/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library 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 2.1 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#ifdef SDL_TIMER_WINCE

#define WIN32_LEAN_AND_MEAN

#include <windows.h>

#include <mmsystem.h>

#include "SDL_thread.h"

#include "SDL_timer.h"

#include "../SDL_timer_c.h"

static Uint64 start_date;

static Uint64 start_ticks;

static Uint64 wce_ticks(void)

{

  return((Uint64)GetTickCount());

}

static Uint64 wce_date(void)

{

  union

  {

	FILETIME ftime;

	Uint64 itime;

  } ftime;

  SYSTEMTIME stime;

  GetSystemTime(&stime);

  SystemTimeToFileTime(&stime,&ftime.ftime);

  ftime.itime/=10000; // Convert 100ns intervals to 1ms intervals

  // Remove ms portion, which can't be relied on

  ftime.itime -= (ftime.itime % 1000);

  return(ftime.itime);

}

static Sint32 wce_rel_ticks(void)

{

  return((Sint32)(wce_ticks()-start_ticks));

}

static Sint32 wce_rel_date(void)

{

  return((Sint32)(wce_date()-start_date));

}

/* Return time in ms relative to when SDL was started */

Uint32 SDL_GetTicks()

{

  Sint32 offset=wce_rel_date()-wce_rel_ticks();

  if((offset < -1000) || (offset > 1000))

  {

//    fprintf(stderr,"Time desync(%+d), resyncing\n",offset/1000);

	start_ticks-=offset;

  }

  return((Uint32)wce_rel_ticks());

}

/* Give up approx. givem milliseconds to the OS. */

void SDL_Delay(Uint32 ms)

{

  Sleep(ms);

}

/* Recard start-time of application for reference */

void SDL_StartTicks(void)

{

  start_date=wce_date();

  start_ticks=wce_ticks();

}

static UINT WIN_timer;

#if ( _WIN32_WCE <= 420 )

static HANDLE timersThread = 0;

static HANDLE timersQuitEvent = 0;

DWORD TimersThreadProc(void *data)

{

	while(WaitForSingleObject(timersQuitEvent, 10) == WAIT_TIMEOUT)

	{

		SDL_ThreadedTimerCheck();

	}

	return 0;

}

int SDL_SYS_TimerInit(void)

{

	// create a thread to process a threaded timers

	// SetTimer does not suit the needs because 

	// TimerCallbackProc will be called only when WM_TIMER occured

	timersQuitEvent = CreateEvent(0, TRUE, FALSE, 0);

	if( !timersQuitEvent )

	{

		SDL_SetError("Cannot create event for timers thread");

		return -1;

	}

	timersThread = CreateThread(NULL, 0, TimersThreadProc, 0, 0, 0);

	if( !timersThread )

	{

		SDL_SetError("Cannot create timers thread, check amount of RAM available");

		return -1;

	}

	SetThreadPriority(timersThread, THREAD_PRIORITY_HIGHEST);

	return(SDL_SetTimerThreaded(1));

}

void SDL_SYS_TimerQuit(void)

{

	SetEvent(timersQuitEvent);

	if( WaitForSingleObject(timersThread, 2000) == WAIT_TIMEOUT )

		TerminateThread(timersThread, 0);

	CloseHandle(timersThread);

	CloseHandle(timersQuitEvent);

	return;

}

#else

#pragma comment(lib, "mmtimer.lib")

/* Data to handle a single periodic alarm */

static UINT timerID = 0;

static void CALLBACK HandleAlarm(UINT uID,  UINT uMsg, DWORD dwUser,

						DWORD dw1, DWORD dw2)

{

	SDL_ThreadedTimerCheck();

}

int SDL_SYS_TimerInit(void)

{

	MMRESULT result;

	/* Set timer resolution */

	result = timeBeginPeriod(TIMER_RESOLUTION);

	if ( result != TIMERR_NOERROR ) {

		SDL_SetError("Warning: Can't set %d ms timer resolution",

							TIMER_RESOLUTION);

	}

	/* Allow 10 ms of drift so we don't chew on CPU */

	timerID = timeSetEvent(TIMER_RESOLUTION,1,HandleAlarm,0,TIME_PERIODIC);

	if ( ! timerID ) {

		SDL_SetError("timeSetEvent() failed");

		return(-1);

	}

	return(SDL_SetTimerThreaded(1));

}

void SDL_SYS_TimerQuit(void)

{

	if ( timerID ) {

		timeKillEvent(timerID);

	}

	timeEndPeriod(TIMER_RESOLUTION);

}

#endif

int SDL_SYS_StartTimer(void)

{

	SDL_SetError("Internal logic error: WinCE uses threaded timer");

	return(-1);

}

void SDL_SYS_StopTimer(void)

{

	return;

}

#endif /* SDL_TIMER_WINCE */