/* NSCalendarDate+Scheduler.m - this file is part of SOGo
   Copyright (C) 2000-2004 SKYRIX Software AG

   This file is part of OGo

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

   OGo 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 Lesser General Public
   License for more details.

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

#import <NGExtensions/NSCalendarDate+misc.h>

#import "NSCalendarDate+Scheduler.h"

@implementation NSCalendarDate (SchedulerExtensions)

- (BOOL) isDateInSameMonth: (NSCalendarDate *) _other
{
  return (([_other yearOfCommonEra] == [self yearOfCommonEra]) &&
          ([_other monthOfYear] == [self monthOfYear]));
}

- (NSCalendarDate *) dayOfWeeK: (unsigned) _day 
              offsetFromSunday: (unsigned) _offset
{
  unsigned dayOfWeek, distance;
    
  /* perform "locale" correction */
  dayOfWeek = (7 + [self dayOfWeek] - _offset) % 7;

  _day = (_day % 7);
  if(_day == dayOfWeek)
    return self;

  distance = _day - dayOfWeek;
  return [self dateByAddingYears:0 months:0 days:distance];
}

/* this implies that monday is the start of week! */

- (NSCalendarDate *) sundayOfWeek
{
  return [self dayOfWeeK:6 offsetFromSunday:1];
}

@end