// The UGC server: makes the meshes and icons of what players build and serves them, and the models' LXFML, to the
// game client over HTTP. See docs/UgcServer.md.

#include <algorithm>
#include <chrono>
#include <csignal>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <random>
#include <sstream>
#include <set>
#include <thread>

#include "BinaryPathFinder.h"
#include "CDClientDatabase.h"
#include "ConfigSync.h"
#include "Database.h"
#include "Diagnostics.h"
#include "Game.h"
#include "GeneralUtils.h"
#include "Logger.h"
#include "Server.h"
#include "ServiceType.h"
#include "Web.h"
#include "dConfig.h"
#include "dServer.h"
#include "TrafficStats.h"
#include "eHTTPMethod.h"
#include "json.hpp"

#include "UgcBricks.h"
#include "UgcCdClient.h"
#include "UgcJobs.h"
#include "UgcModel.h"
#include "UgcProcessor.h"
#include "UgcStorage.h"
#include "UgcThrottle.h"

namespace Game {
	Logger* logger = nullptr;
	dServer* server = nullptr;
	dConfig* config = nullptr;
	Game::signal_t lastSignal = 0;
	std::mt19937 randomEngine;
}

namespace {
	dServer* g_Server = nullptr;
	UgcProcessor* g_Processor = nullptr;
	UgcStorage* g_Storage = nullptr;

	template<typename T>
	T Setting(const std::string& key, T fallback) {
		return GeneralUtils::TryParse<T>(Game::config->GetValue(key)).value_or(fallback);
	}

	std::vector<uint32_t> ParseLods(const std::string& text) {
		std::vector<uint32_t> lods;
		std::stringstream stream(text);
		std::string item;
		while (std::getline(stream, item, ',')) {
			std::erase_if(item, [](unsigned char c) { return std::isspace(c); });
			if (const auto lod = GeneralUtils::TryParse<uint32_t>(item); lod && *lod <= 3) lods.push_back(*lod);
		}
		return lods;
	}

	// ugcconfig.ini (and the dashboard's settings); the defaults are LU Toolbox's
	UgcJobs::Settings ReadSettings() {
		UgcJobs::Settings settings;
		settings.build.palette = Game::config->GetValue("color_palette") == "brickdb" ? UgcModel::ePalette::BRICKDB : UgcModel::ePalette::LU_TOOLBOX;
		settings.build.colorVariation = std::clamp(Setting<float>("color_variation", 5.0f), 0.0f, 100.0f);
		settings.build.transparentOpacity = std::clamp(Setting<float>("transparent_opacity", 58.82f), 0.0f, 100.0f);
		const auto lods = ParseLods(Game::config->GetValue("lods").empty() ? "0,2" : Game::config->GetValue("lods"));
		if (!lods.empty()) settings.lods = lods;
		settings.lodDistances.lod0 = Setting<float>("lod_distance_0", 0.0f);
		settings.lodDistances.lod1 = Setting<float>("lod_distance_1", 50.0f);
		settings.lodDistances.lod2 = Setting<float>("lod_distance_2", 100.0f);
		settings.lodDistances.lod3 = Setting<float>("lod_distance_3", 280.0f);
		settings.lodDistances.cull = Setting<float>("lod_cull", 10000.0f);
		if (!Game::config->GetValue("shader_opaque").empty()) settings.shaderOpaque = Game::config->GetValue("shader_opaque");
		settings.optimize.removeHidden = Setting<int32_t>("remove_hidden_faces", 1) != 0;
		settings.optimize.groundPlane = Setting<int32_t>("hsr_ground_plane", 0) != 0;
		settings.optimize.resolution = Setting<int32_t>("optimize_resolution", 1024);
		settings.ao.enabled = Setting<int32_t>("bake_ao", 1) != 0;
		settings.ao.distance = Setting<float>("ao_distance", 5.0f);
		settings.ao.samples = std::clamp(Setting<int32_t>("ao_samples", 64), 1, 1024);
		settings.ao.strength = Setting<float>("ao_strength", 1.0f);
		settings.ao.glowStrength = Setting<float>("glow_strength", 6.0f);
		settings.icon.size = Setting<int32_t>("icon_size", 128);
		settings.icon.yawDegrees = Setting<float>("icon_yaw", 53.36f);
		settings.icon.pitchDegrees = Setting<float>("icon_pitch", 19.54f);
		settings.icon.fovDegrees = Setting<float>("icon_fov", 39.6f);
		settings.icon.margin = Setting<float>("icon_margin", 1.03f);
		settings.icon.sunYawDegrees = Setting<float>("icon_sun_yaw", 21.0f);
		settings.icon.sunPitchDegrees = Setting<float>("icon_sun_pitch", 50.3f);
		settings.icon.sunStrength = Setting<float>("icon_sun_strength", 2.5f);
		settings.icon.ambient = Setting<float>("icon_ambient", 0.192f);
		settings.icon.shadows = Setting<int32_t>("icon_shadows", 1) != 0;
		settings.icon.ao.enabled = Setting<int32_t>("icon_ao", 1) != 0;
		settings.icon.ao.distance = settings.ao.distance;
		settings.iconCorrectColors = Setting<int32_t>("icon_correct_colors", 1) != 0;
		settings.iconColorVariation = std::clamp(Setting<float>("icon_color_variation", 0.0f), 0.0f, 100.0f);
		settings.modularIcon = settings.icon;
		settings.modularIcon.yawDegrees = Setting<float>("modular_icon_yaw", 53.36f);
		settings.modularIcon.pitchDegrees = Setting<float>("modular_icon_pitch", 19.54f);
		settings.maxBricks = Setting<uint32_t>("max_model_bricks", 0);
		return settings;
	}

	UgcProcessor::Limits ReadLimits() {
		UgcProcessor::Limits limits;
		const auto cores = std::max<unsigned>(std::thread::hardware_concurrency(), 1);
		limits.maxCpus = std::clamp(Setting<double>("max_cpu_percent", 0.0), 0.0, 100.0) / 100.0 * cores;
		limits.maxMemoryBytes = Setting<uint64_t>("max_memory_mb", 0) * 1024 * 1024;
		limits.nice = std::clamp(Setting<int32_t>("worker_nice", 0), 0, 19);
		UgcThrottle::ParseHours(Game::config->GetValue("pause_hours"), limits.pauseFromHour, limits.pauseToHour);
		return limits;
	}

	std::vector<std::string> Segments(const std::string& path) {
		std::vector<std::string> segments;
		size_t start = 0;
		while (start < path.size()) {
			auto end = path.find('/', start);
			if (end == std::string::npos) end = path.size();
			if (end > start) segments.push_back(path.substr(start, end - start));
			start = end + 1;
		}
		return segments;
	}

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

	void NotFound(HTTPReply& reply) {
		reply.status = eHTTPStatusCode::NOT_FOUND;
		reply.message = "Not Found";
		reply.contentType = eContentType::TEXT_PLAIN;
	}

	void ServeFile(HTTPReply& reply, UgcStorage::Kind kind, LWOOBJID id, const std::string& name, eContentType type, bool crossOrigin) {
		switch (g_Processor->Request(kind, id)) {
		case UgcProcessor::Availability::READY:
			break;
		case UgcProcessor::Availability::QUEUED:
			// The client asks again later on 408
			reply.status = eHTTPStatusCode::REQUEST_TIMEOUT;
			reply.message = "Being made";
			reply.contentType = eContentType::TEXT_PLAIN;
			reply.headers.push_back("Retry-After: 5");
			return;
		case UgcProcessor::Availability::UNKNOWN:
			NotFound(reply);
			return;
		}
		const auto path = g_Storage->File(kind, id, name);
		if (!path) {
			NotFound(reply);
			return;
		}
		reply.status = eHTTPStatusCode::OK;
		reply.file = path->string();
		reply.contentType = type;
		reply.headers.push_back("Cache-Control: public, max-age=3600");
		if (crossOrigin) reply.headers.push_back("Access-Control-Allow-Origin: *");
	}

	/**
	 * A game client download (3D services): <client_path>/UGCC<dc>/[3DOPTIMIZED/|IMAGE128DDS/]<dc><id><.ext>(.gz|.checksum).
	 * `segments` are the path's parts after client_path.
	 */
	void ServeClientDownload(HTTPReply& reply, const std::vector<std::string>& segments) {
		NotFound(reply);
		if (segments.size() < 2 || segments.size() > 3) return;
		const auto folder = Lower(segments[0]);
		if (!folder.starts_with("ugcc")) return;
		const auto datacenter = folder.substr(4);
		const std::string typeFolder = segments.size() == 3 ? Lower(segments[1]) : "";
		auto file = Lower(segments.back());

		std::string suffix;
		if (file.ends_with(".gz")) suffix = ".gz";
		else if (file.ends_with(".checksum")) suffix = ".checksum";
		else return;
		file.resize(file.size() - suffix.size());
		const auto dot = file.rfind('.');
		if (dot == std::string::npos) return;
		const auto extension = file.substr(dot);
		auto number = file.substr(0, dot);
		// The file name starts with the datacenter id
		if (!number.starts_with(datacenter)) return;
		number = number.substr(datacenter.size());
		const auto id = GeneralUtils::TryParse<uint64_t>(number);
		if (!id || number.empty()) return;
		const auto blueprint = static_cast<LWOOBJID>(*id);

		const auto type = suffix == ".gz" ? eContentType::APPLICATION_OCTET_STREAM : eContentType::TEXT_PLAIN;
		if (extension == ".lxfml" && typeFolder.empty()) {
			ServeFile(reply, UgcStorage::Kind::MODEL, blueprint, "model.lxfml" + suffix, type, false);
		} else if (extension == ".nif" && typeFolder == "3doptimized") {
			ServeFile(reply, UgcStorage::Kind::MODEL, blueprint, "model.nif" + suffix, type, false);
		} else if (extension == ".dds" && typeFolder == "image128dds") {
			// A player model's icon, else a modular build's
			ServeFile(reply, UgcStorage::Kind::MODEL, blueprint, "icon.dds" + suffix, type, false);
			if (reply.status == eHTTPStatusCode::NOT_FOUND) ServeFile(reply, UgcStorage::Kind::MODULAR, blueprint, "icon.dds" + suffix, type, false);
		}
		// .hkx: no physics is made
	}

	void RegisterRoutes() {
		const auto prefix = Segments(Lower(Game::config->GetValue("client_path").empty() ? "/ugc" : Game::config->GetValue("client_path")));
		std::string base;
		for (const auto& segment : prefix) base += "/" + segment;

		const auto clientRoute = [prefixSize = prefix.size()](HTTPReply& reply, const HTTPContext& context) {
			auto segments = Segments(context.originalPath);
			if (segments.size() <= prefixSize) {
				NotFound(reply);
				return;
			}
			segments.erase(segments.begin(), segments.begin() + static_cast<std::ptrdiff_t>(prefixSize));
			ServeClientDownload(reply, segments);
		};
		Game::web.RegisterHTTPRoute({ .path = base + "/:folder/:file", .method = eHTTPMethod::GET, .middleware = {}, .handle = clientRoute });
		Game::web.RegisterHTTPRoute({ .path = base + "/:folder/:type/:file", .method = eHTTPMethod::GET, .middleware = {}, .handle = clientRoute });

		// Previews for the dashboard
		Game::web.RegisterHTTPRoute({ .path = "/files/:kind/:id/:file", .method = eHTTPMethod::GET, .middleware = {},
			.handle = [](HTTPReply& reply, const HTTPContext& context) {
				const auto segments = Segments(context.originalPath);
				NotFound(reply);
				reply.headers.push_back("Access-Control-Allow-Origin: *");
				if (segments.size() != 4) return;
				const auto id = GeneralUtils::TryParse<uint64_t>(segments[2]);
				const auto kind = segments[1] == "model" ? std::optional(UgcStorage::Kind::MODEL) : segments[1] == "modular" ? std::optional(UgcStorage::Kind::MODULAR) : std::nullopt;
				const auto& name = segments[3];
				static const std::set<std::string> PREVIEWS = { "icon.png", "model.nif", "model.noao.nif", "stats.json",
					"previous.icon.png", "previous.model.nif", "previous.model.noao.nif", "previous.stats.json" };
				if (!id || !kind || !PREVIEWS.contains(name)) return;
				reply.headers.clear();
				const auto type = name.ends_with(".png") ? eContentType::IMAGE_PNG : name.ends_with(".json") ? eContentType::APPLICATION_JSON : eContentType::APPLICATION_OCTET_STREAM;
				ServeFile(reply, *kind, static_cast<LWOOBJID>(*id), name, type, true);
				// Made again since: the newest files differ, so they mustn't be cached as long as the client's
				if (reply.status == eHTTPStatusCode::OK) {
					std::erase_if(reply.headers, [](const std::string& header) { return header.starts_with("Cache-Control"); });
					reply.headers.push_back("Cache-Control: no-cache");
				}
			} });

		Game::web.RegisterHTTPRoute({ .path = "/status", .method = eHTTPMethod::GET, .middleware = {},
			.handle = [](HTTPReply& reply, const HTTPContext&) {
				reply.status = eHTTPStatusCode::OK;
				reply.contentType = eContentType::APPLICATION_JSON;
				reply.message = g_Processor->Status().dump();
				reply.headers.push_back("Access-Control-Allow-Origin: *");
				reply.headers.push_back("Cache-Control: no-store");
			} });
		LOG("Serving the client's downloads under %s/UGCC<datacenter>/", base.c_str());
	}

	std::filesystem::path ResPath() {
		const auto client = Game::config->GetValue("client_location");
		return client.empty() ? std::filesystem::path{} : std::filesystem::path(client) / "res";
	}

	// Command line tools: make one model's or modular build's files into a folder, without a database
	int MakeFromCommandLine(const std::string& mode, const std::string& input, const std::filesystem::path& output) {
		const auto res = ResPath();
		const auto settings = ReadSettings();
		UgcBricks::BrickLibrary library(res, 0);
		if (!library.LoadMaterials()) std::cerr << "Couldn't read Materials.xml from " << (res / "brickdb.zip") << "; bricks will be grey\n";
		UgcJobs::Outcome outcome;
		const auto start = std::chrono::steady_clock::now();
		if (mode == "--make-model") {
			const auto data = UgcBricks::ReadFile(input);
			if (!data) {
				std::cerr << "Can't read " << input << "\n";
				return EXIT_FAILURE;
			}
			outcome = UgcJobs::ProcessModel(*data, library, settings);
		} else {
			CDClientDatabase::Connect((BinaryPathFinder::GetBinaryDir() / "resServer/CDServer.sqlite").string());
			UgcJobs::ModularInput modular;
			std::string error;
			if (!UgcCdClient::GatherModular(input, modular, error)) {
				std::cerr << error << "\n";
				return EXIT_FAILURE;
			}
			outcome = UgcJobs::ProcessModular(modular, res, settings);
		}
		const auto ms = std::chrono::duration<double, std::milli>(std::chrono::steady_clock::now() - start).count();
		if (!outcome.ok) {
			std::cerr << "Failed: " << outcome.error << "\n";
			return EXIT_FAILURE;
		}
		std::filesystem::create_directories(output);
		for (const auto& [name, data] : outcome.files) {
			std::ofstream(output / name, std::ios::binary).write(data.data(), static_cast<std::streamsize>(data.size()));
		}
		std::cout << "Made " << outcome.files.size() << " files in " << ms << " ms" << (outcome.note.empty() ? "" : ": " + outcome.note) << "\n";
		return EXIT_SUCCESS;
	}
}

int main(int argc, char** argv) {
	// Crash dumps and the log file share this name (Crash_UgcServer_<start time>_<pid>.log), like the other servers
	const auto serviceName = "UgcServer_" + std::to_string(time(nullptr));
	Diagnostics::SetProcessName(serviceName);
	Diagnostics::SetProcessFileName(argv[0]);
	Diagnostics::Initialize();
	Diagnostics::SetProduceMemoryDump(true);
	std::signal(SIGINT, Game::OnSignal);
	std::signal(SIGTERM, Game::OnSignal);

	Game::config = new dConfig("ugcconfig.ini");

	// UgcServer --make-model <file.lxfml> <folder> or --make-modular "1:4713+1:4714+1:4715" <folder>
	if (argc == 4 && (std::string(argv[1]) == "--make-model" || std::string(argv[1]) == "--make-modular")) {
		return MakeFromCommandLine(argv[1], argv[2], argv[3]);
	}

	// Like the other servers: logs/UgcServer/UgcServer_<start time>.log
	Server::SetupLogger(serviceName, "UgcServer");
	if (!Game::logger) return EXIT_FAILURE;
	// Crash reports go where the dashboard lists them (Server Health, crash dumps)
	if (!Game::config->GetValue("dump_folder").empty()) Diagnostics::SetOutDirectory(Game::config->GetValue("dump_folder"));
	Game::config->LogSettings();
	LOG("Starting UGC Server");

	const auto res = ResPath();
	if (res.empty() || !std::filesystem::exists(res)) {
		LOG("client_location is not set or has no res folder; the UGC server needs the client's brick data");
		return EXIT_FAILURE;
	}

	try {
		CDClientDatabase::Connect((BinaryPathFinder::GetBinaryDir() / "resServer/CDServer.sqlite").string());
	} catch (std::exception& ex) {
		LOG("Failed to connect to CDClient database: %s", ex.what());
		return EXIT_FAILURE;
	}

	try {
		Database::Connect();
	} catch (std::exception& ex) {
		LOG("Failed to connect to the database: %s", ex.what());
		return EXIT_FAILURE;
	}

	// Settings edited on the dashboard (server_config table) are layered over the files from here on
	Game::config->SetDatabaseSync(ConfigSync::Sync);

	std::string masterIP = "localhost";
	uint32_t masterPort = 1000;
	std::string masterPassword;
	if (const auto masterInfo = Database::Get()->GetMasterInfo()) {
		masterIP = masterInfo->ip;
		masterPort = masterInfo->port;
		masterPassword = masterInfo->password;
	}

	// The master starts it again when this link drops
	g_Server = new dServer(masterIP, Setting<uint32_t>("net_port", 2012), 0, 16, false, false, Game::logger, masterIP, masterPort,
		ServiceType::UGC, Game::config, &Game::lastSignal, masterPassword);
	Game::server = g_Server;

	UgcBricks::BrickLibrary library(res, 0);
	if (!library.LoadMaterials()) LOG("Couldn't read Materials.xml from %s; bricks will be grey", (res / "brickdb.zip").string().c_str());

	auto outputDir = std::filesystem::path(Game::config->GetValue("ugc_output_dir").empty() ? "ugc" : Game::config->GetValue("ugc_output_dir"));
	if (outputDir.is_relative()) outputDir = BinaryPathFinder::GetBinaryDir() / outputDir;
	UgcStorage storage(outputDir);
	g_Storage = &storage;

	UgcProcessor::Config processorConfig;
	processorConfig.pollIntervalMs = std::max<uint32_t>(Setting<uint32_t>("poll_interval_ms", 2000), 100);
	processorConfig.pollBatch = std::max<uint32_t>(Setting<uint32_t>("poll_batch", 32), 1);
	processorConfig.maxAttempts = std::max<uint32_t>(Setting<uint32_t>("max_attempts", 3), 1);
	processorConfig.maxStorageBytes = Setting<uint64_t>("ugc_max_storage_mb", 2048) * 1024 * 1024;
	const auto threads = Setting<uint32_t>("worker_threads", 0);
	processorConfig.threads = threads > 0 ? threads : std::max<size_t>(std::thread::hardware_concurrency() / 2, 1);
	UgcProcessor processor(processorConfig, storage, library, ReadSettings());
	processor.Configure(ReadSettings(), ReadLimits());
	g_Processor = &processor;
	// Sent with the traffic reports to the dashboard (Diagnostics)
	TrafficStats::Local().SetGauge("workers_busy", [&processor] { return static_cast<double>(processor.Busy()); });
	TrafficStats::Local().SetGauge("workers_queued", [&processor] { return static_cast<double>(processor.Queued()); });
	TrafficStats::Local().SetGauge("workers_threads", [&processor] { return static_cast<double>(processor.Threads()); });
	// Read on this thread, when a traffic report is taken (dServer::ReceiveFromMaster)
	const std::vector<std::pair<std::string, std::function<double()>>> ugcGauges{
		{ "ugc_made_total", [&processor] { return static_cast<double>(processor.Made()); } },
		{ "ugc_failed_total", [&processor] { return static_cast<double>(processor.Failed()); } },
		{ "ugc_evicted_total", [&processor] { return static_cast<double>(processor.Evicted()); } },
		{ "ugc_stored_bytes", [&processor] { return static_cast<double>(processor.StoredBytes()); } },
		{ "ugc_max_storage_bytes", [&processor] { return static_cast<double>(processor.MaxStorageBytes()); } },
	};
	for (const auto& [name, gauge] : ugcGauges) TrafficStats::Local().SetGauge(name, gauge);
	TrafficStats::Local().SetGauge("cpu_percent", [&processor] { return processor.CpuPercent(); });
	TrafficStats::Local().SetGauge("memory_mb", [] { return static_cast<double>(UgcProcessor::ResidentBytes()) / (1024.0 * 1024.0); });
	TrafficStats::Local().SetGauge("job_memory_mb", [&processor] { return static_cast<double>(processor.JobMemory()) / (1024.0 * 1024.0); });
	TrafficStats::Local().SetGauge("throttled", [&processor] { return processor.Throttled() ? 1.0 : 0.0; });

	const auto listenIp = Game::config->GetValue("listen_ip").empty() ? std::string("0.0.0.0") : Game::config->GetValue("listen_ip");
	const auto port = Setting<uint32_t>("port", 2008);
	if (!Game::web.Startup(listenIp, port)) {
		LOG("Failed to start the web server on %s:%u", listenIp.c_str(), port);
		return EXIT_FAILURE;
	}
	RegisterRoutes();
	processor.Start();
	LOG("UGC Server started on %s:%u, files in %s", listenIp.c_str(), port, outputDir.string().c_str());

	auto lastTick = std::chrono::steady_clock::now();
	auto lastConfigure = lastTick;
	while (!Game::ShouldShutdown()) {
		// The poll's wait for network traffic is also this loop's sleep
		Game::web.ReceiveRequests(10);
		const auto now = std::chrono::steady_clock::now();
		if (now - lastTick < std::chrono::milliseconds(16)) continue;
		lastTick = now;

		Packet* packet = g_Server->ReceiveFromMaster();
		while (packet) {
			g_Server->DeallocateMasterPacket(packet);
			packet = g_Server->ReceiveFromMaster();
		}
		processor.Update();
		// Settings the dashboard changed arrive as a config reload; pick them up
		if (now - lastConfigure >= std::chrono::seconds(5)) {
			lastConfigure = now;
			processor.Configure(ReadSettings(), ReadLimits());
		}
	}

	LOG("Stopping the UGC server");
	processor.Stop();
	TrafficStats::Local().SetGauge("workers_busy", nullptr);
	TrafficStats::Local().SetGauge("workers_queued", nullptr);
	TrafficStats::Local().SetGauge("workers_threads", nullptr);
	for (const auto& [name, gauge] : ugcGauges) TrafficStats::Local().SetGauge(name, nullptr);
	for (const auto* gauge : { "cpu_percent", "memory_mb", "job_memory_mb", "throttled" }) TrafficStats::Local().SetGauge(gauge, nullptr);
	Game::web.Shutdown();
	g_Processor = nullptr;
	Database::Destroy("UgcServer");
	delete g_Server;
	g_Server = nullptr;
	Game::server = nullptr;
	delete Game::logger;
	Game::logger = nullptr;
	delete Game::config;
	Game::config = nullptr;
	return EXIT_SUCCESS;
}