#include <catch.hpp>
#include "../common.h"

#include <pfor/mp/meta.h>

template<typename T>
struct Sizeof {
	static constexpr std::size_t value = sizeof(T);
};

TEST_CASE("Meta") {
	SECTION("If") {
		TEST(REQUIRE, is_same_v<pfor::If<false, char, int>, int>);
		TEST(REQUIRE, is_same_v<pfor::If<true, char, int>, char>);
	}

	SECTION("accumulate") {
		using E = pfor::Pack<>;
		using T = pfor::Pack<char, int, float>;

		std::size_t esize = pfor::accumulate<Sizeof, E>(0, std::plus<std::size_t>{});
		std::size_t tsize = pfor::accumulate<Sizeof, T>(1, std::multiplies<std::size_t>{});

		REQUIRE(esize == 0);
		REQUIRE(tsize == sizeof(char)*sizeof(int)*sizeof(float));
	}

	SECTION("GCD") {
		pfor::IntToType<pfor::gcd(1, 0)> a; // ensure gcd can be computed at compile-time

		REQUIRE(pfor::gcd(5, 0) == 5);
		REQUIRE(pfor::gcd(9, 0) == 9);
		REQUIRE(pfor::gcd(-21, 9) == 3);
		REQUIRE(pfor::gcd(2*3*7*11*17, 11*19*23) == 11);
		REQUIRE(pfor::gcd(2*3*7*11*17*23, -11*19*23) == 11*23);
	}
}