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

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

/// <summary>
/// Tests for the <see cref="FloralHealing"/> move script.
/// Gen VII Bulbapedia behavior: Floral Healing restores up to half of the target's maximum HP, or up to
/// two thirds when Grassy Terrain is in effect.
/// </summary>
public class FloralHealingTests
{
    private static (FloralHealing script, IExecutingMove move, IBattlePokemon target) CreateTestSetup(uint maxHp,
        string? terrainName = null, bool isFainted = false)
    {
        var script = new FloralHealing();
        var move = Substitute.For<IExecutingMove>();

        var battle = Substitute.For<IBattle>();
        battle.TerrainName.Returns(terrainName == null ? null : new StringKey?(new StringKey(terrainName)));

        var target = Substitute.For<IBattlePokemon>();
        target.IsFainted.Returns(isFainted);
        target.BoostedStats.Returns(new StatisticSet<uint>(maxHp, 0, 0, 0, 0, 0));
        target.Battle.Returns(battle);

        return (script, move, target);
    }

    /// <summary>
    /// Helper to extract the heal amount from the target's received Heal calls.
    /// </summary>
    private static uint? GetHealAmount(IBattlePokemon target)
    {
        var call = target.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "Heal");
        return call != null ? (uint)call.GetArguments()[0]! : null;
    }

    /// <summary>
    /// Bulbapedia: "Floral Healing restores up to ½ of the target's maximum HP."
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_NoTerrain_HealsHalfOfMaximumHp()
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(100);

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

        // Assert
        await Assert.That(GetHealAmount(target)!.Value).IsEqualTo(50u);
    }

    /// <summary>
    /// Bulbapedia: "Floral Healing restores up to ½ of the target's maximum HP."
    /// Various maximum HP values verify the fractional amount is truncated to a whole number.
    /// </summary>
    [Test, Arguments(200u, 100u), Arguments(101u, 50u), Arguments(99u, 49u), Arguments(3u, 1u)]
    public async Task OnSecondaryEffect_NoTerrain_HealCalculation(uint maxHp, uint expectedHeal)
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(maxHp);

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

        // Assert
        await Assert.That(GetHealAmount(target)!.Value).IsEqualTo(expectedHeal);
    }

    /// <summary>
    /// Bulbapedia: "If Grassy Terrain is in effect, Floral Healing will restore up to ⅔ of the target's
    /// maximum HP."
    /// </summary>
    [Test, Arguments(99u, 66u), Arguments(100u, 66u), Arguments(3u, 2u)]
    public async Task OnSecondaryEffect_GrassyTerrain_HealsTwoThirdsOfMaximumHp(uint maxHp, uint expectedHeal)
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(maxHp, "grassy_terrain");

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

        // Assert
        await Assert.That(GetHealAmount(target)!.Value).IsEqualTo(expectedHeal);
    }

    /// <summary>
    /// Bulbapedia: only "If Grassy Terrain is in effect" is the restored amount increased to ⅔; any other
    /// terrain keeps the regular ½ of maximum HP.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_OtherTerrain_HealsHalfOfMaximumHp()
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(100, "misty_terrain");

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

        // Assert
        await Assert.That(GetHealAmount(target)!.Value).IsEqualTo(50u);
    }

    /// <summary>
    /// Bulbapedia: Floral Healing "restores" HP of the target; a fainted Pokémon can no longer be healed,
    /// so no heal is applied when the target <see cref="IBattlePokemon.IsFainted"/>.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_TargetFainted_DoesNotHeal()
    {
        // Arrange
        var (script, move, target) = CreateTestSetup(100, isFainted: true);

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

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