#pragma once

#include <tuple>
#include <string>
#include <algorithm>

template <class T>
inline void ToString(std::string& ret, T&& val)
{
	ret.append(std::to_string(std::forward<T>(val)));
}

inline void ToString(std::string& ret, const std::string& val)
{
	ret.append(val);
}

inline void ToString(std::string& ret, const char* val)
{
	ret.append(val);
}

template <int N>
struct SFormatN {
	static std::string Format(const char* fmt)
	{
		//static_assert(false, "This should never happen");
	}
};

template <>
struct SFormatN<0> {
	template <class ...ARGS>
	static std::string Format(const char* fmt, const std::tuple<ARGS...>&)
	{
		return fmt;
	}
};

template <class ...ARGS>
std::string SFormat(const char* fmt, const ARGS &...args)
{
	const auto tuple = std::forward_as_tuple(args...);
	return SFormatN<sizeof...(args)>::Format(fmt, tuple);
}

#define FMT_N(idx)	case idx: ToString(ret, std::get<idx>(args)); break;

#define FMT_PARSE(N, ...)															\
template <>																			\
struct SFormatN<N> {																\
	template <class... ARGS>														\
	static std::string Format(const char * fmt, const std::tuple<ARGS...> & args)	\
	{	std::string ret;															\
		while (*fmt != '\0') { auto idx = -1;										\
			if (*fmt == '{') { idx = 0; ++fmt;										\
				while (*fmt >= '0' && *fmt <= '9')									\
					{ idx *= 10; idx += (int)(*fmt++ - '0'); }						\
				if (*fmt != '}') idx = -1; else ++fmt;								\
			}																		\
			switch (idx) { __VA_ARGS__ default: ret.append(1, *fmt++); break; }		\
		}																			\
		return ret;																	\
	}																				\
};

FMT_PARSE(1, FMT_N(0))
FMT_PARSE(2, FMT_N(0) FMT_N(1))
FMT_PARSE(3, FMT_N(0) FMT_N(1) FMT_N(2))
FMT_PARSE(4, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3))
FMT_PARSE(5, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4))
FMT_PARSE(6, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5))
FMT_PARSE(7, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6))
FMT_PARSE(8, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7))
FMT_PARSE(9, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8))
FMT_PARSE(10, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9))
FMT_PARSE(11, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10))
FMT_PARSE(12, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11))
FMT_PARSE(13, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12))
FMT_PARSE(14, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13))
FMT_PARSE(15, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14))
FMT_PARSE(16, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15))
FMT_PARSE(17, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16))
FMT_PARSE(18, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17))
FMT_PARSE(19, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17) FMT_N(18))
FMT_PARSE(20, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17) FMT_N(18) FMT_N(19))
FMT_PARSE(21, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17) FMT_N(18) FMT_N(19) FMT_N(20))
FMT_PARSE(22, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17) FMT_N(18) FMT_N(19) FMT_N(20) FMT_N(21))
FMT_PARSE(23, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17) FMT_N(18) FMT_N(19) FMT_N(20) FMT_N(21) FMT_N(22))
FMT_PARSE(24, FMT_N(0) FMT_N(1) FMT_N(2) FMT_N(3) FMT_N(4) FMT_N(5) FMT_N(6) FMT_N(7) FMT_N(8) FMT_N(9) FMT_N(10) FMT_N(11) FMT_N(12) FMT_N(13) FMT_N(14) FMT_N(15) FMT_N(16) FMT_N(17) FMT_N(18) FMT_N(19) FMT_N(20) FMT_N(21) FMT_N(22) FMT_N(23))