/** <title>NSDocument</title>

   <abstract>The abstract document class</abstract>

   Copyright (C) 1999 Free Software Foundation, Inc.

   Author: Carl Lindberg <Carl.Lindberg@hbo.com>
   Date: 1999
   Modifications: Fred Kiefer <FredKiefer@gmx.de>
   Date: June 2000

   This file is part of the GNUstep GUI Library.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this library; see the file COPYING.LIB.
   If not, write to the Free Software Foundation,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include <Foundation/NSData.h>
#include "AppKit/NSDocument.h"
#include "AppKit/NSFileWrapper.h"
#include "AppKit/NSSavePanel.h"
#include "AppKit/NSPrintInfo.h"
#include "AppKit/NSPageLayout.h"
#include "AppKit/NSView.h"
#include "AppKit/NSPopUpButton.h"
#include "AppKit/NSDocumentFrameworkPrivate.h"

#include "GSGuiPrivate.h"

@implementation NSDocument

+ (NSArray *)readableTypes
{
  return [[NSDocumentController sharedDocumentController]
	   _editorAndViewerTypesForClass: self];
}

+ (NSArray *)writableTypes
{
  return [[NSDocumentController sharedDocumentController] 
	   _editorTypesForClass: self];
}

+ (BOOL)isNativeType: (NSString *)type
{
  return ([[self readableTypes] containsObject: type] &&
	  [[self writableTypes] containsObject: type]);
}


- (id) init
{
  static int untitledCount = 1;
  NSArray *fileTypes;
  
  self = [super init];
  if (self != nil)
    {
      _documentIndex = untitledCount++;
      _windowControllers = [[NSMutableArray alloc] init];
      fileTypes = [[self class] readableTypes];
      _docFlags.hasUndoManager = YES;

      /* Set our default type */
      if ([fileTypes count])
       { 
         [self setFileType: [fileTypes objectAtIndex: 0]];
       }
    }
  return self;
}

/**
 * Initialises the receiver with the contents of the document at fileName
 * assuming that the type of data is as specified by fileType.<br />
 * Destroys the receiver and returns nil on failure.
 */
- (id) initWithContentsOfFile: (NSString*)fileName ofType: (NSString*)fileType
{
  self = [self init];
  if (self != nil)
    {
      if ([self readFromFile: fileName ofType: fileType])
	{
	  [self setFileType: fileType];
	  [self setFileName: fileName];
	}
      else
	{
	  NSRunAlertPanel (_(@"Load failed"),
			   _(@"Could not load file %@."),
			   nil, nil, nil, fileName);
	  DESTROY(self);
	}
    }
  return self;
}

/**
 * Initialises the receiver with the contents of the document at url
 * assuming that the type of data is as specified by fileType.<br />
 * Destroys the receiver and returns nil on failure.
 */
- (id) initWithContentsOfURL: (NSURL*)url ofType: (NSString*)fileType
{
  self = [self init];
  if (self != nil)
    {
      if ([self readFromURL: url ofType: fileType])
	{
	  [self setFileType: fileType];
	  [self setFileName:[url path]];
	}
      else
	{
	  NSRunAlertPanel(_(@"Load failed"),
			  _(@"Could not load URL %@."),
			  nil, nil, nil, [url absoluteString]);
	  DESTROY(self);
	}
    }  
  return self;
}

- (void) dealloc
{
  [[NSNotificationCenter defaultCenter] removeObserver: self];
  RELEASE(_undoManager);
  RELEASE(_fileName);
  RELEASE(_fileType);
  RELEASE(_windowControllers);
  RELEASE(_window);
  RELEASE(_printInfo);
  RELEASE(savePanelAccessory);
  RELEASE(spaButton);
  [super dealloc];
}

- (NSString *)fileName
{
  return _fileName;
}

- (void)setFileName: (NSString *)fileName
{
  ASSIGN(_fileName, fileName);
	
  [_windowControllers makeObjectsPerformSelector:
			@selector(synchronizeWindowTitleWithDocumentName)];
}

- (NSString *)fileType
{
  return _fileType;
}

- (void)setFileType: (NSString *)type
{
  ASSIGN(_fileType, type);
}

- (NSArray *)windowControllers
{
  return _windowControllers;
}

- (void)addWindowController: (NSWindowController *)windowController
{
  [_windowControllers addObject: windowController];
  if ([windowController document] != self)
    {
      [windowController setDocument: self];
    }
}

- (void)removeWindowController: (NSWindowController *)windowController
{
  if ([_windowControllers containsObject: windowController])
    {
      [windowController setDocument: nil];
      [_windowControllers removeObject: windowController];
    }
}

- (NSString *)windowNibName
{
  return nil;
}

// private; called during nib load.  
// we do not retain the window, since it should
// already have a retain from the nib.
- (void)setWindow: (NSWindow *)aWindow
{
  _window = aWindow;
}

//FIXME: In the later specification this method has a different return type!! 
- (void) makeWindowControllers
{
  NSString *name = [self windowNibName];

  if (name != nil && [name length] > 0)
    {
      NSWindowController *controller;

      controller = [[NSWindowController alloc] initWithWindowNibName: name
							       owner: self];
      [self addWindowController: controller];
      RELEASE(controller);
    }
  else
    {
      [NSException raise: NSInternalInconsistencyException
		  format: @"%@ must override either -windowNibName "
	@"or -makeWindowControllers", NSStringFromClass([self class])];
    }
}

/**
 * Makes all the documents windows visible by ordering them to the
 * front and making them main or key.<br />
 * If the document has no windows, this method has no effect.
 */
- (void) showWindows
{
  [_windowControllers makeObjectsPerformSelector: @selector(showWindow:)
				      withObject: self];
}

- (BOOL) isDocumentEdited
{
  return _changeCount != 0;
}

- (void)updateChangeCount: (NSDocumentChangeType)change
{
  int i, count = [_windowControllers count];
  BOOL isEdited;
  
  switch (change)
    {
    case NSChangeDone:		_changeCount++; break;
    case NSChangeUndone:	_changeCount--; break;
    case NSChangeCleared:	_changeCount = 0; break;
    }
  
    /*
     * NOTE: Apple's implementation seems to not call -isDocumentEdited
     * here but directly checks to see if _changeCount == 0.  It seems it
     * would be better to call the method in case it's overridden by a
     * subclass, but we may want to keep Apple's behavior.
     */
  isEdited = [self isDocumentEdited];

  for (i=0; i<count; i++)
    {
      [[_windowControllers objectAtIndex: i] setDocumentEdited: isEdited];
    }
}

- (BOOL)canCloseDocument
{
  int result;

  if (![self isDocumentEdited])
    return YES;

  result = NSRunAlertPanel (_(@"Close"), 
			    _(@"%@ has changed.  Save?"),
			    _(@"Save"), _(@"Cancel"), _(@"Don't Save"), 
			    [self displayName]);
  
#define Save     NSAlertDefaultReturn
#define Cancel   NSAlertAlternateReturn
#define DontSave NSAlertOtherReturn

  switch (result)
    {
      // return NO if save failed
    case Save:
      {
	[self saveDocument: nil]; 
	return ![self isDocumentEdited];
      }
    case DontSave:	return YES;
    case Cancel:
    default:		return NO;
    }
}

- (void)canCloseDocumentWithDelegate: (id)delegate 
		 shouldCloseSelector: (SEL)shouldCloseSelector 
			 contextInfo: (void *)contextInfo
{
  BOOL result = [self canCloseDocument];

  if (delegate != nil && shouldCloseSelector != NULL)
    {
      void (*meth)(id, SEL, id, BOOL, void*);
      meth = (void (*)(id, SEL, id, BOOL, void*))[delegate methodForSelector: 
							       shouldCloseSelector];
      if (meth)
	meth(delegate, shouldCloseSelector, self, result, contextInfo);
    }
}

- (BOOL)shouldCloseWindowController: (NSWindowController *)windowController
{
  if (![_windowControllers containsObject: windowController]) return YES;

  /* If it's the last window controller, pop up a warning */
  /* maybe we should count only loaded window controllers (or visible windows). */
  if ([windowController shouldCloseDocument]
      || [_windowControllers count] == 1)
    {
      return [self canCloseDocument];
    }
	
  return YES;
}

- (void)shouldCloseWindowController: (NSWindowController *)windowController 
			   delegate: (id)delegate 
		shouldCloseSelector: (SEL)callback
			contextInfo: (void *)contextInfo
{
  BOOL result = [self shouldCloseWindowController: windowController];

  if (delegate != nil && callback != NULL)
    {
      void (*meth)(id, SEL, id, BOOL, void*);
      meth = (void (*)(id, SEL, id, BOOL, void*))[delegate methodForSelector: 
							       callback];
      
      if (meth)
	meth(delegate, callback, self, result, contextInfo);
    }
}

- (NSString *)displayName
{
  if ([self fileName] != nil)
    {
      return [[[self fileName] lastPathComponent] stringByDeletingPathExtension];
    }
  else
    {
      return [NSString stringWithFormat: _(@"Untitled-%d"), _documentIndex];
    }
}

- (BOOL)keepBackupFile
{
  return NO;
}

- (NSData *)dataRepresentationOfType: (NSString *)type
{
  [NSException raise: NSInternalInconsistencyException format:@"%@ must implement %@",
	       NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
  return nil;
}

- (BOOL)loadDataRepresentation: (NSData *)data ofType: (NSString *)type
{
  [NSException raise: NSInternalInconsistencyException format:@"%@ must implement %@",
	       NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
  return NO;
}

- (NSFileWrapper *)fileWrapperRepresentationOfType: (NSString *)type
{
  NSData *data = [self dataRepresentationOfType: type];
  
  if (data == nil) 
    return nil;

  return AUTORELEASE([[NSFileWrapper alloc] initRegularFileWithContents: data]);
}

- (BOOL)loadFileWrapperRepresentation: (NSFileWrapper *)wrapper ofType: (NSString *)type
{
  if ([wrapper isRegularFile])
    {
      return [self loadDataRepresentation:[wrapper regularFileContents] ofType: type];
    }
  
    /*
     * This even happens on a symlink.  May want to use
     * -stringByResolvingAllSymlinksInPath somewhere, but Apple doesn't.
     */
  NSLog(@"%@ must be overridden if your document deals with file packages.",
	NSStringFromSelector(_cmd));

  return NO;
}

- (BOOL)writeToFile: (NSString *)fileName ofType: (NSString *)type
{
  return [[self fileWrapperRepresentationOfType: type]
	   writeToFile: fileName atomically: YES updateFilenames: YES];
}

- (BOOL)readFromFile: (NSString *)fileName ofType: (NSString *)type
{
  NSFileWrapper *wrapper = AUTORELEASE([[NSFileWrapper alloc] initWithPath: fileName]);
  return [self loadFileWrapperRepresentation: wrapper ofType: type];
}

- (BOOL)revertToSavedFromFile: (NSString *)fileName ofType: (NSString *)type
{
  return [self readFromFile: fileName ofType: type];
}

- (BOOL)writeToURL: (NSURL *)url ofType: (NSString *)type
{
  NSData *data = [self dataRepresentationOfType: type];
  
  if (data == nil) 
    return NO;

  return [url setResourceData: data];
}

- (BOOL)readFromURL: (NSURL *)url ofType: (NSString *)type
{
  NSData *data = [url resourceDataUsingCache: YES];

  if (data == nil) 
    return NO;

  return [self loadDataRepresentation: data ofType: type];
}

- (BOOL)revertToSavedFromURL: (NSURL *)url ofType: (NSString *)type
{
  return [self readFromURL: url ofType: type];
}

- (IBAction)changeSaveType: (id)sender
{ 
//FIXME if we have accessory -- store the desired save type somewhere.
}

- (int)runModalSavePanel: (NSSavePanel *)savePanel 
       withAccessoryView: (NSView *)accessoryView
{
  [savePanel setAccessoryView: accessoryView];
  return [savePanel runModal];
}

- (BOOL)shouldRunSavePanelWithAccessoryView
{
  return YES;
}

- (void) _loadPanelAccessoryNib
{
// FIXME.  We need to load the pop-up button
}
- (void) _addItemsToSpaButtonFromArray: (NSArray *)types
{
// FIXME.  Add types to popup.
}

- (NSString *)fileNameFromRunningSavePanelForSaveOperation: (NSSaveOperationType)saveOperation
{
  NSView *accessory = nil;
  NSString *title;
  NSString *directory;
  NSArray *extensions;
  NSDocumentController *controller;
  NSSavePanel *savePanel = [NSSavePanel savePanel];

  controller = [NSDocumentController sharedDocumentController];
  extensions = [controller fileExtensionsFromType:[self fileType]];
  
  if ([self shouldRunSavePanelWithAccessoryView])
    {
      if (savePanelAccessory == nil)
	[self _loadPanelAccessoryNib];
      
      [self _addItemsToSpaButtonFromArray: extensions];
      
      accessory = savePanelAccessory;
    }

  if ([extensions count] > 0)
    [savePanel setRequiredFileType:[extensions objectAtIndex:0]];

  switch (saveOperation)
    {
    case NSSaveAsOperation: title = _(@"Save As"); break;
    case NSSaveToOperation: title = _(@"Save To"); break; 
    case NSSaveOperation: 
    default:
      title = _(@"Save");    
      break;
   }
  
  [savePanel setTitle: title];
  
  if ([self fileName])
    directory = [[self fileName] stringByDeletingLastPathComponent];
  else
    directory = [controller currentDirectory];
  [savePanel setDirectory: directory];
	
  if (![self prepareSavePanel: savePanel])
    {
      return nil;
    }

  if ([self runModalSavePanel: savePanel withAccessoryView: accessory])
    {
      return [savePanel filename];
    }
  
  return nil;
}

- (BOOL)shouldChangePrintInfo: (NSPrintInfo *)newPrintInfo
{
  return YES;
}

- (NSPrintInfo *)printInfo
{
  return _printInfo? _printInfo : [NSPrintInfo sharedPrintInfo];
}

- (void)setPrintInfo: (NSPrintInfo *)printInfo
{
  ASSIGN(_printInfo, printInfo);
}


// Page layout panel (Page Setup)

- (int)runModalPageLayoutWithPrintInfo: (NSPrintInfo *)printInfo
{
  return [[NSPageLayout pageLayout] runModalWithPrintInfo: printInfo];
}

- (IBAction)runPageLayout: (id)sender
{
  NSPrintInfo *printInfo = [self printInfo];
  
  if ([self runModalPageLayoutWithPrintInfo: printInfo]
      && [self shouldChangePrintInfo: printInfo])
    {
      [self setPrintInfo: printInfo];
      [self updateChangeCount: NSChangeDone];
    }
}

/* This is overridden by subclassers; the default implementation does nothing. */
- (void)printShowingPrintPanel: (BOOL)flag
{
}

- (IBAction)printDocument: (id)sender
{
  [self printShowingPrintPanel: YES];
}

- (BOOL)validateMenuItem: (NSMenuItem *)anItem
{
  BOOL result = YES;
  SEL  action = [anItem action];

  // FIXME should validate spa popup items; return YES if it's a native type.
  if (sel_eq(action, @selector(revertDocumentToSaved:)))
    {
      result = ([self fileName] != nil && [self isDocumentEdited]);
    }
  else if (sel_eq(action, @selector(undo:)))
    {
      if(_undoManager == nil)
	{
	  result = NO;
	}
      else
	{
	  if([_undoManager canUndo])
	    {
	      [anItem setTitle: [_undoManager undoMenuItemTitle]];
	      result = YES;
	    }
	  else
	    {
	      [anItem setTitle: [_undoManager undoMenuTitleForUndoActionName: @""]];
	      result = NO;
	    }
	}
    }
  else if (sel_eq(action, @selector(redo:)))
    {
      if(_undoManager == nil)
	{
	  result = NO;
	}
      else
	{
	  if([_undoManager canRedo])
	    {
	      [anItem setTitle: [_undoManager redoMenuItemTitle]];
	      result = YES;
	    }
	  else
	    {
	      [anItem setTitle: [_undoManager redoMenuTitleForUndoActionName: @""]];
	      result = NO;
	    }
	}
    }
    
  return result;
}

- (BOOL)validateUserInterfaceItem: (id <NSValidatedUserInterfaceItem>)anItem
{
  if ([anItem action] == @selector(revertDocumentToSaved:))
    return ([self fileName] != nil);

  return YES;
}

- (NSString *)fileTypeFromLastRunSavePanel
{
  // FIXME this should return type picked on save accessory
  // return [spaPopupButton title];
  return [self fileType];
}

- (NSDictionary *)fileAttributesToWriteToFile: (NSString *)fullDocumentPath 
				       ofType: (NSString *)docType 
				saveOperation: (NSSaveOperationType)saveOperationType
{
  // FIXME: Implement.
  return [NSDictionary dictionary];
}

- (BOOL)writeToFile: (NSString *)fileName 
	     ofType: (NSString *)type 
       originalFile: (NSString *)origFileName
      saveOperation: (NSSaveOperationType)saveOp
{
  return [self writeToFile: fileName ofType: type];
}

- (BOOL)writeWithBackupToFile: (NSString *)fileName 
		       ofType: (NSString *)fileType 
		saveOperation: (NSSaveOperationType)saveOp
{
  NSFileManager *fileManager = [NSFileManager defaultManager];
  NSString *backupFilename = nil;

  if (fileName)
    {
      if ([fileManager fileExistsAtPath: fileName])
	{
	  NSString *extension  = [fileName pathExtension];
	  
	  backupFilename = [fileName stringByDeletingPathExtension];
	  backupFilename = [backupFilename stringByAppendingString:@"~"];
	  backupFilename = [backupFilename stringByAppendingPathExtension: extension];

	  /* Save panel has already asked if the user wants to replace it */

	  /* NSFileManager movePath: will fail if destination exists */
	  if ([fileManager fileExistsAtPath: backupFilename])
	    [fileManager removeFileAtPath: backupFilename handler: nil];

	  // Move or copy?
	  if (![fileManager movePath: fileName toPath: backupFilename handler: nil] &&
	      [self keepBackupFile])
            {
	      int result = NSRunAlertPanel(_(@"File Error"),
					   _(@"Can't create backup file.  Save anyways?"),
					   _(@"Save"), _(@"Cancel"), nil);
	      
	      if (result != NSAlertDefaultReturn) return NO;
            }
	}
      if ([self writeToFile: fileName 
		ofType: fileType
		originalFile: backupFilename
		saveOperation: saveOp])
	{
	  if (saveOp != NSSaveToOperation)
	    {
	      [self setFileName: fileName];
	      [self setFileType: fileType];
	      [self updateChangeCount: NSChangeCleared];
	    }

	  // FIXME: Should set the file attributes

	  if (backupFilename && ![self keepBackupFile])
	    {
	      [fileManager removeFileAtPath: backupFilename handler: nil];
	    }

	  return YES;
	}
    }

  return NO;
}

- (IBAction)saveDocument: (id)sender
{
  NSString *filename = [self fileName];

  if (filename == nil)
    {
      [self saveDocumentAs: sender];
      return;
    }

  [self writeWithBackupToFile: filename 
	ofType: [self fileType]
	saveOperation: NSSaveOperation];
}

- (IBAction)saveDocumentAs: (id)sender
{
  NSString *filename = 
      [self fileNameFromRunningSavePanelForSaveOperation: 
		NSSaveAsOperation];

  [self writeWithBackupToFile: filename 
	ofType: [self fileTypeFromLastRunSavePanel]
	saveOperation: NSSaveAsOperation];
}

- (IBAction)saveDocumentTo: (id)sender
{
  NSString *filename = 
      [self fileNameFromRunningSavePanelForSaveOperation: 
		NSSaveToOperation];

  [self writeWithBackupToFile: filename 
	ofType: [self fileTypeFromLastRunSavePanel]
	saveOperation: NSSaveToOperation];
}

- (void)saveDocumentWithDelegate: (id)delegate 
		 didSaveSelector: (SEL)didSaveSelector 
		     contextInfo: (void *)contextInfo
{
  [self runModalSavePanelForSaveOperation: NSSaveOperation 
	delegate: delegate
	didSaveSelector: didSaveSelector 
	contextInfo: contextInfo];
}

- (void)saveToFile: (NSString *)fileName 
     saveOperation: (NSSaveOperationType)saveOperation 
	  delegate: (id)delegate
   didSaveSelector: (SEL)didSaveSelector 
       contextInfo: (void *)contextInfo
{
  BOOL saved = NO;
 
  if (fileName != nil)
  {
    saved = [self writeWithBackupToFile: fileName 
		  ofType: [self fileTypeFromLastRunSavePanel]
		  saveOperation: saveOperation];
  }

  if (delegate != nil && didSaveSelector != NULL)
    {
      void (*meth)(id, SEL, id, BOOL, void*);
      meth = (void (*)(id, SEL, id, BOOL, void*))[delegate methodForSelector: 
							       didSaveSelector];
      if (meth)
	meth(delegate, didSaveSelector, self, saved, contextInfo);
    }
}

- (BOOL)prepareSavePanel: (NSSavePanel *)savePanel
{
  return YES;
}

- (void)runModalSavePanelForSaveOperation: (NSSaveOperationType)saveOperation 
				 delegate: (id)delegate
			  didSaveSelector: (SEL)didSaveSelector 
			      contextInfo: (void *)contextInfo
{
  NSString *fileName;

  // FIXME: Setting of the delegate of the save panel is missing
  fileName = [self fileNameFromRunningSavePanelForSaveOperation: saveOperation];
  [self saveToFile: fileName 
	saveOperation: saveOperation 
	delegate: delegate
	didSaveSelector: didSaveSelector 
	contextInfo: contextInfo];
}

- (IBAction)revertDocumentToSaved: (id)sender
{
  int result;

  result = NSRunAlertPanel 
    (_(@"Revert"),
     _(@"%@ has been edited.  Are you sure you want to undo changes?"),
     _(@"Revert"), _(@"Cancel"), nil, 
     [self displayName]);
  
  if (result == NSAlertDefaultReturn &&
      [self revertToSavedFromFile:[self fileName] ofType:[self fileType]])
    {
      [self updateChangeCount: NSChangeCleared];
    }
}

/** Closes all the windows owned by the document, then removes itself
    from the list of documents known by the NSDocumentController. This
    method does not ask the user if they want to save the document before
    closing. It is closed without saving any information.
 */
- (void)close
{
  if (_docFlags.inClose == NO)
    {
      int count = [_windowControllers count];
      /* Closing a windowController will also send us a close, so make
	 sure we don't go recursive */
      _docFlags.inClose = YES;

      if (count > 0)
	{
	  NSWindowController *array[count];
	  [_windowControllers getObjects: array];
	  while (count-- > 0)
	    [array[count] close];
	}
      [[NSDocumentController sharedDocumentController] removeDocument: self];
    }
}

- (void)windowControllerWillLoadNib: (NSWindowController *)windowController {}
- (void)windowControllerDidLoadNib: (NSWindowController *)windowController  {}

- (NSUndoManager *)undoManager
{
  if (_undoManager == nil && [self hasUndoManager])
    {
      [self setUndoManager: AUTORELEASE([[NSUndoManager alloc] init])];
    }
  
  return _undoManager;
}

- (void)setUndoManager: (NSUndoManager *)undoManager
{
  if (undoManager != _undoManager)
    {
      NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
      
      if (_undoManager)
        {
	  [center removeObserver: self
		  name: NSUndoManagerWillCloseUndoGroupNotification
		  object:_undoManager];
	  [center removeObserver: self
		  name: NSUndoManagerDidUndoChangeNotification
		  object:_undoManager];
	  [center removeObserver: self
		  name: NSUndoManagerDidRedoChangeNotification
		  object:_undoManager];
        }
      
      ASSIGN(_undoManager, undoManager);
      
      if (_undoManager == nil)
        {
	  [self setHasUndoManager: NO];
        }
      else
        {
	  [center addObserver: self
		  selector:@selector(_changeWasDone:)
		  name: NSUndoManagerWillCloseUndoGroupNotification
		  object:_undoManager];
	  [center addObserver: self
		  selector:@selector(_changeWasUndone:)
		  name: NSUndoManagerDidUndoChangeNotification
		  object:_undoManager];
	  [[NSNotificationCenter defaultCenter]
	    addObserver: self
	    selector:@selector(_changeWasRedone:)
	    name: NSUndoManagerDidRedoChangeNotification
	    object:_undoManager];
        }
    }
}

- (BOOL)hasUndoManager
{
  return _docFlags.hasUndoManager;
}

- (void)setHasUndoManager: (BOOL)flag
{
  if (_undoManager && !flag)
    [self setUndoManager: nil];
  
  _docFlags.hasUndoManager = flag;
}
@end

@implementation NSDocument(Private)

/*
 * This private method is used to transfer window ownership to the
 * NSWindowController in situations (such as the default) where the
 * document is set to the nib owner, and thus owns the window immediately
 * following the loading of the nib.
 */
- (NSWindow *) _transferWindowOwnership
{
  NSWindow *window = _window;
  _window = nil;
  return AUTORELEASE(window);
}

- (void) _removeWindowController: (NSWindowController *)windowController
{
  if ([_windowControllers containsObject: windowController])
    {
      BOOL autoClose = [windowController shouldCloseDocument];
      
      [windowController setDocument: nil];
      [_windowControllers removeObject: windowController];
      
      if (autoClose || [_windowControllers count] == 0)
        {
	  [self close];
	}
    }
}

- (void) _changeWasDone: (NSNotification *)notification
{
  [self updateChangeCount: NSChangeDone];
}

- (void) _changeWasUndone: (NSNotification *)notification
{
  [self updateChangeCount: NSChangeUndone];
}

- (void) _changeWasRedone: (NSNotification *)notification
{
  [self updateChangeCount: NSChangeDone];
}

- (void) undo: (id)sender
{
  [[self undoManager] undo];
}

- (void) redo: (id)sender
{
  [[self undoManager] redo];
}

@end