MORE_SPACE: 'drive-buy-more-space',
  DRIVE_GO_TO_DRIVE: 'drive-go-to-drive',
  HIDDEN_FILES_SHOW: 'toggle-hidden-files-on',
  HIDDEN_FILES_HIDE: 'toggle-hidden-files-off',
  MOBILE_DATA_ON: 'drive-sync-settings-enabled',
  MOBILE_DATA_OFF: 'drive-sync-settings-disabled',
  SHOW_GOOGLE_DOCS_FILES_OFF: 'drive-hosted-settings-disabled',
  SHOW_GOOGLE_DOCS_FILES_ON: 'drive-hosted-settings-enabled',
  HIDDEN_ANDROID_FOLDERS_SHOW: 'toggle-hidden-android-folders-on',
  HIDDEN_ANDROID_FOLDERS_HIDE: 'toggle-hidden-android-folders-off',
  SHARE_WITH_LINUX: 'share-with-linux',
  MANAGE_LINUX_SHARING: 'manage-linux-sharing',
};

/**
 * Keep the order of this in sync with FileManagerMenuCommands in
 * tools/metrics/histograms/enums.xml.
 * The array indices will be recorded in UMA as enum values. The index for each
 * root type should never be renumbered nor reused in this array.
 *
 * @type {!Array<CommandHandler.MenuCommandsForUMA>}
 * @const
 */
CommandHandler.ValidMenuCommandsForUMA = [
  CommandHandler.MenuCommandsForUMA.HELP,
  CommandHandler.MenuCommandsForUMA.DRIVE_HELP,
  CommandHandler.MenuCommandsForUMA.DRIVE_BUY_MORE_SPACE,
  CommandHandler.MenuCommandsForUMA.DRIVE_GO_TO_DRIVE,
  CommandHandler.MenuCommandsForUMA.HIDDEN_FILES_SHOW,
  CommandHandler.MenuCommandsForUMA.HIDDEN_FILES_HIDE,
  CommandHandler.MenuCommandsForUMA.MOBILE_DATA_ON,
  CommandHandler.MenuCommandsForUMA.MOBILE_DATA_OFF,
  CommandHandler.MenuCommandsForUMA.SHOW_GOOGLE_DOCS_FILES_ON,
  CommandHandler.MenuCommandsForUMA.SHOW_GOOGLE_DOCS_FILES_OFF,
  CommandHandler.MenuCommandsForUMA.HIDDEN_ANDROID_FOLDERS_SHOW,
  CommandHandler.MenuCommandsForUMA.HIDDEN_ANDROID_FOLDERS_HIDE,
  CommandHandler.MenuCommandsForUMA.SHARE_WITH_LINUX,
  CommandHandler.MenuCommandsForUMA.MANAGE_LINUX_SHARING,
];
console.assert(
    Object.keys(CommandHandler.MenuCommandsForUMA).length ===
        CommandHandler.ValidMenuCommandsForUMA.length,
    'Members in ValidMenuCommandsForUMA do not match those in ' +
        'MenuCommandsForUMA.');

/**
 * Records the menu item as selected in UMA.
 * @param {CommandHandler.MenuCommandsForUMA} menuItem The selected menu item.
 */
CommandHandler.recordMenuItemSelected_ = function(menuItem) {
  metrics.recordEnum(
      'MenuItemSelected', menuItem, CommandHandler.ValidMenuCommandsForUMA);
};

/**
 * Updates the availability of all commands.
 */
CommandHandler.prototype.updateAvailability = function() {
  for (var id in this.commands_) {
    this.commands_[id].canExecuteChange();
  }
};

/**
 * Checks if the handler should ignore the current event, eg. since there is
 * a popup dialog currently opened.
 *
 * @return {boolean} True if the event should be ignored, false otherwise.
 * @private
 */
CommandHandler.prototype.shouldIgnoreEvents_ = function() {
  // Do not handle commands, when a dialog is shown. Do not use querySelector
  // as it's much slower, and this method is executed often.
  var dialogs = this.fileManager_.document.getElementsByClassName(
      'cr-dialog-container');
  if (dialogs.length !== 0 && dialogs[0].classList.contains('shown'))
    return true;

  return false;  // Do not ignore.
};

/**
 * Handles command events.
 * @param {!Event} event Command event.
 * @private
 */
CommandHandler.prototype.onCommand_ = function(event) {
  if (this.shouldIgnoreEvents_())
    return;
  var handler = CommandHandler.COMMANDS_[event.command.id];
  handler.execute.call(/** @type {Command} */ (handler), event,
                       this.fileManager_);
};

/**
 * Handles canExecute events.
 * @param {!Event} event Can execute event.
 * @private
 */
CommandHandler.prototype.onCanExecute_ = function(event) {
  if (this.shouldIgnoreEvents_())
    return;
  var handler = CommandHandler.COMMANDS_[event.command.id];
  handler.canExecute.call(/** @type {Command} */ (handler), event,
                          this.fileManager_);
};

/**
 * Commands.
 * @type {Object<Command>}
 * @const
 * @private
 */
CommandHandler.COMMANDS_ = {};

/**
 * Unmounts external drive.
 * @type {Command}
 */
CommandHandler.COMMANDS_['unmount'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager The file manager instance.
   */
  execute: function(event, fileManager) {
    /** @param {VolumeManagerCommon.VolumeType=} opt_volumeType */
    var errorCallback = function(opt_volumeType) {
      if (opt_volumeType === VolumeManagerCommon.VolumeType.REMOVABLE) {
        fileManager.ui.alertDialog.showHtml(
            '', str('UNMOUNT_FAILED'), null, null, null);
      } else {
        fileManager.ui.alertDialog.showHtml(
            '', str('UNMOUNT_PROVIDED_FAILED'), null, null, null);
      }
    };

    var volumeInfo =
        CommandUtil.getElementVolumeInfo(event.target, fileManager) ||
        CommandUtil.getCurrentVolumeInfo(fileManager);
    if (!volumeInfo) {
      errorCallback();
      return;
    }

    fileManager.volumeManager.unmount(volumeInfo, function() {
    }, errorCallback.bind(null, volumeInfo.volumeType));
  },
  /**
   * @param {!Event} event Command event.
   * @this {CommandHandler}
   */
  canExecute: function(event, fileManager) {
    var volumeInfo =
        CommandUtil.getElementVolumeInfo(event.target, fileManager) ||
        CommandUtil.getCurrentVolumeInfo(fileManager);
    if (!volumeInfo) {
      event.canExecute = false;
      event.command.setHidden(true);
      return;
    }

    var volumeType = volumeInfo.volumeType;
    event.canExecute = (
        volumeType === VolumeManagerCommon.VolumeType.ARCHIVE ||
        volumeType === VolumeManagerCommon.VolumeType.REMOVABLE ||
        volumeType === VolumeManagerCommon.VolumeType.PROVIDED);
    event.command.setHidden(!event.canExecute);

    switch (volumeType) {
      case VolumeManagerCommon.VolumeType.ARCHIVE:
      case VolumeManagerCommon.VolumeType.PROVIDED:
        event.command.label = str('CLOSE_VOLUME_BUTTON_LABEL');
        break;
      case VolumeManagerCommon.VolumeType.REMOVABLE:
        event.command.label = str('UNMOUNT_DEVICE_BUTTON_LABEL');
        break;
    }
  }
});

/**
 * Formats external drive.
 * @type {Command}
 */
CommandHandler.COMMANDS_['format'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager The file manager instance.
   */
  execute: function(event, fileManager) {
    var directoryModel = fileManager.directoryModel;
    var root = CommandUtil.getCommandEntry(event.target);
    // If an entry is not found from the event target, use the current
    // directory. This can happen for the format button for unsupported and
    // unrecognized volumes.
    if (!root)
      root = directoryModel.getCurrentDirEntry();

    var volumeInfo = fileManager.volumeManager.getVolumeInfo(assert(root));
    if (volumeInfo) {
      fileManager.ui.confirmDialog.show(
          loadTimeData.getString('FORMATTING_WARNING'),
          chrome.fileManagerPrivate.formatVolume.bind(null,
                                                      volumeInfo.volumeId),
          null, null);
    }
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager The file manager instance.
   */
  canExecute: function(event, fileManager) {
    var directoryModel = fileManager.directoryModel;
    var root = CommandUtil.getCommandEntry(event.target);
    // |root| is null for unrecognized volumes. Enable format command for such
    // volumes.
    var isUnrecognizedVolume = (root == null);
    // See the comment in execute() for why doing this.
    if (!root)
      root = directoryModel.getCurrentDirEntry();
    var location = root && fileManager.volumeManager.getLocationInfo(root);
    var writable = location && !location.isReadOnly;
    var removable = location && location.rootType ===
        VolumeManagerCommon.RootType.REMOVABLE;
    event.canExecute = removable && (isUnrecognizedVolume || writable);
    event.command.setHidden(!removable);
  }
});

/**
 * Initiates new folder creation.
 * @type {Command}
 */
CommandHandler.COMMANDS_['new-folder'] = (function() {
  /**
   * @constructor
   * @struct
   */
  var NewFolderCommand = function() {};

  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  NewFolderCommand.prototype.execute = function(event, fileManager) {
    var targetDirectory;
    var executedFromDirectoryTree;

    if (event.target instanceof DirectoryTree) {
      targetDirectory = event.target.selectedItem.entry;
      executedFromDirectoryTree = true;
    } else if (event.target instanceof DirectoryItem) {
      targetDirectory = event.target.entry;
      executedFromDirectoryTree = true;
    } else {
      targetDirectory = fileManager.directoryModel.getCurrentDirEntry();
      executedFromDirectoryTree = false;
    }

    var directoryModel = fileManager.directoryModel;
    var directoryTree = fileManager.ui.directoryTree;
    var listContainer = fileManager.ui.listContainer;

    this.generateNewDirectoryName_(targetDirectory).then(function(newName) {
      if (!executedFromDirectoryTree)
        listContainer.startBatchUpdates();

      return new Promise(targetDirectory.getDirectory.bind(targetDirectory,
          newName,
          {create: true, exclusive: true})).then(function(newDirectory) {
            metrics.recordUserAction('CreateNewFolder');

            // Select new directory and start rename operation.
            if (executedFromDirectoryTree) {
              directoryTree.updateAndSelectNewDirectory(
                  targetDirectory, newDirectory);
              fileManager.directoryTreeNamingController.attachAndStart(
                  assert(fileManager.ui.directoryTree.selectedItem), false,
                  null);
            } else {
              directoryModel.updateAndSelectNewDirectory(
                  newDirectory).then(function() {
                listContainer.endBatchUpdates();
                fileManager.namingController.initiateRename();
              }, function() {
                listContainer.endBatchUpdates();
              });
            }
          }, function(error) {
            if (!executedFromDirectoryTree)
              listContainer.endBatchUpdates();

            fileManager.ui.alertDialog.show(
                strf('ERROR_CREATING_FOLDER',
                     newName,
                     util.getFileErrorString(error.name)),
                null, null);
          });
    });
  };

  /**
   * Generates new directory name.
   * @param {!DirectoryEntry} parentDirectory
   * @param {number=} opt_index
   * @private
   */
  NewFolderCommand.prototype.generateNewDirectoryName_ = function(
      parentDirectory, opt_index) {
    var index = opt_index || 0;

    var defaultName = str('DEFAULT_NEW_FOLDER_NAME');
    var newName = index === 0 ? defaultName :
        defaultName + ' (' + index + ')';

    return new Promise(parentDirectory.getDirectory.bind(
        parentDirectory, newName, {create: false})).then(function(newEntry) {
      return this.generateNewDirectoryName_(parentDirectory, index + 1);
    }.bind(this)).catch(function() {
      return newName;
    });
  };

  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  NewFolderCommand.prototype.canExecute = function(event, fileManager) {
    if (event.target instanceof DirectoryItem ||
        event.target instanceof DirectoryTree) {
      var entry = CommandUtil.getCommandEntry(event.target);
      if (!entry || util.isFakeEntry(entry) ||
          util.isTeamDrivesGrandRoot(entry)) {
        event.canExecute = false;
        event.command.setHidden(true);
        return;
      }

      var locationInfo = fileManager.volumeManager.getLocationInfo(entry);
      event.canExecute = locationInfo && !locationInfo.isReadOnly &&
          CommandUtil.hasCapability([entry], 'canAddChildren');
      event.command.setHidden(
          CommandUtil.isRootEntry(fileManager.volumeManager, entry));
    } else {
      var directoryModel = fileManager.directoryModel;
      var directoryEntry = fileManager.getCurrentDirectoryEntry();
      event.canExecute = !fileManager.directoryModel.isReadOnly() &&
          !fileManager.namingController.isRenamingInProgress() &&
          !directoryModel.isSearching() && !directoryModel.isScanning() &&
          CommandUtil.hasCapability([directoryEntry], 'canAddChildren');
      event.command.setHidden(false);
    }
  };

  return new NewFolderCommand();
})();

/**
 * Initiates new window creation.
 * @type {Command}
 */
CommandHandler.COMMANDS_['new-window'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.backgroundPage.launcher.launchFileManager({
      currentDirectoryURL: fileManager.getCurrentDirectoryEntry() &&
          fileManager.getCurrentDirectoryEntry().toURL()
    });
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute =
        fileManager.getCurrentDirectoryEntry() &&
        (fileManager.dialogType === DialogType.FULL_PAGE);
  }
});

CommandHandler.COMMANDS_['select-all'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.directoryModel.getFileListSelection().selectAll();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    // Check we are not inside an input element (e.g. the search box).
    const inputElementActive =
        document.activeElement instanceof HTMLInputElement ||
        document.activeElement instanceof HTMLTextAreaElement ||
        document.activeElement.tagName.toLowerCase() === 'cr-input';
    event.canExecute = !inputElementActive &&
        fileManager.directoryModel.getFileList().length > 0;
  }
});

CommandHandler.COMMANDS_['toggle-hidden-files'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    var visible = !fileManager.fileFilter.isHiddenFilesVisible();
    fileManager.fileFilter.setHiddenFilesVisible(visible);
    event.command.checked = visible;  // Checkmark for "Show hidden files".
    CommandHandler.recordMenuItemSelected_(
        visible ? CommandHandler.MenuCommandsForUMA.HIDDEN_FILES_SHOW :
                  CommandHandler.MenuCommandsForUMA.HIDDEN_FILES_HIDE);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Toggles visibility of top-level Android folders which are not visible by
 * default.
 * @type {Command}
 */
CommandHandler.COMMANDS_['toggle-hidden-android-folders'] =
    /** @type {Command} */ ({
      /**
       * @param {!Event} event Command event.
       * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
       */
      execute: function(event, fileManager) {
        var visible = !fileManager.fileFilter.isAllAndroidFoldersVisible();
        fileManager.fileFilter.setAllAndroidFoldersVisible(visible);
        event.command.checked = visible;
        CommandHandler.recordMenuItemSelected_(
            visible ?
                CommandHandler.MenuCommandsForUMA.HIDDEN_ANDROID_FOLDERS_SHOW :
                CommandHandler.MenuCommandsForUMA.HIDDEN_ANDROID_FOLDERS_HIDE);
      },
      /**
       * @param {!Event} event Command event.
       * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
       */
      canExecute: function(event, fileManager) {
        var hasAndroidFilesVolumeInfo =
            !!fileManager.volumeManager.getCurrentProfileVolumeInfo(
                VolumeManagerCommon.VolumeType.ANDROID_FILES);
        var currentRootType = fileManager.directoryModel.getCurrentRootType();
        var isInMyFiles =
            currentRootType == VolumeManagerCommon.RootType.MY_FILES ||
            currentRootType == VolumeManagerCommon.RootType.DOWNLOADS ||
            currentRootType == VolumeManagerCommon.RootType.CROSTINI ||
            currentRootType == VolumeManagerCommon.RootType.ANDROID_FILES;
        event.canExecute = hasAndroidFilesVolumeInfo && isInMyFiles;
        event.command.setHidden(!event.canExecute);
        event.command.checked =
            fileManager.fileFilter.isAllAndroidFoldersVisible();
      }
    });

/**
 * Toggles drive sync settings.
 * @type {Command}
 */
CommandHandler.COMMANDS_['drive-sync-settings'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    // If checked, the sync is disabled.
    var nowCellularDisabled =
        fileManager.ui.gearMenu.syncButton.hasAttribute('checked');
    var changeInfo = {cellularDisabled: !nowCellularDisabled};
    chrome.fileManagerPrivate.setPreferences(changeInfo);
    CommandHandler.recordMenuItemSelected_(
        nowCellularDisabled ?
            CommandHandler.MenuCommandsForUMA.MOBILE_DATA_OFF :
            CommandHandler.MenuCommandsForUMA.MOBILE_DATA_ON);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute = fileManager.directoryModel.isOnDrive() &&
        fileManager.volumeManager.getDriveConnectionState()
            .hasCellularNetworkAccess;
    event.command.setHidden(!event.canExecute);
  }
});

/**
 * Toggles drive hosted settings.
 * @type {Command}
 */
CommandHandler.COMMANDS_['drive-hosted-settings'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    // If checked, showing drive hosted files is enabled.
    var nowHostedFilesEnabled =
        fileManager.ui.gearMenu.hostedButton.hasAttribute('checked');
    var nowHostedFilesDisabled = !nowHostedFilesEnabled;

    /*
    var changeInfo = {hostedFilesDisabled: !nowHostedFilesDisabled};
    */
    var changeInfo = {};
    changeInfo['hostedFilesDisabled'] = !nowHostedFilesDisabled;
    chrome.fileManagerPrivate.setPreferences(changeInfo);
    CommandHandler.recordMenuItemSelected_(
        nowHostedFilesDisabled ?
            CommandHandler.MenuCommandsForUMA.SHOW_GOOGLE_DOCS_FILES_OFF :
            CommandHandler.MenuCommandsForUMA.SHOW_GOOGLE_DOCS_FILES_ON);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute = fileManager.directoryModel.isOnDrive();
    event.command.setHidden(!event.canExecute);
  }
});

/**
 * Deletes selected files.
 * @type {Command}
 */
CommandHandler.COMMANDS_['delete'] = (function() {
  /**
   * @constructor
   * @implements {Command}
   */
  var DeleteCommand = function() {};

  DeleteCommand.prototype = {
    /**
     * @param {!Event} event Command event.
     * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
     */
    execute: function(event, fileManager) {
      var entries = CommandUtil.getCommandEntries(event.target);

      // Execute might be called without a call of canExecute method,
      // e.g. called directly from code. Double check here not to delete
      // undeletable entries.
      if (!entries.every(CommandUtil.shouldShowMenuItemsForEntry.bind(
              null, fileManager.volumeManager)) ||
          this.containsReadOnlyEntry_(entries, fileManager))
        return;

      var message = entries.length === 1 ?
          strf('GALLERY_CONFIRM_DELETE_ONE', entries[0].name) :
          strf('GALLERY_CONFIRM_DELETE_SOME', entries.length);

      fileManager.ui.deleteConfirmDialog.show(message, function() {
        fileManager.fileOperationManager.deleteEntries(entries);
      }, null, null);
    },

    /**
     * @param {!Event} event Command event.
     * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
     */
    canExecute: function(event, fileManager) {
      var entries = CommandUtil.getCommandEntries(event.target);

      // If entries contain fake or root entry, hide delete option.
      if (!entries.every(CommandUtil.shouldShowMenuItemsForEntry.bind(
              null, fileManager.volumeManager))) {
        event.canExecute = false;
        event.command.setHidden(true);
        return;
      }

      event.canExecute = entries.length > 0 &&
          !this.containsReadOnlyEntry_(entries, fileManager) &&
          !fileManager.directoryModel.isReadOnly() &&
          CommandUtil.hasCapability(entries, 'canDelete');
      event.command.setHidden(false);
    },

    /**
     * @param {!Array<!Entry>} entries
     * @param {!CommandHandlerDeps} fileManager
     * @return {boolean} True if entries contain read only entry.
     */
    containsReadOnlyEntry_: function(entries, fileManager) {
      return entries.some(function(entry) {
        var locationInfo = fileManager.volumeManager.getLocationInfo(entry);
        return locationInfo && locationInfo.isReadOnly;
      });
    }
  };

  return new DeleteCommand();
})();

/**
 * Pastes files from clipboard.
 * @type {Command}
 */
CommandHandler.COMMANDS_['paste'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.document.execCommand(event.command.id);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var fileTransferController = fileManager.fileTransferController;

    event.canExecute = !!fileTransferController &&
        fileTransferController.queryPasteCommandEnabled(
            fileManager.directoryModel.getCurrentDirEntry());

    // Hide this command if only one folder is selected.
    event.command.setHidden(!!CommandUtil.getOnlyOneSelectedDirectory(
        fileManager.getSelection()));
  }
});

/**
 * Pastes files from clipboard. This is basically same as 'paste'.
 * This command is used for always showing the Paste command to gear menu.
 * @type {Command}
 */
CommandHandler.COMMANDS_['paste-into-current-folder'] =
    /** @type {Command} */ ({
      /**
       * @param {!Event} event Command event.
       * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
       */
      execute: function(event, fileManager) {
        fileManager.document.execCommand('paste');
      },
      /**
       * @param {!Event} event Command event.
       * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
       */
      canExecute: function(event, fileManager) {
        var fileTransferController = fileManager.fileTransferController;

        event.canExecute = !!fileTransferController &&
            fileTransferController.queryPasteCommandEnabled(
                fileManager.directoryModel.getCurrentDirEntry());
      }
    });

/**
 * Pastes files from clipboard into the selected folder.
 * @type {Command}
 */
CommandHandler.COMMANDS_['paste-into-folder'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    var entries = CommandUtil.getCommandEntries(event.target);
    if (entries.length !== 1 || !entries[0].isDirectory ||
        !CommandUtil.shouldShowMenuItemsForEntry(
            fileManager.volumeManager, entries[0])) {
      return;
    }

    // This handler tweaks the Event object for 'paste' event so that
    // the FileTransferController can distinguish this 'paste-into-folder'
    // command and know the destination directory.
    var handler = function(inEvent) {
      inEvent.destDirectory = entries[0];
    };
    fileManager.document.addEventListener('paste', handler, true);
    fileManager.document.execCommand('paste');
    fileManager.document.removeEventListener('paste', handler, true);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var entries = CommandUtil.getCommandEntries(event.target);

    // Show this item only when one directory is selected.
    if (entries.length !== 1 || !entries[0].isDirectory ||
        !CommandUtil.shouldShowMenuItemsForEntry(
            fileManager.volumeManager, entries[0])) {
      event.canExecute = false;
      event.command.setHidden(true);
      return;
    }

    var fileTransferController = fileManager.fileTransferController;
    var directoryEntry = /** @type {DirectoryEntry|FakeEntry} */ (entries[0]);
    event.canExecute = !!fileTransferController &&
        fileTransferController.queryPasteCommandEnabled(directoryEntry);
    event.command.setHidden(false);
  }
});

/**
 * Cut/Copy command.
 * @type {Command}
 * @private
 */
CommandHandler.cutCopyCommand_ = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    // Cancel check-select-mode on cut/copy.  Any further selection of a dir
    // should start a new selection rather than add to the existing selection.
    fileManager.directoryModel.getFileListSelection().setCheckSelectMode(false);
    fileManager.document.execCommand(event.command.id);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute =
        fileManager.document.queryCommandEnabled(event.command.id);
  }
});

CommandHandler.COMMANDS_['cut'] = CommandHandler.cutCopyCommand_;
CommandHandler.COMMANDS_['copy'] = CommandHandler.cutCopyCommand_;

/**
 * Initiates file renaming.
 * @type {Command}
 */
CommandHandler.COMMANDS_['rename'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    if (event.target instanceof DirectoryTree ||
        event.target instanceof DirectoryItem) {
      var isRemovableRoot = false;
      var entry = CommandUtil.getCommandEntry(event.target);
      var volumeInfo = null;
      if (entry) {
        volumeInfo = fileManager.volumeManager.getVolumeInfo(entry);
        // Checks whether the target is actually external drive or just a folder
        // inside the drive.
        if (volumeInfo &&
            CommandUtil.isRootEntry(fileManager.volumeManager, entry)) {
          isRemovableRoot = true;
        }
      }

      if (event.target instanceof DirectoryTree) {
        var directoryTree = event.target;
        assert(fileManager.directoryTreeNamingController)
            .attachAndStart(
                assert(directoryTree.selectedItem), isRemovableRoot,
                volumeInfo);
      } else if (event.target instanceof DirectoryItem) {
        var directoryItem = event.target;
        assert(fileManager.directoryTreeNamingController)
            .attachAndStart(directoryItem, isRemovableRoot, volumeInfo);
      }
    } else {
      fileManager.namingController.initiateRename();
    }
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    // Check if it is removable drive
    if ((() => {
          var root = CommandUtil.getCommandEntry(event.target);
          // |root| is null for unrecognized volumes. Do not enable rename
          // command for such volumes because they need to be formatted prior to
          // rename.
          if (!root ||
              !CommandUtil.isRootEntry(fileManager.volumeManager, root)) {
            return false;
          }
          var volumeInfo = fileManager.volumeManager.getVolumeInfo(root);
          var location = fileManager.volumeManager.getLocationInfo(root);
          if (!volumeInfo || !location) {
            event.command.setHidden(true);
            event.canExecute = false;
            return true;
          }
          var writable = !location.isReadOnly;
          var removable =
              location.rootType === VolumeManagerCommon.RootType.REMOVABLE;
          event.canExecute = removable && writable &&
              CommandHandler.RENAME_DISK_FILE_SYSYTEM_SUPPORT_.indexOf(
                  volumeInfo.diskFileSystemType) > -1;
          event.command.setHidden(!removable);
          return removable;
        })()) {
      return;
    }

    // Check if it is file or folder
    var renameTarget = CommandUtil.isFromSelectionMenu(event) ?
        fileManager.ui.listContainer.currentList :
        event.target;
    var entries = CommandUtil.getCommandEntries(renameTarget);
    if (entries.length === 0 ||
        !CommandUtil.shouldShowMenuItemsForEntry(
            fileManager.volumeManager, entries[0])) {
      event.canExecute = false;
      event.command.setHidden(true);
      return;
    }

    var parentEntry =
        CommandUtil.getParentEntry(renameTarget, fileManager.directoryModel);
    var locationInfo = parentEntry ?
        fileManager.volumeManager.getLocationInfo(parentEntry) : null;
    const volumeIsNotReadOnly = !!locationInfo && !locationInfo.isReadOnly;
    event.canExecute = entries.length === 1 && volumeIsNotReadOnly &&
        CommandUtil.hasCapability(entries, 'canRename');
    event.command.setHidden(false);
  }
});

/**
 * Opens drive help.
 * @type {Command}
 */
CommandHandler.COMMANDS_['volume-help'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    if (fileManager.directoryModel.isOnDrive()) {
      util.visitURL(str('GOOGLE_DRIVE_HELP_URL'));
      CommandHandler.recordMenuItemSelected_(
          CommandHandler.MenuCommandsForUMA.DRIVE_HELP);
    } else {
      util.visitURL(str('FILES_APP_HELP_URL'));
      CommandHandler.recordMenuItemSelected_(
          CommandHandler.MenuCommandsForUMA.HELP);
    }
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    // Hides the help menu in modal dialog mode. It does not make much sense
    // because after all, users cannot view the help without closing, and
    // besides that the help page is about the Files app as an app, not about
    // the dialog mode itself. It can also lead to hard-to-fix bug
    // crbug.com/339089.
    var hideHelp = DialogType.isModal(fileManager.dialogType);
    event.canExecute = !hideHelp;
    event.command.setHidden(hideHelp);
    fileManager.document.getElementById('help-separator').hidden = hideHelp;
  }
});

/**
 * Opens drive buy-more-space url.
 * @type {Command}
 */
CommandHandler.COMMANDS_['drive-buy-more-space'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    util.visitURL(str('GOOGLE_DRIVE_BUY_STORAGE_URL'));
    CommandHandler.recordMenuItemSelected_(
        CommandHandler.MenuCommandsForUMA.DRIVE_BUY_MORE_SPACE);
  },
  canExecute: CommandUtil.canExecuteVisibleOnDriveInNormalAppModeOnly
});

/**
 * Opens drive.google.com.
 * @type {Command}
 */
CommandHandler.COMMANDS_['drive-go-to-drive'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    util.visitURL(str('GOOGLE_DRIVE_ROOT_URL'));
    CommandHandler.recordMenuItemSelected_(
        CommandHandler.MenuCommandsForUMA.DRIVE_GO_TO_DRIVE);
  },
  canExecute: CommandUtil.canExecuteVisibleOnDriveInNormalAppModeOnly
});

/**
 * Opens a file with default task.
 * @type {Command}
 */
CommandHandler.COMMANDS_['default-task'] = /** @type {Command} */ ({
  execute: function(event, fileManager) {
    fileManager.taskController.executeDefaultTask();
  },
  canExecute: function(event, fileManager) {
    var canExecute = fileManager.taskController.canExecuteDefaultTask();
    event.canExecute = canExecute;
    event.command.setHidden(!canExecute);
  }
});

/**
 * Displays "open with" dialog for current selection.
 * @type {Command}
 */
CommandHandler.COMMANDS_['open-with'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.taskController.getFileTasks()
        .then(function(tasks) {
          tasks.showTaskPicker(
              fileManager.ui.defaultTaskPicker, str('OPEN_WITH_BUTTON_LABEL'),
              '', function(task) {
                tasks.execute(task);
              }, FileTasks.TaskPickerType.OpenWith);
        })
        .catch(function(error) {
          if (error)
            console.error(error.stack || error);
        });
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var canExecute = fileManager.taskController.canExecuteOpenActions();
    event.canExecute = canExecute;
    event.command.setHidden(!canExecute);
  }
});

/**
 * Displays "More actions" dialog for current selection.
 * @type {Command}
 */
CommandHandler.COMMANDS_['more-actions'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.taskController.getFileTasks()
        .then(function(tasks) {
          tasks.showTaskPicker(
              fileManager.ui.defaultTaskPicker,
              str('MORE_ACTIONS_BUTTON_LABEL'), '', function(task) {
                tasks.execute(task);
              }, FileTasks.TaskPickerType.MoreActions);
        })
        .catch(function(error) {
          if (error)
            console.error(error.stack || error);
        });
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var canExecute = fileManager.taskController.canExecuteMoreActions();
    event.canExecute = canExecute;
    event.command.setHidden(!canExecute);
  }
});

/**
 * Displays QuickView for current selection.
 * @type {Command}
 */
CommandHandler.COMMANDS_['get-info'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager fileManager to use.
   */
  execute: function(event, fileManager) {
    // 'get-info' command is executed by 'command' event handler in
    // QuickViewController.
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    // QuickViewModel refers the file selection instead of event target.
    var entries = fileManager.getSelection().entries;
    if (entries.length === 0) {
      event.canExecute = false;
      event.command.setHidden(true);
      return;
    }

    event.canExecute =  entries.length === 1;
    event.command.setHidden(false);
  }
});

/**
 * Focuses search input box.
 * @type {Command}
 */
CommandHandler.COMMANDS_['search'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    // Cancel item selection.
    fileManager.directoryModel.clearSelection();

    // Focus and unhide the search box.
    var element = fileManager.document.querySelector('#search-box cr-input');
    element.hidden = false;
    (/** @type {!CrInputElement} */ (element)).select();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute = !fileManager.namingController.isRenamingInProgress();
  }
});

/**
 * Activates the n-th volume.
 * @type {Command}
 */
CommandHandler.COMMANDS_['volume-switch-1'] =
    CommandUtil.createVolumeSwitchCommand(1);
CommandHandler.COMMANDS_['volume-switch-2'] =
    CommandUtil.createVolumeSwitchCommand(2);
CommandHandler.COMMANDS_['volume-switch-3'] =
    CommandUtil.createVolumeSwitchCommand(3);
CommandHandler.COMMANDS_['volume-switch-4'] =
    CommandUtil.createVolumeSwitchCommand(4);
CommandHandler.COMMANDS_['volume-switch-5'] =
    CommandUtil.createVolumeSwitchCommand(5);
CommandHandler.COMMANDS_['volume-switch-6'] =
    CommandUtil.createVolumeSwitchCommand(6);
CommandHandler.COMMANDS_['volume-switch-7'] =
    CommandUtil.createVolumeSwitchCommand(7);
CommandHandler.COMMANDS_['volume-switch-8'] =
    CommandUtil.createVolumeSwitchCommand(8);
CommandHandler.COMMANDS_['volume-switch-9'] =
    CommandUtil.createVolumeSwitchCommand(9);

/**
 * Flips 'available offline' flag on the file.
 * @type {Command}
 */
CommandHandler.COMMANDS_['toggle-pinned'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event
   * @param {!CommandHandlerDeps} fileManager
   */
  execute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelFor(
        event.target);
    var saveForOfflineAction = actionsModel ? actionsModel.getAction(
        ActionsModel.CommonActionId.SAVE_FOR_OFFLINE) : null;
    var offlineNotNeededAction = actionsModel ? actionsModel.getAction(
        ActionsModel.CommonActionId.OFFLINE_NOT_NECESSARY) : null;
    // Saving for offline has a priority if both actions are available.
    var action = saveForOfflineAction || offlineNotNeededAction;
    if (action)
      action.execute();
  },

  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelFor(
        event.target);
    var saveForOfflineAction = actionsModel ? actionsModel.getAction(
        ActionsModel.CommonActionId.SAVE_FOR_OFFLINE) : null;
    var offlineNotNeededAction = actionsModel ? actionsModel.getAction(
        ActionsModel.CommonActionId.OFFLINE_NOT_NECESSARY) : null;
    var action = saveForOfflineAction || offlineNotNeededAction;

    event.canExecute = action && action.canExecute();
    // If model is not computed yet, then keep the previous visibility to avoid
    // flickering.
    if (actionsModel) {
      event.command.setHidden(actionsModel && !action);
      event.command.checked = !!offlineNotNeededAction;
    }
  }
});

/**
 * Creates zip file for current selection.
 * @type {Command}
 */
CommandHandler.COMMANDS_['zip-selection'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    var dirEntry = fileManager.getCurrentDirectoryEntry();
    if (!dirEntry)
      return;

    if (CommandHandler.IS_ZIP_ARCHIVER_PACKER_ENABLED_) {
      fileManager.taskController.getFileTasks()
          .then(function(tasks) {
            if (fileManager.directoryModel.isOnDrive() ||
                fileManager.directoryModel.isOnMTP()) {
              tasks.execute(/** @type {chrome.fileManagerPrivate.FileTask} */ (
                  {taskId: FileTasks.ZIP_ARCHIVER_ZIP_USING_TMP_TASK_ID}));
            } else {
              tasks.execute(/** @type {chrome.fileManagerPrivate.FileTask} */ (
                  {taskId: FileTasks.ZIP_ARCHIVER_ZIP_TASK_ID}));
            }
          })
          .catch(function(error) {
            if (error)
              console.error(error.stack || error);
          });
    } else {
      var selectionEntries = fileManager.getSelection().entries;
      fileManager.fileOperationManager.zipSelection(
          selectionEntries, /** @type {!DirectoryEntry} */ (dirEntry));
    }
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var dirEntry = fileManager.getCurrentDirectoryEntry();
    var selection = fileManager.getSelection();

    var isOnEligibleLocation = CommandHandler.IS_ZIP_ARCHIVER_PACKER_ENABLED_ ?
        true :
        !fileManager.directoryModel.isOnDrive() &&
            !fileManager.directoryModel.isOnMTP();

    event.canExecute = dirEntry && !fileManager.directoryModel.isReadOnly() &&
        isOnEligibleLocation && selection && selection.totalCount > 0;
  }
});

/**
 * Shows the share dialog for the current selection (single only).
 * @type {Command}
 */
CommandHandler.COMMANDS_['share'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    // To toolbar buttons are always related to the file list, even though the
    // focus is on the navigation list. This assumption will break once we add
    // Share to the context menu on the navigation list. crbug.com/530418
    var actionsModel = fileManager.actionsController.getActionsModelForContext(
        ActionsController.Context.FILE_LIST);
    var action = actionsModel ? actionsModel.getAction(
        ActionsModel.CommonActionId.SHARE) : null;
    if (action)
      action.execute();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelForContext(
        ActionsController.Context.FILE_LIST);
    var action = actionsModel ? actionsModel.getAction(
        ActionsModel.CommonActionId.SHARE) : null;
    event.canExecute = action && action.canExecute();
    // If model is not computed yet, then keep the previous visibility to avoid
    // flickering.
    if (actionsModel)
      event.command.setHidden(actionsModel && !action);
  }
});

/**
 * Opens the file in Drive for the user to manage sharing permissions etc.
 * @type {Command}
 */
CommandHandler.COMMANDS_['manage-in-drive'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager The file manager instance.
   */
  execute: function(event, fileManager) {
    var actionsModel =
        fileManager.actionsController.getActionsModelFor(event.target);
    var action = actionsModel ?
        actionsModel.getAction(ActionsModel.InternalActionId.MANAGE_IN_DRIVE) :
        null;
    if (action)
      action.execute();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var actionsModel =
        fileManager.actionsController.getActionsModelFor(event.target);
    var action = actionsModel ?
        actionsModel.getAction(ActionsModel.InternalActionId.MANAGE_IN_DRIVE) :
        null;
    event.canExecute = action && action.canExecute();
    if (actionsModel)
      event.command.setHidden(!action);
  }
});


/**
 * Shares the selected (single only) Downloads subfolder with crostini
 * container.
 * @type {Command}
 */
CommandHandler.COMMANDS_['share-with-linux'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    const entry = CommandUtil.getCommandEntry(event.target);
    if (entry && entry.isDirectory) {
      const dir = /** @type {!DirectoryEntry} */ (entry);
      // Always persist shares via right-click > Share with Linux.
      chrome.fileManagerPrivate.sharePathWithCrostini(
          dir, true /* persist */, () => {
            if (chrome.runtime.lastError) {
              console.error(
                  'Error sharing with linux: ' +
                  chrome.runtime.lastError.message);
            } else {
              Crostini.registerSharedPath(dir, fileManager.volumeManager);
            }
          });
      CommandHandler.recordMenuItemSelected_(
          CommandHandler.MenuCommandsForUMA.SHARE_WITH_LINUX);
    }
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    // Must be single directory subfolder of Downloads not already shared.
    const entries = CommandUtil.getCommandEntries(event.target);
    event.canExecute = entries.length === 1 && entries[0].isDirectory &&
        !Crostini.isPathShared(entries[0], fileManager.volumeManager) &&
        Crostini.canSharePath(
            entries[0], true /* persist */, fileManager.volumeManager);
    event.command.setHidden(!event.canExecute);
  }
});

/**
 * Link to settings page to manage files and folders shared with crostini
 * container.
 * @type {Command}
 */
CommandHandler.COMMANDS_['manage-linux-sharing'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.openSettingsSubpage('crostini/sharedPaths');
    CommandHandler.recordMenuItemSelected_(
        CommandHandler.MenuCommandsForUMA.MANAGE_LINUX_SHARING);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute = Crostini.IS_CROSTINI_FILES_ENABLED;
    event.command.setHidden(!event.canExecute);
  }
});

/**
 * Creates a shortcut of the selected folder (single only).
 * @type {Command}
 */
CommandHandler.COMMANDS_['create-folder-shortcut'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager The file manager instance.
   */
  execute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelFor(
        event.target);
    var action = actionsModel ? actionsModel.getAction(
        ActionsModel.InternalActionId.CREATE_FOLDER_SHORTCUT) : null;
    if (action)
      action.execute();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelFor(
        event.target);
    var action = actionsModel ? actionsModel.getAction(
        ActionsModel.InternalActionId.CREATE_FOLDER_SHORTCUT) : null;
    event.canExecute = action && action.canExecute();
    if (actionsModel)
      event.command.setHidden(!action);
  }
});

/**
 * Removes the folder shortcut.
 * @type {Command}
 */
CommandHandler.COMMANDS_['remove-folder-shortcut'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager The file manager instance.
   */
  execute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelFor(
        event.target);
    var action = actionsModel ? actionsModel.getAction(
        ActionsModel.InternalActionId.REMOVE_FOLDER_SHORTCUT) : null;
    if (action)
      action.execute();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    var actionsModel = fileManager.actionsController.getActionsModelFor(
        event.target);
    var action = actionsModel ? actionsModel.getAction(
        ActionsModel.InternalActionId.REMOVE_FOLDER_SHORTCUT) : null;
    event.canExecute = action && action.canExecute();
    if (actionsModel)
      event.command.setHidden(!action);
  }
});

/**
 * Zoom in to the Files app.
 * @type {Command}
 */
CommandHandler.COMMANDS_['zoom-in'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.zoom('in');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Zoom out from the Files app.
 * @type {Command}
 */
CommandHandler.COMMANDS_['zoom-out'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.zoom('out');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Reset the zoom factor.
 * @type {Command}
 */
CommandHandler.COMMANDS_['zoom-reset'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.zoom('reset');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Sort the file list by name (in ascending order).
 * @type {Command}
 */
CommandHandler.COMMANDS_['sort-by-name'] = /** @type {Command} */ ({
  execute: function(event, fileManager) {
    if (fileManager.directoryModel.getFileList())
      fileManager.directoryModel.getFileList().sort('name', 'asc');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Sort the file list by size (in descending order).
 * @type {Command}
 */
CommandHandler.COMMANDS_['sort-by-size'] = /** @type {Command} */ ({
  execute: function(event, fileManager) {
    if (fileManager.directoryModel.getFileList())
      fileManager.directoryModel.getFileList().sort('size', 'desc');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Sort the file list by type (in ascending order).
 * @type {Command}
 */
CommandHandler.COMMANDS_['sort-by-type'] = /** @type {Command} */ ({
  execute: function(event, fileManager) {
    if (fileManager.directoryModel.getFileList())
      fileManager.directoryModel.getFileList().sort('type', 'asc');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Sort the file list by date-modified (in descending order).
 * @type {Command}
 */
CommandHandler.COMMANDS_['sort-by-date'] = /** @type {Command} */ ({
  execute: function(event, fileManager) {
    if (fileManager.directoryModel.getFileList())
      fileManager.directoryModel.getFileList().sort('modificationTime', 'desc');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Open inspector for foreground page.
 * @type {Command}
 */
CommandHandler.COMMANDS_['inspect-normal'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.openInspector('normal');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Open inspector for foreground page and bring focus to the console.
 * @type {Command}
 */
CommandHandler.COMMANDS_['inspect-console'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.openInspector('console');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Open inspector for foreground page in inspect element mode.
 * @type {Command}
 */
CommandHandler.COMMANDS_['inspect-element'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.openInspector('element');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Open inspector for background page.
 * @type {Command}
 */
CommandHandler.COMMANDS_['inspect-background'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.openInspector('background');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Shows a suggest dialog with new services to be added to the left nav.
 * @type {Command}
 */
CommandHandler.COMMANDS_['install-new-extension'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.ui.suggestAppsDialog.showProviders(
        function(result, itemId) {
          // If a new provider is installed, then launch it so the configuration
          // dialog is shown (if it's available).
          if (result === SuggestAppsDialog.Result.SUCCESS)
            fileManager.providersModel.requestMount(assert(itemId));
        });
  },
  canExecute: function(event, fileManager) {
    event.canExecute = fileManager.dialogType === DialogType.FULL_PAGE;
    event.command.setHidden(!event.canExecute);
  }
});

/**
 * Opens the gear menu.
 * @type {Command}
 */
CommandHandler.COMMANDS_['open-gear-menu'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.ui.gearButton.showMenu(true);
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute = CommandUtil.canExecuteAlways;
  }
});

/**
 * Focus the first button visible on action bar (at the top).
 * @type {Command}
 */
CommandHandler.COMMANDS_['focus-action-bar'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.ui.actionbar.querySelector('button:not([hidden])').focus();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Handle back button.
 * @type {Command}
 */
CommandHandler.COMMANDS_['browser-back'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    // TODO(fukino): It should be better to minimize Files app only when there
    // is no back stack, and otherwise use BrowserBack for history navigation.
    // https://crbug.com/624100.
    const currentWindow = chrome.app.window.current();
    if (currentWindow)
      currentWindow.minimize();
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute = CommandUtil.canExecuteAlways;
  }
});

/**
 * Configures the currently selected volume.
 */
CommandHandler.COMMANDS_['configure'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    var volumeInfo =
        CommandUtil.getElementVolumeInfo(event.target, fileManager) ||
        CommandUtil.getCurrentVolumeInfo(fileManager);
    if (volumeInfo && volumeInfo.configurable)
      fileManager.volumeManager.configure(volumeInfo);
  },
  canExecute: function(event, fileManager) {
    var volumeInfo =
        CommandUtil.getElementVolumeInfo(event.target, fileManager) ||
        CommandUtil.getCurrentVolumeInfo(fileManager);
    event.canExecute = volumeInfo && volumeInfo.configurable;
    event.command.setHidden(!event.canExecute);
  }
});

/**
 * Refreshes the currently selected directory.
 */
CommandHandler.COMMANDS_['refresh'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    fileManager.directoryModel.rescan(true /* refresh */);
    fileManager.spinnerController.blink();
  },
  canExecute: function(event, fileManager) {
    var currentDirEntry = fileManager.directoryModel.getCurrentDirEntry();
    var volumeInfo = currentDirEntry &&
        fileManager.volumeManager.getVolumeInfo(currentDirEntry);
    event.canExecute = volumeInfo && !volumeInfo.watchable;
    event.command.setHidden(!event.canExecute ||
        fileManager.directoryModel.getFileListSelection().getCheckSelectMode());
  }
});

/**
 * Refreshes the currently selected directory.
 */
CommandHandler.COMMANDS_['set-wallpaper'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    var entry = fileManager.getSelection().entries[0];
    new Promise(function(resolve, reject) {
      entry.file(resolve, reject);
    }).then(function(blob) {
      var fileReader = new FileReader();
      return new Promise(function(resolve, reject) {
        fileReader.onload = function() {
          resolve(fileReader.result);
        };
        fileReader.onerror = function() {
          reject(fileReader.error);
        };
        fileReader.readAsArrayBuffer(blob);
      });
    }).then(function(/** @type {!ArrayBuffer} */ arrayBuffer) {
      return new Promise(function(resolve, reject) {
        chrome.wallpaper.setWallpaper({
            data: arrayBuffer,
            layout: chrome.wallpaper.WallpaperLayout.CENTER_CROPPED,
            filename: 'wallpaper'
          }, function() {
            if (chrome.runtime.lastError) {
              reject(chrome.runtime.lastError);
            }else{
              resolve(null);
            }
          });
      });
    }).catch(function() {
      fileManager.ui.alertDialog.showHtml(
          '', str('ERROR_INVALID_WALLPAPER'), null, null, null);
    });
  },
  canExecute: function(event, fileManager) {
    var entries = fileManager.getSelection().entries;
    if (entries.length === 0) {
      event.canExecute = false;
      event.command.setHidden(true);
      return;
    }
    var type = FileType.getType(entries[0]);
    if (entries.length !== 1 || type.type !== 'image') {
      event.canExecute = false;
      event.command.setHidden(true);
      return;
    }

    event.canExecute = type.subtype === 'JPEG' || type.subtype === 'PNG';
    event.command.setHidden(false);
  }
});

/**
 * Opens settings/storage sub page.
 * @type {Command}
 */
CommandHandler.COMMANDS_['volume-storage'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    chrome.fileManagerPrivate.openSettingsSubpage('storage');
  },
  canExecute: CommandUtil.canExecuteAlways
});

/**
 * Opens "providers menu" to allow users to install new providers/FSPs.
 * @type {Command}
 */
CommandHandler.COMMANDS_['new-service'] = /** @type {Command} */ ({
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  execute: function(event, fileManager) {
    const menuButton = fileManager.ui.newServiceButton;
    // Make the button visible because showMenu positions the menu relative to
    // to this button.
    menuButton.hidden = false;

    // Fire update event to display services that are already installed.
    const updateEvent =
        /** @type {MenuItemUpdateEvent} */ (new Event('update'));

    // Display the menu near gearMenu, since menuButton will be hidden.
    // The event listener (ProvidersMenu) only uses this menuButton for
    // positioning.
    updateEvent.menuButton = fileManager.ui.gearButton;
    menuButton.menu.dispatchEvent(updateEvent);
    menuButton.showMenu(false);

    // Hide it back.
    menuButton.hidden = true;
  },
  /**
   * @param {!Event} event Command event.
   * @param {!CommandHandlerDeps} fileManager CommandHandlerDeps to use.
   */
  canExecute: function(event, fileManager) {
    event.canExecute =
        (fileManager.dialogType === DialogType.FULL_PAGE &&
         !chrome.extension.inIncognitoContext);
  }
});