/* bzflag
 * Copyright (c) 1993-2017 Tim Riker
 *
 * This package is free software;  you can redistribute it and/or
 * modify it under the terms of the license found in the file
 * named COPYING that should have accompanied this file.
 *
 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/* interface header */
#include "TimeKeeper.h"

/* system implementation headers */
#include <time.h>
#include <string>
#include <string.h>
#ifdef HAVE_UNISTD_H
#  include <unistd.h>
#endif
#ifdef __BEOS__
#  include <OS.h>
#endif
#if !defined(_WIN32)
#  include <sys/time.h>
#  include <sys/types.h>
static struct timeval	lastTime = { 0, 0 };
#else /* !defined(_WIN32) */
#  include <mmsystem.h>
static unsigned long int	lastTime = 0;
static LARGE_INTEGER	qpcLastTime;
static LONGLONG		qpcFrequency = 0;
static LONGLONG	 qpcLastCalibration;
static DWORD	    timeLastCalibration;
#endif /* !defined(_WIN32) */

/* common implementation headers */
#include "TextUtils.h"
#include "bzfio.h"


TimeKeeper TimeKeeper::currentTime;
TimeKeeper TimeKeeper::tickTime;
TimeKeeper TimeKeeper::sunExplodeTime;
TimeKeeper TimeKeeper::sunGenesisTime;
TimeKeeper TimeKeeper::nullTime;
TimeKeeper TimeKeeper::startTime = TimeKeeper::getCurrent();

const TimeKeeper&	TimeKeeper::getCurrent(void)
{
  // if not first call then update current time, else use default initial time
#if !defined(_WIN32)
  if (lastTime.tv_sec != 0) {
    struct timeval now;
    gettimeofday(&now, NULL);
    currentTime += double(now.tv_sec - lastTime.tv_sec) +
		1.0e-6 * double(now.tv_usec - lastTime.tv_usec);
    lastTime = now;
  }
  else {
    gettimeofday(&lastTime, NULL);
  }
#else /* !defined(_WIN32) */
  if (qpcFrequency != 0) {

    // main timer is qpc
    LARGE_INTEGER now;
    QueryPerformanceCounter(&now);

    LONGLONG diff     = now.QuadPart - qpcLastTime.QuadPart;
    LONGLONG clkSpent = now.QuadPart - qpcLastCalibration;

    if (clkSpent > qpcFrequency) {
      // Recalibrate Frequency
      DWORD tgt	   = timeGetTime();
      DWORD deltaTgt      = tgt - timeLastCalibration;
      timeLastCalibration = tgt;
      qpcLastCalibration  = now.QuadPart;
      if (deltaTgt > 0) {
	LONGLONG oldqpcfreq = qpcFrequency;
	qpcFrequency	= (clkSpent * 1000) / deltaTgt;
	if (qpcFrequency != oldqpcfreq)
	  logDebugMessage(4,"Recalibrated QPC frequency.  Old: %f ; New: %f\n",
		 (double)oldqpcfreq, (double)qpcFrequency);
      }
    }

    currentTime += (double) diff / (double) qpcFrequency;
    qpcLastTime = now;
  } else if (lastTime != 0) {
    unsigned long int now = (unsigned long int)timeGetTime();
    unsigned long int diff;
    if (now <= lastTime) {
      // eh, how'd we go back in time?
      diff = 0;
    } else {
      diff = now - lastTime;
    }
    currentTime += 1.0e-3 * (double)diff;
    lastTime = now;
  } else {
    static bool sane = true;

    // should only get into here once on app start
    if (!sane) {
      logDebugMessage(1,"Sanity check failure in TimeKeeper::getCurrent()\n");
    }
    sane = false;

    LARGE_INTEGER freq;
    if (QueryPerformanceFrequency(&freq)) {
      QueryPerformanceCounter(&qpcLastTime);
      qpcFrequency	= freq.QuadPart;
      logDebugMessage(4,"Actual reported QPC Frequency: %f\n", (double)qpcFrequency);
      qpcLastCalibration  = qpcLastTime.QuadPart;
      timeLastCalibration = timeGetTime();
    } else {
      logDebugMessage(1,"QueryPerformanceFrequency failed with error %d\n", GetLastError());

      // make sure we're at our best timer resolution possible
      timeBeginPeriod(1);

      lastTime = (unsigned long int)timeGetTime();
    }
  }
#endif /* !defined(_WIN32) */
  return currentTime;
}

const TimeKeeper&	TimeKeeper::getStartTime(void) // const
{
  return startTime;
}

const TimeKeeper&	TimeKeeper::getTick(void) // const
{
  return tickTime;
}

void			TimeKeeper::setTick(void)
{
  tickTime = getCurrent();
}

const TimeKeeper& TimeKeeper::getSunExplodeTime(void)
{
  sunExplodeTime.seconds = 10000.0 * 365 * 24 * 60 * 60;
  return sunExplodeTime;
}

const TimeKeeper& TimeKeeper::getSunGenesisTime(void)
{
  sunGenesisTime.seconds = -10000.0 * 365 * 24 * 60 * 60;
  return sunGenesisTime;
}

const TimeKeeper& TimeKeeper::getNullTime(void)
{
  nullTime.seconds = 0;
  return nullTime;
}

const char *TimeKeeper::timestamp(void) // const
{
  static char buffer[256]; // static, so that it doesn't vanish
  time_t tnow = time(0);
  struct tm *now = localtime(&tnow);
  now->tm_year += 1900;
  ++now->tm_mon;

  strncpy(buffer, TextUtils::format("%04d-%02d-%02d %02d:%02d:%02d",
		     now->tm_year, now->tm_mon, now->tm_mday,
		     now->tm_hour, now->tm_min, now->tm_sec).c_str(), 256);
  buffer[255] = '\0'; // safety

  return buffer;
}

void TimeKeeper::localTime(int *year, int *month, int* day, int* hour, int* min, int* sec, bool* dst) // const
{
	time_t tnow = time(0);
	struct tm *now = localtime(&tnow);
	now->tm_year += 1900;
	++now->tm_mon;

	if ( year )
		*year = now->tm_year;
	if ( month )
		*month = now->tm_mon;
	if ( day )
		*day = now->tm_mday;
	if ( hour )
		*hour = now->tm_hour;
	if ( min )
		*min = now->tm_min;
	if ( sec )
		*sec = now->tm_sec;
	if ( dst )
		*dst = now->tm_isdst != 0;
}


void TimeKeeper::UTCTime(int *year, int *month, int* day, int* wday,
		     int* hour, int* min, int* sec, bool* dst) // const
{
  time_t tnow = time(0);
  struct tm *now = gmtime(&tnow);
  now->tm_year += 1900;
  ++now->tm_mon;

  if (year)  { *year  = now->tm_year; }
  if (month) { *month = now->tm_mon;  }
  if (day)   { *day   = now->tm_mday; }
  if (wday)  { *wday  = now->tm_wday; }
  if (hour)  { *hour  = now->tm_hour; }
  if (min)   { *min   = now->tm_min;  }
  if (sec)   { *sec   = now->tm_sec;  }
  if (dst)   { *dst   = (now->tm_isdst != 0); }
}

// function for converting a float time (e.g. difference of two TimeKeepers)
// into an array of ints
void TimeKeeper::convertTime(double raw, long int convertedTimes[])
{
  long int day, hour, min, sec, remainder;
  static const int secondsInDay = 86400;

  sec = (long int)raw;
  day = sec / secondsInDay;
  remainder = sec - (day * secondsInDay);
  hour = remainder / 3600;
  remainder = sec - ((hour * 3600) + (day * secondsInDay));
  min = remainder / 60;
  remainder = sec - ((hour * 3600) + (day * secondsInDay) + (min * 60));
  sec = remainder;

  convertedTimes[0] = day;
  convertedTimes[1] = hour;
  convertedTimes[2] = min;
  convertedTimes[3] = sec;

  return;
}

// function for printing an array of ints representing a time
// as a human-readable string
const std::string TimeKeeper::printTime(long int timeValue[])
{
  std::string valueNames;
  char temp[20];

  if (timeValue[0] > 0) {
    snprintf(temp, 20, "%ld day%s", timeValue[0], timeValue[0] == 1 ? "" : "s");
    valueNames.append(temp);
  }
  if (timeValue[1] > 0) {
    if (timeValue[0] > 0) {
      valueNames.append(", ");
    }
    snprintf(temp, 20, "%ld hour%s", timeValue[1], timeValue[1] == 1 ? "" : "s");
    valueNames.append(temp);
  }
  if (timeValue[2] > 0) {
    if ((timeValue[1] > 0) || (timeValue[0] > 0)) {
      valueNames.append(", ");
    }
    snprintf(temp, 20, "%ld min%s", timeValue[2], timeValue[2] == 1 ? "" : "s");
    valueNames.append(temp);
  }
  if (timeValue[3] > 0) {
    if ((timeValue[2] > 0) || (timeValue[1] > 0) || (timeValue[0] > 0)) {
      valueNames.append(", ");
    }
    snprintf(temp, 20, "%ld sec%s", timeValue[3], timeValue[3] == 1 ? "" : "s");
    valueNames.append(temp);
  }

  return valueNames;
}

// function for printing a float time difference as a human-readable string
const std::string TimeKeeper::printTime(double diff)
{
  long int temp[4];
  convertTime(diff, temp);
  return printTime(temp);
}


void TimeKeeper::sleep(double seconds)
{
  if (seconds <= 0.0) {
    return;
  }

#ifdef HAVE_USLEEP
  usleep((unsigned int)(1.0e6 * seconds));
  return;
#endif
#if defined(HAVE_SLEEP) && !defined(__APPLE__)
  // equivalent to _sleep() on win32 (not sleep(3))
  Sleep((DWORD)(seconds * 1000.0));
  return;
#endif
#ifdef HAVE_SNOOZE
  snooze((bigtime_t)(1.0e6 * seconds));
  return;
#endif
#ifdef HAVE_SELECT
  struct timeval tv;
  tv.tv_sec = (long)seconds;
  tv.tv_usec = (long)(1.0e6 * (seconds - tv.tv_sec));
  select(0, NULL, NULL, NULL, &tv);
  return;
#endif
#ifdef HAVE_WAITFORSINGLEOBJECT
  HANDLE dummyEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
  WaitForSingleObject(dummyEvent, (DWORD)(1000.0 * seconds));
  CloseHandle(dummyEvent);
  return;
#endif

  // fall-back case is fugly manual timekeeping
  TimeKeeper now = TimeKeeper::getCurrent();
  while ((TimeKeeper::getCurrent() - now) < seconds) {
    continue;
  }
  return;
}


// Local Variables: ***
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