PkmnLib.NET/Plugins/PkmnLib.Plugin.Gen7.Tests/Scripts/Moves/FuryCutterTests.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.Pokemon;
using PkmnLib.Static.Moves;
using PkmnLib.Static.Utils;

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

/// <summary>
/// Tests for the <see cref="FuryCutter"/> move script and its <see cref="FuryCutterEffect"/> volatile.
/// Gen VII Bulbapedia behavior: "Every time Fury Cutter hits the power will double", and (Generation VI
/// onwards) "Fury Cutter's base power increased even further from 20 to 40, meaning that it takes three
/// consecutive turns to reach the maximum power of 160."
/// </summary>
public class FuryCutterTests
{
    /// <summary>
    /// Creates a fully mocked test setup where the user's volatile scripts are a real
    /// <see cref="ScriptSet"/>, so the <see cref="FuryCutterEffect"/> added by the move can be inspected.
    /// </summary>
    private static (FuryCutter script, IExecutingMove move, IPokemon target, IPokemon user, ScriptSet userVolatile)
        CreateTestSetup()
    {
        var script = new FuryCutter();
        var move = Substitute.For<IExecutingMove>();
        var target = Substitute.For<IPokemon>();
        var user = Substitute.For<IPokemon>();
        var userVolatile = new ScriptSet(user);
        user.Volatile.Returns(userVolatile);
        user.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        move.User.Returns(user);
        return (script, move, target, user, userVolatile);
    }

    /// <summary>
    /// Simulates the given number of consecutive uses of Fury Cutter, feeding the Gen VII base power of 40
    /// into each use, and returns the base power of the final use.
    /// </summary>
    private static ushort SimulateConsecutiveUses(FuryCutter script, IExecutingMove move, IPokemon target, int uses)
    {
        ushort basePower = 40;
        for (var i = 0; i < uses; i++)
        {
            basePower = 40;
            script.ChangeBasePower(move, target, 0, ref basePower);
        }

        return basePower;
    }

    /// <summary>
    /// Bulbapedia (Generation VI onwards): "Fury Cutter's base power increased even further from 20 to 40" —
    /// on the first use there is no previous hit, so the base power is not modified.
    /// </summary>
    [Test]
    public async Task ChangeBasePower_FirstUse_BasePowerUnchanged()
    {
        // Arrange
        var (script, move, target, _, _) = CreateTestSetup();

        // Act
        var basePower = SimulateConsecutiveUses(script, move, target, 1);

        // Assert
        await Assert.That(basePower).IsEqualTo((ushort)40);
    }

    /// <summary>
    /// Bulbapedia: the power doubles on consecutive hits — the first use attaches the
    /// <see cref="FuryCutterEffect"/> volatile to the user so the next use is recognized as consecutive.
    /// </summary>
    [Test]
    public async Task ChangeBasePower_FirstUse_AddsFuryCutterEffectToUser()
    {
        // Arrange
        var (script, move, target, _, userVolatile) = CreateTestSetup();

        // Act
        SimulateConsecutiveUses(script, move, target, 1);

        // Assert
        await Assert.That(userVolatile.Contains(ScriptUtils.ResolveName<FuryCutterEffect>())).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Every time Fury Cutter hits the power will double" — the second consecutive use has
    /// power 80 and the third consecutive use reaches the maximum of 160.
    /// </summary>
    [Test, Arguments(2, (ushort)80), Arguments(3, (ushort)160)]
    public async Task ChangeBasePower_ConsecutiveUses_PowerDoublesEachTurn(int uses, ushort expectedPower)
    {
        // Arrange
        var (script, move, target, _, _) = CreateTestSetup();

        // Act
        var basePower = SimulateConsecutiveUses(script, move, target, uses);

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

    /// <summary>
    /// Bulbapedia (Generation VI onwards): "it takes three consecutive turns to reach the maximum power of
    /// 160" — uses beyond the third consecutive turn stay capped at 160 and do not keep doubling.
    /// </summary>
    [Test, Arguments(4), Arguments(5), Arguments(6)]
    public async Task ChangeBasePower_BeyondThirdConsecutiveUse_PowerCappedAt160(int uses)
    {
        // Arrange
        var (script, move, target, _, _) = CreateTestSetup();

        // Act
        var basePower = SimulateConsecutiveUses(script, move, target, uses);

        // Assert
        await Assert.That(basePower).IsEqualTo((ushort)160);
    }

    /// <summary>
    /// Bulbapedia (Generation V onwards): "If another move is selected, its power resets to normal." — when
    /// the user executes a different move, the <see cref="FuryCutterEffect"/> removes itself, resetting the
    /// doubling progression.
    /// </summary>
    [Test]
    public async Task OnBeforeMove_DifferentMoveUsed_EffectRemovesItself()
    {
        // Arrange
        var user = Substitute.For<IPokemon>();
        user.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        var userVolatile = new ScriptSet(user);
        var effect = new FuryCutterEffect();
        userVolatile.Add(effect);

        var otherMove = Substitute.For<IExecutingMove>();
        var otherMoveData = Substitute.For<IMoveData>();
        otherMoveData.Name.Returns(new StringKey("tackle"));
        otherMove.UseMove.Returns(otherMoveData);

        // Act
        effect.OnBeforeMove(otherMove);

        // Assert
        await Assert.That(userVolatile.Contains(ScriptUtils.ResolveName<FuryCutterEffect>())).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: the doubling continues on "consecutive turns" — when Fury Cutter is used again, the
    /// <see cref="FuryCutterEffect"/> stays on the user so the progression continues.
    /// </summary>
    [Test]
    public async Task OnBeforeMove_FuryCutterUsedAgain_EffectPersists()
    {
        // Arrange
        var user = Substitute.For<IPokemon>();
        user.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        var userVolatile = new ScriptSet(user);
        var effect = new FuryCutterEffect();
        userVolatile.Add(effect);

        var furyCutterMove = Substitute.For<IExecutingMove>();
        var furyCutterMoveData = Substitute.For<IMoveData>();
        furyCutterMoveData.Name.Returns(new StringKey("fury_cutter"));
        furyCutterMove.UseMove.Returns(furyCutterMoveData);

        // Act
        effect.OnBeforeMove(furyCutterMove);

        // Assert
        await Assert.That(userVolatile.Contains(ScriptUtils.ResolveName<FuryCutterEffect>())).IsTrue();
    }
}