// Copyright (C) 2007 EQ2EMulator Development Team - GPL v3 License

#pragma once

#include <chrono>
#include <cstdint>
#include <fstream>
#include <functional>
#include <iostream>
#include <mutex>
#include <string>
#include <unistd.h>

// Debug level configuration - controls verbosity of logging output
#ifndef EQDEBUG
	#define EQDEBUG 1
#endif

#ifndef ThrowError
	void CatchSignal(int);
	#if defined(CATCH_CRASH) || defined(_EQDEBUG)
		#define ThrowError(errstr) { std::cout << "Fatal error: " << errstr << " (" << __FILE__ << ", line " << __LINE__ << ")" << std::endl; LogWrite(WORLD__ERROR, 0, "Debug", "Thrown Error: %s (%s:%i)", errstr, __FILE__, __LINE__); throw errstr; }
	#else
		#define ThrowError(errstr) { std::cout << "Fatal error: " << errstr << " (" << __FILE__ << ", line " << __LINE__ << ")" << std::endl; LogWrite(WORLD__ERROR, 0, "Debug", "Thrown Error: %s (%s:%i)", errstr, __FILE__, __LINE__); CatchSignal(0); }
	#endif
#endif

/**
 * Main logging system for EQ2Emulator
 * Provides file and console logging with multiple log levels and categories
 */
class EQEMuLog
{
public:
	// Log category enumeration - defines different types of log messages
	enum LogIDs {
		Status = 0,		// Server status messages (must stay first)
		Normal,			// General operational messages
		Error,			// Error conditions and failures
		Debug,			// Debug information for development
		Quest,			// Quest system specific messages
		Commands,		// Player command execution logs
		MaxLogID		// Total number of log categories
	};
	
	// Callback function types for custom log handling
	using msgCallbackBuf = std::function<void(LogIDs id, const char *buf, int8_t size, int32_t count)>;
	using msgCallbackFmt = std::function<void(LogIDs id, const char *fmt, va_list ap)>;
	
	/**
	 * Constructor - initializes logging system with default settings
	 * Sets up file pointers, log status flags, and callback handlers
	 */
	EQEMuLog()
	{
		for (int i = 0; i < MaxLogID; i++) {
			fp[i] = nullptr;
#if EQDEBUG >= 2
			pLogStatus[i] = 1 | 2;	// Enable file and console output for debug builds
#else
			pLogStatus[i] = 0;		// Disable logging for release builds
#endif
			logCallbackFmt[i] = nullptr;
			logCallbackBuf[i] = nullptr;
		}
#if EQDEBUG < 2
		// Configure specific log levels for release builds
		pLogStatus[Status] = 3;		// File + console
		pLogStatus[Error] = 3;		// File + console
		pLogStatus[Debug] = 3;		// File + console
		pLogStatus[Quest] = 2;		// Console only
		pLogStatus[Commands] = 2;	// Console only
#endif
	}

	/**
	 * Destructor - closes all open log files
	 * Ensures proper cleanup of file handles
	 */
	~EQEMuLog()
	{
		for (int i = 0; i < MaxLogID; i++) {
			if (fp[i]) {
				fp[i]->close();
				delete fp[i];
			}
		}
	}

	/**
	 * Sets callback function for all log categories (formatted version)
	 * @param proc Callback function to handle formatted log messages
	 */
	void SetAllCallbacks(msgCallbackFmt proc)
	{
		for (int r = Status; r < MaxLogID; r++) {
			SetCallback(static_cast<LogIDs>(r), proc);
		}
	}

	/**
	 * Sets callback function for all log categories (buffer version)
	 * @param proc Callback function to handle raw buffer log messages
	 */
	void SetAllCallbacks(msgCallbackBuf proc)
	{
		for (int r = Status; r < MaxLogID; r++) {
			SetCallback(static_cast<LogIDs>(r), proc);
		}
	}

	/**
	 * Sets callback function for specific log category (formatted version)
	 * @param id Log category to set callback for
	 * @param proc Callback function to handle formatted messages
	 */
	void SetCallback(LogIDs id, msgCallbackFmt proc)
	{
		if (id >= MaxLogID) {
			return;
		}
		logCallbackFmt[id] = proc;
	}

	/**
	 * Sets callback function for specific log category (buffer version)
	 * @param id Log category to set callback for
	 * @param proc Callback function to handle buffer messages
	 */
	void SetCallback(LogIDs id, msgCallbackBuf proc)
	{
		if (id >= MaxLogID) {
			return;
		}
		logCallbackBuf[id] = proc;
	}

	/**
	 * Writes raw buffer data to log with timestamp
	 * @param id Log category to write to
	 * @param buf Raw data buffer to write
	 * @param size Size of each element in buffer
	 * @param count Number of elements to write
	 * @return True if write was successful
	 */
	bool writebuf(LogIDs id, const char *buf, int8_t size, int32_t count)
	{
		if (id >= MaxLogID) {
			return false;
		}
		
		bool dofile = false;
		if (pLogStatus[id] & 1) {
			dofile = open(id);
		}
		if (!(dofile || pLogStatus[id] & 2)) {
			return false;
		}
		
		std::lock_guard<std::mutex> lock(MLog[id]);
		
		auto now = std::chrono::system_clock::now();
		auto time_t = std::chrono::system_clock::to_time_t(now);
		auto tm = *std::localtime(&time_t);
		
		if (dofile) {
			*fp[id] << std::format("{:04d} [{:04d}{:02d}{:02d} {:02d}:{:02d}:{:02d}] ",
				getpid(), tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
				tm.tm_hour, tm.tm_min, tm.tm_sec);
			fp[id]->write(buf, size * count);
			*fp[id] << "\n";
			fp[id]->flush();
		}
		
		if (logCallbackBuf[id]) {
			logCallbackBuf[id](id, buf, size, count);
		}
		
		if (pLogStatus[id] & 2) {
			auto& stream = (pLogStatus[id] & 8) ? std::cerr : std::cout;
			stream << "[" << LogNames[id] << "] ";
			stream.write(buf, size * count);
			stream << "\n";
		}
		
		return true;
	}

	/**
	 * Writes formatted message to log with timestamp
	 * @param id Log category to write to
	 * @param fmt Printf-style format string
	 * @param ... Variable arguments for format string
	 * @return True if write was successful
	 */
	template<typename... Args>
	bool write(LogIDs id, const std::string& fmt, Args&&... args)
	{
		if (id >= MaxLogID) {
			return false;
		}
		
		bool dofile = false;
		if (pLogStatus[id] & 1) {
			dofile = open(id);
		}
		if (!(dofile || pLogStatus[id] & 2)) {
			return false;
		}
		
		std::lock_guard<std::mutex> lock(MLog[id]);
		
		auto now = std::chrono::system_clock::now();
		auto time_t = std::chrono::system_clock::to_time_t(now);
		auto tm = *std::localtime(&time_t);
		
		std::string buffer;
		if constexpr (sizeof...(args) > 0) {
			buffer = std::vformat(fmt, std::make_format_args(args...));
		} else {
			buffer = fmt;
		}
		
		if (dofile) {
			*fp[id] << std::format("[{:04d}{:02d}{:02d} {:02d}:{:02d}:{:02d}] {}\n",
				tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
				tm.tm_hour, tm.tm_min, tm.tm_sec, buffer);
			fp[id]->flush();
		}
		
		if (pLogStatus[id] & 2) {
			auto& stream = (pLogStatus[id] & 8) ? std::cerr : std::cout;
			stream << std::format("[{:04d}{:02d}{:02d} {:02d}:{:02d}:{:02d}] [{}] {}\n",
				tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
				tm.tm_hour, tm.tm_min, tm.tm_sec, LogNames[id], buffer);
		}
		
		return true;
	}

	/**
	 * Dumps binary data in hexadecimal format with ASCII representation
	 * @param id Log category to write to
	 * @param data Binary data to dump
	 * @param size Number of bytes to dump
	 * @param cols Number of columns per row (default 16)
	 * @param skip Number of bytes to skip at beginning (default 0)
	 * @return True if dump was successful
	 */
	bool Dump(LogIDs id, const int8_t* data, int32_t size, int32_t cols = 16, int32_t skip = 0)
	{
		if (size == 0) {
			return true;
		}
		if (id >= MaxLogID) {
			return false;
		}
		
		bool dofile = false;
		if (pLogStatus[id] & 1) {
			dofile = open(id);
		}
		if (!(dofile || pLogStatus[id] & 2)) {
			return false;
		}
		
		std::lock_guard<std::mutex> lock(MLog[id]);
		write(id, "Dumping Packet: {}", size);
		
		// Output data in hexadecimal format with ASCII representation
		std::string ascii(cols, '\0');
		int j = 0;
		
		for (int32_t i = skip; i < size; i++) {
			if ((i - skip) % cols == 0) {
				if (i != skip) {
					writeNTS(id, dofile, " | {}\n", ascii);
				}
				writeNTS(id, dofile, "{:4}: ", i - skip);
				ascii.assign(cols, '\0');
				j = 0;
			} else if ((i - skip) % (cols / 2) == 0) {
				writeNTS(id, dofile, "- ");
			}
			
			writeNTS(id, dofile, "{:02X} ", static_cast<unsigned char>(data[i]));
			
			if (data[i] >= 32 && data[i] < 127) {
				ascii[j++] = data[i];
			} else {
				ascii[j++] = '.';
			}
		}
		
		// Pad final line if necessary
		int32_t k = ((size - skip) - 1) % cols;
		if (k < 8) {
			writeNTS(id, dofile, "  ");
		}
		for (int32_t h = k + 1; h < cols; h++) {
			writeNTS(id, dofile, "   ");
		}
		writeNTS(id, dofile, " | {}\n", ascii.substr(0, j));
		
		if (dofile) {
			fp[id]->flush();
		}
		
		return true;
	}

private:
	/**
	 * Opens log file for specified category
	 * @param id Log category to open file for
	 * @return True if file opened successfully
	 */
	bool open(LogIDs id)
	{
		if (id >= MaxLogID) {
			return false;
		}
		
		std::lock_guard<std::mutex> lock(MOpen);
		
		if (pLogStatus[id] & 4) {		// File error state
			return false;
		}
		if (fp[id]) {					// Already open
			return true;
		}
		
		std::string exename;
#if defined(WORLD)
		exename = "_world";
#elif defined(ZONE)
		exename = "_zone";
#endif
		
		std::string filename = std::format("{}{}_{:04d}.log", FileNames[id], exename, getpid());
		
		fp[id] = new std::ofstream(filename, std::ios::app);
		if (!fp[id]->is_open()) {
			std::cerr << "Failed to open log file: " << filename << std::endl;
			pLogStatus[id] |= 4;		// Set error state
			delete fp[id];
			fp[id] = nullptr;
			return false;
		}
		
		*fp[id] << "---------------------------------------------\n";
		return true;
	}

	/**
	 * Internal write function without timestamp or locking (Not Thread Safe)
	 * @param id Log category to write to
	 * @param dofile Whether to write to file
	 * @param fmt Format string
	 * @param args Format arguments
	 */
	template<typename... Args>
	void writeNTS(LogIDs id, bool dofile, const std::string& fmt, Args&&... args)
	{
		std::string buffer;
		if constexpr (sizeof...(args) > 0) {
			buffer = std::vformat(fmt, std::make_format_args(args...));
		} else {
			buffer = fmt;
		}
		
		if (dofile) {
			*fp[id] << buffer;
		}
		if (pLogStatus[id] & 2) {
			auto& stream = (pLogStatus[id] & 8) ? std::cerr : std::cout;
			stream << buffer;
		}
	}

	// File management
	std::mutex MOpen;								// Mutex for file opening operations
	std::mutex MLog[MaxLogID];						// Per-category logging mutexes
	std::ofstream* fp[MaxLogID];					// File pointers for each log category
	
	// Log status flags (bitwise)
	// 1 = output to file, 2 = output to stdout, 4 = file error, 8 = use stderr
	int8_t pLogStatus[MaxLogID];
	
	// Callback function pointers for custom log handling
	msgCallbackFmt logCallbackFmt[MaxLogID];		// Formatted message callbacks
	msgCallbackBuf logCallbackBuf[MaxLogID];		// Buffer message callbacks
	
	// Static configuration arrays
	static constexpr const char* FileNames[MaxLogID] = {
		"logs/eq2emu", "logs/eq2emu", "logs/eq2emu_error", 
		"logs/eq2emu_debug", "logs/eq2emu_quest", "logs/eq2emu_commands"
	};
	
	static constexpr const char* LogNames[MaxLogID] = {
		"Status", "Normal", "Error", "Debug", "Quest", "Command"
	};
};

#ifdef _EQDEBUG
/**
 * Performance monitoring utility for debug builds
 * Measures execution time between construction and destruction
 */
class PerformanceMonitor
{
public:
	/**
	 * Constructor - starts timing measurement
	 * @param ip Pointer to variable to store elapsed time
	 */
	PerformanceMonitor(int64_t* ip) : p(ip), start_time(std::chrono::high_resolution_clock::now()) 
	{
	}
	
	/**
	 * Destructor - calculates and stores elapsed time
	 */
	~PerformanceMonitor() 
	{
		auto end_time = std::chrono::high_resolution_clock::now();
		auto duration = std::chrono::duration_cast<std::chrono::microseconds>(end_time - start_time);
		*p += duration.count();
	}

private:
	std::chrono::high_resolution_clock::time_point start_time;	// Start time measurement
	int64_t* p;														// Pointer to elapsed time storage
};
#endif