#include <cstdlib>
#include <ctime>

#include "boost_timegm.h"
#include "fsfw/ipc/MutexGuard.h"
#include "fsfw/timemanager/Clock.h"

uint16_t Clock::leapSeconds = 0;
MutexIF* Clock::timeMutex = nullptr;
bool Clock::leapSecondsSet = false;

ReturnValue_t Clock::convertUTCToTT(timeval utc, timeval* tt) {
  uint16_t leapSeconds;
  ReturnValue_t result = getLeapSeconds(&leapSeconds);
  if (result != returnvalue::OK) {
    return result;
  }
  timeval leapSeconds_timeval = {0, 0};
  leapSeconds_timeval.tv_sec = leapSeconds;

  // initial offset between UTC and TAI
  timeval UTCtoTAI1972 = {10, 0};

  timeval TAItoTT = {32, 184000};

  *tt = utc + leapSeconds_timeval + UTCtoTAI1972 + TAItoTT;

  return returnvalue::OK;
}

ReturnValue_t Clock::setLeapSeconds(const uint16_t leapSeconds_) {
  if (checkOrCreateClockMutex() != returnvalue::OK) {
    return returnvalue::FAILED;
  }
  MutexGuard helper(timeMutex);

  leapSeconds = leapSeconds_;
  leapSecondsSet = true;

  return returnvalue::OK;
}

ReturnValue_t Clock::getLeapSeconds(uint16_t* leapSeconds_) {
  if (not leapSecondsSet) {
    return returnvalue::FAILED;
  }
  if (checkOrCreateClockMutex() != returnvalue::OK) {
    return returnvalue::FAILED;
  }
  MutexGuard helper(timeMutex);

  *leapSeconds_ = leapSeconds;

  return returnvalue::OK;
}

ReturnValue_t Clock::convertTimevalToTimeOfDay(const timeval* from, TimeOfDay_t* to) {
  struct tm time_tm;
  // WINDOWS does not provide gmtime_r, but gmtime_s
#ifdef _MSC_VER
  time_t seconds = from->tv_sec;
  errno_t result = gmtime_s(&time_tm, &seconds);
  if (result != 0) {
    return returnvalue::FAILED;
  }
#else
  void* result = gmtime_r(&from->tv_sec, &time_tm);

  if (result == nullptr) {
    return returnvalue::FAILED;
  }
#endif

  to->year = time_tm.tm_year + 1900;
  to->month = time_tm.tm_mon + 1;
  to->day = time_tm.tm_mday;
  to->hour = time_tm.tm_hour;
  to->minute = time_tm.tm_min;
  to->second = time_tm.tm_sec;
  to->usecond = from->tv_usec;
  return returnvalue::OK;
}

ReturnValue_t Clock::convertTimeOfDayToTimeval(const TimeOfDay_t* from, timeval* to) {
  struct tm time_tm = {};

  time_tm.tm_year = from->year - 1900;
  time_tm.tm_mon = from->month - 1;
  time_tm.tm_mday = from->day;

  time_tm.tm_hour = from->hour;
  time_tm.tm_min = from->minute;
  time_tm.tm_sec = from->second;

  time_tm.tm_isdst = 0;

  time_t seconds = internal_timegm(&time_tm);

  to->tv_sec = seconds;
  to->tv_usec = from->usecond;

  return returnvalue::OK;
}

ReturnValue_t Clock::convertTimevalToJD2000(timeval time, double* JD2000) {
  *JD2000 = (time.tv_sec - 946728000. + time.tv_usec / 1000000.) / 24. / 3600.;
  return returnvalue::OK;
}

ReturnValue_t Clock::checkOrCreateClockMutex() {
  if (timeMutex == nullptr) {
    MutexFactory* mutexFactory = MutexFactory::instance();
    if (mutexFactory == nullptr) {
      return returnvalue::FAILED;
    }
    timeMutex = mutexFactory->createMutex();
    if (timeMutex == nullptr) {
      return returnvalue::FAILED;
    }
  }
  return returnvalue::OK;
}

ReturnValue_t Clock::getDateAndTime(TimeOfDay_t* time) {
  timeval time_timeval;
  ReturnValue_t result = getClock_timeval(&time_timeval);
  if (result != returnvalue::OK) {
    return result;
  }
  return convertTimevalToTimeOfDay(&time_timeval, time);
}

ReturnValue_t Clock::getClock_usecs(uint64_t* time) {
  timeval timeVal{};
  ReturnValue_t result = getClock_timeval(&timeVal);
  if (result != returnvalue::OK) {
    return result;
  }
  *time = static_cast<uint64_t>(timeVal.tv_sec) * 1e6 + timeVal.tv_usec;

  return returnvalue::OK;
}

ReturnValue_t Clock::setClock(const TimeOfDay_t* time) {
  timeval timeTimeval{};
  ReturnValue_t result = convertTimeOfDayToTimeval(time, &timeTimeval);
  if (result != returnvalue::OK) {
    return result;
  }
  return setClock(&timeTimeval);
}
uint32_t Clock::getUptime_ms() {
  timeval uptime = getUptime();
  // TODO verify that overflow is correct
  return uptime.tv_sec * 1e3 + uptime.tv_usec / 1e3;
}