#include "VideoPlayoutScheduler.h"

#include <cmath>
#include <iostream>

namespace
{
int gFailures = 0;

void Expect(bool condition, const char* message)
{
	if (condition)
		return;

	std::cerr << "FAIL: " << message << "\n";
	++gFailures;
}

void ExpectNear(double actual, double expected, double tolerance, const char* message)
{
	Expect(std::fabs(actual - expected) <= tolerance, message);
}

void TestScheduleAdvancesFromZero()
{
	VideoPlayoutScheduler scheduler;
	scheduler.Configure(1001, 60000);

	const VideoIOScheduleTime first = scheduler.NextScheduleTime();
	const VideoIOScheduleTime second = scheduler.NextScheduleTime();
	const VideoIOScheduleTime third = scheduler.NextScheduleTime();

	Expect(first.streamTime == 0, "first frame starts at stream time zero");
	Expect(first.duration == 1001, "duration is preserved");
	Expect(first.timeScale == 60000, "time scale is preserved");
	Expect(second.streamTime == 1001, "second frame advances by one duration");
	Expect(third.streamTime == 2002, "third frame advances by two durations");
}

void TestLateAndDroppedSkipAhead()
{
	VideoPlayoutScheduler scheduler;
	scheduler.Configure(1000, 50000);

	(void)scheduler.NextScheduleTime();
	scheduler.AccountForCompletionResult(VideoIOCompletionResult::DisplayedLate);
	Expect(scheduler.NextScheduleTime().streamTime == 3000, "late completion preserves the existing two-frame skip policy");

	scheduler.AccountForCompletionResult(VideoIOCompletionResult::Dropped);
	Expect(scheduler.NextScheduleTime().streamTime == 6000, "dropped completion preserves the existing two-frame skip policy");
}

void TestFrameBudgets()
{
	VideoPlayoutScheduler scheduler;
	scheduler.Configure(1000, 50000);
	ExpectNear(scheduler.FrameBudgetMilliseconds(), 20.0, 0.0001, "50 fps budget");

	scheduler.Configure(1001, 60000);
	ExpectNear(scheduler.FrameBudgetMilliseconds(), 16.6833, 0.0001, "59.94 fps budget");

	scheduler.Configure(1, 60);
	ExpectNear(scheduler.FrameBudgetMilliseconds(), 16.6667, 0.0001, "60 fps budget");
}
}

int main()
{
	TestScheduleAdvancesFromZero();
	TestLateAndDroppedSkipAhead();
	TestFrameBudgets();

	if (gFailures != 0)
	{
		std::cerr << gFailures << " VideoPlayoutScheduler test failure(s).\n";
		return 1;
	}

	std::cout << "VideoPlayoutScheduler tests passed.\n";
	return 0;
}