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

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

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

/// <summary>
/// Tests for the <see cref="MeFirst"/> move script and its <see cref="MeFirstPowerBoost"/> volatile.
/// Gen VII Bulbapedia behavior: "If the target has not made its move this turn, but has selected a
/// damage-dealing move, Me First copies that move preemptively and increases the power by 50%."
/// "Me First will fail if the target selected a non-damaging move, or if the target already executed its
/// move this turn."
/// </summary>
public class MeFirstTests
{
    /// <summary>
    /// Creates a substitute move choice for the target, queued with the given move name and category.
    /// </summary>
    private static IMoveChoice CreateTargetMoveChoice(IBattlePokemon target, string moveName,
        MoveCategory category = MoveCategory.Physical)
    {
        var moveData = Substitute.For<IMoveData>();
        moveData.Name.Returns(new StringKey(moveName));
        moveData.Category.Returns(category);
        var learnedMove = Substitute.For<ILearnedMove>();
        learnedMove.MoveData.Returns(moveData);
        var moveChoice = Substitute.For<IMoveChoice>();
        moveChoice.User.Returns(target);
        moveChoice.ChosenMove.Returns(learnedMove);
        return moveChoice;
    }

    /// <summary>
    /// Creates a fully mocked test setup for Me First tests. The user's move choice targets side 0,
    /// position 0, where <paramref name="target"/> is standing (or nothing, when null). The battle's
    /// choice queue holds the given remaining choices for this turn.
    /// </summary>
    private static (MeFirst script, IMoveChoice choice) CreateTestSetup(IBattlePokemon? target,
        ITurnChoice[] queuedChoices, bool targetChoiceIsReplacement = false)
    {
        var script = new MeFirst();

        var side = Substitute.For<IBattleSide>();
        side.Pokemon.Returns(new List<IBattlePokemon?> { target });

        var miscLibrary = Substitute.For<IMiscLibrary>();
        miscLibrary.IsReplacementChoice(Arg.Any<ITurnChoice>()).Returns(targetChoiceIsReplacement);
        var library = Substitute.For<IDynamicLibrary>();
        library.MiscLibrary.Returns(miscLibrary);

        var battle = Substitute.For<IBattle>();
        battle.Sides.Returns(new[] { side });
        battle.ChoiceQueue.Returns(new BattleChoiceQueue(queuedChoices));
        battle.Library.Returns(library);

        var user = Substitute.For<IBattlePokemon>();

        user.Battle.Returns(battle);
        var choice = Substitute.For<IMoveChoice>();
        choice.User.Returns(user);
        choice.TargetSide.Returns((byte)0);
        choice.TargetPosition.Returns((byte)0);
        // Use a real script set so the volatile script added by Me First can be inspected afterwards.
        choice.Volatile.Returns(new ScriptSet(choice));
        choice.GetScripts().Returns(_ => new ScriptIterator(new List<IEnumerable<ScriptContainer>>()));

        return (script, choice);
    }

    /// <summary>
    /// Bulbapedia: "If the target has not made its move this turn, but has selected a damage-dealing move,
    /// Me First copies that move preemptively".
    /// The executed move is replaced by the move the target has queued.
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetSelectedDamagingMove_ChangesMoveToTargetsMove()
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var targetChoice = CreateTargetMoveChoice(target, "tackle");
        var (script, choice) = CreateTestSetup(target, [targetChoice]);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        await Assert.That(moveName).IsEqualTo(new StringKey("tackle"));
        choice.DidNotReceive().Fail();
    }

    /// <summary>
    /// Bulbapedia: "Me First copies that move preemptively and increases the power by 50%."
    /// Copying the move attaches the <see cref="MeFirstPowerBoost"/> volatile to the move choice, which is
    /// responsible for the power increase.
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetSelectedDamagingMove_AddsPowerBoostVolatile()
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var targetChoice = CreateTargetMoveChoice(target, "tackle");
        var (script, choice) = CreateTestSetup(target, [targetChoice]);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        await Assert.That(choice.Volatile.Contains(ScriptUtils.ResolveName<MeFirstPowerBoost>())).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Me First copies that move preemptively and increases the power by 50%."
    /// The <see cref="MeFirstPowerBoost"/> volatile multiplies the copied move's base power by 1.5,
    /// truncating fractions and capping at <see cref="ushort.MaxValue"/>.
    /// </summary>
    [Test, Arguments((ushort)100, (ushort)150), Arguments((ushort)60, (ushort)90), Arguments((ushort)5, (ushort)7),
     Arguments((ushort)85, (ushort)127), Arguments(ushort.MaxValue, ushort.MaxValue)]
    public async Task ChangeBasePower_MeFirstPowerBoost_IncreasesPowerByFiftyPercent(ushort basePower, ushort expected)
    {
        // Arrange
        var boost = new MeFirstPowerBoost();
        var move = Substitute.For<IExecutingMove>();
        var target = Substitute.For<IBattlePokemon>();

        // Act
        boost.ChangeBasePower(move, target, 0, ref basePower);

        // Assert
        await Assert.That(basePower).IsEqualTo(expected);
    }

    /// <summary>
    /// Bulbapedia: "Me First will fail if the target selected a non-damaging move, or if the target already
    /// executed its move this turn."
    /// The target's choice is no longer in the queue, so the move fails.
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetAlreadyExecutedMove_Fails()
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var (script, choice) = CreateTestSetup(target, []);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        choice.Received(1).Fail();
        await Assert.That(moveName).IsEqualTo(new StringKey("me_first"));
    }

    /// <summary>
    /// Bulbapedia: "Unlike other moves, if the target of Me First is a vacant slot or a Pokémon that already
    /// fainted before the Me First user's turn, Me First will fail instead of being redirected to an adjacent
    /// non-fainted opponent."
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetSlotIsVacant_Fails()
    {
        // Arrange
        var (script, choice) = CreateTestSetup(null, []);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        choice.Received(1).Fail();
        await Assert.That(moveName).IsEqualTo(new StringKey("me_first"));
    }

    /// <summary>
    /// Bulbapedia: Me First only copies a move the target "has selected". A target that chose to switch out
    /// instead of using a move has no selected move to copy, so Me First fails.
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetChoiceIsNotAMoveChoice_Fails()
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var switchChoice = Substitute.For<ISwitchChoice>();
        switchChoice.User.Returns(target);
        var (script, choice) = CreateTestSetup(target, [switchChoice]);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        choice.Received(1).Fail();
        await Assert.That(moveName).IsEqualTo(new StringKey("me_first"));
    }

    /// <summary>
    /// Bulbapedia: "Me First will fail if the target chose a Z-Move or any of the following moves."
    /// Struggle is one of those moves; a replacement choice (the forced choice used when a Pokémon cannot
    /// select a move, usually Struggle) cannot be copied.
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetChoiceIsReplacementChoice_Fails()
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var targetChoice = CreateTargetMoveChoice(target, "struggle");
        var (script, choice) = CreateTestSetup(target, [targetChoice], true);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        choice.Received(1).Fail();
        await Assert.That(moveName).IsEqualTo(new StringKey("me_first"));
    }

    /// <summary>
    /// Bulbapedia: "Me First will fail if the target selected a non-damaging move, or if the target already
    /// executed its move this turn."
    /// A queued status move must make Me First fail instead of being copied.
    /// </summary>
    [Test]
    public async Task ChangeMove_TargetSelectedNonDamagingMove_Fails()
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var targetChoice = CreateTargetMoveChoice(target, "swords_dance", MoveCategory.Status);
        var (script, choice) = CreateTestSetup(target, [targetChoice]);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        choice.Received(1).Fail();
        await Assert.That(moveName).IsEqualTo(new StringKey("me_first"));
    }

    /// <summary>
    /// Bulbapedia: "Me First will fail if the target chose a Z-Move or any of the following moves." In
    /// Generation VII the listed moves are Beak Blast, Belch, Chatter, Counter, Covet, Focus Punch, Me First,
    /// Metal Burst, Mirror Coat, Shell Trap, Struggle and Thief.
    /// </summary>
    [Test, Arguments("beak_blast"), Arguments("belch"), Arguments("chatter"), Arguments("counter"), Arguments("covet"),
     Arguments("focus_punch"), Arguments("metal_burst"), Arguments("mirror_coat"), Arguments("shell_trap"),
     Arguments("thief")]
    public async Task ChangeMove_TargetSelectedUncopyableMove_Fails(string targetMove)
    {
        // Arrange
        var target = Substitute.For<IBattlePokemon>();
        var targetChoice = CreateTargetMoveChoice(target, targetMove);
        var (script, choice) = CreateTestSetup(target, [targetChoice]);
        StringKey moveName = "me_first";

        // Act
        script.ChangeMove(choice, ref moveName);

        // Assert
        choice.Received(1).Fail();
        await Assert.That(moveName).IsEqualTo(new StringKey("me_first"));
    }
}