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

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

/// <summary>
/// Tests for the <see cref="GearUp"/> move script.
/// Gen VII Bulbapedia behavior: "Gear Up raises the Attack and Special Attack stats of allied Pokémon
/// (including the user) with the Ability Plus or Minus by one stage each."
/// </summary>
public class GearUpTests
{
    /// <summary>
    /// Creates a fully mocked test setup for Gear Up tests. The user is on side 0; the given side lists
    /// are installed as the battle's sides.
    /// </summary>
    private static (GearUp script, IExecutingMove move, IPokemon user) CreateTestSetup(
        params IReadOnlyList<IPokemon?>[] sidePokemon)
    {
        var script = new GearUp();
        var move = Substitute.For<IExecutingMove>();

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

        var user = Substitute.For<IPokemon>();
        var battleData = Substitute.For<IPokemonBattleData>();
        battleData.Battle.Returns(battle);
        battleData.SideIndex.Returns((byte)0);
        user.BattleData.Returns(battleData);
        move.User.Returns(user);

        return (script, move, user);
    }

    /// <summary>
    /// Creates a mocked Pokémon whose <see cref="IPokemon.ActiveAbility"/> has the given name, or no
    /// ability at all when <paramref name="abilityName"/> is null.
    /// </summary>
    private static IPokemon CreatePokemon(string? abilityName)
    {
        var pokemon = Substitute.For<IPokemon>();
        if (abilityName != null)
        {
            var ability = Substitute.For<IAbility>();
            ability.Name.Returns(new StringKey(abilityName));
            pokemon.ActiveAbility.Returns(ability);
        }
        else
        {
            pokemon.ActiveAbility.Returns((IAbility?)null);
        }

        return pokemon;
    }

    /// <summary>
    /// Helper to extract the arguments of the received ChangeStatBoost call for the given statistic, or
    /// null when that stat was not boosted. Received-call inspection is used instead of NSubstitute
    /// argument matchers because the trailing EventBatchId parameter cannot be bound by <c>Arg.Any</c>.
    /// </summary>
    private static object?[]? GetStatBoostArgs(IPokemon pokemon, Statistic stat) =>
        pokemon.ReceivedCalls().Where(c => c.GetMethodInfo().Name == "ChangeStatBoost").Select(c => c.GetArguments())
            .FirstOrDefault(args => (Statistic)args[0]! == stat);

    /// <summary>
    /// Bulbapedia: "Gear Up raises the Attack and Special Attack stats of allied Pokémon ... with the
    /// Ability Plus ... by one stage each." An ally's boost is not self-inflicted.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_AllyWithPlus_AttackAndSpecialAttackRaisedByOneStage()
    {
        // Arrange
        var ally = CreatePokemon("plus");
        var (script, move, _) = CreateTestSetup(new List<IPokemon?> { ally });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

        // Assert
        var attackArgs = GetStatBoostArgs(ally, Statistic.Attack);
        var specialAttackArgs = GetStatBoostArgs(ally, Statistic.SpecialAttack);
        await Assert.That(attackArgs).IsNotNull();
        await Assert.That((sbyte)attackArgs![1]!).IsEqualTo((sbyte)1);
        await Assert.That((bool)attackArgs[2]!).IsFalse(); // not self-inflicted
        await Assert.That(specialAttackArgs).IsNotNull();
        await Assert.That((sbyte)specialAttackArgs![1]!).IsEqualTo((sbyte)1);
    }

    /// <summary>
    /// Bulbapedia: the boost also applies to allies "with the Ability ... Minus".
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_AllyWithMinus_AttackAndSpecialAttackRaisedByOneStage()
    {
        // Arrange
        var ally = CreatePokemon("minus");
        var (script, move, _) = CreateTestSetup(new List<IPokemon?> { ally });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

        // Assert
        await Assert.That(GetStatBoostArgs(ally, Statistic.Attack)).IsNotNull();
        await Assert.That(GetStatBoostArgs(ally, Statistic.SpecialAttack)).IsNotNull();
    }

    /// <summary>
    /// Bulbapedia: the boost applies to allied Pokémon "including the user" — a user with Plus boosts
    /// itself, and that boost is self-inflicted.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserHasPlus_UserBoostIsSelfInflicted()
    {
        // Arrange
        var (script, move, user) = CreateTestSetup();
        var ability = Substitute.For<IAbility>();
        ability.Name.Returns(new StringKey("plus"));
        user.ActiveAbility.Returns(ability);
        var side = Substitute.For<IBattleSide>();
        side.Pokemon.Returns(new List<IPokemon?> { user });
        user.BattleData!.Battle.Sides.Returns(new[] { side });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

        // Assert
        var attackArgs = GetStatBoostArgs(user, Statistic.Attack);
        await Assert.That(attackArgs).IsNotNull();
        await Assert.That((bool)attackArgs![2]!).IsTrue(); // self-inflicted for the user itself
    }

    /// <summary>
    /// Bulbapedia: only allies "with the Ability Plus or Minus" are raised — an ally with a different
    /// Ability is unaffected.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_AllyWithOtherAbility_NotBoosted()
    {
        // Arrange
        var ally = CreatePokemon("levitate");
        var (script, move, _) = CreateTestSetup(new List<IPokemon?> { ally });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

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

    /// <summary>
    /// Bulbapedia: the boost applies to "allied Pokémon" — an opposing Pokémon with Plus is not raised.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_OpponentWithPlus_NotBoosted()
    {
        // Arrange
        var opponent = CreatePokemon("plus");
        var (script, move, _) = CreateTestSetup(new List<IPokemon?>(), new List<IPokemon?> { opponent });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

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

    /// <summary>
    /// Technical test: an ally without an active Ability is skipped without throwing.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_AllyWithoutAbility_NotBoosted()
    {
        // Arrange
        var ally = CreatePokemon(null);
        var (script, move, _) = CreateTestSetup(new List<IPokemon?> { ally });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

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

    /// <summary>
    /// Technical test: empty (null) slots on the user's side are skipped without throwing.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_EmptyPokemonSlot_IsSkipped()
    {
        // Arrange
        var ally = CreatePokemon("plus");
        var (script, move, _) = CreateTestSetup(new List<IPokemon?> { null, ally });

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

        // Assert
        await Assert.That(GetStatBoostArgs(ally, Statistic.Attack)).IsNotNull();
    }

    /// <summary>
    /// Technical test: when the user 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 ally = CreatePokemon("plus");
        var (script, move, user) = CreateTestSetup(new List<IPokemon?> { ally });
        user.BattleData.Returns((IPokemonBattleData?)null);

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IPokemon>(), 0);

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