using PkmnLib.Dynamic.Events;
using PkmnLib.Dynamic.Models;
using PkmnLib.Dynamic.ScriptHandling;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
using PkmnLib.Static;

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

/// <summary>
/// Tests for the <see cref="FlowerShield"/> move script.
/// Gen VII Bulbapedia behavior: "Flower Shield raises the Defense stat of all Grass-type Pokémon on the
/// field by one stage, except those that are in the semi-invulnerable turn of a move such as Fly or Dig."
/// </summary>
public class FlowerShieldTests
{
    private static readonly TypeIdentifier GrassType;
    private static readonly TypeIdentifier WaterType;

    static FlowerShieldTests()
    {
        var library = LibraryHelpers.LoadLibrary();
        library.StaticLibrary.Types.TryGetTypeIdentifier("grass", out GrassType);
        library.StaticLibrary.Types.TryGetTypeIdentifier("water", out WaterType);
    }

    private static (FlowerShield script, IExecutingMove move, IPokemon target, IBattle battle) CreateTestSetup(
        params IReadOnlyList<IPokemon?>[] sidePokemon)
    {
        var script = new FlowerShield();
        var move = Substitute.For<IExecutingMove>();
        var user = Substitute.For<IPokemon>();
        move.User.Returns(user);

        var library = LibraryHelpers.LoadLibrary();
        var battle = Substitute.For<IBattle>();
        battle.Library.Returns(library);
        var sides = sidePokemon.Select(pokemon =>
        {
            var side = Substitute.For<IBattleSide>();
            side.Pokemon.Returns(pokemon);
            return side;
        }).ToArray();
        battle.Sides.Returns(sides);

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

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

    private static IPokemon CreatePokemon(TypeIdentifier type, bool isFainted = false)
    {
        var pokemon = Substitute.For<IPokemon>();
        pokemon.Types.Returns(new[] { type });
        pokemon.IsFainted.Returns(isFainted);
        return pokemon;
    }

    private static bool ReceivedStatBoost(IPokemon pokemon) =>
        pokemon.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "ChangeStatBoost");

    /// <summary>
    /// Helper to extract the arguments of the received ChangeStatBoost call, or null when no stat boost
    /// was requested. Received-call inspection is used instead of NSubstitute argument matchers because
    /// the trailing <see cref="EventBatchId"/> parameter cannot be bound by <c>Arg.Any</c> (its
    /// parameterless constructor initializes a fresh id, so it never equals the matcher's default value).
    /// </summary>
    private static object?[]? GetStatBoostArgs(IPokemon pokemon)
    {
        var call = pokemon.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "ChangeStatBoost");
        return call?.GetArguments();
    }

    /// <summary>
    /// Bulbapedia: "Flower Shield raises the Defense stat of all Grass-type Pokémon on the field by one
    /// stage". The boost on another Pokémon is not self-inflicted.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_GrassTypeOnField_DefenseRaisedByOneStage()
    {
        // Arrange
        var grassPokemon = CreatePokemon(GrassType);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { grassPokemon });

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

        // Assert
        var args = GetStatBoostArgs(grassPokemon);
        await Assert.That(args).IsNotNull();
        await Assert.That((Statistic)args![0]!).IsEqualTo(Statistic.Defense);
        await Assert.That((sbyte)args[1]!).IsEqualTo((sbyte)1);
        await Assert.That((bool)args[2]!).IsFalse(); // not self-inflicted
        await Assert.That((bool)args[3]!).IsFalse(); // not forced
    }

    /// <summary>
    /// Bulbapedia: the Defense boost applies to "all Grass-type Pokémon on the field", so Grass-types on
    /// every side (allies and opponents alike) are raised.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_GrassTypesOnBothSides_AllAreRaised()
    {
        // Arrange
        var allyGrass = CreatePokemon(GrassType);
        var opposingGrass = CreatePokemon(GrassType);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { allyGrass },
            new List<IPokemon?> { opposingGrass });

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

        // Assert
        await Assert.That(ReceivedStatBoost(allyGrass)).IsTrue();
        await Assert.That(ReceivedStatBoost(opposingGrass)).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: only "Grass-type Pokémon on the field" are affected; a non-Grass-type Pokémon does not
    /// have its Defense raised.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_NonGrassType_DefenseNotRaised()
    {
        // Arrange
        var waterPokemon = CreatePokemon(WaterType);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { waterPokemon });

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

        // Assert
        await Assert.That(ReceivedStatBoost(waterPokemon)).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: the boost applies to Pokémon "on the field"; a fainted Grass-type Pokémon is no longer
    /// battling and is not affected.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_FaintedGrassType_DefenseNotRaised()
    {
        // Arrange
        var faintedGrass = CreatePokemon(GrassType, true);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { faintedGrass });

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

        // Assert
        await Assert.That(ReceivedStatBoost(faintedGrass)).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: "Flower Shield raises the Defense stat of all Grass-type Pokémon on the field",
    /// including the user itself. For the user the boost counts as self-inflicted.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserIsGrassType_BoostIsSelfInflicted()
    {
        // Arrange
        var (script, move, target, battle) = CreateTestSetup();
        var user = move.User;
        user.Types.Returns(new[] { GrassType });
        user.IsFainted.Returns(false);
        var side = Substitute.For<IBattleSide>();
        side.Pokemon.Returns(new List<IPokemon?> { user });
        battle.Sides.Returns(new[] { side });

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

        // Assert
        var args = GetStatBoostArgs(user);
        await Assert.That(args).IsNotNull();
        await Assert.That((Statistic)args![0]!).IsEqualTo(Statistic.Defense);
        await Assert.That((sbyte)args[1]!).IsEqualTo((sbyte)1);
        await Assert.That((bool)args[2]!).IsTrue(); // self-inflicted for the user itself
    }

    /// <summary>
    /// Bulbapedia: Grass-type Pokémon are raised "except those that are in the semi-invulnerable turn of a
    /// move such as Fly or Dig". A Grass-type currently flying (holding the <see cref="ChargeFlyEffect"/>
    /// volatile) must not have its Defense raised.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_SemiInvulnerableGrassType_DefenseNotRaised()
    {
        // Arrange
        var flyingGrass = CreatePokemon(GrassType);
        flyingGrass.GetScripts().Returns(_ => new ScriptIterator(new List<IEnumerable<ScriptContainer>>()));
        var flyingGrassVolatile = new ScriptSet(flyingGrass);
        flyingGrassVolatile.Add(new ChargeFlyEffect(flyingGrass));
        flyingGrass.Volatile.Returns(flyingGrassVolatile);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { flyingGrass });

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

        // Assert
        await Assert.That(ReceivedStatBoost(flyingGrass)).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: "The move fails if no eligible Grass-type Pokémon are present." When no Grass-type is
    /// on the field, the hit must be marked as failed.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_NoGrassTypesOnField_HitFails()
    {
        // Arrange
        var waterPokemon = CreatePokemon(WaterType);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { waterPokemon });
        var hitData = Substitute.For<IHitData>();
        move.GetHitData(target, 0).Returns(hitData);

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

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

    /// <summary>
    /// Technical test: empty (null) slots on a side are skipped without throwing.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_EmptyPokemonSlot_IsSkipped()
    {
        // Arrange
        var grassPokemon = CreatePokemon(GrassType);
        var (script, move, target, _) = CreateTestSetup(new List<IPokemon?> { null, grassPokemon });

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

        // Assert
        await Assert.That(ReceivedStatBoost(grassPokemon)).IsTrue();
    }

    /// <summary>
    /// Technical test: when the target has no <see cref="IPokemon.BattleData"/> (it is not in a battle),
    /// the script does nothing instead of throwing.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_NullBattleData_DoesNothing()
    {
        // Arrange
        var grassPokemon = CreatePokemon(GrassType);
        var (script, move, _, _) = CreateTestSetup(new List<IPokemon?> { grassPokemon });
        var target = Substitute.For<IPokemon>();
        target.BattleData.Returns((IPokemonBattleData?)null);

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

        // Assert
        await Assert.That(ReceivedStatBoost(grassPokemon)).IsFalse();
    }
}