#pragma once

#include <atlcomtime.h>
#include <io.h>
#include <direct.h>
#include "String.Format.tlh"


class SimpleLog
{
private:
	FILE * fpLog = nullptr;

	enum enLogLevel
	{
		enDebug = 1,
		enInfo  = 2,
		enWarn  = 3,
		enError = 4,
		enFatal = 5
	};

	static inline char LogLevelToName (int level)
	{
		static char Name [6] = { ' ', ' ', ' ', 'W', 'E', 'F' };
		if (level < enDebug)  return ' ';
		else
		if (level > enFatal)   return ' ';
		return Name [level];
	}

public:
	SimpleLog () = default;

	SimpleLog (const char* LogName)
	{
		Open (LogName);
	}

	bool Open (const char * LogName)
	{
		if (fpLog)  fclose (fpLog);

		char AppPath [_MAX_PATH + _MAX_PATH];
		int len = GetModuleFileName (NULL, AppPath, _MAX_PATH);
		len--;
		while (AppPath [len] != '\\')
			AppPath [len--] = '\0';

		COleDateTime now = COleDateTime::GetCurrentTime ();
		int Y = now.GetYear ();
		int M = now.GetMonth ();
		int D = now.GetDay ();
		int H = now.GetHour ();
		int T = now.GetMinute ();
		int S = now.GetSecond ();

		char logPath[_MAX_PATH];
		ECOM::Utility::StringFormat(logPath, _MAX_PATH)
			.Format("{$}\\Logs",
				AppPath);

		if (_access(logPath,0) != 0)
		{
			assert(_mkdir(logPath) == 0);
		}

		char logFileName [_MAX_PATH];

		ECOM::Utility::StringFormat (logFileName, _MAX_PATH)
			.Format ("{$}\\Logs\\{$}.{$:d04}{$:d02}{$:d02}.log",
				AppPath, LogName, Y, M, D);

		fpLog = fopen (logFileName, "ab+");
		assert (fpLog);
		return (fpLog != NULL);
	}

	void Close ()
	{
		if (fpLog)
			fclose (fpLog);
		fpLog = nullptr;
	}

public:
	template <typename... Args>
	inline int  Debug (const char * fmt, Args... args)
	{
		return LogOut (enDebug, fmt, args...);
	}

	template <typename... Args>
	inline int  Info (const char* fmt, Args... args)
	{
		return LogOut (enInfo, fmt, args...);
	}

	template <typename... Args>
	inline int  Warn (const char* fmt, Args... args)
	{
		return LogOut (enWarn, fmt, args...);
	}

	template <typename... Args>
	inline int  Error (const char* fmt, Args... args)
	{
		return LogOut (enError, fmt, args...);
	}

	template <typename... Args>
	inline int  Fatal (const char* fmt, Args... args)
	{
		return LogOut (enFatal, fmt, args...);
	}

protected:
	template <typename... Args>
	inline int  LogOut (int Level, const char * fmt, Args... args)
	{
		if (! fpLog)  return 0;

		static const int MaxLen = 8192;
		char * buf = new char [MaxLen];

		struct timeb tp;
		ftime (&tp);
		tm tmNow;
		_localtime64_s (&tmNow, &tp.time);
		auto Y = tmNow.tm_year + 1900;
		auto M = tmNow.tm_mon + 1;
		auto D = tmNow.tm_mday;
		auto H = tmNow.tm_hour;
		auto T = tmNow.tm_min;
		auto S = tmNow.tm_sec;

		int len1 = ECOM::Utility::StringFormat (buf, MaxLen).Format ("{$} {$:d04}{$:d02}{$:d02} {$:d02}:{$:d02}:{$:d02}:{$:d03} [{$:x04}]  ",
			LogLevelToName (Level), Y, M, D, H, T, S, tp.millitm, GetCurrentThreadId ());

		int len2 = ECOM::Utility::StringFormat (buf+len1, MaxLen-len1).Format (fmt, args...);
		buf [len1 + len2 + 0] = '\r';
		buf [len1 + len2 + 1] = '\n';
		auto rc = (int) Flush (buf, len1+len2+2 );
		delete[]buf;
		return rc;
	}

	int Flush (const char * buf, int len)
	{
		assert (buf);
		assert (fpLog);
		if (! fpLog)  return 0;
		auto rc = (int) fwrite (buf, len, 1, fpLog);
		fflush (fpLog);
		return rc;
	}
};