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

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

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

/// <summary>
/// Tests for the <see cref="Instruct"/> move script.
/// Gen VII Bulbapedia behavior: "Instruct causes the target to immediately repeat its most recent move". It
/// fails against targets with no prior moves, and "cannot force repetition of Instruct itself, Sketch,
/// Transform, Mimic, King's Shield, Struggle, moves requiring recharge (like Hyper Beam), moves with charging
/// turns (like Dig), moves calling other moves (like Metronome), Z-Moves, or Max Moves."
/// </summary>
public class InstructTests
{
    /// <summary>
    /// Creates a fully mocked test setup for Instruct tests. When <paramref name="lastMoveName"/> is given,
    /// the target has a repeatable last move choice of that name; otherwise it has not moved yet.
    /// </summary>
    private static (Instruct script, IExecutingMove move, IBattle battle, IBattlePokemon target, IHitData hitData,
        IMoveChoice? lastChoice) CreateTestSetup(string? lastMoveName)
    {
        var script = new Instruct();
        var move = Substitute.For<IExecutingMove>();
        var user = Substitute.For<IBattlePokemon>();
        move.User.Returns(user);

        var battle = Substitute.For<IBattle>();
        user.Battle.Returns(battle);

        var target = Substitute.For<IBattlePokemon>();
        target.IsUsable.Returns(true);

        IMoveChoice? lastChoice = null;
        if (lastMoveName != null)
        {
            lastChoice = Substitute.For<IMoveChoice>();
            // The choice needs a real (empty) script iterator so the turn runner's hook pass works on it.
            lastChoice.GetScripts().Returns(_ => new ScriptIterator(new List<IEnumerable<ScriptContainer>>()));
            lastChoice.User.Returns(Substitute.For<IBattlePokemon>());
            var moveData = Substitute.For<IMoveData>();
            moveData.Name.Returns(new StringKey(lastMoveName));
            var learnedMove = Substitute.For<ILearnedMove>();
            learnedMove.MoveData.Returns(moveData);
            lastChoice.ChosenMove.Returns(learnedMove);
        }
        target.LastMoveChoice.Returns(lastChoice);

        var hitData = Substitute.For<IHitData>();
        move.GetHitData(target, 0).Returns(hitData);

        return (script, move, battle, target, hitData, lastChoice);
    }

    /// <summary>
    /// Bulbapedia: Instruct "fails against targets with no prior moves." A target that has not used a move
    /// yet has no choice to repeat, so the hit fails.
    /// </summary>
    [Test]
    public void OnSecondaryEffect_TargetHasNotMovedYet_HitFails()
    {
        // Arrange
        var (script, move, _, target, hitData, _) = CreateTestSetup(null);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        hitData.Received(1).Fail();
    }

    /// <summary>
    /// Bulbapedia: the repeated move must actually be usable (e.g. it fails if the move has no PP left).
    /// When the battle reports the last choice as unusable, the hit fails.
    /// </summary>
    [Test]
    public void OnSecondaryEffect_LastChoiceCannotBeUsed_HitFails()
    {
        // Arrange
        var (script, move, battle, target, hitData, lastChoice) = CreateTestSetup("tackle");
        battle.CanUse(lastChoice!).Returns(false);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        hitData.Received(1).Fail();
    }

    /// <summary>
    /// Bulbapedia: "Instruct causes the target to immediately repeat its most recent move". With a usable
    /// last move choice the move does not fail (the choice is handed to the turn runner for execution).
    /// </summary>
    [Test]
    public void OnSecondaryEffect_LastChoiceUsable_HitDoesNotFail()
    {
        // Arrange
        var (script, move, battle, target, hitData, lastChoice) = CreateTestSetup("tackle");
        battle.CanUse(lastChoice!).Returns(true);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        hitData.DidNotReceive().Fail();
    }

    /// <summary>
    /// Technical test: an unusable (e.g. fainted) target is skipped entirely — nothing is executed and the
    /// hit is not failed.
    /// </summary>
    [Test]
    public void OnSecondaryEffect_TargetNotUsable_DoesNothing()
    {
        // Arrange
        var (script, move, _, target, hitData, _) = CreateTestSetup("tackle");
        target.IsUsable.Returns(false);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        hitData.DidNotReceive().Fail();
    }

    /// <summary>
    /// Bulbapedia: "The move cannot force repetition of Instruct itself, Sketch, Transform, Mimic, King's
    /// Shield, Struggle, moves requiring recharge (like Hyper Beam), moves with charging turns (like Dig),
    /// moves calling other moves (like Metronome), Z-Moves, or Max Moves." When the target's last move is
    /// such a move, Instruct fails.
    /// </summary>
    [Test]
    public void OnSecondaryEffect_LastMoveIsInstructItself_HitFails()
    {
        // Arrange
        var (script, move, battle, target, hitData, lastChoice) = CreateTestSetup("instruct");
        battle.CanUse(lastChoice!).Returns(true);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        hitData.Received(1).Fail();
    }
}