#include "RenderSnapshotBuilder.h"

#include "RuntimeClock.h"
#include "RuntimeParameterUtils.h"
#include "RuntimeStore.h"
#include "ShaderCompiler.h"

#include <algorithm>
#include <chrono>
#include <filesystem>
#include <mutex>
#include <utility>

RenderSnapshotBuilder::RenderSnapshotBuilder(RuntimeStore& runtimeStore) :
	mRuntimeStore(runtimeStore)
{
}

bool RenderSnapshotBuilder::BuildLayerPassFragmentShaderSources(const std::string& layerId, std::vector<ShaderPassBuildSource>& passSources, std::string& error) const
{
	try
	{
		ShaderPackage shaderPackage;
		if (!mRuntimeStore.CopyShaderPackageForStoredLayer(layerId, shaderPackage, error))
			return false;

		std::filesystem::path repoRoot;
		std::filesystem::path wrapperPath;
		std::filesystem::path generatedGlslPath;
		std::filesystem::path patchedGlslPath;
		unsigned maxTemporalHistoryFrames = 0;
		mRuntimeStore.GetShaderCompilerInputs(repoRoot, wrapperPath, generatedGlslPath, patchedGlslPath, maxTemporalHistoryFrames);

		ShaderCompiler compiler(
			repoRoot,
			wrapperPath,
			generatedGlslPath,
			patchedGlslPath,
			maxTemporalHistoryFrames);
		passSources.clear();
		passSources.reserve(shaderPackage.passes.size());
		for (const ShaderPassDefinition& pass : shaderPackage.passes)
		{
			ShaderPassBuildSource passSource;
			passSource.passId = pass.id;
			passSource.inputNames = pass.inputNames;
			passSource.outputName = pass.outputName;
			if (!compiler.BuildPassFragmentShaderSource(shaderPackage, pass, passSource.fragmentShaderSource, error))
				return false;
			passSources.push_back(std::move(passSource));
		}
		return true;
	}
	catch (const std::exception& exception)
	{
		error = std::string("RenderSnapshotBuilder::BuildLayerPassFragmentShaderSources exception: ") + exception.what();
		return false;
	}
	catch (...)
	{
		error = "RenderSnapshotBuilder::BuildLayerPassFragmentShaderSources threw a non-standard exception.";
		return false;
	}
}

unsigned RenderSnapshotBuilder::GetMaxTemporalHistoryFrames() const
{
	return mRuntimeStore.GetConfiguredMaxTemporalHistoryFrames();
}

RuntimeSnapshotVersions RenderSnapshotBuilder::GetVersions() const
{
	RuntimeSnapshotVersions versions;
	versions.renderStateVersion = mRenderStateVersion.load(std::memory_order_relaxed);
	versions.parameterStateVersion = mParameterStateVersion.load(std::memory_order_relaxed);
	return versions;
}

void RenderSnapshotBuilder::AdvanceFrame()
{
	++mFrameCounter;
}

void RenderSnapshotBuilder::BuildLayerRenderStates(unsigned outputWidth, unsigned outputHeight, std::vector<RuntimeRenderState>& states) const
{
	std::lock_guard<std::mutex> lock(mRuntimeStore.mMutex);
	BuildLayerRenderStatesLocked(outputWidth, outputHeight, states);
}

bool RenderSnapshotBuilder::TryBuildLayerRenderStates(unsigned outputWidth, unsigned outputHeight, std::vector<RuntimeRenderState>& states) const
{
	std::unique_lock<std::mutex> lock(mRuntimeStore.mMutex, std::try_to_lock);
	if (!lock.owns_lock())
		return false;

	BuildLayerRenderStatesLocked(outputWidth, outputHeight, states);
	return true;
}

bool RenderSnapshotBuilder::TryRefreshLayerParameters(std::vector<RuntimeRenderState>& states) const
{
	std::unique_lock<std::mutex> lock(mRuntimeStore.mMutex, std::try_to_lock);
	if (!lock.owns_lock())
		return false;

	RefreshLayerParametersLocked(states);
	return true;
}

void RenderSnapshotBuilder::RefreshDynamicRenderStateFields(std::vector<RuntimeRenderState>& states) const
{
	std::lock_guard<std::mutex> lock(mRuntimeStore.mMutex);
	RefreshDynamicRenderStateFieldsLocked(states);
}

void RenderSnapshotBuilder::MarkRenderStateDirty()
{
	mRenderStateVersion.fetch_add(1, std::memory_order_relaxed);
	mParameterStateVersion.fetch_add(1, std::memory_order_relaxed);
}

void RenderSnapshotBuilder::MarkParameterStateDirty()
{
	mParameterStateVersion.fetch_add(1, std::memory_order_relaxed);
}

void RenderSnapshotBuilder::BuildLayerRenderStatesLocked(unsigned outputWidth, unsigned outputHeight, std::vector<RuntimeRenderState>& states) const
{
	states.clear();
	const HealthTelemetry::SignalStatusSnapshot signalStatus = mRuntimeStore.mHealthTelemetry.GetSignalStatusSnapshot();

	for (const RuntimeStore::LayerPersistentState& layer : mRuntimeStore.mLayerStack.Layers())
	{
		const ShaderPackage* shaderPackage = mRuntimeStore.mShaderCatalog.FindPackage(layer.shaderId);
		if (!shaderPackage)
			continue;

		RuntimeRenderState state;
		state.layerId = layer.id;
		state.shaderId = layer.shaderId;
		state.shaderName = shaderPackage->displayName;
		state.mixAmount = 1.0;
		state.bypass = layer.bypass ? 1.0 : 0.0;
		state.inputWidth = signalStatus.width;
		state.inputHeight = signalStatus.height;
		state.outputWidth = outputWidth;
		state.outputHeight = outputHeight;
		state.parameterDefinitions = shaderPackage->parameters;
		state.textureAssets = shaderPackage->textureAssets;
		state.fontAssets = shaderPackage->fontAssets;
		state.isTemporal = shaderPackage->temporal.enabled;
		state.temporalHistorySource = shaderPackage->temporal.historySource;
		state.requestedTemporalHistoryLength = shaderPackage->temporal.requestedHistoryLength;
		state.effectiveTemporalHistoryLength = shaderPackage->temporal.effectiveHistoryLength;
		state.feedback = shaderPackage->feedback;

		for (const ShaderParameterDefinition& definition : shaderPackage->parameters)
		{
			ShaderParameterValue value = DefaultValueForDefinition(definition);
			auto valueIt = layer.parameterValues.find(definition.id);
			if (valueIt != layer.parameterValues.end())
				value = valueIt->second;
			state.parameterValues[definition.id] = value;
		}

		states.push_back(state);
	}

	RefreshDynamicRenderStateFieldsLocked(states);
}

void RenderSnapshotBuilder::RefreshLayerParametersLocked(std::vector<RuntimeRenderState>& states) const
{
	for (RuntimeRenderState& state : states)
	{
		const auto layerIt = std::find_if(mRuntimeStore.mLayerStack.Layers().begin(), mRuntimeStore.mLayerStack.Layers().end(),
			[&state](const RuntimeStore::LayerPersistentState& layer) { return layer.id == state.layerId; });
		if (layerIt == mRuntimeStore.mLayerStack.Layers().end())
			continue;

		state.bypass = layerIt->bypass ? 1.0 : 0.0;
		state.parameterValues.clear();
		for (const ShaderParameterDefinition& definition : state.parameterDefinitions)
		{
			ShaderParameterValue value = DefaultValueForDefinition(definition);
			auto valueIt = layerIt->parameterValues.find(definition.id);
			if (valueIt != layerIt->parameterValues.end())
				value = valueIt->second;
			state.parameterValues[definition.id] = value;
		}
	}
}

void RenderSnapshotBuilder::RefreshDynamicRenderStateFieldsLocked(std::vector<RuntimeRenderState>& states) const
{
	const RuntimeClockSnapshot clock = GetRuntimeClockSnapshot();
	const double timeSeconds = std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::steady_clock::now() - mRuntimeStore.mStartTime).count();
	const double frameCount = static_cast<double>(mFrameCounter.load(std::memory_order_relaxed));

	for (RuntimeRenderState& state : states)
	{
		state.timeSeconds = timeSeconds;
		state.utcTimeSeconds = clock.utcTimeSeconds;
		state.utcOffsetSeconds = clock.utcOffsetSeconds;
		state.startupRandom = mRuntimeStore.mStartupRandom;
		state.frameCount = frameCount;
	}
}