using AcDream.App.Rendering;

namespace AcDream.App.Tests.Rendering;

public sealed class GameWindowRenderLeafCompositionTests
{
    [Fact]
    public void ProductionRender_PreservesPrivatePresentationAndCaptureOrder()
    {
        string source = GameWindowSource();

        AssertAppearsInOrder(
            source,
            "_localPlayerTeleport?.DrawPortalViewport(",
            "_paperdollFramePresenter?.Render();",
            "_retailUiRuntime.Tick(deltaSeconds);",
            "_devToolsFramePresenter?.Render(",
            "_frameScreenshots?.CapturePending() == true;",
            "_renderFrameDiagnostics?.Publish(");
    }

    [Fact]
    public void ProductionRender_BeginsDevToolsBeforeWorldAndBeginsDispatcherOnce()
    {
        string source = GameWindowSource();

        AssertAppearsInOrder(
            source,
            "_devToolsFramePresenter?.BeginFrame((float)deltaSeconds);",
            "Weather.Tick(nowSeconds: _weatherAccum",
            "_retailSelectionScene?.BeginFrame();");
        Assert.Equal(1, CountOccurrences(source, "_wbDrawDispatcher?.BeginFrame("));
    }

    [Fact]
    public void ProductionComposition_RemovesLegacyLeafOwnership()
    {
        string source = GameWindowSource();

        string[] removed =
        [
            "_imguiBootstrap",
            "_panelHost",
            "_paperdollDollDirty",
            "RefreshPaperdollDoll",
            "ApplyPaperdollPose",
            "ResolvePaperdollPoseDid",
            "EnumerateDebugPanel",
            "ResetPanelLayout",
            "SetPanelLayout",
            "_lastRenderSignature",
            "private void EmitRenderSignatureIfChanged(",
            "private void EmitRetailPViewDiagnostics(",
            "EmitGlStateTripwireIfChanged();",
            "EmitClipRouteScissorProbe(scissor",
            "_lastVisibleLandblocks",
            "_perfAccum",
        ];
        foreach (string identifier in removed)
            Assert.DoesNotContain(identifier, source, StringComparison.Ordinal);

        Assert.Contains("new AcDream.App.Rendering.PaperdollFramePresenter(", source);
        Assert.Contains("new AcDream.App.Rendering.DevToolsFramePresenter(", source);
        Assert.Contains("_inputCapture.WantCaptureMouse", source);
    }

    [Fact]
    public void Shutdown_PreservesBorrowedDevtoolsLifetimeAndDrainsGpuBeforeFrontends()
    {
        string source = GameWindowSource();

        AssertAppearsInOrder(
            source,
            "new ResourceShutdownStage(\"submitted GPU work\"",
            "new ResourceShutdownStage(\"render frontends\"",
            "new(\"portal tunnel\"",
            "new(\"paperdoll viewport\"",
            "new ResourceShutdownStage(\"OpenGL context\"");
        Assert.DoesNotContain("_devToolsBackend?.Dispose()", source);
    }

    [Fact]
    public void ProductionOutcome_UsesObservedWorldAndScreenshotFacts()
    {
        string source = GameWindowSource();

        Assert.Contains("bool normalWorldDrawn = false;", source);
        AssertAppearsInOrder(
            source,
            "if (IsLiveModeWaitingForLogin)",
            "goto SkipWorldGeometry;",
            "normalWorldDrawn = true;",
            "bool screenshotCaptured = _frameScreenshots?.CapturePending() == true;",
            "normalWorldDrawn),",
            "screenshotCaptured)));");
    }

    [Fact]
    public void PaperdollComposition_SkipsEitherMissingOptionalUiSurface()
    {
        string source = GameWindowSource();

        AssertAppearsInOrder(
            source,
            "PaperdollViewportWidget is { } paperdollViewport",
            "InventoryFrame is { } paperdollInventoryFrame",
            "new AcDream.App.Rendering.PaperdollFramePresenter(");
        Assert.DoesNotContain("Paperdoll inventory frame is required.", source);
    }

    [Fact]
    public void TerrainAndFrameDiagnostics_CommitOneSharedCadenceAfterBothWrites()
    {
        string source = GameWindowSource();

        AssertAppearsInOrder(
            source,
            "_worldRenderDiagnostics?.PublishTerrainDiagnostics(",
            "PublishFrameDiagnostics();",
            "_frameDiagLastPublicationMilliseconds = now;");
    }

    private static string GameWindowSource() => File.ReadAllText(Path.Combine(
        FindRepoRoot(),
        "src",
        "AcDream.App",
        "Rendering",
        "GameWindow.cs"));

    private static void AssertAppearsInOrder(string source, params string[] needles)
    {
        int cursor = -1;
        foreach (string needle in needles)
        {
            int next = source.IndexOf(needle, cursor + 1, StringComparison.Ordinal);
            Assert.True(next >= 0, $"Missing expected source fragment: {needle}");
            Assert.True(next > cursor, $"Out-of-order source fragment: {needle}");
            cursor = next;
        }
    }

    private static int CountOccurrences(string source, string needle)
    {
        int count = 0;
        int cursor = 0;
        while ((cursor = source.IndexOf(needle, cursor, StringComparison.Ordinal)) >= 0)
        {
            count++;
            cursor += needle.Length;
        }

        return count;
    }

    private static string FindRepoRoot()
    {
        DirectoryInfo? directory = new(AppContext.BaseDirectory);
        while (directory is not null)
        {
            if (File.Exists(Path.Combine(directory.FullName, "AcDream.slnx")))
                return directory.FullName;
            directory = directory.Parent;
        }

        throw new DirectoryNotFoundException("Could not find AcDream.slnx.");
    }
}