#include <rsl/random.hpp>

#include <catch2/catch_approx.hpp>

#include <catch2/catch_test_macros.hpp>

#include <catch2/matchers/catch_matchers_string.hpp>

#include <thread>

namespace {

auto const* const rng = &rsl::rng({0, 1});

}

TEST_CASE("rsl::rng") {

SECTION("Repeated calls in thread yield same object") {

CHECK(rng == &rsl::rng());

CHECK(rng == &rsl::rng());

CHECK(rng == &rsl::rng());

}

SECTION("Calls from separate threads yield separate objects") {

// Test using randomly generated seed

auto thread1 = std::thread([] { CHECK(rng != &rsl::rng()); });

// Test that custom seed in separate thread does not throw

auto thread2 = std::thread([] { CHECK(rng != &rsl::rng({2, 3})); });

thread1.join();

thread2.join();

}

SECTION("Throw if seeded after first call") {

CHECK_NOTHROW(rsl::rng({}));

CHECK_THROWS_WITH(rsl::rng({1, 2, 3, 4}), Catch::Matchers::ContainsSubstring(

"rng cannot be re-seeded on this thread"));

}

}

TEST_CASE("rsl::uniform_real") {

constexpr auto lower = -100.;

constexpr auto upper = 100.;

for (int i = 0; i < 1'000; ++i) {

auto const value = rsl::uniform_real(lower, upper);

CHECK(value >= lower);

CHECK(value < upper);

}

}

TEST_CASE("rsl::uniform_int") {

constexpr auto lower = -100;

constexpr auto upper = 100;

for (int i = 0; i < 1'000; ++i) {

auto const value = rsl::uniform_int(lower, upper);

CHECK(value >= lower);

CHECK(value <= upper);

}

}

TEST_CASE("rsl::random_unit_quaternion") {

for (int i = 0; i < 1'000; ++i)

CHECK(rsl::random_unit_quaternion().norm() == Catch::Approx(1.).epsilon(0).margin(1e-6));

}