Reactor/lib/Utilities.hpp

#pragma once

#include <string>
#include <memory>
#include <functional>
#include <atomic>
#include <vector>
#include <mutex>
#include <thread>
#include <condition_variable>
#include <queue>
#include <stop_token>
#include <iostream>
#include <fstream>
#include <chrono>
#include <type_traits>
#include <algorithm>
#include <sstream>
#include <ranges>
#include <bit>
#include <syncstream>
#include <future>

namespace reactor
{

// Use compiler intrinsics for efficient byte swapping
#if defined(_MSC_VER)
	#include <stdlib.h>
	#define bswap_64(x) _byteswap_uint64(x)
#elif defined(__GNUC__) || defined(__clang__)
	#define bswap_64(x) __builtin_bswap64(x)
#else
	// Generic fallback implementation
	inline uint64_t bswap_64(uint64_t val)
	{
		uint64_t temp = val;
		char* ptr = reinterpret_cast<char*>(&temp);
		std::reverse(ptr, ptr + sizeof(uint64_t));
		return temp;
	}
#endif

// NonCopyable base class (unchanged, follows modern practice)
class NonCopyable
{
protected:
	NonCopyable() = default;
	~NonCopyable() = default;
	NonCopyable(const NonCopyable&) = delete;
	NonCopyable& operator=(const NonCopyable&) = delete;
	NonCopyable(NonCopyable&&) noexcept = default;
	NonCopyable& operator=(NonCopyable&&) noexcept = default;
};

// C++20 Network byte order utilities
inline uint64_t hton64(uint64_t host_uint64)
{
	if constexpr (std::endian::native == std::endian::little) {
		return bswap_64(host_uint64);
	} else {
		return host_uint64;
	}
}

inline uint64_t ntoh64(uint64_t net_uint64)
{
	return hton64(net_uint64);
}


// Object Pool (unchanged, this is a standard pattern)
template<typename T>
class ObjectPool : public NonCopyable, public std::enable_shared_from_this<ObjectPool<T>>
{
private:
	std::vector<std::unique_ptr<T>> objects_;
	std::mutex mutex_;

public:
	std::shared_ptr<T> getObject()
	{
		static_assert(!std::is_pointer_v<T>, "ObjectPool type cannot be a pointer");

		std::unique_ptr<T> p = nullptr;
		{
			std::lock_guard<std::mutex> lock(mutex_);
			if (!objects_.empty()) {
				p = std::move(objects_.back());
				objects_.pop_back();
			}
		}

		if (!p) {
			p = std::make_unique<T>();
		}

		std::weak_ptr<ObjectPool<T>> weakPtr = this->shared_from_this();
		return std::shared_ptr<T>(p.release(), [weakPtr](T* ptr) {
			auto self = weakPtr.lock();
			if (self) {
				std::lock_guard<std::mutex> lock(self->mutex_);
				self->objects_.push_back(std::unique_ptr<T>(ptr));
			} else {
				delete ptr;
			}
		});
	}
};

enum class LogLevel { TRACE, DEBUG, INFO, WARN, ERROR, FATAL };

class Logger : public NonCopyable
{
private:
	static inline LogLevel level_ = LogLevel::INFO;
	static inline std::unique_ptr<std::ofstream> file_;

	std::ostringstream stream_;
	LogLevel msgLevel_;

	static const char* levelString(LogLevel level)
	{
		switch (level) {
		case LogLevel::TRACE: return "TRACE";
		case LogLevel::DEBUG: return "DEBUG";
		case LogLevel::INFO:  return "INFO ";
		case LogLevel::WARN:  return "WARN ";
		case LogLevel::ERROR: return "ERROR";
		case LogLevel::FATAL: return "FATAL";
		}
		return "UNKNOWN";
	}

	static std::string timestamp()
	{
		auto now = std::chrono::system_clock::now();
		auto time_t = std::chrono::system_clock::to_time_t(now);
		auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(
			now.time_since_epoch()) % 1000;

		char buf[64];
		std::strftime(buf, sizeof(buf), "%Y%m%d %H:%M:%S", std::localtime(&time_t));
		return std::string(buf) + "." + std::to_string(ms.count());
	}

public:
	Logger(LogLevel level) : msgLevel_(level)
	{
		if (level >= level_) {
			stream_ << timestamp() << " " << levelString(level) << " ";
		}
	}

	~Logger()
	{
		if (msgLevel_ >= level_) {
			stream_ << "\n";
			// std::osyncstream handles synchronized, atomic writes
			if (file_ && file_->is_open()) {
				std::osyncstream(*file_) << stream_.str();
			} else {
				std::osyncstream(std::cout) << stream_.str();
			}
		}
	}

	template<typename T>
	Logger& operator<<(const T& value)
	{
		if (msgLevel_ >= level_) {
			stream_ << value;
		}
		return *this;
	}

	static void setLevel(LogLevel level) { level_ = level; }
	static void setLogFile(const std::string& filename)
	{
		file_ = std::make_unique<std::ofstream>(filename, std::ios::app);
	}
};

// C++20 Concurrent Task Queue using jthread and stop_token
class ConcurrentTaskQueue : public NonCopyable
{
private:
	std::vector<std::jthread> threads_;
	std::queue<std::function<void()>> taskQueue_;
	std::mutex mutex_;
	std::condition_variable_any taskCond_;
	std::stop_source stopSource_;
	std::string name_;

	void workerThread(std::stop_token token)
	{
		while (!token.stop_requested()) {
			std::function<void()> task;
			{
				std::unique_lock<std::mutex> lock(mutex_);
				taskCond_.wait(lock, token, [this] { return !taskQueue_.empty(); });

				if (token.stop_requested() && taskQueue_.empty()) {
					return;
				}

				task = std::move(taskQueue_.front());
				taskQueue_.pop();
			}
			task();
		}
	}

public:
	ConcurrentTaskQueue(size_t threadNum, const std::string& name = "ConcurrentTaskQueue")
		: name_(name)
	{
		for (size_t i = 0; i < threadNum; ++i) {
			threads_.emplace_back(&ConcurrentTaskQueue::workerThread, this, stopSource_.get_token());
		}
	}

	~ConcurrentTaskQueue()
	{
		stopSource_.request_stop();
		taskCond_.notify_all();
		// std::jthread destructors automatically join
	}

	template<typename F>
	void runTaskInQueue(F&& task)
	{
		{
			std::lock_guard<std::mutex> lock(mutex_);
			if (stopSource_.stop_requested()) return;
			taskQueue_.emplace(std::forward<F>(task));
		}
		taskCond_.notify_one();
	}

	template<typename F>
	void syncTaskInQueue(F&& task)
	{
		auto promise = std::make_shared<std::promise<void>>();
		auto future = promise->get_future();
		runTaskInQueue([promise, task = std::forward<F>(task)]() mutable
		{
			task();
			promise->set_value();
		});
		future.wait();
	}

	std::string getName() const { return name_; }

	size_t getTaskCount()
	{
		std::lock_guard<std::mutex> lock(mutex_);
		return taskQueue_.size();
	}
};

// Logging macros (unchanged)
#define LOG_TRACE reactor::Logger(reactor::LogLevel::TRACE)
#define LOG_DEBUG reactor::Logger(reactor::LogLevel::DEBUG)
#define LOG_INFO  reactor::Logger(reactor::LogLevel::INFO)
#define LOG_WARN  reactor::Logger(reactor::LogLevel::WARN)
#define LOG_ERROR reactor::Logger(reactor::LogLevel::ERROR)
#define LOG_FATAL reactor::Logger(reactor::LogLevel::FATAL)

// Utility functions
template<typename T>
void hashCombine(std::size_t& seed, const T& value)
{
	std::hash<T> hasher;
	seed ^= hasher(value) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}

// C++20 string splitting using ranges
inline std::vector<std::string> splitString(const std::string& s, const std::string& delimiter)
{
	std::vector<std::string> result;
	for (const auto& range : std::views::split(s, delimiter)) {
		result.emplace_back(range.begin(), range.end());
	}
	return result;
}

} // namespace reactor