#pragma once

#include <cstdint>

namespace sp {

/// @brief Default case, see field_index specialization for implementation details
template <size_t N, typename T, template <size_t, typename> typename U, typename = void>
static constexpr size_t field_index = 0;

/// @brief A templated size_t that counts the number of existing classes U with a "field_name" member
/// @tparam N Current counter for recursion (user should always call it with 0)
/// @tparam T Can be any type, must be different for each field we want to be counted later (used because we can't have a empty
/// template<> specialization nested in a class)
/// @tparam U The templated class that will be searched for match
template <size_t N, typename T, template <size_t, typename> typename U>
static constexpr size_t field_index<N, T, U, std::void_t<decltype(U<N, T>::field_name)>> = 1 + field_index<N + 1, T, U>;

/// @brief Concat multiple tuples in one big tuple
/// @tparam ...input_t Multiple std::tuple types to concat
template <typename... input_t>
using tuple_cat_t = decltype(std::tuple_cat(std::declval<input_t>()...));

template <typename T, typename Tuple>
constexpr bool tuple_contains_type = false;
template <typename T, typename... Ts>
constexpr bool tuple_contains_type<T, std::tuple<Ts...>> = std::disjunction_v<std::is_same<T, Ts>...>;

template <typename T, typename Tuple>
constexpr int get_tuple_index = 0;
template <typename T, typename... Rest>
constexpr int get_tuple_index<T, std::tuple<T, Rest...>> = 0;
template <typename T, typename First, typename... Rest>
constexpr int get_tuple_index<T, std::tuple<First, Rest...>> = 1 + get_tuple_index<T, std::tuple<Rest...>>;

// Template black magic to loop at compile time
template <std::size_t... indices, class LoopBody>
void loop_impl(std::index_sequence<indices...>, LoopBody&& loop_body) {
	(loop_body(std::integral_constant<std::size_t, indices>{}), ...);
}

template <std::size_t N, class LoopBody>
void loop(LoopBody&& loop_body) {
	loop_impl(std::make_index_sequence<N>{}, std::forward<LoopBody>(loop_body));
}

namespace details {
template <std::size_t TRem>
class TupleForEachHelper {
  public:
	template <typename TTuple, typename TFunc>
	static void exec(TTuple&& tuple, TFunc&& func) {
		using Tuple = typename std::decay<TTuple>::type;
		static const std::size_t TupleSize = std::tuple_size<Tuple>::value;
		static_assert(TRem <= TupleSize, "Incorrect parameters");

		// Invoke function with current element
		static const std::size_t Idx = TupleSize - TRem;
		func(std::get<Idx>(std::forward<TTuple>(tuple)));

		// Compile time recursion - invoke function with the remaining elements
		TupleForEachHelper<TRem - 1>::exec(std::forward<TTuple>(tuple), std::forward<TFunc>(func));
	}
};

template <>
class TupleForEachHelper<0> {
  public:
	// Stop compile time recursion
	template <typename TTuple, typename TFunc>
	static void exec(TTuple&& tuple, TFunc&& func) {
		static_cast<void>(tuple);
		static_cast<void>(func);
	}
};
}  // namespace details

template <typename TTuple, typename TFunc>
void tupleForEach(TTuple&& tuple, TFunc&& func) {
	using Tuple = typename std::decay<TTuple>::type;
	static const std::size_t TupleSize = std::tuple_size<Tuple>::value;

	details::TupleForEachHelper<TupleSize>::exec(std::forward<TTuple>(tuple), std::forward<TFunc>(func));
}

}  // namespace sp