#ifndef _LOGGER_H_
#define _LOGGER_H_

#include "log_queue.h"

#include <sstream>
#include <stdexcept>
#include <iostream>
#include <atomic>
#include <functional>
#include <ctime>

class logger
{
private:
	std::atomic<bool> _enabled;
    std::stringstream _logLine;
	log_queue _queue;

	typedef std::chrono::high_resolution_clock hr_clock;
	typedef std::chrono::system_clock sys_clock;
	typedef std::chrono::system_clock::time_point sys_tp;
	typedef std::chrono::high_resolution_clock::time_point hr_tp;

public:
    logger();
	
	void set_enabled(bool enabled);

	template<typename... Args> void log_info(const char* s, const Args&... args)
	{
		log("info", s, args...);
	}

	template<typename... Args> void log_warning(const char* s, const Args&... args)
	{
		log("warning", s, args...);
	}

	template<typename... Args> void log_error(const char* s, const Args&... args)
	{
		log("error", s, args...);
	}
    
private:

	template<typename... Args> void log(const char* log_level, const char* s, const Args&... args)
	{
		if (_enabled)
		{
			_queue.add_log(std::bind(&logger::log_impl<Args...>, this, s, args..., sys_clock::now(), hr_clock::now(), log_level));
		}
	}
	
	template<typename... Args> void log_impl(const char* s, const Args&... args, sys_tp sc, hr_tp hrc, const char* log_level)
	{
		_logLine.str("");
		//_logLine << "[" << hrc.time_since_epoch().count() << "] ";

		char tm_buffer[50];
		std::time_t tm = std::chrono::system_clock::to_time_t(sc);
		std::strftime(tm_buffer, 50, "%F %T", std::localtime(&tm));
		_logLine << "[" << tm_buffer << "] ";

		_logLine << "[" << log_level << "] ";

		form_log_line(s, args...);

		std::cout << _logLine.str() << std::endl;
	}
	
    void form_log_line(const char* s);

	template<typename T, typename... Args> void form_log_line(const char* s, const T& value, const Args&... args)
    {
        while (*s)
        {
            if (*s == '%' && *++s != '%')
            {
                _logLine << value;
				return form_log_line(s, args...);
            }
            _logLine << *s++;
        }
        throw std::runtime_error("extra arguments provided");
    }
};

extern logger ulog;

#endif // _LOGGER_H_