#ifndef UTIL_H
#define UTIL_H

#include <cstring>
#include <memory>
#include <string>
#include <SWI-Prolog.h>
#include <windows.h>

#define CONCAT_IMPL(a, b) a##b
#define CONCAT(a, b) CONCAT_IMPL(a, b)
#define _ CONCAT(unused_, __LINE__)

template <typename F>
struct Finally
{
	F f;
	inline Finally(F f) : f(f) {}
	inline ~Finally() { f(); }
};
#define FINALLY Finally _ = [=]()

/* Generic RAII type. */
template <typename T, auto F, typename U, auto E = 0>
struct Managed
{
	T obj;
	Managed(T obj) : obj(obj)
	{
		if (obj == reinterpret_cast<T>(E))
			throw U();
	}
	~Managed() { F(obj); }
	operator T() { return obj; }
	auto& operator *() { return *obj; }
	auto& operator ->() { return obj; }
	auto& operator [](size_t i) { return obj[i]; }
};

/* Buf is a span-like structure of a buffer and its size. */
template <typename T>
struct Buf
{
	T* data;
	size_t c;
	Buf(T* data, size_t c) : data(data), c(c) {}
	Buf(std::basic_string<T>& s) : data(s.data()), c(s.capacity()) {}
	template <size_t N> Buf(T (&data)[N]) : data(data), c(N) {}
	operator T*() { return data; }
	T& operator *() { return *data; }
	T& operator [](size_t i) { return data[i]; }
	Buf<T> operator +(size_t i) { return {data+i, c-i}; }
	//T operator -(size_t i) { return {data-i, c+i}; }
};

inline int Cmp(const int a, const int b)
{
	if (a == b) return 0;
	if (a > b) return 1;
	return -1;
}

inline size_t Min(size_t a, size_t b)
{
	return a < b? a: b;
}

template <typename T, size_t N>
inline size_t Len(T (&)[N])
{
	return N-1;
}

/* Format wide string. */
template<typename... T>
inline int Swprintf(Buf<wchar_t> buf, const wchar_t* const fmt, T... xs)
{
	return _snwprintf_s(buf, buf.c, _TRUNCATE, fmt, xs...);
}

/* Format static narrow string. */
template<typename... T>
inline int Sprintf(Buf<char> buf, const char* const fmt, T... xs)
{
	return _snprintf_s(buf, buf.c, _TRUNCATE, fmt, xs...);
}

/* Copy to static wide string buffer. */
inline wchar_t* Wcscpy(Buf<wchar_t> dst, const wchar_t* const src)
{
	const size_t len = Min(dst.c, wcslen(src)+1);
	memcpy(dst, src, len*sizeof(wchar_t));
	dst[len-1] = 0;
	return dst;
}

/* Copy to static narrow string buffer. */
inline char* Strcpy(Buf<char> dst, const char* const src)
{
	const size_t len = Min(dst.c, strlen(src)+1);
	memcpy(dst, src, len);
	dst[len-1] = 0;
	return dst;
}

#endif