#include "RenderEngine.h"

#include <gl/gl.h>

#include <algorithm>

RenderEngine::RenderEngine(
	RuntimeSnapshotProvider& runtimeSnapshotProvider,
	HealthTelemetry& healthTelemetry,
	CRITICAL_SECTION& mutex,
	HDC hdc,
	HGLRC hglrc,
	RenderEffectCallback renderEffect,
	ScreenshotCallback screenshotReady,
	PreviewPaintCallback previewPaint) :
	mRenderer(),
	mRenderPass(mRenderer),
	mRenderPipeline(mRenderer, runtimeSnapshotProvider, healthTelemetry, std::move(renderEffect), std::move(screenshotReady), std::move(previewPaint)),
	mShaderPrograms(mRenderer, runtimeSnapshotProvider),
	mMutex(mutex),
	mHdc(hdc),
	mHglrc(hglrc),
	mFrameStateResolver(runtimeSnapshotProvider)
{
}

RenderEngine::~RenderEngine()
{
	mRenderer.DestroyResources();
}

bool RenderEngine::CompileDecodeShader(int errorMessageSize, char* errorMessage)
{
	return mShaderPrograms.CompileDecodeShader(errorMessageSize, errorMessage);
}

bool RenderEngine::CompileOutputPackShader(int errorMessageSize, char* errorMessage)
{
	return mShaderPrograms.CompileOutputPackShader(errorMessageSize, errorMessage);
}

bool RenderEngine::InitializeResources(
	unsigned inputFrameWidth,
	unsigned inputFrameHeight,
	unsigned captureTextureWidth,
	unsigned outputFrameWidth,
	unsigned outputFrameHeight,
	unsigned outputPackTextureWidth,
	std::string& error)
{
	return mRenderer.InitializeResources(
		inputFrameWidth,
		inputFrameHeight,
		captureTextureWidth,
		outputFrameWidth,
		outputFrameHeight,
		outputPackTextureWidth,
		error);
}

bool RenderEngine::CompileLayerPrograms(unsigned inputFrameWidth, unsigned inputFrameHeight, int errorMessageSize, char* errorMessage)
{
	return mShaderPrograms.CompileLayerPrograms(inputFrameWidth, inputFrameHeight, errorMessageSize, errorMessage);
}

bool RenderEngine::CommitPreparedLayerPrograms(const PreparedShaderBuild& preparedBuild, unsigned inputFrameWidth, unsigned inputFrameHeight, int errorMessageSize, char* errorMessage)
{
	return mShaderPrograms.CommitPreparedLayerPrograms(preparedBuild, inputFrameWidth, inputFrameHeight, errorMessageSize, errorMessage);
}

bool RenderEngine::ApplyPreparedShaderBuild(
	const PreparedShaderBuild& preparedBuild,
	unsigned inputFrameWidth,
	unsigned inputFrameHeight,
	bool preserveFeedbackState,
	int errorMessageSize,
	char* errorMessage)
{
	if (!CommitPreparedLayerPrograms(preparedBuild, inputFrameWidth, inputFrameHeight, errorMessageSize, errorMessage))
		return false;

	mFrameStateResolver.StoreCommittedSnapshot(preparedBuild.renderSnapshot, mShaderPrograms.CommittedLayerStates());
	ResetTemporalHistoryState();
	if (!preserveFeedbackState)
		ResetShaderFeedbackState();
	return true;
}

void RenderEngine::ResetTemporalHistoryState()
{
	mRenderCommandQueue.RequestRenderReset(RenderCommandResetScope::TemporalHistoryOnly);
	ProcessRenderResetCommandsOnRenderThread();
}

void RenderEngine::ResetShaderFeedbackState()
{
	mRenderCommandQueue.RequestRenderReset(RenderCommandResetScope::ShaderFeedbackOnly);
	ProcessRenderResetCommandsOnRenderThread();
}

void RenderEngine::ApplyRuntimeCoordinatorRenderReset(RuntimeCoordinatorRenderResetScope resetScope)
{
	switch (resetScope)
	{
	case RuntimeCoordinatorRenderResetScope::TemporalHistoryOnly:
		mRenderCommandQueue.RequestRenderReset(RenderCommandResetScope::TemporalHistoryOnly);
		ProcessRenderResetCommandsOnRenderThread();
		break;
	case RuntimeCoordinatorRenderResetScope::TemporalHistoryAndFeedback:
		mRenderCommandQueue.RequestRenderReset(RenderCommandResetScope::TemporalHistoryAndFeedback);
		ProcessRenderResetCommandsOnRenderThread();
		break;
	case RuntimeCoordinatorRenderResetScope::None:
	default:
		break;
	}
}

void RenderEngine::ResetTemporalHistoryStateOnRenderThread()
{
	mShaderPrograms.ResetTemporalHistoryState();
}

void RenderEngine::ResetShaderFeedbackStateOnRenderThread()
{
	mShaderPrograms.ResetShaderFeedbackState();
}

void RenderEngine::ApplyRenderResetOnRenderThread(RenderCommandResetScope resetScope)
{
	switch (resetScope)
	{
	case RenderCommandResetScope::ShaderFeedbackOnly:
		ResetShaderFeedbackStateOnRenderThread();
		break;
	case RenderCommandResetScope::TemporalHistoryOnly:
		ResetTemporalHistoryStateOnRenderThread();
		break;
	case RenderCommandResetScope::TemporalHistoryAndFeedback:
		ResetTemporalHistoryStateOnRenderThread();
		ResetShaderFeedbackStateOnRenderThread();
		break;
	case RenderCommandResetScope::None:
	default:
		break;
	}
}

void RenderEngine::ProcessRenderResetCommandsOnRenderThread()
{
	RenderCommandResetScope resetScope = RenderCommandResetScope::None;
	while (mRenderCommandQueue.TryTakeRenderReset(resetScope))
		ApplyRenderResetOnRenderThread(resetScope);
}

void RenderEngine::ClearOscOverlayState()
{
	mRuntimeLiveState.Clear();
}

void RenderEngine::UpdateOscOverlayState(
	const std::vector<OscOverlayUpdate>& updates,
	const std::vector<OscOverlayCommitCompletion>& completedCommits)
{
	std::vector<RuntimeLiveOscCommitCompletion> liveCompletions;
	liveCompletions.reserve(completedCommits.size());
	for (const OscOverlayCommitCompletion& completedCommit : completedCommits)
		liveCompletions.push_back({ completedCommit.routeKey, completedCommit.generation });
	mRuntimeLiveState.ApplyOscCommitCompletions(liveCompletions);

	std::vector<RuntimeLiveOscUpdate> liveUpdates;
	liveUpdates.reserve(updates.size());
	for (const OscOverlayUpdate& update : updates)
		liveUpdates.push_back({ update.routeKey, update.layerKey, update.parameterKey, update.targetValue });
	mRuntimeLiveState.ApplyOscUpdates(liveUpdates);
}

void RenderEngine::ResizeView(int width, int height)
{
	mRenderer.ResizeView(width, height);
}

bool RenderEngine::TryPresentPreview(bool force, unsigned previewFps, unsigned outputFrameWidth, unsigned outputFrameHeight)
{
	if (!force)
	{
		if (previewFps == 0)
			return false;

		const auto now = std::chrono::steady_clock::now();
		const auto minimumInterval = std::chrono::microseconds(1000000 / (previewFps == 0 ? 1u : previewFps));
		if (mLastPreviewPresentTime != std::chrono::steady_clock::time_point() &&
			now - mLastPreviewPresentTime < minimumInterval)
		{
			return false;
		}
	}

	if (!TryEnterCriticalSection(&mMutex))
		return false;

	mRenderCommandQueue.RequestPreviewPresent({ outputFrameWidth, outputFrameHeight });
	RenderPreviewPresentRequest request;
	const bool presented = mRenderCommandQueue.TryTakePreviewPresent(request) &&
		PresentPreviewOnRenderThread(request.outputFrameWidth, request.outputFrameHeight);
	LeaveCriticalSection(&mMutex);
	return presented;
}

bool RenderEngine::PresentPreviewOnRenderThread(unsigned outputFrameWidth, unsigned outputFrameHeight)
{
	mRenderer.PresentToWindow(mHdc, outputFrameWidth, outputFrameHeight);
	mLastPreviewPresentTime = std::chrono::steady_clock::now();
	return true;
}

bool RenderEngine::TryUploadInputFrame(const VideoIOFrame& inputFrame, const VideoIOState& videoState)
{
	if (inputFrame.hasNoInputSource || inputFrame.bytes == nullptr)
		return true;

	if (!TryEnterCriticalSection(&mMutex))
		return false;

	wglMakeCurrent(mHdc, mHglrc);
	const bool uploaded = UploadInputFrameOnRenderThread(inputFrame, videoState);
	wglMakeCurrent(NULL, NULL);
	LeaveCriticalSection(&mMutex);
	return uploaded;
}

bool RenderEngine::UploadInputFrameOnRenderThread(const VideoIOFrame& inputFrame, const VideoIOState& videoState)
{
	const long textureSize = inputFrame.rowBytes * static_cast<long>(inputFrame.height);
	glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
	glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, mRenderer.TextureUploadBuffer());
	glBufferData(GL_PIXEL_UNPACK_BUFFER, textureSize, inputFrame.bytes, GL_DYNAMIC_DRAW);
	glBindTexture(GL_TEXTURE_2D, mRenderer.CaptureTexture());
	if (inputFrame.pixelFormat == VideoIOPixelFormat::V210)
		glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, videoState.captureTextureWidth, videoState.inputFrameSize.height, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
	else
		glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, videoState.captureTextureWidth, videoState.inputFrameSize.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);
	glBindTexture(GL_TEXTURE_2D, 0);
	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);

	return true;
}

bool RenderEngine::RenderOutputFrame(const RenderPipelineFrameContext& context, VideoIOOutputFrame& outputFrame)
{
	EnterCriticalSection(&mMutex);
	wglMakeCurrent(mHdc, mHglrc);
	const bool rendered = RenderOutputFrameOnRenderThread(context, outputFrame);
	wglMakeCurrent(NULL, NULL);
	LeaveCriticalSection(&mMutex);
	return rendered;
}

bool RenderEngine::RenderOutputFrameOnRenderThread(const RenderPipelineFrameContext& context, VideoIOOutputFrame& outputFrame)
{
	ProcessRenderResetCommandsOnRenderThread();
	return mRenderPipeline.RenderFrame(context, outputFrame);
}

bool RenderEngine::ResolveRenderFrameState(
	const RenderFrameInput& input,
	std::vector<OscOverlayCommitRequest>* commitRequests,
	RenderFrameState& frameState)
{
	std::vector<RuntimeLiveOscCommitRequest> liveCommitRequests;
	const bool resolved = mFrameStateResolver.Resolve(
		input,
		mShaderPrograms.CommittedLayerStates(),
		mRuntimeLiveState,
		commitRequests ? &liveCommitRequests : nullptr,
		frameState);

	if (commitRequests)
	{
		for (const RuntimeLiveOscCommitRequest& request : liveCommitRequests)
			commitRequests->push_back({ request.routeKey, request.layerKey, request.parameterKey, request.value, request.generation });
	}
	return resolved;
}

void RenderEngine::RenderPreparedFrame(const RenderFrameState& frameState)
{
	RenderLayerStack(
		frameState.hasInputSource,
		frameState.layerStates,
		frameState.inputFrameWidth,
		frameState.inputFrameHeight,
		frameState.captureTextureWidth,
		frameState.inputPixelFormat,
		frameState.historyCap);
}

void RenderEngine::RenderLayerStack(
	bool hasInputSource,
	const std::vector<RuntimeRenderState>& layerStates,
	unsigned inputFrameWidth,
	unsigned inputFrameHeight,
	unsigned captureTextureWidth,
	VideoIOPixelFormat inputPixelFormat,
	unsigned historyCap)
{
	mRenderPass.Render(
		hasInputSource,
		layerStates,
		inputFrameWidth,
		inputFrameHeight,
		captureTextureWidth,
		inputPixelFormat,
		historyCap,
		[this](const RuntimeRenderState& state, OpenGLRenderer::LayerProgram::TextBinding& textBinding, std::string& error) {
			return mShaderPrograms.UpdateTextBindingTexture(state, textBinding, error);
		},
		[this](const RuntimeRenderState& state, unsigned availableSourceHistoryLength, unsigned availableTemporalHistoryLength, bool feedbackAvailable) {
			return mShaderPrograms.UpdateGlobalParamsBuffer(state, availableSourceHistoryLength, availableTemporalHistoryLength, feedbackAvailable);
		});
}

bool RenderEngine::ReadOutputFrameRgbaOnRenderThread(unsigned width, unsigned height, std::vector<unsigned char>& bottomUpPixels)
{
	if (width == 0 || height == 0)
		return false;

	bottomUpPixels.resize(static_cast<std::size_t>(width) * height * 4);
	glBindFramebuffer(GL_READ_FRAMEBUFFER, mRenderer.OutputFramebuffer());
	glReadBuffer(GL_COLOR_ATTACHMENT0);
	glPixelStorei(GL_PACK_ALIGNMENT, 1);
	glPixelStorei(GL_PACK_ROW_LENGTH, 0);
	glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, bottomUpPixels.data());
	glPixelStorei(GL_PACK_ALIGNMENT, 4);

	return true;
}

bool RenderEngine::CaptureOutputFrameRgbaTopDown(unsigned width, unsigned height, std::vector<unsigned char>& topDownPixels)
{
	EnterCriticalSection(&mMutex);
	wglMakeCurrent(mHdc, mHglrc);
	mRenderCommandQueue.RequestScreenshotCapture({ width, height });
	RenderScreenshotCaptureRequest request;
	const bool captured = mRenderCommandQueue.TryTakeScreenshotCapture(request) &&
		CaptureOutputFrameRgbaTopDownOnRenderThread(request.width, request.height, topDownPixels);
	wglMakeCurrent(NULL, NULL);
	LeaveCriticalSection(&mMutex);
	return captured;
}

bool RenderEngine::CaptureOutputFrameRgbaTopDownOnRenderThread(unsigned width, unsigned height, std::vector<unsigned char>& topDownPixels)
{
	std::vector<unsigned char> bottomUpPixels;
	if (!ReadOutputFrameRgbaOnRenderThread(width, height, bottomUpPixels))
		return false;

	topDownPixels.resize(bottomUpPixels.size());
	const std::size_t rowBytes = static_cast<std::size_t>(width) * 4;
	for (unsigned y = 0; y < height; ++y)
	{
		const unsigned sourceY = height - 1 - y;
		std::copy(
			bottomUpPixels.begin() + static_cast<std::ptrdiff_t>(sourceY * rowBytes),
			bottomUpPixels.begin() + static_cast<std::ptrdiff_t>((sourceY + 1) * rowBytes),
			topDownPixels.begin() + static_cast<std::ptrdiff_t>(y * rowBytes));
	}

	return true;
}