#pragma once

#include "core/memory.h"

#include <string>
#include <vector>
#include <sstream>
#include <iostream>
#include <fstream>
#include <chrono>
#include <iomanip>
#include <mutex>
#include <string_view>

namespace Donut
{
    enum class LogLevel
    {
        trace = 0,
        Info  = 2,
        Warn  = 3,
        Err   = 4,
        Fatal = 5
    };

    class Logger 
    {
    public:
        static void init();
        static void shutdown();

        static Ref<Logger> get_logger();

        template<typename... Args>
        static void trace(const std::string_view& format, const Args&... args) 
        {
            auto logger = get_logger();
            if (logger) logger->log_message(LogLevel::trace, format, args...);
        }

        template<typename... Args>
        static void info(const std::string_view& format, const Args&... args) 
        {
            auto logger = get_logger();
            if (logger) logger->log_message(LogLevel::Info, format, args...);
        }

        template<typename... Args>
        static void warn(const std::string_view& format, const Args&... args) 
        {
            auto logger = get_logger();
            if (logger) logger->log_message(LogLevel::Warn, format, args...);
        }

        template<typename... Args>
        static void error(const std::string_view& format, const Args&... args) 
        {
            auto logger = get_logger();
            if (logger) logger->log_message(LogLevel::Err, format, args...);
        }

        template<typename... Args>
        static void fatal(const std::string_view& format, const Args&... args) 
        {
            auto logger = get_logger();
            if (logger) logger->log_message(LogLevel::Fatal, format, args...);
        }

        template<typename... Args>
        void log_message(LogLevel level, const std::string_view& format, const Args&... args) 
        {
            if (level < m_log_level) 
                return;

            std::lock_guard<std::mutex> lock(m_mutex);
            std::string message = format_string(format, args...);
            std::string full_message = get_time_stamp() + " [" + get_log_level_string(level) + "] " + message;
            
            if (m_console_output) 
            {
                set_console_color(level);
                std::cout << full_message << std::endl;
                reset_console_color();
            }
            
            if (m_file_output && m_log_file.is_open()) 
            {
                m_log_file << full_message << std::endl;
                m_log_file.flush();
            }
        }

        template<typename... Args>
        std::string format_string(const std::string_view& format, const Args&... args)
        {
            std::string result = format.data();
            std::vector<std::string> arg_strings = { to_string(args)... };
            
            size_t arg_index = 0;
            size_t pos = 0;
            
            while ((pos = result.find("{}", pos)) != std::string::npos && arg_index < arg_strings.size())
            {
                result.replace(pos, 2, arg_strings[arg_index]);
                pos += arg_strings[arg_index].length();
                arg_index++;
            }
            
            return result;
        }

        template<typename T>
        std::string to_string(const T& value)
        {
            std::stringstream ss;
            ss << value;
            return ss.str();
        }

        void set_log_level(LogLevel level)      { m_log_level      = level;  }
        void enable_console_output(bool enable) { m_console_output = enable; }
        void enable_file_output(bool enable)    { m_file_output    = enable; }
        void set_log_file(const std::string& filename);
    public:
        Logger();
        ~Logger();

        std::string get_time_stamp();
        std::string get_log_level_string(LogLevel level);
        void set_console_color(LogLevel level);
        void reset_console_color();
    private:
        LogLevel      m_log_level;
        bool          m_console_output;
        bool          m_file_output;
        std::ofstream m_log_file;
        std::mutex    m_mutex;

        static Ref<Logger> s_logger;
    };
}

#if defined(DONUT_DEBUG)
    #define DONUT_TRACE(format, ...)    ::Donut::Logger::trace(format, ##__VA_ARGS__)
    #define DONUT_INFO(format, ...)     ::Donut::Logger::info(format, ##__VA_ARGS__)
    #define DONUT_WARN(format, ...)     ::Donut::Logger::warn(format, ##__VA_ARGS__)
    #define DONUT_ERROR(format, ...)    ::Donut::Logger::error(format, ##__VA_ARGS__)
    #define DONUT_FATAL(format, ...)    ::Donut::Logger::fatal(format, ##__VA_ARGS__)
#else
    #define DONUT_TRACE(format, ...)    {}
    #define DONUT_INFO(format, ...)     {}
    #define DONUT_WARN(format, ...)     {}
    #define DONUT_ERROR(format, ...)    {}
    #define DONUT_FATAL(format, ...)    {}
#endif