using System.Numerics;
using AcDream.App.Physics;
using AcDream.App.Rendering;
using AcDream.App.Rendering.Vfx;
using AcDream.Core.Physics;
using AcDream.Core.World;

namespace AcDream.App.Tests.Physics;

public sealed class RemotePhysicsUpdaterTests
{
    [Fact]
    public void TickHidden_AppliesPositionManagerOffsetWithoutAdvancingPhysics()
    {
        var motion = new GameWindow.RemoteMotion();
        motion.Body.Position = Vector3.Zero;
        motion.Body.Orientation = Quaternion.Identity;
        motion.Body.Velocity = new Vector3(4f, 0f, 5f);
        motion.Body.Acceleration = new Vector3(0f, 0f, -9.8f);
        motion.CellId = 0x01010001u;
        motion.Interp.Enqueue(
            new Vector3(1f, 0f, 0f),
            heading: 0f,
            isMovingTo: false,
            currentBodyPosition: Vector3.Zero);
        var entity = new WorldEntity
        {
            Id = 1u,
            ServerGuid = 0x70000001u,
            SourceGfxObjOrSetupId = 0x02000001u,
            Position = Vector3.Zero,
            Rotation = Quaternion.Identity,
            MeshRefs = Array.Empty<MeshRef>(),
        };

        var updater = new RemotePhysicsUpdater(
            new PhysicsEngine(),
            (_, _) => (0.48f, 1.835f),
            (_, _, _, _) => { });
        var poses = new EntityEffectPoseRegistry();
        poses.Publish(entity, Array.Empty<Matrix4x4>());
        updater.TickHidden(motion, entity, 0.1f);
        Assert.True(poses.UpdateRoot(entity));

        Assert.InRange(motion.Body.Position.X, 0.01f, 1f);
        Assert.Equal(0f, motion.Body.Position.Z);
        Assert.Equal(new Vector3(4f, 0f, 5f), motion.Body.Velocity);
        Assert.Equal(motion.Body.Position, entity.Position);
        Assert.Equal(motion.CellId, entity.ParentCellId);
        Assert.True(poses.TryGetRootPose(entity.Id, out Matrix4x4 root));
        Assert.Equal(entity.Position, root.Translation);
    }

    [Fact]
    public void TickHidden_CrossCellCommitUpdatesCanonicalCellBeforeUnhide()
    {
        var engine = BuildBoundaryEngine();
        var updater = new RemotePhysicsUpdater(
            engine,
            (_, _) => (0.48f, 1.835f),
            (_, _, _, _) => { });
        var motion = new GameWindow.RemoteMotion();
        motion.Body.Position = new Vector3(191f, 10f, 50f);
        motion.Body.Orientation = Quaternion.Identity;
        motion.Body.TransientState = TransientStateFlags.Contact
                                   | TransientStateFlags.OnWalkable;
        uint canonicalCell = 0xA9B40039u;
        int canonicalWrites = 0;
        motion.BindCanonicalCell(
            () => canonicalCell,
            value =>
            {
                canonicalCell = value;
                canonicalWrites++;
            });
        motion.CellId = canonicalCell;
        canonicalWrites = 0;
        motion.Interp.Enqueue(
            new Vector3(193f, 10f, 50f),
            heading: 0f,
            isMovingTo: false,
            currentBodyPosition: motion.Body.Position);
        var entity = new WorldEntity
        {
            Id = 1u,
            ServerGuid = 0x70000002u,
            SourceGfxObjOrSetupId = 0x02000001u,
            Position = motion.Body.Position,
            Rotation = Quaternion.Identity,
            MeshRefs = Array.Empty<MeshRef>(),
        };

        updater.TickHidden(motion, entity, 2f);

        Assert.Equal(0xAAB40001u, canonicalCell);
        Assert.Equal(canonicalCell, entity.ParentCellId);
        Assert.True(canonicalWrites > 0);
        Assert.True(entity.Position.X > 192f);
    }

    [Fact]
    public void TickHidden_LandingSynchronizesRemoteAirborneState()
    {
        var engine = BuildBoundaryEngine();
        var updater = new RemotePhysicsUpdater(
            engine,
            (_, _) => (0.48f, 1.835f),
            (_, _, _, _) => { });
        var motion = new GameWindow.RemoteMotion
        {
            Airborne = true,
        };
        motion.Body.Position = new Vector3(10f, 10f, 50f);
        motion.Body.Orientation = Quaternion.Identity;
        motion.Body.TransientState = TransientStateFlags.Active;
        motion.CellId = 0xA9B40001u;
        motion.Interp.Enqueue(
            new Vector3(11f, 10f, 50f),
            heading: 0f,
            isMovingTo: false,
            currentBodyPosition: motion.Body.Position);
        var entity = new WorldEntity
        {
            Id = 3u,
            ServerGuid = 0x70000003u,
            SourceGfxObjOrSetupId = 0x02000001u,
            Position = motion.Body.Position,
            Rotation = Quaternion.Identity,
            MeshRefs = Array.Empty<MeshRef>(),
        };

        updater.TickHidden(motion, entity, 0.1f);

        Assert.True(motion.Body.InContact);
        Assert.True(motion.Body.OnWalkable);
        Assert.False(motion.Airborne);
    }

    private static PhysicsEngine BuildBoundaryEngine()
    {
        static TerrainSurface FlatTerrain()
        {
            var heights = new byte[81];
            var table = new float[256];
            Array.Fill(table, 50f);
            return new TerrainSurface(heights, table);
        }

        var engine = new PhysicsEngine { DataCache = new PhysicsDataCache() };
        engine.AddLandblock(
            0xA9B4FFFFu,
            FlatTerrain(),
            Array.Empty<CellSurface>(),
            Array.Empty<PortalPlane>(),
            0f,
            0f);
        engine.AddLandblock(
            0xAAB4FFFFu,
            FlatTerrain(),
            Array.Empty<CellSurface>(),
            Array.Empty<PortalPlane>(),
            192f,
            0f);
        return engine;
    }
}