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

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

/// <summary>
/// Tests for the <see cref="GuardSplit"/> move script.
/// Gen VII Bulbapedia behavior: "Guard Split averages the user's Defense and Special Defense stats with
/// those of the target Pokémon." and "Both the user's and the target's stat changes are ignored when
/// calculating the average." (the calculation therefore uses the flat, unboosted stats).
/// </summary>
public class GuardSplitTests
{
    private static (GuardSplit script, IExecutingMove move, IBattlePokemon user, IBattlePokemon target) CreateTestSetup(
        uint userDefense, uint userSpecialDefense, uint targetDefense, uint targetSpecialDefense)
    {
        var script = new GuardSplit();
        var move = Substitute.For<IExecutingMove>();

        var user = Substitute.For<IBattlePokemon>();
        user.FlatStats.Returns(new StatisticSet<uint>(100, 100, userDefense, 100, userSpecialDefense, 100));
        move.User.Returns(user);

        var target = Substitute.For<IBattlePokemon>();
        target.FlatStats.Returns(new StatisticSet<uint>(100, 100, targetDefense, 100, targetSpecialDefense, 100));

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

    /// <summary>
    /// Bulbapedia: "Guard Split averages the user's Defense and Special Defense stats with those of the
    /// target Pokémon." — both Pokémon end up with the averaged Defense value.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_DifferentDefenseStats_BothGetAveragedDefense()
    {
        // Arrange
        var (script, move, user, target) = CreateTestSetup(40, 100, 60, 100);

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

        // Assert
        await Assert.That(user.FlatStats.GetStatistic(Statistic.Defense)).IsEqualTo(50u);
        await Assert.That(target.FlatStats.GetStatistic(Statistic.Defense)).IsEqualTo(50u);
    }

    /// <summary>
    /// Bulbapedia: the averaging also covers "Special Defense" — both Pokémon end up with the averaged
    /// Special Defense value.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_DifferentSpecialDefenseStats_BothGetAveragedSpecialDefense()
    {
        // Arrange
        var (script, move, user, target) = CreateTestSetup(100, 80, 100, 120);

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

        // Assert
        await Assert.That(user.FlatStats.GetStatistic(Statistic.SpecialDefense)).IsEqualTo(100u);
        await Assert.That(target.FlatStats.GetStatistic(Statistic.SpecialDefense)).IsEqualTo(100u);
    }

    /// <summary>
    /// The average of an odd sum is truncated by integer division, matching the games' integer stat
    /// arithmetic.
    /// </summary>
    [Test, Arguments(35u, 40u, 37u), Arguments(1u, 2u, 1u), Arguments(99u, 100u, 99u)]
    public async Task OnSecondaryEffect_OddDefenseSum_AverageIsTruncated(uint userDefense, uint targetDefense,
        uint expectedAverage)
    {
        // Arrange
        var (script, move, user, target) = CreateTestSetup(userDefense, 100, targetDefense, 100);

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

        // Assert
        await Assert.That(user.FlatStats.GetStatistic(Statistic.Defense)).IsEqualTo(expectedAverage);
        await Assert.That(target.FlatStats.GetStatistic(Statistic.Defense)).IsEqualTo(expectedAverage);
    }

    /// <summary>
    /// Bulbapedia: only Defense and Special Defense are averaged — the other stats are left untouched.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_Always_OtherStatsUnchanged()
    {
        // Arrange
        var (script, move, user, target) = CreateTestSetup(40, 80, 60, 120);

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

        // Assert
        await Assert.That(user.FlatStats.GetStatistic(Statistic.Attack)).IsEqualTo(100u);
        await Assert.That(user.FlatStats.GetStatistic(Statistic.SpecialAttack)).IsEqualTo(100u);
        await Assert.That(user.FlatStats.GetStatistic(Statistic.Speed)).IsEqualTo(100u);
        await Assert.That(user.FlatStats.GetStatistic(Statistic.Hp)).IsEqualTo(100u);
    }

    /// <summary>
    /// The changed flat stats must be propagated to the effective in-battle stats — both Pokémon get
    /// their boosted stats recalculated.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_Always_RecalculatesBoostedStatsOnBothPokemon()
    {
        // Arrange
        var (script, move, user, target) = CreateTestSetup(40, 80, 60, 120);

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

        // Assert
        user.Received(1).RecalculateBoostedStats();
        target.Received(1).RecalculateBoostedStats();
        await Assert.That(user.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "RecalculateBoostedStats")).IsTrue();
    }
}