/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

[scriptable, uuid(44d9ef13-83be-4ab9-a2a1-95d9cbd96acd)]
interface nsIBidiKeyboard : nsISupports
{
  /**
   * Inspects the installed keyboards and resets the bidi keyboard state
   */
  void reset();

  /**
   * Determines if the current keyboard language is right-to-left
   * @throws NS_ERROR_FAILURE if no right-to-left keyboards are installed
   */
  boolean isLangRTL();

  /**
   * Sets the keyboard language to left-to-right or right-to-left
   * @param aLevel - if odd set the keyboard to RTL, if even set LTR 
   * @throws NS_ERROR_FAILURE if no right-to-left keyboards are installed
   */
  void setLangFromBidiLevel(in uint8_t aLevel);

  /**
   * Determines whether the system has at least one keyboard of each direction
   * installed.
   *
   * @throws NS_ERROR_NOT_IMPLEMENTED if the widget layer does not provide this
   * information.
   */
  readonly attribute boolean haveBidiKeyboards;
};