using AcDream.Core.Rendering;
using Xunit;

namespace AcDream.Core.Tests.Rendering;

public sealed class RenderingDiagnosticsTests
{
    // Each flag-mutating test snapshots the IndoorAll state on entry and
    // restores it via try/finally. RenderingDiagnostics is a process-wide
    // static (env-var-initialized); without restoration a mutated state
    // leaks into other tests + into parallel test runs. Mirrors the
    // PhysicsDiagnosticsTests pattern at line 30-49.

    [Fact]
    public void IndoorAll_True_TurnsAllFlagsOn()
    {
        bool initial = RenderingDiagnostics.IndoorAll;
        try
        {
            // Reset all flags off first to make the test deterministic
            // regardless of env-var state on the test runner.
            RenderingDiagnostics.ProbeIndoorWalkEnabled   = false;
            RenderingDiagnostics.ProbeIndoorLookupEnabled = false;
            RenderingDiagnostics.ProbeIndoorUploadEnabled = false;
            RenderingDiagnostics.ProbeIndoorXformEnabled  = false;
            RenderingDiagnostics.ProbeIndoorCullEnabled   = false;

            RenderingDiagnostics.IndoorAll = true;

            Assert.True(RenderingDiagnostics.ProbeIndoorWalkEnabled);
            Assert.True(RenderingDiagnostics.ProbeIndoorLookupEnabled);
            Assert.True(RenderingDiagnostics.ProbeIndoorUploadEnabled);
            Assert.True(RenderingDiagnostics.ProbeIndoorXformEnabled);
            Assert.True(RenderingDiagnostics.ProbeIndoorCullEnabled);
            Assert.True(RenderingDiagnostics.IndoorAll);
        }
        finally
        {
            RenderingDiagnostics.IndoorAll = initial;
        }
    }

    [Fact]
    public void IndoorAll_False_TurnsAllFlagsOff()
    {
        bool initial = RenderingDiagnostics.IndoorAll;
        try
        {
            RenderingDiagnostics.IndoorAll = true;  // start from all-on
            RenderingDiagnostics.IndoorAll = false;

            Assert.False(RenderingDiagnostics.ProbeIndoorWalkEnabled);
            Assert.False(RenderingDiagnostics.ProbeIndoorLookupEnabled);
            Assert.False(RenderingDiagnostics.ProbeIndoorUploadEnabled);
            Assert.False(RenderingDiagnostics.ProbeIndoorXformEnabled);
            Assert.False(RenderingDiagnostics.ProbeIndoorCullEnabled);
            Assert.False(RenderingDiagnostics.IndoorAll);
        }
        finally
        {
            RenderingDiagnostics.IndoorAll = initial;
        }
    }

    [Fact]
    public void IndoorAll_OneOff_ReadsAsFalse()
    {
        bool initial = RenderingDiagnostics.IndoorAll;
        try
        {
            RenderingDiagnostics.IndoorAll = true;
            RenderingDiagnostics.ProbeIndoorCullEnabled = false;  // flip one off
            Assert.False(RenderingDiagnostics.IndoorAll);
        }
        finally
        {
            RenderingDiagnostics.IndoorAll = initial;
        }
    }

    [Theory]
    [InlineData(0x00000029ul, false)]   // outdoor cell 0x29 in 8x8 grid
    [InlineData(0xA9B40029ul, false)]   // outdoor cell with landblock prefix
    [InlineData(0x00000100ul, true)]    // indoor cell minimum
    [InlineData(0x00000105ul, true)]    // typical Holtburg Inn interior
    [InlineData(0xA9B40105ul, true)]    // indoor with landblock prefix
    [InlineData(0xA9B401FFul, true)]    // indoor near top of range
    public void IsEnvCellId_DistinguishesOutdoorVsIndoorByLow16Bits(ulong id, bool expected)
    {
        Assert.Equal(expected, RenderingDiagnostics.IsEnvCellId(id));
    }

    // ── Render inside/outside branch (retail RenderNormalMode is_player_outside) ──
    // The top-level render branch decides DrawInside vs DrawOutside. Retail
    // (SmartBox::RenderNormalMode 0x453aa0:92665) keys it on is_player_outside (the
    // PLAYER's cell, 0x451e80), NOT the camera cell. acdream previously branched on the
    // camera cell, so a chase camera lagging in a doorway while the player was already
    // outside took the DrawInside path and degenerated to a grey world + entities showing
    // through walls. These pin the player-keyed branch (DrawInside root stays the viewer cell).

    [Fact]
    public void ShouldRenderIndoor_PlayerOutside_CameraInside_ReturnsFalse()
    {
        // THE doorway-grey regression: the player stepped onto a landcell (0x...0031) but the
        // chase camera still resolves an interior EnvCell. Branch on the PLAYER → outdoor.
        Assert.False(RenderingDiagnostics.ShouldRenderIndoor(playerCellId: 0xA9B40031u, viewerCellResolved: true));
    }

    [Fact]
    public void ShouldRenderIndoor_PlayerInside_CameraInside_ReturnsTrue()
    {
        Assert.True(RenderingDiagnostics.ShouldRenderIndoor(playerCellId: 0xA9B40171u, viewerCellResolved: true));
    }

    [Fact]
    public void ShouldRenderIndoor_PlayerInside_NoViewerCell_ReturnsFalse()
    {
        // Opposite lag (camera pulled outside while the player is inside): no viewer cell to
        // root DrawInside at → outdoor. Defensive; matches prior null-CameraCell behavior.
        Assert.False(RenderingDiagnostics.ShouldRenderIndoor(playerCellId: 0xA9B40171u, viewerCellResolved: false));
    }

    [Fact]
    public void ShouldRenderIndoor_PlayerOutside_CameraOutside_ReturnsFalse()
    {
        Assert.False(RenderingDiagnostics.ShouldRenderIndoor(playerCellId: 0xA9B40031u, viewerCellResolved: false));
    }

    [Fact]
    public void ShouldRenderIndoor_UnknownPlayerCell_TreatedAsOutside_ReturnsFalse()
    {
        // playerCellId == 0 (unresolved) → treat as outside (safe default: outdoor render).
        Assert.False(RenderingDiagnostics.ShouldRenderIndoor(playerCellId: 0u, viewerCellResolved: true));
    }
}