/* 
   NSInterfaceStyle.m

   Copyright (C) 1999 Free Software Foundation, Inc.

   Author:	Richard Frith-Macdonald <richard@brainstorm.co.uk>
   Date:	1999
   
   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 <gnustep/gui/config.h>
#include <Foundation/NSString.h>
#include <Foundation/NSDictionary.h>
#include <Foundation/NSException.h>
#include <Foundation/NSNotification.h>
#include <Foundation/NSUserDefaults.h>
#include <Foundation/NSMapTable.h>

#include <AppKit/NSResponder.h>
#include <AppKit/NSInterfaceStyle.h>

NSString	*NSInterfaceStyleDefault = @"NSInterfaceStyleDefault";

static NSMapTable	*styleMap = 0;
static NSInterfaceStyle	defStyle;

static NSInterfaceStyle
styleFromString(NSString* str)
{
  if ([str isEqualToString: @"NSNextStepInterfaceStyle"])
    return NSNextStepInterfaceStyle;
  if ([str isEqualToString: @"NSMacintoshInterfaceStyle"])
    return NSMacintoshInterfaceStyle;
  if ([str isEqualToString: @"NSWindows95InterfaceStyle"])
    return NSWindows95InterfaceStyle;
  if ([str isEqualToString: @"GSWindowMakerInterfaceStyle"])
    return GSWindowMakerInterfaceStyle;
  return NSNoInterfaceStyle;
}

@interface	GSInterfaceStyle : NSObject
+ (void) defaultsDidChange: (NSNotification*)notification;
@end



typedef struct {
  @defs(NSResponder)
} *accessToResponder;

extern  NSInterfaceStyle
NSInterfaceStyleForKey(NSString *key, NSResponder *responder)
{
  NSInterfaceStyle	style;

  /*
   *	If the specified responder has a style set, return it.
   */
  if (responder)
    {
      style = (NSInterfaceStyle)((accessToResponder)responder)->interface_style;
      if (style != NSNoInterfaceStyle)
	{
	  return style;
	}
    }

  /*
   *	If there is no style map, the defaults/cache management class must be
   *	initialised.
   */
  if (styleMap == 0)
    [GSInterfaceStyle class];

  /*
   *	If there is a style for the given defaults key, return it - after
   *	caching it in a map table if necessary.
   */
  if (key)
    {
      /*
       *	First try the cache - then, if no style is found,  use the
       *	defaults system and add the results into the cache.
       */
      style = (NSInterfaceStyle)NSMapGet(styleMap, key);
      if (style == NSNoInterfaceStyle)
	{
	  NSUserDefaults	*defs;
	  NSString		*def;
      
	  defs = [NSUserDefaults standardUserDefaults];
	  def = [defs stringForKey: key];
	  if (def == nil
	    || (style = styleFromString(def)) == NSNoInterfaceStyle)
	    {
	      style = NSNextStepInterfaceStyle;
	    }
	  NSMapInsert(styleMap, (void*)key, (void*)style);
	}
      return style;
    }

  /*
   *	No responder and no key - return the default style.
   */
  return defStyle;
}



/*
 *	The GSInterfaceStyle class is used solely to maintain our map of
 *	know interface styles by updating when user defaults change.
 */
@implementation	GSInterfaceStyle

+ (void) initialize
{
  if (self == [GSInterfaceStyle class])
    {
      styleMap = NSCreateMapTable(NSObjectMapKeyCallBacks,
			     NSIntMapValueCallBacks, 8);

      [NSUserDefaults standardUserDefaults];
      [self defaultsDidChange: nil];
      [[NSNotificationCenter defaultCenter]
	addObserver: self
	   selector: @selector(defaultsDidChange:)
	       name: NSUserDefaultsDidChangeNotification
	     object: nil];
    }
}

+ (void) defaultsDidChange: (NSNotification*)notification
{
  NSUserDefaults	*defs;
  NSMapEnumerator	enumerator;
  NSString		*key;
  NSInterfaceStyle	val;

  defs = [NSUserDefaults standardUserDefaults];

  /*
   *	Determine the default interface style for the application.
   */
  key = [defs stringForKey: NSInterfaceStyleDefault];
  if (key == nil || (defStyle = styleFromString(key)) == NSNoInterfaceStyle)
    defStyle = NSNextStepInterfaceStyle;
    
  /*
   *	Now check the interface styles for all the keys in use and adjust our
   *	map table for any changes.
   */
  enumerator = NSEnumerateMapTable(styleMap);
  while (NSNextMapEnumeratorPair(&enumerator, (void**)&key, (void**)&val))
    {
      NSInterfaceStyle	newStyle;
      NSString		*def = [defs stringForKey: key];

      if (def == nil)
	{
	  newStyle = defStyle;
	}
      else
	{
	  newStyle = styleFromString(def);
	  if (newStyle == NSNoInterfaceStyle)
	    {
	      newStyle = defStyle;
	    }
	}

      if (newStyle != val)
	{
	  NSMapInsert(styleMap, (void*)key, (void*)newStyle);
	}
    }
}

@end