// SPDX-License-Identifier: MPL-2.0
#include "sequa/core/sim/fixed.hpp"

#include <doctest/doctest.h>

#include <cstdint>
#include <limits>

using sequa::core::sim::Fixed;

TEST_CASE("Fixed : conversions entieres et rationnelles")
{
    CHECK(Fixed::from_int(3).raw() == 3 * 65536);
    CHECK(Fixed::from_int(-2).raw() == -2 * 65536);
    CHECK(Fixed::from_ratio(1, 2).raw() == 32768);
    CHECK(Fixed::from_ratio(1, 60).raw() == 1092); // arrondi vers zero
    CHECK(Fixed::from_ratio(-1, 60).raw() == -1092);
}

TEST_CASE("Fixed : arithmetique exacte et arrondis documentes")
{
    const Fixed a = Fixed::from_int(5);
    const Fixed b = Fixed::from_ratio(1, 4);
    CHECK((a + b).raw() == 5 * 65536 + 16384);
    CHECK((a - b).raw() == 5 * 65536 - 16384);
    CHECK((a * b).raw() == 5 * 16384);
    CHECK((a / b).raw() == 20 * 65536);
    CHECK((-a).raw() == -5 * 65536);

    // Produit : arrondi vers moins l'infini ; quotient : vers zero.
    const Fixed tiny = Fixed::from_raw(1);
    const Fixed half = Fixed::from_ratio(1, 2);
    CHECK((tiny * half).raw() == 0);
    CHECK(((-tiny) * half).raw() == -1);
    CHECK((Fixed::from_raw(-1) / Fixed::from_int(2)).raw() == 0);
}

TEST_CASE("Fixed : un depassement est modulaire, donc deterministe")
{
    const Fixed max = Fixed::from_raw(std::numeric_limits<std::int32_t>::max());
    CHECK((max + Fixed::from_raw(1)).raw() == std::numeric_limits<std::int32_t>::min());
}

TEST_CASE("Fixed : comparaisons, abs et clamp")
{
    const Fixed one = Fixed::from_int(1);
    CHECK(one > Fixed{});
    CHECK(abs(-one) == one);
    CHECK(clamp(Fixed::from_int(7), -one, one) == one);
    CHECK(clamp(Fixed::from_int(-7), -one, one) == -one);
    CHECK(Fixed::from_ratio(3, 2).to_double() == doctest::Approx(1.5));
}