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

using PkmnLib.Dynamic.Events;
using PkmnLib.Dynamic.Models;
using PkmnLib.Dynamic.Models.Choices;
using PkmnLib.Dynamic.ScriptHandling;
using PkmnLib.Dynamic.ScriptHandling.Registry;
using PkmnLib.Plugin.Gen7.Scripts.Battle;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Plugin.Gen7.Scripts.Side;
using PkmnLib.Static.Moves;

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

/// <summary>
/// Tests for the <see cref="FutureSight"/> move script and its <see cref="FutureSightEffect"/>.
/// Gen VII Bulbapedia behavior: "On the turn Future Sight is selected, this attack will do nothing other
/// than say that the user has foreseen an attack. Two turns later, Future Sight will do damage against the
/// target", where (from Generation V onwards) the damage calculation occurs "when it hits rather than when
/// it is selected".
/// </summary>
public class FutureSightTests
{
    /// <summary>
    /// Creates a fully mocked test setup for the <see cref="FutureSight"/> script where the battle's
    /// volatile scripts are a real <see cref="ScriptSet"/>.
    /// </summary>
    private static (FutureSight script, IExecutingMove move, IPokemon user, IScriptSet battleVolatile)
        CreateScriptSetup()
    {
        var script = new FutureSight();
        var move = Substitute.For<IExecutingMove>();

        var battle = Substitute.For<IBattle>();
        battle.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet battleVolatile = new ScriptSet(battle);
        battle.Volatile.Returns(battleVolatile);

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

        var moveChoice = Substitute.For<IMoveChoice>();
        move.MoveChoice.Returns(moveChoice);

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

    /// <summary>
    /// Creates a fully mocked test setup for the <see cref="FutureSightEffect"/>, with a target at side 1,
    /// position 0 and a damage calculator that computes the given damage when the delayed strike lands.
    /// </summary>
    private static (FutureSightEffect effect, IBattle battle, IPokemon target, EventHook eventHook) CreateEffectSetup(
        uint damage = 100, bool targetUsable = true)
    {
        var moveData = Substitute.For<IMoveData>();
        var learnedMove = Substitute.For<ILearnedMove>();
        learnedMove.MoveData.Returns(moveData);
        var moveChoice = Substitute.For<IMoveChoice>();
        moveChoice.ChosenMove.Returns(learnedMove);
        moveChoice.TargetSide.Returns((byte)1);
        moveChoice.TargetPosition.Returns((byte)0);

        var battle = Substitute.For<IBattle>();
        var eventHook = new EventHook();
        battle.EventHook.Returns(eventHook);

        var target = Substitute.For<IPokemon>();
        target.IsUsable.Returns(targetUsable);
        battle.GetPokemon(1, 0).Returns(target);

        battle.Library.DamageCalculator.GetDamage(Arg.Any<IExecutingMove?>(), Arg.Any<MoveCategory>(),
                Arg.Any<IPokemon>(), Arg.Any<IPokemon>(), Arg.Any<int>(), Arg.Any<byte>(), Arg.Any<IHitData>())
            .Returns(damage);

        var effect = new FutureSightEffect(moveChoice);
        return (effect, battle, target, eventHook);
    }

    /// <summary>
    /// Bulbapedia: "On the turn Future Sight is selected, this attack will do nothing other than say that
    /// the user has foreseen an attack." — the immediate execution of the move is stopped.
    /// </summary>
    [Test]
    public async Task StopBeforeMove_UserInBattle_StopsImmediateExecution()
    {
        // Arrange
        var (script, move, _, _) = CreateScriptSetup();
        var stop = false;

        // Act
        script.StopBeforeMove(move, ref stop);

        // Assert
        await Assert.That(stop).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Two turns later, Future Sight will do damage against the target" — selecting the move
    /// queues a pending <see cref="FutureSightEffect"/> on the battle.
    /// </summary>
    [Test]
    public async Task StopBeforeMove_UserInBattle_AddsFutureSightEffectToBattleVolatile()
    {
        // Arrange
        var (script, move, _, battleVolatile) = CreateScriptSetup();
        var stop = false;

        // Act
        script.StopBeforeMove(move, ref stop);

        // Assert
        await Assert.That(battleVolatile.Contains(ScriptUtils.ResolveName<FutureSightEffect>())).IsTrue();
    }

    /// <summary>
    /// Technical test: outside of battle (no battle data on the user) the hook does nothing and does not
    /// stop the move.
    /// </summary>
    [Test]
    public async Task StopBeforeMove_UserHasNoBattleData_DoesNotStopMove()
    {
        // Arrange
        var (script, move, user, _) = CreateScriptSetup();
        user.BattleData.Returns((IPokemonBattleData?)null);
        var stop = false;

        // Act
        script.StopBeforeMove(move, ref stop);

        // Assert
        await Assert.That(stop).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: "Two turns later, Future Sight will do damage against the target." One end-of-turn tick
    /// after selection (the selection turn itself) plus one more is not enough for the strike to land.
    /// </summary>
    [Test]
    public async Task OnEndTurn_TwoTurnTicks_DoesNotDamageTargetYet()
    {
        // Arrange
        var (effect, battle, target, _) = CreateEffectSetup();

        // Act - end of the selection turn and of the first turn after it
        effect.OnEndTurn(battle, battle);
        effect.OnEndTurn(battle, battle);

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

    /// <summary>
    /// Bulbapedia: "Two turns later, Future Sight will do damage against the target." At the end of the
    /// second turn after selection the delayed strike lands on the Pokémon in the targeted spot.
    /// </summary>
    [Test]
    public async Task OnEndTurn_ThreeTurnTicks_DamagesTarget()
    {
        // Arrange
        var (effect, battle, target, _) = CreateEffectSetup(123);

        // Act - selection turn plus the two turns after it
        effect.OnEndTurn(battle, battle);
        effect.OnEndTurn(battle, battle);
        effect.OnEndTurn(battle, battle);

        // Assert
        var damageCall = target.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "Damage");
        await Assert.That(damageCall).IsNotNull();
        await Assert.That((uint)damageCall!.GetArguments()[0]!).IsEqualTo(123u);
    }

    /// <summary>
    /// Bulbapedia (Generation V onwards): the damage calculation "occurs when it hits rather than when it
    /// is selected" — the damage calculator is only consulted on the turn the strike lands, not before.
    /// </summary>
    [Test]
    public async Task OnEndTurn_BeforeStrikeLands_DamageCalculatorNotConsulted()
    {
        // Arrange
        var (effect, battle, _, _) = CreateEffectSetup();

        // Act
        effect.OnEndTurn(battle, battle);
        effect.OnEndTurn(battle, battle);

        // Assert
        await Assert.That(battle.Library.DamageCalculator.ReceivedCalls()
            .Any(c => c.GetMethodInfo().Name == "GetDamage")).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: the delayed attack does damage "against the target" — when the targeted spot no longer
    /// holds a usable Pokémon, the move fails and no damage is dealt.
    /// </summary>
    [Test]
    public async Task OnEndTurn_TargetNotUsable_MoveFailsWithoutDamage()
    {
        // Arrange
        var (effect, battle, target, eventHook) = CreateEffectSetup(targetUsable: false);
        DialogEvent? capturedDialog = null;
        eventHook.Handler += (_, args) =>
        {
            if (args is DialogEvent dialogEvent)
                capturedDialog = dialogEvent;
        };

        // Act
        effect.OnEndTurn(battle, battle);
        effect.OnEndTurn(battle, battle);
        effect.OnEndTurn(battle, battle);

        // Assert
        await Assert.That(target.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Damage")).IsFalse();
        await Assert.That(capturedDialog).IsNotNull();
        await Assert.That(capturedDialog!.Message).IsEqualTo("move_failed");
    }

    /// <summary>
    /// Creates a mocked battle whose volatile scripts are a real <see cref="ScriptSet"/>, for tests that
    /// exercise multiple Future Sight uses against the same battle.
    /// </summary>
    private static (IBattle battle, IScriptSet battleVolatile) CreateBattleWithRealVolatile()
    {
        var battle = Substitute.For<IBattle>();
        battle.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet battleVolatile = new ScriptSet(battle);
        battle.Volatile.Returns(battleVolatile);
        return (battle, battleVolatile);
    }

    /// <summary>
    /// Creates a mocked executing Future Sight use in the given battle, whose move choice targets the given
    /// side and position.
    /// </summary>
    private static IExecutingMove CreateFutureSightUse(IBattle battle, byte targetSide, byte targetPosition)
    {
        var moveData = Substitute.For<IMoveData>();
        var learnedMove = Substitute.For<ILearnedMove>();
        learnedMove.MoveData.Returns(moveData);
        var moveChoice = Substitute.For<IMoveChoice>();
        moveChoice.ChosenMove.Returns(learnedMove);
        moveChoice.TargetSide.Returns(targetSide);
        moveChoice.TargetPosition.Returns(targetPosition);

        var battleData = Substitute.For<IPokemonBattleData>();
        battleData.Battle.Returns(battle);
        var user = Substitute.For<IPokemon>();
        user.BattleData.Returns(battleData);

        var move = Substitute.For<IExecutingMove>();
        move.User.Returns(user);
        move.MoveChoice.Returns(moveChoice);
        return move;
    }

    /// <summary>
    /// Bulbapedia: "Future Sight fails when used if the target is already set to be hit by Future Sight or
    /// Doom Desire." — a second Future Sight against a spot that already has one queued fails instead of
    /// being silently swallowed.
    /// </summary>
    [Test]
    public async Task StopBeforeMove_FutureSightAlreadyQueuedOnTarget_SecondUseFails()
    {
        // Arrange - a Future Sight is already queued against side 1, position 0
        var script = new FutureSight();
        var (battle, _) = CreateBattleWithRealVolatile();
        var firstUse = CreateFutureSightUse(battle, 1, 0);
        var secondUse = CreateFutureSightUse(battle, 1, 0);
        var stop = false;
        script.StopBeforeMove(firstUse, ref stop);
        stop = false;

        // Act - a second Future Sight is used against the same spot
        script.StopBeforeMove(secondUse, ref stop);

        // Assert - the second use fails
        secondUse.MoveChoice.Received(1).Fail();
        await Assert.That(secondUse.MoveChoice.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Fail")).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Future Sight fails when used if the target is already set to be hit by Future Sight or
    /// Doom Desire." — a pending <see cref="DoomDesireEffect"/> against the targeted spot also makes Future
    /// Sight fail.
    /// </summary>
    [Test]
    public async Task StopBeforeMove_DoomDesireAlreadyQueuedOnTarget_MoveFails()
    {
        // Arrange - a Doom Desire strike is pending against side 1, position 0
        var script = new FutureSight();
        var (battle, _) = CreateBattleWithRealVolatile();

        var opposingSide = Substitute.For<IBattleSide>();
        opposingSide.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet sideScripts = new ScriptSet(opposingSide);
        opposingSide.VolatileScripts.Returns(sideScripts);
        var doomDesire = new DoomDesireEffect(opposingSide);
        doomDesire.AddTarget(0, 100);
        sideScripts.Add(doomDesire);
        battle.Sides.Returns(new[] { Substitute.For<IBattleSide>(), opposingSide });

        var move = CreateFutureSightUse(battle, 1, 0);
        var stop = false;

        // Act
        script.StopBeforeMove(move, ref stop);

        // Assert - the move fails
        move.MoveChoice.Received(1).Fail();
        await Assert.That(move.MoveChoice.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Fail")).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Two turns later, Future Sight will do damage against the target." — the failure clause
    /// only covers a target that is "already set to be hit", so two Future Sights queued by different users
    /// against different spots are both tracked and both delayed strikes land.
    /// </summary>
    [Test]
    public async Task StopBeforeMove_TwoUsersTargetDifferentSpots_BothDelayedStrikesLand()
    {
        // Arrange - two users queue Future Sight against different spots on side 1
        var script = new FutureSight();
        var (battle, battleVolatile) = CreateBattleWithRealVolatile();
        battle.EventHook.Returns(new EventHook());

        var targetA = Substitute.For<IPokemon>();
        targetA.IsUsable.Returns(true);
        battle.GetPokemon(1, 0).Returns(targetA);
        var targetB = Substitute.For<IPokemon>();
        targetB.IsUsable.Returns(true);
        battle.GetPokemon(1, 1).Returns(targetB);

        battle.Library.DamageCalculator.GetDamage(Arg.Any<IExecutingMove?>(), Arg.Any<MoveCategory>(),
                Arg.Any<IPokemon>(), Arg.Any<IPokemon>(), Arg.Any<int>(), Arg.Any<byte>(), Arg.Any<IHitData>())
            .Returns(100u);

        var useA = CreateFutureSightUse(battle, 1, 0);
        var useB = CreateFutureSightUse(battle, 1, 1);
        var stop = false;
        script.StopBeforeMove(useA, ref stop);
        stop = false;
        script.StopBeforeMove(useB, ref stop);

        // Act - tick the end of the selection turn and of the two turns after it for all pending strikes
        for (var turn = 0; turn < 3; turn++)
        {
            foreach (var container in battleVolatile.ToList())
            {
                if (container.Script is IScriptOnEndTurn onEndTurn)
                    onEndTurn.OnEndTurn(battle, battle);
            }
        }

        // Assert - both delayed strikes land
        await Assert.That(targetA.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Damage")).IsTrue();
        await Assert.That(targetB.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Damage")).IsTrue();
    }
}