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

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

/// <summary>
/// Tests for the <see cref="HighJumpKick"/> move script.
/// Gen VII Bulbapedia behavior: if the move misses, the user takes crash damage. Generation V onwards:
/// "The crash damage is now (always) equal to half of the user's max HP, rounded down."
/// Crash damage also applies when the move is protected against (Generation II onwards: "The user will take
/// crash damage if Hi Jump Kick is protected against by a move such as Protect") and due to a target's type
/// immunity (Generation IV onwards: "The user can now crash due to a target's type immunity").
/// The script implements <see cref="IScriptOnAfterHits"/> and applies crash damage when none of the move's
/// hits executed with damage.
/// </summary>
public class HighJumpKickTests
{
    /// <summary>
    /// Creates a fully mocked test setup for High Jump Kick tests, with the given user max HP
    /// (<see cref="IBattlePokemon.BoostedStats"/>) and hit data. The engine calculates a hit's damage before the
    /// accuracy and block checks, so a missed or blocked hit still carries a damage value but has
    /// <see cref="IHitData.HasExecuted"/> set to false.
    /// </summary>
    private static (HighJumpKick script, IExecutingMove move, IBattlePokemon target, IBattlePokemon user)
        CreateTestSetup(uint maxHp, params (bool hasExecuted, uint damage)[] hits)
    {
        var script = new HighJumpKick();
        var move = Substitute.For<IExecutingMove>();
        var target = Substitute.For<IBattlePokemon>();
        var hitData = hits.Select(h =>
        {
            var hit = Substitute.For<IHitData>();
            hit.HasExecuted.Returns(h.hasExecuted);
            hit.Damage.Returns(h.damage);
            return hit;
        }).ToArray();
        move.Hits.Returns(hitData);

        var user = Substitute.For<IBattlePokemon>();
        user.BoostedStats.Returns(new StatisticSet<uint>(maxHp, 0, 0, 0, 0, 0));
        move.User.Returns(user);
        return (script, move, target, user);
    }

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

    /// <summary>
    /// Helper to extract the damage source from the user's received Damage calls.
    /// </summary>
    private static DamageSource? GetDamageSource(IBattlePokemon user)
    {
        var call = user.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "Damage");
        return call != null ? (DamageSource)call.GetArguments()[1]! : null;
    }

    /// <summary>
    /// Bulbapedia (Generation V onwards): "The crash damage is now (always) equal to half of the user's max
    /// HP, rounded down."
    /// When the move misses, the hit never executes; after the hit loop the engine invokes
    /// <see cref="IScriptOnAfterHits"/> and the user takes half of its own max HP as crash damage.
    /// </summary>
    [Test]
    public async Task OnAfterHits_MoveMissed_UserTakesHalfMaxHpCrashDamage()
    {
        // Arrange - the missed hit has its would-be damage calculated but never executed.
        var (script, move, target, user) = CreateTestSetup(200, (false, 400));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        await Assert.That(GetDamageAmount(user)!.Value).IsEqualTo(100u);
    }

    /// <summary>
    /// Bulbapedia (Generation V onwards): "The crash damage is now (always) equal to half of the user's max
    /// HP, rounded down."
    /// Odd max HP values are rounded down when halved.
    /// </summary>
    [Test, Arguments(200u, 100u), Arguments(301u, 150u), Arguments(75u, 37u)]
    public async Task OnAfterHits_MoveMissed_CrashDamageIsHalfMaxHpRoundedDown(uint maxHp, uint expectedCrash)
    {
        // Arrange
        var (script, move, target, user) = CreateTestSetup(maxHp, (false, 400));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        await Assert.That(GetDamageAmount(user)!.Value).IsEqualTo(expectedCrash);
    }

    /// <summary>
    /// With a max HP of 1 the crash damage rounds down to 0, and the script does not invoke a zero-damage
    /// call on the user at all.
    /// </summary>
    [Test]
    public async Task OnAfterHits_MaxHpOne_NoDamageCallOnUser()
    {
        // Arrange
        var (script, move, target, user) = CreateTestSetup(1, (false, 400));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        await Assert.That(GetDamageAmount(user)).IsNull();
    }

    /// <summary>
    /// Bulbapedia (Generation V onwards): "The crash damage is now (always) equal to half of the user's max
    /// HP, rounded down."
    /// Since Generation V the crash damage no longer depends on the damage the move would have dealt (that
    /// was the Generation III/IV mechanic), so a low would-be damage still results in half the user's max HP.
    /// </summary>
    [Test]
    public async Task OnAfterHits_LowWouldBeDamage_CrashDamageStillHalfMaxHp()
    {
        // Arrange
        var (script, move, target, user) = CreateTestSetup(200, (false, 10));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        await Assert.That(GetDamageAmount(user)!.Value).IsEqualTo(100u);
    }

    /// <summary>
    /// When the move hits and deals damage, the user takes no crash damage.
    /// </summary>
    [Test]
    public async Task OnAfterHits_MoveHitWithDamage_NoCrashDamage()
    {
        // Arrange
        var (script, move, target, user) = CreateTestSetup(200, (true, 400));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        await Assert.That(GetDamageAmount(user)).IsNull();
    }

    /// <summary>
    /// Bulbapedia (Generation V onwards): "The crash damage is now (always) equal to half of the user's max
    /// HP, rounded down."
    /// Crash damage is indirect damage, not move damage, so it uses <see cref="DamageSource.Misc"/>.
    /// </summary>
    [Test]
    public async Task OnAfterHits_MoveMissed_UsesMiscDamageSource()
    {
        // Arrange
        var (script, move, target, user) = CreateTestSetup(200, (false, 400));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        await Assert.That(GetDamageSource(user)!.Value).IsEqualTo(DamageSource.Misc);
    }

    /// <summary>
    /// Bulbapedia (Generation II onwards): "The user will take crash damage if Hi Jump Kick is protected
    /// against by a move such as Protect".
    /// When the hit is blocked by protection, the engine (MoveTurnExecutor) breaks out of the hit loop
    /// without executing the hit, then invokes <see cref="IScriptOnAfterHits"/>; the blocked hit's would-be
    /// damage was already calculated but the hit never executed, so crash damage applies.
    /// </summary>
    [Test]
    public async Task OnAfterHits_MoveBlockedByProtect_UserTakesCrashDamage()
    {
        // Arrange - a blocked hit carries its calculated would-be damage but never executed.
        var (script, move, target, user) = CreateTestSetup(200, (false, 400));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        var damage = GetDamageAmount(user);
        await Assert.That(damage).IsNotNull();
        await Assert.That(damage!.Value).IsEqualTo(100u);
    }

    /// <summary>
    /// Bulbapedia (Generation IV onwards): "The user can now crash due to a target's type immunity", with the
    /// Generation V onwards amount: "The crash damage is now (always) equal to half of the user's max HP,
    /// rounded down."
    /// Against a Ghost-type target the hit deals no damage (effectiveness 0), so the engine never marks the
    /// hit as executed; <see cref="IScriptOnAfterHits"/> still runs and applies crash damage.
    /// </summary>
    [Test]
    public async Task OnAfterHits_TargetImmuneToMove_UserTakesCrashDamage()
    {
        // Arrange - a Ghost-type target: the hit deals no damage and is never marked as executed.
        var (script, move, target, user) = CreateTestSetup(200, (false, 0));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        var damage = GetDamageAmount(user);
        await Assert.That(damage).IsNotNull();
        await Assert.That(damage!.Value).IsEqualTo(100u);
    }

    /// <summary>
    /// A miss caused by the target being in the semi-invulnerable turn of a move such as Fly or Dig is still
    /// a miss, so per Bulbapedia (Generation V onwards) the user takes crash damage "equal to half of the
    /// user's max HP, rounded down." For a semi-invulnerable target
    /// (<see cref="IScriptIsInvulnerableToMove"/>) the engine skips the hit loop entirely and invokes
    /// <see cref="IScriptOnAfterHits"/> before returning, so the hit data is left untouched (not executed,
    /// no damage calculated) and the script applies crash damage.
    /// </summary>
    [Test]
    public async Task OnAfterHits_MoveAvoidedBySemiInvulnerableTarget_UserTakesCrashDamage()
    {
        // Arrange - the hit loop never ran, so the hit was never executed and carries no damage.
        var (script, move, target, user) = CreateTestSetup(200, (false, 0));

        // Act
        script.OnAfterHits(move, target);

        // Assert
        var damage = GetDamageAmount(user);
        await Assert.That(damage).IsNotNull();
        await Assert.That(damage!.Value).IsEqualTo(100u);
    }
}