using System.Numerics;
using AcDream.App.Rendering;
using AcDream.Core.Physics;
using Xunit;

namespace AcDream.App.Tests.Rendering;

public class PhysicsCameraCollisionProbeTests
{
    // The probe must convert the desired eye path (where the SPHERE CENTER
    // should travel) into the foot-capsule path InitPath expects (which offsets
    // sphere0 up by radius), then invert it on the result. Verify the round trip.
    [Fact]
    public void SpherePathOffset_RoundTrips()
    {
        var p = new Vector3(10f, 20f, 30f);
        const float r = 0.3f;

        var path = PhysicsCameraCollisionProbe.ToSpherePath(p, r);
        Assert.Equal(p.Z - r, path.Z, 5);
        Assert.Equal(p.X, path.X, 5);
        Assert.Equal(p.Y, path.Y, 5);

        var back = PhysicsCameraCollisionProbe.FromSpherePath(path, r);
        Assert.Equal(p.X, back.X, 5);
        Assert.Equal(p.Y, back.Y, 5);
        Assert.Equal(p.Z, back.Z, 5);
    }

    // cellId == 0 means "no starting cell" — retail update_viewer snaps the viewer
    // to the player position (set_viewer(player_pos), viewer_cell = null; pc:92775),
    // so the probe must short-circuit to playerPos without touching the engine.
    [Fact]
    public void SweepEye_NoStartingCell_SnapsToPlayer()
    {
        var probe  = new PhysicsCameraCollisionProbe(new PhysicsEngine());
        var pivot  = new Vector3(0f, 0f, 1.5f);
        var eye    = new Vector3(-2f, 0f, 2.2f);
        var player = new Vector3(0f, 0f, 0f);

        var result = probe.SweepEye(pivot, eye, cellId: 0, selfEntityId: 0, playerPos: player);

        Assert.Equal(player, result.Eye);
        Assert.Equal(0u, result.ViewerCellId);   // cellId==0 → snap to player, null viewer cell
    }
}