#include "CountdownTimerSDL.hpp"

CountdownTimerSDL::CountdownTimerSDL(unsigned frequency):
  mDesiredFrequency{frequency},
  mSDLFrequency{SDL_GetPerformanceFrequency()},
  mStartTime{0},
  mStartValue{0} {}

void CountdownTimerSDL::set(unsigned value) {
  mStartTime = SDL_GetPerformanceCounter();
  mStartValue = value;
}

unsigned CountdownTimerSDL::get() const {
  Uint64 elapsedTime = SDL_GetPerformanceCounter() - mStartTime;
  Uint64 elapsedTicks = (elapsedTime * mDesiredFrequency) / mSDLFrequency;
  return elapsedTicks >= mStartValue ? 0 : mStartValue - elapsedTicks;
}