using System;
using System.Linq;
using System.Numerics;
using AcDream.Core.Physics;
using DatReaderWriter.DBObjs;
using DatReaderWriter.Enums;
using DatReaderWriter.Types;
using Xunit;

namespace AcDream.Core.Tests.Physics;

public class ShadowShapeBuilderTests
{
    /// <summary>
    /// Synthetic Setup mirroring live dump of 0x020019FF (cottage door)
    /// captured 2026-05-24: 0 cylSpheres, 1 sphere (r=0.100, origin=(0,0,0.018)),
    /// 3 parts (0x010044B5 + 0x010044B6 + 0x010044B6), setup.Radius=0.141,
    /// setup.Height=0.200. PlacementFrames[Default] has identity transforms
    /// for all 3 parts.
    /// </summary>
    private static Setup CreateDoorSetup()
    {
        var setup = new Setup
        {
            Radius         = 0.141f,
            Height         = 0.200f,
            StepUpHeight   = 0.090f,
            StepDownHeight = 0.090f,
            Parts          = { 0x010044B5u, 0x010044B6u, 0x010044B6u },
            Spheres        =
            {
                new Sphere { Radius = 0.100f, Origin = new Vector3(0f, 0f, 0.018f) }
            },
            PlacementFrames =
            {
                [Placement.Default] = new AnimationFrame(3)
                {
                    Frames =
                    {
                        new Frame { Origin = Vector3.Zero, Orientation = Quaternion.Identity },
                        new Frame { Origin = Vector3.Zero, Orientation = Quaternion.Identity },
                        new Frame { Origin = Vector3.Zero, Orientation = Quaternion.Identity }
                    }
                }
            }
        };
        return setup;
    }

    [Fact]
    public void FromSetup_DoorSetup_ProducesFourShapes()
    {
        var setup = CreateDoorSetup();
        Func<uint, bool> hasBsp = id => id == 0x010044B5u || id == 0x010044B6u;

        var shapes = ShadowShapeBuilder.FromSetup(setup, entScale: 1.0f, hasBsp);

        Assert.Equal(4, shapes.Count);

        int cylinderCount = 0;
        int bspCount = 0;
        foreach (var s in shapes)
        {
            if (s.CollisionType == ShadowCollisionType.Cylinder) cylinderCount++;
            else if (s.CollisionType == ShadowCollisionType.BSP) bspCount++;
        }
        Assert.Equal(1, cylinderCount);
        Assert.Equal(3, bspCount);
    }

    [Fact]
    public void FromSetup_DoorSetup_SphereAtExpectedLocalOffset()
    {
        var setup = CreateDoorSetup();
        var shapes = ShadowShapeBuilder.FromSetup(setup, 1.0f, _ => true);

        var sphereAsCyl = shapes.FirstOrDefault(s => s.CollisionType == ShadowCollisionType.Cylinder);
        Assert.NotEqual(default, sphereAsCyl);
        Assert.Equal(0f, sphereAsCyl.LocalPosition.X, 4);
        Assert.Equal(0f, sphereAsCyl.LocalPosition.Y, 4);
        Assert.Equal(0.018f, sphereAsCyl.LocalPosition.Z, 4);
        Assert.Equal(0.100f, sphereAsCyl.Radius, 4);
    }

    [Fact]
    public void FromSetup_PartWithoutBsp_SkipsBspShape()
    {
        var setup = CreateDoorSetup();
        Func<uint, bool> hasBsp = id => id == 0x010044B5u;

        var shapes = ShadowShapeBuilder.FromSetup(setup, 1.0f, hasBsp);

        int bspCount = 0;
        foreach (var s in shapes)
            if (s.CollisionType == ShadowCollisionType.BSP) bspCount++;
        Assert.Equal(1, bspCount);
    }

    [Fact]
    public void FromSetup_CreatureWithCylSpheres_OnlyEmitsCylinders()
    {
        var setup = new Setup
        {
            Parts      = { 0x02000001u },
            CylSpheres =
            {
                new CylSphere { Radius = 0.40f, Height = 1.20f, Origin = new Vector3(0, 0, 0.6f) }
            },
            Spheres =
            {
                new Sphere { Radius = 0.50f, Origin = new Vector3(0, 0, 0.7f) }
            }
        };

        var shapes = ShadowShapeBuilder.FromSetup(setup, 1.0f, _ => false);

        Assert.Single(shapes);
        Assert.Equal(ShadowCollisionType.Cylinder, shapes[0].CollisionType);
        Assert.Equal(0.40f, shapes[0].Radius, 3);
        Assert.Equal(1.20f, shapes[0].CylHeight, 3);
    }

    [Fact]
    public void FromSetup_ScaleFactor_MultipliesAllRadiiAndOffsets()
    {
        var setup = CreateDoorSetup();

        var shapes = ShadowShapeBuilder.FromSetup(setup, entScale: 2.0f, _ => true);

        foreach (var s in shapes)
        {
            Assert.Equal(2.0f, s.Scale, 3);
            if (s.CollisionType == ShadowCollisionType.Cylinder)
            {
                Assert.Equal(0.200f, s.Radius, 3);
                Assert.Equal(0.036f, s.LocalPosition.Z, 3);
            }
        }
    }

    [Fact]
    public void FromSetup_EmptySetup_ReturnsEmptyList()
    {
        var setup = new Setup();

        var shapes = ShadowShapeBuilder.FromSetup(setup, 1.0f, _ => true);

        Assert.Empty(shapes);
    }

    [Fact]
    public void FromSetup_NullSetup_Throws()
    {
        Assert.Throws<ArgumentNullException>(
            () => ShadowShapeBuilder.FromSetup(null!, 1.0f, _ => true));
    }
}