#include "SystemFrameExchange.h"

#include <chrono>
#include <cstdint>
#include <iostream>

namespace
{
int gFailures = 0;

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

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

SystemFrameExchangeConfig MakeConfig(std::size_t capacity = 2)
{
	SystemFrameExchangeConfig config;
	config.width = 4;
	config.height = 3;
	config.pixelFormat = VideoIOPixelFormat::Bgra8;
	config.capacity = capacity;
	return config;
}

SystemFrameExchangeConfig MakeBoundedCompletedConfig(std::size_t capacity = 4, std::size_t maxCompletedFrames = 2)
{
	SystemFrameExchangeConfig config = MakeConfig(capacity);
	config.maxCompletedFrames = maxCompletedFrames;
	return config;
}

void TestAcquirePublishesAndSchedules()
{
	SystemFrameExchange exchange(MakeConfig(1));

	SystemFrame frame;
	Expect(exchange.AcquireForRender(frame), "frame can be acquired for render");
	Expect(frame.bytes != nullptr, "acquired frame has storage");
	Expect(frame.width == 4, "frame width is configured");
	Expect(frame.height == 3, "frame height is configured");
	Expect(frame.rowBytes == 16, "BGRA8 row bytes are inferred");
	Expect(frame.pixelFormat == VideoIOPixelFormat::Bgra8, "pixel format is configured");

	frame.frameIndex = 42;
	Expect(exchange.PublishCompleted(frame), "rendering frame can be completed");
	Expect(exchange.WaitForCompletedDepth(1, std::chrono::milliseconds(0)), "completed depth can be observed");

	SystemFrame scheduled;
	Expect(exchange.ConsumeCompletedForSchedule(scheduled), "completed frame can be scheduled");
	Expect(scheduled.index == frame.index, "scheduled frame uses completed slot");
	Expect(scheduled.generation == frame.generation, "scheduled frame keeps generation");
	Expect(scheduled.frameIndex == 42, "frame index is preserved");

	Expect(exchange.ReleaseScheduledByBytes(scheduled.bytes), "scheduled frame can be released by bytes");

	SystemFrameExchangeMetrics metrics = exchange.Metrics();
	Expect(metrics.freeCount == 1, "released slot returns to free");
	Expect(metrics.completedFrames == 1, "completed metric is counted");
	Expect(metrics.scheduledFrames == 1, "scheduled metric is counted");
}

void TestAcquirePreservesCompletedFrames()
{
	SystemFrameExchange exchange(MakeConfig(2));

	SystemFrame first;
	SystemFrame second;
	SystemFrame third;
	Expect(exchange.AcquireForRender(first), "first preserving frame can be acquired");
	first.frameIndex = 1;
	Expect(exchange.PublishCompleted(first), "first preserving frame can be completed");
	Expect(exchange.AcquireForRender(second), "second preserving frame can be acquired");
	second.frameIndex = 2;
	Expect(exchange.PublishCompleted(second), "second preserving frame can be completed");

	Expect(!exchange.AcquireForRender(third), "render acquire refuses to drop completed frames");

	SystemFrame scheduled;
	Expect(exchange.ConsumeCompletedForSchedule(scheduled), "oldest completed frame survives acquire miss");
	Expect(scheduled.frameIndex == 1, "preserving acquire keeps FIFO output continuity");

	SystemFrameExchangeMetrics metrics = exchange.Metrics();
	Expect(metrics.completedDrops == 0, "preserving acquire does not count completed drops");
	Expect(metrics.acquireMisses == 1, "preserving acquire miss is counted");
}

void TestCompletedReserveIsBoundedFifo()
{
	SystemFrameExchange exchange(MakeBoundedCompletedConfig(4, 2));

	for (uint64_t frameIndex = 1; frameIndex <= 3; ++frameIndex)
	{
		SystemFrame frame;
		Expect(exchange.AcquireForRender(frame), "bounded reserve frame can be acquired");
		frame.frameIndex = frameIndex;
		Expect(exchange.PublishCompleted(frame), "bounded reserve frame can be completed");
	}

	SystemFrame firstScheduled;
	Expect(exchange.ConsumeCompletedForSchedule(firstScheduled), "bounded reserve oldest retained frame can be scheduled");
	Expect(firstScheduled.frameIndex == 2, "bounded reserve drops oldest overflow and keeps FIFO order");

	SystemFrame secondScheduled;
	Expect(exchange.ConsumeCompletedForSchedule(secondScheduled), "bounded reserve second retained frame can be scheduled");
	Expect(secondScheduled.frameIndex == 3, "bounded reserve schedules next retained frame");

	SystemFrameExchangeMetrics metrics = exchange.Metrics();
	Expect(metrics.completedDrops == 1, "bounded completed reserve records oldest overflow drop");
	Expect(metrics.scheduledFrames == 2, "bounded reserve schedules retained frames");
}

void TestScheduledFramesAreNotDropped()
{
	SystemFrameExchange exchange(MakeConfig(1));

	SystemFrame frame;
	Expect(exchange.AcquireForRender(frame), "single frame can be acquired");
	Expect(exchange.PublishCompleted(frame), "single frame can be completed");

	SystemFrame scheduled;
	Expect(exchange.ConsumeCompletedForSchedule(scheduled), "single frame can be scheduled");

	SystemFrame extra;
	Expect(!exchange.AcquireForRender(extra), "scheduled frame is not dropped for render acquire");

	SystemFrameExchangeMetrics metrics = exchange.Metrics();
	Expect(metrics.acquireMisses == 1, "blocked acquire miss is counted");
	Expect(metrics.completedDrops == 0, "scheduled frame is not counted as a completed drop");
}

void TestGenerationValidationRejectsStaleFrames()
{
	SystemFrameExchange exchange(MakeConfig(1));

	SystemFrame first;
	Expect(exchange.AcquireForRender(first), "frame can be acquired");
	Expect(exchange.PublishCompleted(first), "frame can be completed");

	SystemFrame scheduled;
	Expect(exchange.ConsumeCompletedForSchedule(scheduled), "frame can be scheduled");
	Expect(exchange.ReleaseScheduledByBytes(scheduled.bytes), "frame can be released");

	SystemFrame second;
	Expect(exchange.AcquireForRender(second), "slot can be reacquired");
	Expect(second.index == first.index, "same slot is reused");
	Expect(second.generation != first.generation, "reacquire invalidates stale generation");
	Expect(!exchange.PublishCompleted(first), "stale frame cannot be completed");
}

void TestPixelFormatAwareSizing()
{
	SystemFrameExchangeConfig config;
	config.width = 7;
	config.height = 2;
	config.pixelFormat = VideoIOPixelFormat::V210;
	config.capacity = 1;

	SystemFrameExchange exchange(config);
	SystemFrame frame;
	Expect(exchange.AcquireForRender(frame), "v210 frame can be acquired");
	Expect(frame.pixelFormat == VideoIOPixelFormat::V210, "v210 pixel format is preserved");
	Expect(frame.rowBytes == static_cast<long>(VideoIORowBytes(VideoIOPixelFormat::V210, 7)), "v210 row bytes are inferred");

	config.pixelFormat = VideoIOPixelFormat::Uyvy8;
	config.rowBytes = 64;
	exchange.Configure(config);
	Expect(exchange.AcquireForRender(frame), "explicit row-byte frame can be acquired");
	Expect(frame.pixelFormat == VideoIOPixelFormat::Uyvy8, "reconfigured pixel format is preserved");
	Expect(frame.rowBytes == 64, "explicit row bytes are preserved");
}

void TestCompletedPollMissIsCounted()
{
	SystemFrameExchange exchange(MakeConfig(1));
	SystemFrame frame;
	Expect(!exchange.ConsumeCompletedForSchedule(frame), "empty completed queue cannot be consumed");

	SystemFrameExchangeMetrics metrics = exchange.Metrics();
	Expect(metrics.completedPollMisses == 1, "completed poll miss is counted");
}

void TestStableCompletedDepthCanBeObserved()
{
	SystemFrameExchange exchange(MakeConfig(1));
	SystemFrame frame;
	Expect(exchange.AcquireForRender(frame), "stable-depth frame can be acquired");
	Expect(exchange.PublishCompleted(frame), "stable-depth frame can be completed");

	Expect(
		exchange.WaitForStableCompletedDepth(1, std::chrono::milliseconds(1), std::chrono::milliseconds(50)),
		"stable completed depth can be observed");
}

void TestStableCompletedDepthTimesOut()
{
	SystemFrameExchange exchange(MakeConfig(1));
	Expect(
		!exchange.WaitForStableCompletedDepth(1, std::chrono::milliseconds(1), std::chrono::milliseconds(1)),
		"missing stable completed depth times out");
}
}

int main()
{
	TestAcquirePublishesAndSchedules();
	TestAcquirePreservesCompletedFrames();
	TestCompletedReserveIsBoundedFifo();
	TestScheduledFramesAreNotDropped();
	TestGenerationValidationRejectsStaleFrames();
	TestPixelFormatAwareSizing();
	TestCompletedPollMissIsCounted();
	TestStableCompletedDepthCanBeObserved();
	TestStableCompletedDepthTimesOut();

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

	std::cout << "RenderCadenceCompositor frame exchange tests passed.\n";
	return 0;
}