#include "RuntimeStore.h"

#include "RuntimeStatePresenter.h"

#include <cctype>
#include <fstream>
#include <mutex>
#include <random>
#include <sstream>
#include <windows.h>

namespace
{
std::string ToLowerCopy(std::string text)
{
	std::transform(text.begin(), text.end(), text.begin(),
		[](unsigned char ch) { return static_cast<char>(std::tolower(ch)); });
	return text;
}

double GenerateStartupRandom()
{
	std::random_device randomDevice;
	std::uniform_real_distribution<double> distribution(0.0, 1.0);
	return distribution(randomDevice);
}

}

RuntimeStore::RuntimeStore() :
	mRenderSnapshotBuilder(*this),
	mHealthTelemetry(),
	mReloadRequested(false),
	mCompileSucceeded(false),
	mStartupRandom(GenerateStartupRandom()),
	mServerPort(8080),
	mAutoReloadEnabled(true),
	mStartTime(std::chrono::steady_clock::now()),
	mLastScanTime((std::chrono::steady_clock::time_point::min)())
{
}

HealthTelemetry& RuntimeStore::GetHealthTelemetry()
{
	return mHealthTelemetry;
}

const HealthTelemetry& RuntimeStore::GetHealthTelemetry() const
{
	return mHealthTelemetry;
}

RenderSnapshotBuilder& RuntimeStore::GetRenderSnapshotBuilder()
{
	return mRenderSnapshotBuilder;
}

const RenderSnapshotBuilder& RuntimeStore::GetRenderSnapshotBuilder() const
{
	return mRenderSnapshotBuilder;
}

bool RuntimeStore::InitializeStore(std::string& error)
{
	try
	{
		std::lock_guard<std::mutex> lock(mMutex);

		if (!mConfigStore.Initialize(error))
			return false;
		if (!LoadPersistentState(error))
			return false;
		if (!ScanShaderPackages(error))
			return false;
		mLayerStack.NormalizeLayerIds();
		mLayerStack.EnsureDefaultsForAllLayers(mShaderCatalog);
		mLayerStack.EnsureDefaultLayer(mShaderCatalog);

		mServerPort = mConfigStore.GetConfig().serverPort;
		mAutoReloadEnabled = mConfigStore.GetConfig().autoReload;
		mReloadRequested = true;
		mCompileMessage = "Waiting for shader compile.";
		return true;
	}
	catch (const std::exception& exception)
	{
		error = std::string("RuntimeStore::InitializeStore exception: ") + exception.what();
		return false;
	}
	catch (...)
	{
		error = "RuntimeStore::InitializeStore threw a non-standard exception.";
		return false;
	}
}

std::string RuntimeStore::BuildPersistentStateJson() const
{
	return RuntimeStatePresenter::BuildRuntimeStateJson(*this);
}

bool RuntimeStore::PollStoredFileChanges(bool& registryChanged, bool& reloadRequested, std::string& error)
{
	try
	{
		std::lock_guard<std::mutex> lock(mMutex);
		registryChanged = false;
		reloadRequested = false;

		if (!mAutoReloadEnabled)
		{
			reloadRequested = mReloadRequested;
			return true;
		}

		const auto now = std::chrono::steady_clock::now();
		if (mLastScanTime != (std::chrono::steady_clock::time_point::min)() &&
			std::chrono::duration_cast<std::chrono::milliseconds>(now - mLastScanTime).count() < 250)
		{
			reloadRequested = mReloadRequested;
			return true;
		}

		mLastScanTime = now;

		std::string scanError;
		const ShaderPackageCatalog::Snapshot previousCatalog = mShaderCatalog.CaptureSnapshot();
		if (!ScanShaderPackages(scanError))
		{
			error = scanError;
			return false;
		}

		registryChanged = mShaderCatalog.HasCatalogChangedSince(previousCatalog);

		mLayerStack.EnsureDefaultsForAllLayers(mShaderCatalog);
		for (RuntimeStore::LayerPersistentState& layer : mLayerStack.Layers())
		{
			const ShaderPackage* active = mShaderCatalog.FindPackage(layer.shaderId);
			if (!active)
				continue;
			if (mShaderCatalog.HasPackageChangedSince(previousCatalog, layer.shaderId))
				mReloadRequested = true;
		}

		reloadRequested = mReloadRequested;
		if (registryChanged || reloadRequested)
			MarkRenderStateDirtyLocked();
		return true;
	}
	catch (const std::exception& exception)
	{
		error = std::string("RuntimeStore::PollStoredFileChanges exception: ") + exception.what();
		return false;
	}
	catch (...)
	{
		error = "RuntimeStore::PollStoredFileChanges threw a non-standard exception.";
		return false;
	}
}

bool RuntimeStore::CreateStoredLayer(const std::string& shaderId, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	if (!mLayerStack.CreateLayer(mShaderCatalog, shaderId, error))
		return false;

	mReloadRequested = true;
	MarkRenderStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::DeleteStoredLayer(const std::string& layerId, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	if (!mLayerStack.DeleteLayer(layerId, error))
		return false;

	mReloadRequested = true;
	MarkRenderStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::MoveStoredLayer(const std::string& layerId, int direction, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	bool shouldMove = false;
	if (!mLayerStack.ResolveLayerMove(layerId, direction, shouldMove, error))
		return false;
	if (!shouldMove)
		return true;

	if (!mLayerStack.MoveLayer(layerId, direction, error))
		return false;

	mReloadRequested = true;
	MarkRenderStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::MoveStoredLayerToIndex(const std::string& layerId, std::size_t targetIndex, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	bool shouldMove = false;
	if (!mLayerStack.ResolveLayerMoveToIndex(layerId, targetIndex, shouldMove, error))
		return false;
	if (!shouldMove)
		return true;

	if (!mLayerStack.MoveLayerToIndex(layerId, targetIndex, error))
		return false;

	mReloadRequested = true;
	MarkRenderStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::SetStoredLayerBypassState(const std::string& layerId, bool bypassed, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	if (!mLayerStack.SetLayerBypassState(layerId, bypassed, error))
		return false;

	mReloadRequested = true;
	MarkParameterStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::SetStoredLayerShaderSelection(const std::string& layerId, const std::string& shaderId, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	if (!mLayerStack.SetLayerShaderSelection(mShaderCatalog, layerId, shaderId, error))
		return false;

	mReloadRequested = true;
	MarkRenderStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::SetStoredParameterValue(const std::string& layerId, const std::string& parameterId, const ShaderParameterValue& value, bool persistState, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);

	if (!mLayerStack.SetParameterValue(layerId, parameterId, value, error))
		return false;

	MarkParameterStateDirtyLocked();
	return !persistState || SavePersistentState(error);
}

bool RuntimeStore::ResetStoredLayerParameterValues(const std::string& layerId, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);

	if (!mLayerStack.ResetLayerParameterValues(mShaderCatalog, layerId, error))
		return false;

	MarkParameterStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::SaveStackPresetSnapshot(const std::string& presetName, std::string& error) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	const std::string safeStem = LayerStackStore::MakeSafePresetFileStem(presetName);
	if (safeStem.empty())
	{
		error = "Preset name must include at least one letter or number.";
		return false;
	}

	JsonValue root = JsonValue::MakeObject();
	root = mLayerStack.BuildStackPresetValue(mShaderCatalog, presetName);

	return WriteTextFile(mConfigStore.GetPresetRoot() / (safeStem + ".json"), SerializeJson(root, true), error);
}

bool RuntimeStore::LoadStackPresetSnapshot(const std::string& presetName, std::string& error)
{
	std::lock_guard<std::mutex> lock(mMutex);
	const std::string safeStem = LayerStackStore::MakeSafePresetFileStem(presetName);
	if (safeStem.empty())
	{
		error = "Preset name must include at least one letter or number.";
		return false;
	}

	const std::filesystem::path presetPath = mConfigStore.GetPresetRoot() / (safeStem + ".json");
	std::string presetText = ReadTextFile(presetPath, error);
	if (presetText.empty())
		return false;

	JsonValue root;
	if (!ParseJson(presetText, root, error))
		return false;

	if (!mLayerStack.LoadStackPresetValue(mShaderCatalog, root, error))
		return false;

	mReloadRequested = true;
	MarkRenderStateDirtyLocked();
	return SavePersistentState(error);
}

bool RuntimeStore::HasStoredLayer(const std::string& layerId) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	return mLayerStack.HasLayer(layerId);
}

bool RuntimeStore::HasStoredShader(const std::string& shaderId) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	return mShaderCatalog.HasPackage(shaderId);
}

bool RuntimeStore::TryGetStoredParameterById(const std::string& layerId, const std::string& parameterId, StoredParameterSnapshot& snapshot, std::string& error) const
{
	std::lock_guard<std::mutex> lock(mMutex);

	return mLayerStack.TryGetParameterById(mShaderCatalog, layerId, parameterId, snapshot, error);
}

bool RuntimeStore::TryGetStoredParameterByControlKey(const std::string& layerKey, const std::string& parameterKey, StoredParameterSnapshot& snapshot, std::string& error) const
{
	std::lock_guard<std::mutex> lock(mMutex);

	return mLayerStack.TryGetParameterByControlKey(mShaderCatalog, layerKey, parameterKey, snapshot, error);
}

bool RuntimeStore::ResolveStoredLayerMove(const std::string& layerId, int direction, bool& shouldMove, std::string& error) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	return mLayerStack.ResolveLayerMove(layerId, direction, shouldMove, error);
}

bool RuntimeStore::ResolveStoredLayerMoveToIndex(const std::string& layerId, std::size_t targetIndex, bool& shouldMove, std::string& error) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	return mLayerStack.ResolveLayerMoveToIndex(layerId, targetIndex, shouldMove, error);
}

bool RuntimeStore::IsValidStackPresetName(const std::string& presetName) const
{
	return !LayerStackStore::MakeSafePresetFileStem(presetName).empty();
}

double RuntimeStore::GetRuntimeElapsedSeconds() const
{
	return std::chrono::duration_cast<std::chrono::duration<double>>(
		std::chrono::steady_clock::now() - mStartTime).count();
}

const std::filesystem::path& RuntimeStore::GetRuntimeRepositoryRoot() const
{
	return mConfigStore.GetRepoRoot();
}

const std::filesystem::path& RuntimeStore::GetRuntimeUiRoot() const
{
	return mConfigStore.GetUiRoot();
}

const std::filesystem::path& RuntimeStore::GetRuntimeDocsRoot() const
{
	return mConfigStore.GetDocsRoot();
}

const std::filesystem::path& RuntimeStore::GetRuntimeDataRoot() const
{
	return mConfigStore.GetRuntimeRoot();
}

unsigned short RuntimeStore::GetConfiguredControlServerPort() const
{
	return mServerPort;
}

unsigned short RuntimeStore::GetConfiguredOscPort() const
{
	return mConfigStore.GetConfig().oscPort;
}

const std::string& RuntimeStore::GetConfiguredOscBindAddress() const
{
	return mConfigStore.GetConfig().oscBindAddress;
}

double RuntimeStore::GetConfiguredOscSmoothing() const
{
	return mConfigStore.GetConfig().oscSmoothing;
}

unsigned RuntimeStore::GetConfiguredMaxTemporalHistoryFrames() const
{
	return mConfigStore.GetConfig().maxTemporalHistoryFrames;
}

unsigned RuntimeStore::GetConfiguredPreviewFps() const
{
	return mConfigStore.GetConfig().previewFps;
}

bool RuntimeStore::IsExternalKeyingConfigured() const
{
	return mConfigStore.GetConfig().enableExternalKeying;
}

const std::string& RuntimeStore::GetConfiguredInputVideoFormat() const
{
	return mConfigStore.GetConfig().inputVideoFormat;
}

const std::string& RuntimeStore::GetConfiguredInputFrameRate() const
{
	return mConfigStore.GetConfig().inputFrameRate;
}

const std::string& RuntimeStore::GetConfiguredOutputVideoFormat() const
{
	return mConfigStore.GetConfig().outputVideoFormat;
}

const std::string& RuntimeStore::GetConfiguredOutputFrameRate() const
{
	return mConfigStore.GetConfig().outputFrameRate;
}

void RuntimeStore::SetBoundControlServerPort(unsigned short port)
{
	std::lock_guard<std::mutex> lock(mMutex);
	mServerPort = port;
	mConfigStore.SetBoundControlServerPort(port);
}

void RuntimeStore::SetCompileStatus(bool succeeded, const std::string& message)
{
	std::lock_guard<std::mutex> lock(mMutex);
	mCompileSucceeded = succeeded;
	mCompileMessage = message;
}

void RuntimeStore::ClearReloadRequest()
{
	std::lock_guard<std::mutex> lock(mMutex);
	mReloadRequested = false;
}

bool RuntimeStore::LoadPersistentState(std::string& error)
{
	if (!std::filesystem::exists(mConfigStore.GetRuntimeStatePath()))
		return true;

	std::string stateText = ReadTextFile(mConfigStore.GetRuntimeStatePath(), error);
	if (stateText.empty())
		return false;

	JsonValue root;
	if (!ParseJson(stateText, root, error))
		return false;

	return mLayerStack.LoadPersistentStateValue(root);
}

bool RuntimeStore::SavePersistentState(std::string& error) const
{
	return WriteTextFile(mConfigStore.GetRuntimeStatePath(), SerializeJson(mLayerStack.BuildPersistentStateValue(mShaderCatalog), true), error);
}

bool RuntimeStore::ScanShaderPackages(std::string& error)
{
	if (!mShaderCatalog.Scan(mConfigStore.GetShaderRoot(), mConfigStore.GetConfig().maxTemporalHistoryFrames, error))
		return false;

	mLayerStack.RemoveLayersWithMissingPackages(mShaderCatalog);

	MarkRenderStateDirtyLocked();
	return true;
}

std::string RuntimeStore::ReadTextFile(const std::filesystem::path& path, std::string& error) const
{
	std::ifstream input(path, std::ios::binary);
	if (!input)
	{
		error = "Could not open file: " + path.string();
		return std::string();
	}

	std::ostringstream buffer;
	buffer << input.rdbuf();
	return buffer.str();
}

bool RuntimeStore::WriteTextFile(const std::filesystem::path& path, const std::string& contents, std::string& error) const
{
	std::error_code fsError;
	std::filesystem::create_directories(path.parent_path(), fsError);

	const std::filesystem::path temporaryPath = path.string() + ".tmp";
	std::ofstream output(temporaryPath, std::ios::binary | std::ios::trunc);
	if (!output)
	{
		error = "Could not write file: " + temporaryPath.string();
		return false;
	}

	output << contents;
	output.close();
	if (!output.good())
	{
		error = "Could not finish writing file: " + temporaryPath.string();
		return false;
	}

	if (!MoveFileExA(temporaryPath.string().c_str(), path.string().c_str(), MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH))
	{
		const DWORD lastError = GetLastError();
		std::filesystem::remove(temporaryPath, fsError);
		error = "Could not replace file: " + path.string() + " (Win32 error " + std::to_string(lastError) + ")";
		return false;
	}

	return true;
}

std::vector<std::string> RuntimeStore::GetStackPresetNamesLocked() const
{
	std::vector<std::string> presetNames;
	std::error_code fsError;
	if (!std::filesystem::exists(mConfigStore.GetPresetRoot(), fsError))
		return presetNames;

	for (const auto& entry : std::filesystem::directory_iterator(mConfigStore.GetPresetRoot(), fsError))
	{
		if (!entry.is_regular_file())
			continue;
		if (ToLowerCopy(entry.path().extension().string()) != ".json")
			continue;
		presetNames.push_back(entry.path().stem().string());
	}

	std::sort(presetNames.begin(), presetNames.end());
	return presetNames;
}

bool RuntimeStore::CopyShaderPackageForStoredLayer(const std::string& layerId, ShaderPackage& shaderPackage, std::string& error) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	const RuntimeStore::LayerPersistentState* layer = mLayerStack.FindLayerById(layerId);
	if (!layer)
	{
		error = "Unknown layer id: " + layerId;
		return false;
	}

	if (!mShaderCatalog.CopyPackage(layer->shaderId, shaderPackage))
	{
		error = "Unknown shader id: " + layer->shaderId;
		return false;
	}

	return true;
}

void RuntimeStore::GetShaderCompilerInputs(std::filesystem::path& repoRoot, std::filesystem::path& wrapperPath,
	std::filesystem::path& generatedGlslPath, std::filesystem::path& patchedGlslPath, unsigned& maxTemporalHistoryFrames) const
{
	std::lock_guard<std::mutex> lock(mMutex);
	repoRoot = mConfigStore.GetRepoRoot();
	wrapperPath = mConfigStore.GetWrapperPath();
	generatedGlslPath = mConfigStore.GetGeneratedGlslPath();
	patchedGlslPath = mConfigStore.GetPatchedGlslPath();
	maxTemporalHistoryFrames = mConfigStore.GetConfig().maxTemporalHistoryFrames;
}

void RuntimeStore::MarkRenderStateDirtyLocked()
{
	mRenderSnapshotBuilder.MarkRenderStateDirty();
}

void RuntimeStore::MarkParameterStateDirtyLocked()
{
	mRenderSnapshotBuilder.MarkParameterStateDirty();
}