#pragma once

namespace {

	/**
	 * Recursively generates a tuple out of a subsection of another tuple.
	 *
	 * @tparam T - The base tuple to pull the types from.
	 * @tparam N - The current index of the type to add to the resultant tuple.
	 * @tparam M - The end index of types to pull.
	 * @tparam Args - A pack of the args to add into the resultant tuple.
	 * @returns the subsection of the tuple T as specified by M and N.
	 */
	
	template<typename T, usize N, usize M, typename... Args>
	inline constexpr auto tuple_sub_impl() {
		if constexpr (N <= M) return tuple_sub_impl<T, N + 1, M, Args..., std::tuple_element_t<N, T>>();
		else return std::tuple<Args...> {};
	}
}

/**
 * Struct containing a subsection of a tuple T and start index N and end index M.
 *
 * @tparam T - The tuple to take a subsection of.
 * @tparam N - The start index of the tuple types to include.
 * @tparam M - The end index of the tuple types to include - defaults to the tuple's size.
 */

template <typename T, usize N, usize M = std::tuple_size_v<T> - 1>
struct tuple_sub {

	/** The value of the subsection of the tuple. */
	typedef decltype(tuple_sub_impl<T, N, M>()) value_type;
};

/**
 * Shorthand for the value type of tuple_sub with the provided template arguments.
 */

template <typename T, usize N, usize M = std::tuple_size_v<T> - 1>
using tuple_sub_t = typename tuple_sub<T, N, M>::value_type;