#include "RuntimeLayerController.h"

#include "AppConfigProvider.h"
#include "RuntimeJson.h"
#include "../logging/Logger.h"

#include <filesystem>

namespace RenderCadenceCompositor
{
RuntimeLayerController::RuntimeLayerController(RenderLayerPublisher publisher) :
	mPublisher(std::move(publisher))
{
}

RuntimeLayerController::~RuntimeLayerController()
{
	Stop();
}

void RuntimeLayerController::SetPublisher(RenderLayerPublisher publisher)
{
	mPublisher = std::move(publisher);
}

void RuntimeLayerController::Initialize(const std::string& shaderLibrary, unsigned maxTemporalHistoryFrames, std::string& runtimeShaderId)
{
	LoadSupportedShaderCatalog(shaderLibrary, maxTemporalHistoryFrames);
	InitializeLayerModel(runtimeShaderId);
}

void RuntimeLayerController::StartStartupBuild(const std::string& runtimeShaderId)
{
	if (runtimeShaderId.empty())
	{
		Log("runtime-shader", "Runtime shader build disabled.");
		return;
	}

	Log("runtime-shader", "Starting background Slang build for shader '" + runtimeShaderId + "'.");
	const std::string layerId = FirstRuntimeLayerId();
	if (!layerId.empty())
		StartLayerShaderBuild(layerId, runtimeShaderId);
}

void RuntimeLayerController::Stop()
{
	StopAllRuntimeShaderBuilds();
}

ControlActionResult RuntimeLayerController::HandleAddLayer(const std::string& body)
{
	CleanupRetiredShaderBuilds();

	std::string shaderId;
	std::string error;
	if (!ExtractStringField(body, "shaderId", shaderId, error))
		return { false, error };

	std::string layerId;
	{
		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
		if (!mRuntimeLayerModel.AddLayer(mShaderCatalog, shaderId, layerId, error))
			return { false, error };
	}

	Log("runtime-shader", "Layer added: " + layerId + " shader=" + shaderId);
	StartLayerShaderBuild(layerId, shaderId);
	return { true, std::string() };
}

ControlActionResult RuntimeLayerController::HandleRemoveLayer(const std::string& body)
{
	CleanupRetiredShaderBuilds();

	std::string layerId;
	std::string error;
	if (!ExtractStringField(body, "layerId", layerId, error))
		return { false, error };

	{
		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
		if (!mRuntimeLayerModel.RemoveLayer(layerId, error))
			return { false, error };
	}

	Log("runtime-shader", "Layer removed: " + layerId);
	RetireLayerShaderBuild(layerId);
	PublishRuntimeRenderLayers();
	return { true, std::string() };
}

RuntimeLayerModelSnapshot RuntimeLayerController::Snapshot(const CadenceTelemetrySnapshot& telemetry) const
{
	std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
	RuntimeLayerModelSnapshot snapshot = mRuntimeLayerModel.Snapshot();
	if (telemetry.shaderBuildFailures > 0)
	{
		snapshot.compileSucceeded = false;
		snapshot.compileMessage = "Runtime shader GL commit failed; see logs for details.";
	}
	return snapshot;
}

void RuntimeLayerController::LoadSupportedShaderCatalog(const std::string& shaderLibrary, unsigned maxTemporalHistoryFrames)
{
	const std::filesystem::path shaderRoot = FindRepoPath(shaderLibrary);
	std::string error;
	if (!mShaderCatalog.Load(shaderRoot, maxTemporalHistoryFrames, error))
	{
		LogWarning("runtime-shader", "Supported shader catalog is empty: " + error);
		return;
	}

	Log("runtime-shader", "Supported shader catalog loaded with " + std::to_string(mShaderCatalog.Shaders().size()) + " shader(s).");
}

void RuntimeLayerController::InitializeLayerModel(std::string& runtimeShaderId)
{
	std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
	std::string error;
	if (!mRuntimeLayerModel.InitializeSingleLayer(mShaderCatalog, runtimeShaderId, error))
	{
		LogWarning("runtime-shader", error + " Runtime shader build disabled.");
		runtimeShaderId.clear();
		mRuntimeLayerModel.Clear();
	}
}

void RuntimeLayerController::StartLayerShaderBuild(const std::string& layerId, const std::string& shaderId)
{
	CleanupRetiredShaderBuilds();
	RetireLayerShaderBuild(layerId);

	{
		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
		std::string error;
		mRuntimeLayerModel.MarkBuildStarted(layerId, "Runtime Slang build started for shader '" + shaderId + "'.", error);
	}

	auto bridge = std::make_unique<RuntimeShaderBridge>();
	RuntimeShaderBridge* bridgePtr = bridge.get();
	{
		std::lock_guard<std::mutex> lock(mShaderBuildMutex);
		mShaderBuilds[layerId] = std::move(bridge);
	}

	bridgePtr->Start(
		layerId,
		shaderId,
		[this](const RuntimeShaderArtifact& artifact) {
			if (MarkRuntimeBuildReady(artifact))
				PublishRuntimeRenderLayers();
		},
		[this, layerId](const std::string& message) {
			MarkRuntimeBuildFailedForLayer(layerId, message);
			LogError("runtime-shader", "Runtime Slang build failed: " + message);
		});
}

void RuntimeLayerController::RetireLayerShaderBuild(const std::string& layerId)
{
	std::unique_ptr<RuntimeShaderBridge> bridge;
	{
		std::lock_guard<std::mutex> lock(mShaderBuildMutex);
		auto bridgeIt = mShaderBuilds.find(layerId);
		if (bridgeIt == mShaderBuilds.end())
			return;
		bridge = std::move(bridgeIt->second);
		mShaderBuilds.erase(bridgeIt);
		bridge->RequestStop();
		mRetiredShaderBuilds.push_back(std::move(bridge));
	}
}

void RuntimeLayerController::CleanupRetiredShaderBuilds()
{
	std::vector<std::unique_ptr<RuntimeShaderBridge>> readyToStop;
	{
		std::lock_guard<std::mutex> lock(mShaderBuildMutex);
		for (auto it = mRetiredShaderBuilds.begin(); it != mRetiredShaderBuilds.end();)
		{
			if ((*it)->CanStopWithoutWaiting())
			{
				readyToStop.push_back(std::move(*it));
				it = mRetiredShaderBuilds.erase(it);
				continue;
			}
			++it;
		}
	}

	for (std::unique_ptr<RuntimeShaderBridge>& bridge : readyToStop)
		bridge->Stop();
}

void RuntimeLayerController::StopAllRuntimeShaderBuilds()
{
	std::map<std::string, std::unique_ptr<RuntimeShaderBridge>> builds;
	std::vector<std::unique_ptr<RuntimeShaderBridge>> retiredBuilds;
	{
		std::lock_guard<std::mutex> lock(mShaderBuildMutex);
		builds.swap(mShaderBuilds);
		retiredBuilds.swap(mRetiredShaderBuilds);
	}
	for (auto& entry : builds)
		entry.second->Stop();
	for (auto& bridge : retiredBuilds)
		bridge->Stop();
}

void RuntimeLayerController::PublishRuntimeRenderLayers()
{
	if (!mPublisher)
		return;

	std::vector<RuntimeRenderLayerModel> renderLayers;
	{
		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
		renderLayers = mRuntimeLayerModel.Snapshot().renderLayers;
	}
	mPublisher(renderLayers);
}

bool RuntimeLayerController::MarkRuntimeBuildReady(const RuntimeShaderArtifact& artifact)
{
	std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
	std::string error;
	if (!mRuntimeLayerModel.MarkBuildReady(artifact, error))
	{
		LogWarning("runtime-shader", error);
		return false;
	}
	return true;
}

void RuntimeLayerController::MarkRuntimeBuildFailedForLayer(const std::string& layerId, const std::string& message)
{
	std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
	std::string error;
	if (!mRuntimeLayerModel.MarkBuildFailed(layerId, message, error))
		LogWarning("runtime-shader", error);
}

std::string RuntimeLayerController::FirstRuntimeLayerId() const
{
	std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
	return mRuntimeLayerModel.FirstLayerId();
}

bool RuntimeLayerController::ExtractStringField(const std::string& body, const char* fieldName, std::string& value, std::string& error)
{
	JsonValue root;
	std::string parseError;
	if (!ParseJson(body.empty() ? "{}" : body, root, parseError) || !root.isObject())
	{
		error = parseError.empty() ? "Request body must be a JSON object." : parseError;
		return false;
	}

	const JsonValue* field = root.find(fieldName);
	if (!field || !field->isString() || field->asString().empty())
	{
		error = std::string("Request field '") + fieldName + "' must be a non-empty string.";
		return false;
	}

	value = field->asString();
	error.clear();
	return true;
}
}