PkmnLib.NET/Plugins/PkmnLib.Plugin.Gen7.Tests/Scripts/Moves/MoonlightTests.cs

using PkmnLib.Dynamic.Models;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Static;
using PkmnLib.Static.Utils;

namespace PkmnLib.Plugin.Gen7.Tests.Scripts.Moves;

/// <summary>
/// Tests for the <see cref="Moonlight"/> move script.
/// Gen VII Bulbapedia behavior: "Moonlight restores the user's current HP based on the weather in the battle.
/// During no weather it restores ½ total HP, during harsh sunlight it restores ⅔ total HP, and during other
/// weather it restores ¼ total HP, rounded down." Generation VI onwards: "When used during strong winds it
/// restores ½ total HP, rounded down."
/// </summary>
public class MoonlightTests
{
    /// <summary>
    /// Creates a fully mocked test setup for Moonlight tests. Moonlight targets the user itself, so the
    /// returned Pokémon is used as both the move's user and the target of the secondary effect.
    /// </summary>
    private static (Moonlight moonlight, IExecutingMove move, IPokemon user) CreateTestSetup(uint maxHp,
        string? weatherName)
    {
        var moonlight = new Moonlight();
        var move = Substitute.For<IExecutingMove>();

        var battle = Substitute.For<IBattle>();
        battle.WeatherName.Returns(weatherName == null ? (StringKey?)null : new StringKey(weatherName));
        var battleData = Substitute.For<IPokemonBattleData>();
        battleData.Battle.Returns(battle);

        var user = Substitute.For<IPokemon>();
        user.BattleData.Returns(battleData);
        user.BoostedStats.Returns(new StatisticSet<uint>(maxHp, 0, 0, 0, 0, 0));
        move.User.Returns(user);

        return (moonlight, move, user);
    }

    /// <summary>
    /// Helper to extract the heal amount from the user's received Heal calls.
    /// </summary>
    private static uint? GetHealAmount(IPokemon user)
    {
        var call = user.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "Heal");
        return call != null ? (uint)call.GetArguments()[0]! : null;
    }

    /// <summary>
    /// Bulbapedia: "During no weather it restores ½ total HP ... rounded down."
    /// </summary>
    [Test, Arguments(100u, 50u), Arguments(99u, 49u), Arguments(255u, 127u)]
    public async Task OnSecondaryEffect_NoWeather_HealsHalfMaxHp(uint maxHp, uint expectedHeal)
    {
        // Arrange
        var (moonlight, move, user) = CreateTestSetup(maxHp, null);

        // Act
        moonlight.OnSecondaryEffect(move, user, 0);

        // Assert
        await Assert.That(GetHealAmount(user)!.Value).IsEqualTo(expectedHeal);
    }

    /// <summary>
    /// Bulbapedia: "during harsh sunlight it restores ⅔ total HP ... rounded down."
    /// </summary>
    [Test, Arguments(100u, 66u), Arguments(99u, 66u), Arguments(300u, 200u)]
    public async Task OnSecondaryEffect_HarshSunlight_HealsTwoThirdsMaxHp(uint maxHp, uint expectedHeal)
    {
        // Arrange
        var (moonlight, move, user) = CreateTestSetup(maxHp, "harsh_sunlight");

        // Act
        moonlight.OnSecondaryEffect(move, user, 0);

        // Assert
        await Assert.That(GetHealAmount(user)!.Value).IsEqualTo(expectedHeal);
    }

    /// <summary>
    /// Bulbapedia: "during other weather it restores ¼ total HP, rounded down." Rain, hail and sandstorm all
    /// count as "other weather".
    /// </summary>
    [Test, Arguments("rain", 100u, 25u), Arguments("hail", 100u, 25u), Arguments("sandstorm", 100u, 25u),
     Arguments("rain", 103u, 25u), Arguments("sandstorm", 7u, 1u)]
    public async Task OnSecondaryEffect_OtherWeather_HealsQuarterMaxHp(string weather, uint maxHp, uint expectedHeal)
    {
        // Arrange
        var (moonlight, move, user) = CreateTestSetup(maxHp, weather);

        // Act
        moonlight.OnSecondaryEffect(move, user, 0);

        // Assert
        await Assert.That(GetHealAmount(user)!.Value).IsEqualTo(expectedHeal);
    }

    /// <summary>
    /// Bulbapedia (Generation VI onwards): "When used during strong winds it restores ½ total HP, rounded
    /// down."
    /// </summary>
    [Test, Arguments(100u, 50u), Arguments(99u, 49u)]
    public async Task OnSecondaryEffect_StrongWinds_HealsHalfMaxHp(uint maxHp, uint expectedHeal)
    {
        // Arrange
        var (moonlight, move, user) = CreateTestSetup(maxHp, "strong_winds");

        // Act
        moonlight.OnSecondaryEffect(move, user, 0);

        // Assert
        await Assert.That(GetHealAmount(user)!.Value).IsEqualTo(expectedHeal);
    }

    /// <summary>
    /// Bulbapedia: "Moonlight restores the user's current HP" — the heal is applied to the move's user.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_NoWeather_HealsTheUser()
    {
        // Arrange
        var (moonlight, move, user) = CreateTestSetup(100, null);

        // Act
        moonlight.OnSecondaryEffect(move, user, 0);

        // Assert
        await Assert.That(user.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Heal")).IsTrue();
    }

    /// <summary>
    /// Technical test: without battle data on the user (outside of battle) the secondary effect does nothing
    /// and does not throw.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserHasNoBattleData_DoesNotHeal()
    {
        // Arrange
        var moonlight = new Moonlight();
        var move = Substitute.For<IExecutingMove>();
        var user = Substitute.For<IPokemon>();
        user.BattleData.Returns((IPokemonBattleData?)null);
        move.User.Returns(user);

        // Act
        moonlight.OnSecondaryEffect(move, user, 0);

        // Assert
        await Assert.That(user.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Heal")).IsFalse();
    }
}