#pragma once

#include "string_literal.h"

namespace saw {

template <class T, class... TL> struct parameter_pack_index;

template <class T, class... TL> struct parameter_pack_index<T, T, TL...> {
	static constexpr size_t value = 0u;
};

template <class T, class TL0, class... TL>
struct parameter_pack_index<T, TL0, TL...> {
	static constexpr size_t value =
		1u + parameter_pack_index<T, TL...>::value;
};

template <size_t N, class... T> struct parameter_pack_type {
	static_assert(always_false<T...>, "Should've been caught by the specializations");
};

template <class TN, class... T> struct parameter_pack_type<0, TN, T...> {
	using type = TN;
};

template <size_t N, class TN, class... T>
struct parameter_pack_type<N, TN, T...> {
	static_assert(sizeof...(T) > 0, "Exhausted parameters");
	static_assert(N > 0, "Invalid number. Should've been caught");
	using type = typename parameter_pack_type<N - 1, T...>::type;
};
/*
 * Nightmare inducing compiler problems found here. Somehow non-type
 * string_literals cannot be resolved as non-type primitive template values can.
 * This is the workaround
 */
template <string_literal V, string_literal Key0, string_literal... Keys>
struct parameter_key_pack_index_helper {
	static constexpr size_t value =
		(V == Key0)
			? (0u)
			: (1u + parameter_key_pack_index_helper<V, Keys...>::value);
};

template <string_literal V, string_literal Key0>
struct parameter_key_pack_index_helper<V, Key0> {
	static constexpr size_t value = (V == Key0) ? (0u) : (1u);
};

template <string_literal V, string_literal... Keys>
struct parameter_key_pack_index {
	static constexpr size_t value =
		parameter_key_pack_index_helper<V, Keys...>::value;
	static_assert(value < sizeof...(Keys),
				  "Provided string_literal doesn't exist in searched list");
};

template <size_t i, size_t s, string_literal Key0, string_literal... Keys>
struct parameter_key_pack_type_helper {
	static constexpr string_literal literal = parameter_key_pack_type_helper<i, s+1, Keys...>::literal;
};

template <size_t i, string_literal Key0, string_literal... Keys>
struct parameter_key_pack_type_helper<i, i, Key0, Keys...> {
	static constexpr string_literal literal = Key0;
};

template <size_t i, string_literal... Keys>
struct parameter_key_pack_type {
	static constexpr string_literal literal = parameter_key_pack_type_helper<i, 0, Keys...>::literal;

	static_assert(i < sizeof...(Keys), "Provided index is too large for list");
};

template<std::size_t i, std::size_t s, typename T, T V0, T... VN>
struct parameter_pack_value_helper {
	static constexpr T value = parameter_pack_value_helper<i, s+1, T, VN...>::value;
};

template<std::size_t i, typename T, T V0, T... VN>
struct parameter_pack_value_helper<i, i, T, V0, VN...> {
	static constexpr T value = V0;
};

template<std::size_t i, typename T, T... Values>
struct parameter_pack_value {
	static constexpr T value = parameter_pack_value_helper<i, 0, T, Values...>::value;
	static_assert(i < sizeof...(Values), "Provided index is too large for list");
};

template<typename T, T... V>
struct ct_multiply;

template<typename T>
struct ct_multiply<T> {
	static constexpr T value = 1;
};

template<typename T, T V0, T... VN>
struct ct_multiply<T, V0, VN...> {
	static constexpr T value = V0 * ct_multiply<T,VN...>::value;
};

namespace impl {
template<typename T, size_t i>
struct ct_convert_digits_table_helper {
		static constexpr std::array<T, 16> table = {
				'0', '1', '2', '3',
				'4', '5', '6', '7',
				'8', '9', 'A', 'B',
				'C', 'D', 'E', 'F'
		};

		static constexpr T value = table[i];
};

template<uint64_t Num, uint64_t Base, uint64_t... Digs>
struct ct_convert_digits_helper {
		static constexpr size_t size = ct_convert_digits_helper<Num / Base, Base, Num % Base, Digs...>::size;
		static constexpr std::array<uint64_t, size> value = ct_convert_digits_helper<Num / Base, Base, Num % Base, Digs...>::value;
};

template<uint64_t Base, uint64_t... Digs>
struct ct_convert_digits_helper<0, Base, Digs...> {
		static constexpr size_t size = sizeof...(Digs);
		static constexpr std::array<uint64_t, size> value = {Digs...};
};

template<uint64_t Base>
struct ct_convert_digits_helper<0, Base> {
		static constexpr size_t size = 0;
		static constexpr std::array<uint64_t, 1> value = {0};
};
}

template<uint64_t Num, uint64_t Base>
struct ct_convert_to_digits {
		static_assert(Base <= 16, "Only conversion up to hex is supported");

		static constexpr size_t size = impl::ct_convert_digits_helper<Num, Base>::size;
		static constexpr std::array<uint64_t, size> value = impl::ct_convert_digits_helper<Num, Base>::value;
};
}