// Tests for EnvCellRenderer (Phase A8, 2026-05-28).
// These cover the pure data-handling portions of EnvCellRenderer.
// The GL-dependent Render() and RenderModernMDIInternal() paths require a
// GL context and are visual-verified at the render frame (Task 10).

using System.Collections.Generic;
using AcDream.App.Rendering.Wb;
using Xunit;

namespace AcDream.App.Tests.Rendering.Wb;

public class EnvCellRendererTests
{
    // -----------------------------------------------------------------------
    // GetEnvCellGeomId — verbatim port of WB EnvCellRenderManager.cs:94-103
    // -----------------------------------------------------------------------

    [Fact]
    public void GetEnvCellGeomId_DedupBitSet()
    {
        var id = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, new List<ushort> { 1, 2, 3 });
        // Bit 33 (0x2_0000_0000) must be set — distinguishes dedup geom from per-cell ids.
        Assert.NotEqual(0UL, id & 0x2_0000_0000UL);
    }

    [Fact]
    public void GetEnvCellGeomId_Deterministic()
    {
        var s = new List<ushort> { 1, 2, 3 };
        var a = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, s);
        var b = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, s);
        Assert.Equal(a, b);
    }

    [Fact]
    public void GetEnvCellGeomId_DiffersByEnvironmentId()
    {
        var a = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, new List<ushort> { 1 });
        var b = EnvCellRenderer.GetEnvCellGeomId(0x43, 7, new List<ushort> { 1 });
        Assert.NotEqual(a, b);
    }

    [Fact]
    public void GetEnvCellGeomId_DiffersByCellStructure()
    {
        var a = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, new List<ushort> { 1 });
        var b = EnvCellRenderer.GetEnvCellGeomId(0x42, 8, new List<ushort> { 1 });
        Assert.NotEqual(a, b);
    }

    [Fact]
    public void GetEnvCellGeomId_DiffersBySurfaces()
    {
        var a = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, new List<ushort> { 1 });
        var b = EnvCellRenderer.GetEnvCellGeomId(0x42, 7, new List<ushort> { 2 });
        Assert.NotEqual(a, b);
    }

    // -----------------------------------------------------------------------
    // Constructor — pure data, no GL
    // -----------------------------------------------------------------------

    [Fact]
    public void NewRenderer_NeedsPrepareIsTrue()
    {
        // GL and meshManager are null — only valid for pure-data tests (no
        // Initialize() is called, so no GL calls are made).
        var r = new EnvCellRenderer(gl: null!, meshManager: null!, frustum: new WbFrustum());
        Assert.True(r.NeedsPrepare);
    }

    [Fact]
    public void NewRenderer_NotDisposed()
    {
        var r = new EnvCellRenderer(gl: null!, meshManager: null!, frustum: new WbFrustum());
        Assert.False(r.IsDisposed);
    }

    // -----------------------------------------------------------------------
    // RemoveLandblock — pure data path
    // -----------------------------------------------------------------------

    [Fact]
    public void RemoveLandblock_NonExistent_DoesNotThrow()
    {
        var r = new EnvCellRenderer(gl: null!, meshManager: null!, frustum: new WbFrustum());
        // Should silently no-op.
        r.RemoveLandblock(0xA9B40000u);
        Assert.True(r.NeedsPrepare);
    }

    // -----------------------------------------------------------------------
    // GetEnvCellGeomId — additional edge cases
    // -----------------------------------------------------------------------

    [Fact]
    public void GetEnvCellGeomId_EmptySurfaces_Deterministic()
    {
        var a = EnvCellRenderer.GetEnvCellGeomId(1, 0, new List<ushort>());
        var b = EnvCellRenderer.GetEnvCellGeomId(1, 0, new List<ushort>());
        Assert.Equal(a, b);
        Assert.NotEqual(0UL, a & 0x2_0000_0000UL);
    }

    [Fact]
    public void GetEnvCellGeomId_SurfaceOrderMatters()
    {
        var a = EnvCellRenderer.GetEnvCellGeomId(1, 1, new List<ushort> { 10, 20 });
        var b = EnvCellRenderer.GetEnvCellGeomId(1, 1, new List<ushort> { 20, 10 });
        // The hash is order-sensitive (matches WB's foreach loop), so
        // swapped order should produce a different id.
        Assert.NotEqual(a, b);
    }

    // (Render() requires a GL context — visual-verified in Task 10.)
}