/** Implementation of NSTimer for GNUstep
   Copyright (C) 1995, 1996, 1999 Free Software Foundation, Inc.
   
   Written by:  Andrew Kachites McCallum <mccallum@gnu.ai.mit.edu>
   Created: March 1996
   
   Rewrite by: Richard Frith-Macdonald <rfm@gnu.org>

   This file is part of the GNUstep Base 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; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA.

   <title>NSTimer class reference</title>
   $Date$ $Revision$
   */

#include <config.h>
#include <Foundation/NSTimer.h>
#include <Foundation/NSDate.h>
#include <Foundation/NSException.h>
#include <Foundation/NSRunLoop.h>
#include <Foundation/NSInvocation.h>

@class	NSGDate;
static Class	NSDate_class;

@implementation NSTimer

+ (void) initialize
{
  if (self == [NSTimer class])
    {
      NSDate_class = [NSGDate class];
    }
}

/**
 * <init />
 * Initialise the receive, a newly allocated NSTimer object.<br />
 * The fd argument specifies an initial fire date ... if it is not
 * supplied (a nil object) then the ti argument is used to create
 * a start date relative to the current time.<br />
 * The ti argument specifies the time (in seconds) between the firing.
 * If it is less than or equal to 0.0 then a small interval is chosen
 * automatically.<br />
 * The f argument specifies whether the timer will fire repeatedly
 * or just once.<br />
 * If the selector argument is zero, then then object is an invocation
 * to be used when the timer fires.  otherwise, the object is sent the
 * message specified by the selector and with the timer as an argument.<br />
 * The fd, object and info arguments will be retained until the timer is
 * invalidated.<br />
 */
- (id) initWithFireDate: (NSDate*)fd
	       interval: (NSTimeInterval)ti
		 target: (id)object
	       selector: (SEL)selector
	       userInfo: (id)info
		repeats: (BOOL)f
{
  if (ti <= 0)
    {
      ti = 0.0001;
    }
  _interval = ti;
  if (fd == nil)
    {
      _date = [[NSDate_class allocWithZone: NSDefaultMallocZone()]
        initWithTimeIntervalSinceReferenceDate: _interval];
    }
  else
    {
      _date = [fd copy];
    }
  _target = RETAIN(object);
  _selector = selector;
  _info = RETAIN(info);
  _repeats = f;
  return self;
}

/**
 * Create a timer wchich will fire after ti seconds and, if f is YES,
 * every ti seconds thereafter. On firing, invocation will be performed.<br />
 * NB. To make the timer operate, you must add it to a run loop.
 */
+ (NSTimer*) timerWithTimeInterval: (NSTimeInterval)ti
		        invocation: (NSInvocation*)invocation
			   repeats: (BOOL)f
{
  return AUTORELEASE([[self alloc] initWithFireDate: nil
					   interval: ti
					     target: invocation
					   selector: NULL
					   userInfo: nil
					    repeats: f]);
}

/**
 * Create a timer wchich will fire after ti seconds and, if f is YES,
 * every ti seconds thereafter. On firing, the target object will be
 * sent a message specified by selector and with the object info as an
 * argument.<br />
 * NB. To make the timer operate, you must add it to a run loop.
 */
+ (NSTimer*) timerWithTimeInterval: (NSTimeInterval)ti
			    target: (id)object
			  selector: (SEL)selector
			  userInfo: (id)info
			   repeats: (BOOL)f
{
  return AUTORELEASE([[self alloc] initWithFireDate: nil
					   interval: ti
					     target: object
					   selector: selector
					   userInfo: info
					    repeats: f]);
}

/**
 * Create a timer which will fire after ti seconds and, if f is YES,
 * every ti seconds thereafter. On firing, invocation will be performed.<br />
 * This timer will automatically be added to the current run loop and
 * will fire in the default run loop mode.
 */
+ (NSTimer*) scheduledTimerWithTimeInterval: (NSTimeInterval)ti
				 invocation: (NSInvocation*)invocation
				    repeats: (BOOL)f
{
  id t = [self timerWithTimeInterval: ti
	       invocation: invocation
	       repeats: f];
  [[NSRunLoop currentRunLoop] addTimer: t forMode: NSDefaultRunLoopMode];
  return t;
}

/**
 * Create a timer which will fire after ti seconds and, if f is YES,
 * every ti seconds thereafter. On firing, the target object will be
 * sent a message specified by selector and with the object info as an
 * argument.<br />
 * This timer will automatically be added to the current run loop and
 * will fire in the default run loop mode.
 */
+ (NSTimer*) scheduledTimerWithTimeInterval: (NSTimeInterval)ti
				     target: (id)object
				   selector: (SEL)selector
				   userInfo: (id)info
				    repeats: (BOOL)f
{
  id t = [self timerWithTimeInterval: ti
			      target: object
			    selector: selector
			    userInfo: info
			     repeats: f];
  [[NSRunLoop currentRunLoop] addTimer: t forMode: NSDefaultRunLoopMode];
  return t;
}

- (void) dealloc
{
  if (_invalidated == NO)
    {
      [self invalidate];
    }
  RELEASE(_date);
  [super dealloc];
}

/**
 * Fires the timer ... either performs an invocation or ssends a message
 * to a target object, depending on how the timer was set up.<br />
 * If the timer is not set to repeat, it is automatically invalidated.
 */
- (void) fire
{
  if (_selector == 0)
    {
      [(NSInvocation*)_target invoke];
    }
  else
    {
      [_target performSelector: _selector withObject: self];
    }

  if (_repeats == NO)
    {
      [self invalidate];
    }
  else if (_invalidated == NO)
    {
      NSTimeInterval	now = GSTimeNow();
      NSTimeInterval	nxt = [_date timeIntervalSinceReferenceDate];
      int		inc = -1;

      while (nxt <= now)		// xxx remove this
	{
	  inc++;
	  nxt += _interval;
	}
#ifdef	LOG_MISSED
      if (inc > 0)
	{
	  NSLog(@"Missed %d timeouts at %f second intervals", inc, _interval);
	}
#endif
      RELEASE(_date);
      _date = [[NSDate_class allocWithZone: NSDefaultMallocZone()]
	initWithTimeIntervalSinceReferenceDate: nxt];
    }
}

/**
 * Marks the timer as invalid, causing its target/invocation and user info
 * objects to be released.<br />
 * Invalidated timers are automatically removed from the run loop when it
 * detects them.
 */
- (void) invalidate
{
  if (_target != nil)
    {
      DESTROY(_target);
    }
  if (_info != nil)
    {
      DESTROY(_info);
    }
  /* OPENSTEP allows this method to be called multiple times. */
  //NSAssert(_invalidated == NO, NSInternalInconsistencyException);
  _invalidated = YES;
}

/**
 * Checks to see if the timer has been invalidated.
 */
- (BOOL) isValid
{
  if (_invalidated == NO)
    {
      return YES;
    }
  else
    {
      return NO;
    }
}

/**
 * Returns the date/time at which the timer is next due to fire.
 */
- (NSDate*) fireDate
{
  return _date;
}

/**
 * Change the fire date for the receiver.<br />
 * NB. You should <em>NOT</em> use this method for a timer which has
 * been added to a run loop.  The only time when it is safe to modify
 * the fire date of a timer in a run loop is for a repeating timer
 * when the timer is actually in the process of firing.
 */
- (void) setFireDate: (NSDate*)fireDate
{
  ASSIGN(_date, fireDate);
}

/**
 * Returns the interval beteen firings.
 */
- (NSTimeInterval) timeInterval
{
  return _interval;
}

/**
 * Returns the user info which was set for the timer when it was created,
 * or nil if none was set or the timer is invalid.
 */
- (id) userInfo
{
  return _info;
}

/**
 * Compares timers based on the date at which they should next fire.
 */
- (NSComparisonResult) compare: (NSTimer*)anotherTimer
{
  if (anotherTimer == self)
    {
      return NSOrderedSame;
    }
  else if (anotherTimer == nil)
    {
      [NSException raise: NSInvalidArgumentException
		  format: @"nil argument for compare:"];
    }
  else
    {
      return [_date compare: anotherTimer->_date];
    }
  return 0;
}

@end