#include "AppConfigJson.h"

#include <fstream>
#include <sstream>

namespace RenderCadenceCompositor
{
namespace
{
const JsonValue* Find(const JsonValue& root, const char* key)
{
	return root.find(key);
}

void ApplyString(const JsonValue& root, const char* key, std::string& target)
{
	const JsonValue* value = Find(root, key);
	if (value && value->isString())
		target = value->asString();
}

void ApplyBool(const JsonValue& root, const char* key, bool& target)
{
	const JsonValue* value = Find(root, key);
	if (value && value->isBoolean())
		target = value->asBoolean();
}

void ApplyDouble(const JsonValue& root, const char* key, double& target)
{
	const JsonValue* value = Find(root, key);
	if (value && value->isNumber())
		target = value->asNumber();
}

void ApplySize(const JsonValue& root, const char* key, std::size_t& target)
{
	const JsonValue* value = Find(root, key);
	if (value && value->isNumber() && value->asNumber() >= 0.0)
		target = static_cast<std::size_t>(value->asNumber());
}

void ApplyPort(const JsonValue& root, const char* key, unsigned short& target)
{
	const JsonValue* value = Find(root, key);
	if (!value || !value->isNumber())
		return;

	const double port = value->asNumber();
	if (port >= 1.0 && port <= 65535.0)
		target = static_cast<unsigned short>(port);
}

JsonValue NumberValue(double value)
{
	return JsonValue(value);
}

JsonValue SizeValue(std::size_t value)
{
	return JsonValue(static_cast<double>(value));
}

void ApplyInputConfig(const JsonValue& root, AppConfig& config)
{
	const JsonValue* input = Find(root, "input");
	if (!input || !input->isObject())
		return;

	ApplyString(*input, "backend", config.input.backend);
	ApplyString(*input, "device", config.input.device);
	ApplyString(*input, "resolution", config.input.resolution);
	ApplyString(*input, "frameRate", config.input.frameRate);
}

void ApplyOutputConfig(const JsonValue& root, AppConfig& config)
{
	const JsonValue* output = Find(root, "output");
	if (!output || !output->isObject())
		return;

	ApplyString(*output, "backend", config.output.backend);
	ApplyString(*output, "device", config.output.device);
	ApplyString(*output, "resolution", config.output.resolution);
	ApplyString(*output, "frameRate", config.output.frameRate);
	ApplyString(*output, "pixelFormat", config.output.pixelFormat);

	const JsonValue* keying = Find(*output, "keying");
	if (keying && keying->isObject())
	{
		ApplyBool(*keying, "external", config.output.externalKeyingEnabled);
		ApplyBool(*keying, "alphaRequired", config.output.outputAlphaRequired);
	}
	if (config.output.externalKeyingEnabled)
		config.output.outputAlphaRequired = true;
	if (config.output.backend != "decklink")
		config.output.externalKeyingEnabled = false;
}

JsonValue InputConfigToJson(const VideoInputAppConfig& input)
{
	JsonValue value = JsonValue::MakeObject();
	value.set("backend", JsonValue(input.backend));
	value.set("device", JsonValue(input.device));
	value.set("resolution", JsonValue(input.resolution));
	value.set("frameRate", JsonValue(input.frameRate));
	return value;
}

JsonValue OutputConfigToJson(const VideoOutputAppConfig& output)
{
	JsonValue keying = JsonValue::MakeObject();
	keying.set("external", JsonValue(output.externalKeyingEnabled));
	keying.set("alphaRequired", JsonValue(output.outputAlphaRequired));

	JsonValue value = JsonValue::MakeObject();
	value.set("backend", JsonValue(output.backend));
	value.set("device", JsonValue(output.device));
	value.set("resolution", JsonValue(output.resolution));
	value.set("frameRate", JsonValue(output.frameRate));
	value.set("pixelFormat", JsonValue(output.pixelFormat));
	value.set("keying", keying);
	return value;
}
}

bool ApplyAppConfigJson(const JsonValue& root, AppConfig& config, std::string* error)
{
	if (!root.isObject())
	{
		if (error)
			*error = "Config root must be a JSON object.";
		return false;
	}

	ApplyString(root, "shaderLibrary", config.shaderLibrary);
	ApplyPort(root, "serverPort", config.http.preferredPort);
	ApplyString(root, "oscBindAddress", config.oscBindAddress);
	ApplyPort(root, "oscPort", config.oscPort);
	ApplyDouble(root, "oscSmoothing", config.oscSmoothing);
	ApplyInputConfig(root, config);
	ApplyOutputConfig(root, config);
	ApplyBool(root, "autoReload", config.autoReload);
	ApplySize(root, "maxTemporalHistoryFrames", config.maxTemporalHistoryFrames);
	ApplyBool(root, "previewEnabled", config.previewEnabled);
	ApplyDouble(root, "previewFps", config.previewFps);
	ApplyString(root, "runtimeShaderId", config.runtimeShaderId);
	if (error)
		error->clear();
	return true;
}

bool ParseAppConfigJson(const std::string& text, AppConfig& config, std::string& error)
{
	JsonValue root;
	std::string parseError;
	if (!ParseJson(text, root, parseError))
	{
		error = parseError.empty() ? "Config JSON could not be parsed." : parseError;
		return false;
	}

	config = DefaultAppConfig();
	return ApplyAppConfigJson(root, config, &error);
}

JsonValue AppConfigToJsonValue(const AppConfig& config)
{
	JsonValue root = JsonValue::MakeObject();
	root.set("$schema", JsonValue("./runtime-host.schema.json"));
	root.set("shaderLibrary", JsonValue(config.shaderLibrary));
	root.set("serverPort", NumberValue(config.http.preferredPort));
	root.set("oscBindAddress", JsonValue(config.oscBindAddress));
	root.set("oscPort", NumberValue(config.oscPort));
	root.set("oscSmoothing", NumberValue(config.oscSmoothing));
	root.set("input", InputConfigToJson(config.input));
	root.set("output", OutputConfigToJson(config.output));
	root.set("autoReload", JsonValue(config.autoReload));
	root.set("maxTemporalHistoryFrames", SizeValue(config.maxTemporalHistoryFrames));
	root.set("previewEnabled", JsonValue(config.previewEnabled));
	root.set("previewFps", NumberValue(config.previewFps));
	root.set("runtimeShaderId", JsonValue(config.runtimeShaderId));
	return root;
}

std::string AppConfigToJson(const AppConfig& config)
{
	return SerializeJson(AppConfigToJsonValue(config), true) + "\n";
}

bool SaveAppConfigToFile(const AppConfig& config, const std::filesystem::path& path, std::string& error)
{
	if (path.empty())
	{
		error = "Config path is not available.";
		return false;
	}

	std::ofstream output(path, std::ios::binary | std::ios::trunc);
	if (!output)
	{
		error = "Could not open config file for writing: " + path.string();
		return false;
	}

	output << AppConfigToJson(config);
	if (!output)
	{
		error = "Could not write config file: " + path.string();
		return false;
	}

	error.clear();
	return true;
}
}