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

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

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

/// <summary>
/// Tests for the <see cref="LunarDance"/> move script and its side effect script
/// <see cref="LunarDanceEffect"/>.
/// Gen VII Bulbapedia behavior: "Lunar Dance causes the user to faint, but restores the HP and PP of the
/// Pokémon that is sent out to take its place as well as removing all status conditions (except
/// fainting).", where from Generation V to VII "The receiving Pokémon is now sent out at the end of the
/// turn after all other Pokémon have moved."
/// </summary>
public class LunarDanceTests
{
    /// <summary>
    /// Creates a fully mocked test setup for the <see cref="LunarDance"/> move script, with the user at the
    /// given position and the side's volatile scripts backed by a real <see cref="ScriptSet"/>.
    /// </summary>
    private static (LunarDance script, IExecutingMove move, IPokemon user, IScriptSet sideVolatile) CreateMoveSetup(
        byte position = 1)
    {
        var script = new LunarDance();
        var move = Substitute.For<IExecutingMove>();

        var side = Substitute.For<IBattleSide>();
        // ScriptSet.Add runs the IScriptPreventVolatileAdd hook over the owner's scripts; give the mock a
        // real (empty) iterator so the hook pass runs.
        side.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet sideVolatile = new ScriptSet(side);
        side.VolatileScripts.Returns(sideVolatile);

        var battleData = Substitute.For<IPokemonBattleData>();
        battleData.BattleSide.Returns(side);
        battleData.Position.Returns(position);

        var user = Substitute.For<IPokemon>();
        user.BattleData.Returns(battleData);
        move.User.Returns(user);

        return (script, move, user, sideVolatile);
    }

    /// <summary>
    /// Creates a mocked replacement Pokémon with the given maximum HP for
    /// <see cref="LunarDanceEffect"/> tests.
    /// </summary>
    private static IPokemon CreateReplacement(uint maxHp = 200)
    {
        var pokemon = Substitute.For<IPokemon>();
        pokemon.MaxHealth.Returns(maxHp);
        return pokemon;
    }

    /// <summary>
    /// Helper to extract the heal amount from a substitute's received Heal calls, or null when Heal was
    /// never called.
    /// </summary>
    private static uint? GetHealAmount(IPokemon pokemon)
    {
        var call = pokemon.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "Heal");
        return call != null ? (uint)call.GetArguments()[0]! : null;
    }

    /// <summary>
    /// Bulbapedia (Generations V to VII): "The receiving Pokémon is now sent out at the end of the turn" —
    /// using the move leaves a pending <see cref="LunarDanceEffect"/> on the user's side instead of healing
    /// anything directly.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserInBattle_AddsLunarDanceEffectToUserSide()
    {
        // Arrange
        var (script, move, _, sideVolatile) = CreateMoveSetup();

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

        // Assert
        await Assert.That(sideVolatile.Contains(ScriptUtils.ResolveName<LunarDanceEffect>())).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Lunar Dance causes the user to faint".
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserInBattle_UserFaints()
    {
        // Arrange
        var (script, move, user, _) = CreateMoveSetup();

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

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

    /// <summary>
    /// Bulbapedia: the dance benefits the Pokémon "sent out to take its place" — the pending effect is
    /// bound to the position the user occupied, so a replacement entering that position is healed.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserAtPosition_EffectTargetsUsersPosition()
    {
        // Arrange
        var (script, move, _, sideVolatile) = CreateMoveSetup(1);
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);
        var effect = (LunarDanceEffect)sideVolatile.Get(new StringKey("lunar_dance"))!.Script!;
        var replacement = CreateReplacement();

        // Act
        effect.OnSwitchIn(replacement, 1);

        // Assert
        await Assert.That(GetHealAmount(replacement)).IsNotNull();
    }

    /// <summary>
    /// Technical test: outside of battle (no <see cref="IPokemon.BattleData"/>) the hook does nothing and
    /// does not throw.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_NoBattleData_DoesNothing()
    {
        // Arrange
        var script = new LunarDance();
        var move = Substitute.For<IExecutingMove>();
        var user = Substitute.For<IPokemon>();
        user.BattleData.Returns((IPokemonBattleData?)null);
        move.User.Returns(user);

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

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

    /// <summary>
    /// Bulbapedia: "restores the HP ... of the Pokémon that is sent out to take its place" — the
    /// replacement switching into the dancer's position is healed by its full maximum HP.
    /// </summary>
    [Test, Arguments(200u), Arguments(1u), Arguments(999u)]
    public async Task OnSwitchIn_MatchingPosition_HealsReplacementToFullHp(uint maxHp)
    {
        // Arrange
        var effect = new LunarDanceEffect(1);
        var replacement = CreateReplacement(maxHp);

        // Act
        effect.OnSwitchIn(replacement, 1);

        // Assert
        await Assert.That(GetHealAmount(replacement)!.Value).IsEqualTo(maxHp);
    }

    /// <summary>
    /// Bulbapedia: "restores the HP and PP of the Pokémon that is sent out" — unlike Healing Wish, Lunar
    /// Dance also restores the replacement's PP.
    /// </summary>
    [Test]
    public async Task OnSwitchIn_MatchingPosition_RestoresPP()
    {
        // Arrange
        var effect = new LunarDanceEffect(1);
        var replacement = CreateReplacement();

        // Act
        effect.OnSwitchIn(replacement, 1);

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

    /// <summary>
    /// Bulbapedia: "removing all status conditions (except fainting)".
    /// </summary>
    [Test]
    public async Task OnSwitchIn_MatchingPosition_CuresStatus()
    {
        // Arrange
        var effect = new LunarDanceEffect(1);
        var replacement = CreateReplacement();

        // Act
        effect.OnSwitchIn(replacement, 1);

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

    /// <summary>
    /// Bulbapedia (Generations V to VII): the dance is consumed by the Pokémon sent out at the position —
    /// unlike Generation VIII onwards there is no check on the replacement's HP, status or PP, so the
    /// effect is removed from the side after the first switch-in.
    /// </summary>
    [Test]
    public async Task OnSwitchIn_MatchingPosition_EffectIsRemovedFromSide()
    {
        // Arrange
        var side = Substitute.For<IBattleSide>();
        side.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet sideVolatile = new ScriptSet(side);
        var effect = new LunarDanceEffect(1);
        sideVolatile.Add(effect);

        // Act
        effect.OnSwitchIn(CreateReplacement(), 1);

        // Assert
        await Assert.That(sideVolatile.Contains(ScriptUtils.ResolveName<LunarDanceEffect>())).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: the dance applies to the Pokémon sent out in the user's place — a Pokémon switching in
    /// at a different position on the side is not restored and does not consume the effect.
    /// </summary>
    [Test]
    public async Task OnSwitchIn_DifferentPosition_DoesNotRestoreAndEffectPersists()
    {
        // Arrange
        var side = Substitute.For<IBattleSide>();
        side.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet sideVolatile = new ScriptSet(side);
        var effect = new LunarDanceEffect(1);
        sideVolatile.Add(effect);
        var otherPokemon = CreateReplacement();

        // Act
        effect.OnSwitchIn(otherPokemon, 0);

        // Assert
        await Assert.That(GetHealAmount(otherPokemon)).IsNull();
        await Assert.That(otherPokemon.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "ClearStatus")).IsFalse();
        await Assert.That(sideVolatile.Contains(ScriptUtils.ResolveName<LunarDanceEffect>())).IsTrue();
    }
}