using AcDream.Core.Meshing;
using Xunit;

namespace AcDream.Core.Tests.Meshing;

/// <summary>
/// #79/#93 (2026-07-09) — the Town Network fountain room's only dat-authored
/// light (Setup 0x02000365, a ceiling fixture) never registered: its sole
/// visual part is a #136-class runtime-hidden marker, so it flattens to zero
/// mesh refs, and GameWindow.cs's hydration loop dropped the ENTIRE entity —
/// light included — whenever meshRefs was empty. Retail's light registration
/// (CObjCell::add_light, CEnvCell::UnPack) is entirely independent of a
/// fixture's own mesh visibility; the mesh-empty gate must not also swallow
/// a Setup's Lights.
/// </summary>
public class EntityHydrationRulesTests
{
    [Fact]
    public void ShouldKeepEntity_NoMeshNoLights_False()
    {
        Assert.False(EntityHydrationRules.ShouldKeepEntity(meshRefCount: 0, setupLightCount: 0));
    }

    [Fact]
    public void ShouldKeepEntity_NoMeshWithLights_True()
    {
        // The exact fountain-room case: a mesh-less "light attach point" must
        // still survive hydration so its Lights can be registered.
        Assert.True(EntityHydrationRules.ShouldKeepEntity(meshRefCount: 0, setupLightCount: 1));
    }

    [Fact]
    public void ShouldKeepEntity_HasMesh_TrueRegardlessOfLights()
    {
        Assert.True(EntityHydrationRules.ShouldKeepEntity(meshRefCount: 1, setupLightCount: 0));
        Assert.True(EntityHydrationRules.ShouldKeepEntity(meshRefCount: 3, setupLightCount: 2));
    }
}