/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 *      Simon Fraser <sfraser@netscape.com>
 *
 */

#include "nsISupports.idl"
#include "nsIObserver.idl"
#include "nsICommandParams.idl"

/*
 * nsICommandManager is an interface used to executing user-level commands,
 * and getting the state of available commands.
 *
 * Commands are identified by strings, which are documented elsewhere.
 * In addition, the list of required and optional parameters for
 * each command, that are passed in via the nsICommandParams, are
 * also documented elsewhere. (Where? Need a good location for this).
 */
 
 
[scriptable, uuid(080D2001-F91E-11D4-A73C-F9242928207C)]
interface nsICommandManager : nsISupports
{
  /*
   * Register an observer on the specified command. The observer's Observe
   * method will get called when the state (enabled/disbaled, or toggled etc)
   * of the command changes.
   *
   * You can register the same observer on multiple commmands by calling this
   * multiple times.
   */
  void        addCommandObserver(in nsIObserver aCommandObserver,
                                 in DOMString aCommandToObserve);

  /*
   * Stop an observer from observering the specified command. If the observer
   * was also registered on ther commands, they will continue to be observed.
   *
   * Passing an empty string in 'aCommandObserved' will remove the observer
   * from all commands.
   */
  void        removeCommandObserver(in nsIObserver aCommandObserver,
                                    in DOMString aCommandObserved);

  /*
   * Ask the command manager if the specified command is supported.
   *
   */
  boolean     isCommandSupported(in DOMString aCommandName);

  /*
   * Ask the command manager if the specified command is currently.
   * enabled.
   */
  boolean     isCommandEnabled(in DOMString aCommandName);
  
  /*
   * Get the state of the specified commands.
   *
   * On input: aCommandParams filled in with values that the caller cares
   * about, most of which are command-specific (see the command documentation
   * for details). One boolean value, "enabled", applies to all commands,
   * and, in return will be set to indicate whether the command is enabled
   * (equivalent to calling isCommandEnabled).
   *
   * On output: aCommandParams: values set by the caller filled in with
   * state from the command.
   */
  void        getCommandState(in DOMString aCommandName,
                              inout nsICommandParams aCommandParams);
    
  /*
   * Execute the specified command.
   *
   * param: aCommandParams, a list of name-value pairs of command parameters,
   * may be null for parameter-less commands.
   *
   */
  void        doCommand(in DOMString aCommandName, in nsICommandParams aCommandParams);

};


/*

Arguments to observers "Observe" method are as follows:

  void Observe(   in nsISupports aSubject,          // The nsICommandManager calling this Observer
                  in wstring     aTopic,            // Name of the command whose state changed
                  in wstring     aDummy );          // Unused string

*/


