using System.Numerics;
using AcDream.App.Rendering;
using AcDream.App.Tests.UI.Layout; // InstalledDatFactAttribute (fix round F13)
using AcDream.Content;
using AcDream.Content.CharGen;
using AcDream.Content.Vfx;
using AcDream.Core.CharGen;
using AcDream.Core.Physics.Motion;
using AcDream.Core.World;
using DatReaderWriter;
using DatReaderWriter.Options;
using Xunit;
using Xunit.Abstractions;

namespace AcDream.App.Tests.Rendering;

/// <summary>
/// Campaign CC slice CC6b-MOUNT — installed-DAT gate for
/// <see cref="ChargenPreviewController"/>'s rebuild/render logic, using fake
/// <see cref="IChargenPreviewRenderer"/>/<see cref="IChargenPreviewFrameView"/>
/// implementations (no live GPU device needed — mirrors
/// <c>PaperdollFramePresenterTests</c>'s recording-fake pattern) against a
/// REAL dat-backed <see cref="ChargenOptions"/>/<see cref="ChargenAppearanceCatalog"/>
/// so <c>ChargenAppearanceFactory.TryCompose</c> and
/// <c>ChargenPreviewEntityBuilder.TryBuildAnimated</c> actually run.
///
/// <para>
/// Fix round F13: every case uses
/// <see cref="InstalledDatFactAttribute"/> (shared with
/// <c>CharacterCreationLiveDatTests</c>/<c>CharacterManagementLiveDatTests</c>)
/// instead of plain <c>[Fact]</c>. Before this fix, a bare <c>[Fact]</c> plus
/// <see cref="TryOpen"/>'s own <c>if (!TryOpen(...)) return;</c> guard made
/// all six cases pass SILENTLY with zero assertions run whenever
/// <c>ACDREAM_DAT_DIR</c> was unavailable — indistinguishable in the test
/// runner's summary from an actual passing run. The attribute now reports
/// those runs as Skipped so the counts show "ran" separately from "no-op'd".
/// </para>
/// </summary>
public sealed class ChargenPreviewControllerTests
{
    private readonly ITestOutputHelper _out;
    public ChargenPreviewControllerTests(ITestOutputHelper output) => _out = output;

    private const uint AluvianId = 1u;
    private const uint GearknightId = 6u;

    [InstalledDatFact]
    public void Rebuild_SameSelectionTwice_IsANoOpSecondTime()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            ChargenAppearanceSelection selection = DefaultSelection(options, AluvianId, 1);
            Assert.True(controller.Rebuild(options, AluvianId, 1, selection));
            Assert.True(controller.Rebuild(options, AluvianId, 1, selection));

            Assert.Equal(1, renderer.SetPreviewCallCount);
        }
    }

    [InstalledDatFact]
    public void Rebuild_HeritageChange_ResetsCameraToTheNewHeritagesDefaultEye()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var camera = new ChargenPreviewCamera();
            var controller = new ChargenPreviewController(
                renderer, camera, view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            Assert.True(controller.Rebuild(
                options, AluvianId, 1, DefaultSelection(options, AluvianId, 1)));
            // Poke the SAME camera instance the controller shares (this is
            // exactly the injection seam ChargenPreviewController's own doc
            // comment describes) — simulates the camera having drifted away
            // from the heritage default (e.g. mid zoom-out tween).
            camera.Eye = new Vector3(0f, -99f, 99f);

            if (!options.TryGetHeritage(GearknightId, out ChargenHeritageOptions? gearknight)
                || gearknight!.GendersByKey.Count == 0)
            {
                _out.WriteLine("SKIP: installed dat has no Gearknight gender to switch to.");
                return;
            }
            int gearknightGender = gearknight.GendersByKey.Keys.First();
            Assert.True(controller.Rebuild(
                options, GearknightId, gearknightGender,
                DefaultSelection(options, GearknightId, gearknightGender)));

            Assert.Equal(ChargenPreviewCamera.ResolveDefaultEye(GearknightId), controller.CameraEye);
        }
    }

    /// <summary>
    /// Decomp-cited (<c>gmCGAppearancePage::Update</c>'s two confirmed direct
    /// call sites — <c>InitializePage</c> and the gender-button handlers —
    /// vs the narrower <c>SetSelection</c>/<c>SetColor</c>/<c>SetShade</c>
    /// every spin/color/shade change goes through instead): a rebuild that
    /// changes ONLY the appearance selection (same heritage, same gender)
    /// must NOT snap the camera back to the heritage default.
    /// </summary>
    [InstalledDatFact]
    public void Rebuild_AppearanceOnlyChange_LeavesTheCameraUntouched()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var camera = new ChargenPreviewCamera();
            var controller = new ChargenPreviewController(
                renderer, camera, view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            ChargenAppearanceSelection first = DefaultSelection(options, AluvianId, 1);
            Assert.True(controller.Rebuild(options, AluvianId, 1, first));
            var pokedEye = new Vector3(0f, -99f, 99f);
            camera.Eye = pokedEye;

            ChargenAppearanceSelection second = first with { SkinShade = 0.9 };
            Assert.True(controller.Rebuild(options, AluvianId, 1, second));

            Assert.Equal(pokedEye, controller.CameraEye);
        }
    }

    [InstalledDatFact]
    public void Rebuild_PreservesZoomState_AcrossAnAppearanceOnlyChange()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            ChargenAppearanceSelection first = DefaultSelection(options, AluvianId, 1);
            Assert.True(controller.Rebuild(options, AluvianId, 1, first));
            controller.ZoomIn();
            Assert.True(controller.IsZoomedIn);

            // A DIFFERENT selection, same heritage/gender — retail's
            // gmCGAppearancePage::Update only resets the camera POSITION on
            // heritage/gender change; m_bZoomedIn is untouched by spin/color/
            // shade edits.
            ChargenAppearanceSelection second = first with { SkinShade = 0.9 };
            Assert.True(controller.Rebuild(options, AluvianId, 1, second));

            Assert.True(controller.IsZoomedIn);
        }
    }

    [InstalledDatFact]
    public void Rebuild_ThenRender_SeedsTheEntityHeadingToTheRetailDefault180Degrees()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            Assert.True(controller.Rebuild(
                options, AluvianId, 1, DefaultSelection(options, AluvianId, 1)));
            Assert.NotNull(renderer.LastEntity);

            controller.Render();

            Quaternion expected = MoveToMath.SetHeading(
                Quaternion.Identity, ChargenPreviewRotationController.RetailDefaultHeadingDegrees);
            Quaternion actual = renderer.LastEntity!.Rotation;
            Assert.Equal(expected.X, actual.X, 4);
            Assert.Equal(expected.Y, actual.Y, 4);
            Assert.Equal(expected.Z, actual.Z, 4);
            Assert.Equal(expected.W, actual.W, 4);
        }
    }

    /// <summary>
    /// Campaign CC gate round 1, Batch D (GF-7/GF-14): a successful Rebuild
    /// against a heritage that authors an environment Setup pushes a non-null
    /// backdrop entity to the renderer, sourced from the heritage's own
    /// <c>EnvironmentSetupId</c>.
    /// </summary>
    [InstalledDatFact]
    public void Rebuild_HeritageWithEnvironmentSetupId_SetsANonNullBackdrop()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            Assert.True(options.TryGetHeritage(AluvianId, out ChargenHeritageOptions? aluvian));
            if (aluvian!.EnvironmentSetupId == 0u)
            {
                _out.WriteLine("SKIP: installed dat's Aluvian heritage authors no EnvironmentSetupId.");
                return;
            }

            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            Assert.True(controller.Rebuild(
                options, AluvianId, 1, DefaultSelection(options, AluvianId, 1)));

            Assert.Equal(1, renderer.SetBackdropCallCount);
            Assert.NotNull(renderer.LastBackdropEntity);
            Assert.Equal(aluvian.EnvironmentSetupId, renderer.LastBackdropEntity!.SourceGfxObjOrSetupId);
        }
    }

    /// <summary>Retail's own gate (0x004eed29) skips the backdrop object
    /// entirely for a heritage with no authored environment Setup — the
    /// controller must leave the renderer's backdrop null, not build an empty
    /// placeholder entity.</summary>
    [InstalledDatFact]
    public void Rebuild_HeritageWithNoEnvironmentSetupId_LeavesTheBackdropAbsent()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            Assert.True(options.TryGetHeritage(AluvianId, out ChargenHeritageOptions? aluvian));

            // Synthetic zero-EnvironmentSetupId heritage, otherwise identical
            // to the real installed Aluvian entry (so ChargenAppearanceFactory
            // .TryCompose still succeeds against the SAME options instance) —
            // proves the absent-when-unset path without depending on the
            // installed dat happening to have an unset heritage.
            var heritages = new Dictionary<uint, ChargenHeritageOptions>(options.HeritagesById)
            {
                [AluvianId] = aluvian! with { EnvironmentSetupId = 0u },
            };
            ChargenOptions zeroed = options with { HeritagesById = heritages };

            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            Assert.True(controller.Rebuild(
                zeroed, AluvianId, 1, DefaultSelection(zeroed, AluvianId, 1)));

            Assert.Equal(1, renderer.SetBackdropCallCount);
            Assert.Null(renderer.LastBackdropEntity);
        }
    }

    /// <summary>
    /// The backdrop swaps to the new heritage's own environment Setup on a
    /// heritage change — the SAME <c>gmCG3DView::Update</c> gate
    /// (<c>m_bgSetupID.id != eax_32</c>) that drives the main entity's own
    /// re-dress.
    /// </summary>
    [InstalledDatFact]
    public void Rebuild_HeritageChange_SwapsTheBackdropEntity()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            Assert.True(options.TryGetHeritage(AluvianId, out ChargenHeritageOptions? aluvian));
            if (aluvian!.EnvironmentSetupId == 0u)
            {
                _out.WriteLine("SKIP: installed dat's Aluvian heritage authors no EnvironmentSetupId.");
                return;
            }
            if (!options.TryGetHeritage(GearknightId, out ChargenHeritageOptions? gearknight)
                || gearknight!.GendersByKey.Count == 0
                || gearknight.EnvironmentSetupId == 0u)
            {
                _out.WriteLine("SKIP: installed dat has no usable Gearknight environment/gender to switch to.");
                return;
            }

            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            Assert.True(controller.Rebuild(
                options, AluvianId, 1, DefaultSelection(options, AluvianId, 1)));
            WorldEntity? firstBackdrop = renderer.LastBackdropEntity;
            Assert.NotNull(firstBackdrop);

            int gearknightGender = gearknight.GendersByKey.Keys.First();
            Assert.True(controller.Rebuild(
                options, GearknightId, gearknightGender,
                DefaultSelection(options, GearknightId, gearknightGender)));

            Assert.Equal(2, renderer.SetBackdropCallCount);
            Assert.NotSame(firstBackdrop, renderer.LastBackdropEntity);
            Assert.NotNull(renderer.LastBackdropEntity);
            Assert.Equal(
                gearknight.EnvironmentSetupId, renderer.LastBackdropEntity!.SourceGfxObjOrSetupId);
        }
    }

    /// <summary>
    /// Decomp-cited: the heritage's own <c>environmentSetupID</c> is a pure
    /// function of heritage (<c>HeritageGroup_CG</c>), never gender or
    /// appearance selection — an appearance-only Rebuild must not re-touch
    /// the backdrop at all.
    /// </summary>
    [InstalledDatFact]
    public void Rebuild_AppearanceOnlyChange_DoesNotRebuildTheBackdrop()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView();
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());

            ChargenAppearanceSelection first = DefaultSelection(options, AluvianId, 1);
            Assert.True(controller.Rebuild(options, AluvianId, 1, first));
            Assert.Equal(1, renderer.SetBackdropCallCount);

            ChargenAppearanceSelection second = first with { SkinShade = 0.9 };
            Assert.True(controller.Rebuild(options, AluvianId, 1, second));

            Assert.Equal(1, renderer.SetBackdropCallCount);
        }
    }

    [InstalledDatFact]
    public void Render_WhilePageInvisible_SkipsRenderAndTexturePublication()
    {
        if (!TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter))
            return;
        using (dats)
        using (adapter)
        {
            (ChargenOptions options, ChargenAppearanceCatalog catalog) = LoadFixture(adapter!);
            var renderer = new FakeChargenRenderer();
            var view = new FakeChargenView { Visible = false };
            var controller = new ChargenPreviewController(
                renderer, new ChargenPreviewCamera(), view,
                adapter!, new RetailAnimationLoader(adapter!), catalog, catalog, new object());
            Assert.True(controller.Rebuild(
                options, AluvianId, 1, DefaultSelection(options, AluvianId, 1)));

            controller.Render();

            Assert.Equal(0, renderer.RenderCallCount);
            Assert.Null(view.LastTextureHandle);
        }
    }

    private static ChargenAppearanceSelection DefaultSelection(
        ChargenOptions options, uint heritageId, int genderKey)
    {
        Assert.True(options.TryGetHeritage(heritageId, out ChargenHeritageOptions? heritage));
        Assert.True(heritage!.GendersByKey.TryGetValue(genderKey, out ChargenGenderOptions? gender));
        return ChargenAppearanceSelection.Default with
        {
            HairStyle = gender!.HairStyles.Count > 0 ? 0u : ChargenAppearanceSelection.Unset,
            SkinShade = 0.5,
        };
    }

    private static (ChargenOptions, ChargenAppearanceCatalog) LoadFixture(IDatReaderWriter dats) =>
        (ChargenTableReader.Load(dats), new ChargenAppearanceCatalog(dats));

    /// <summary>
    /// Fix round F13: <see cref="InstalledDatFactAttribute"/> already gates
    /// every case above this call, so <c>datDir is null</c> should not be
    /// reachable in practice once a case actually runs — this stays as
    /// defense-in-depth (a DAT directory that exists but a corrupt/renamed
    /// <c>client_portal.dat</c> the attribute's own lighter check missed)
    /// rather than a silent no-assertions pass.
    /// </summary>
    private bool TryOpen(out DatCollection? dats, out DatCollectionAdapter? adapter)
    {
        string? datDir = CornerFloodReplayTests.ResolveDatDir();
        if (datDir is null)
        {
            _out.WriteLine("SKIP: dats unavailable");
            dats = null;
            adapter = null;
            return false;
        }
        dats = new DatCollection(datDir, DatAccessType.Read);
        adapter = new DatCollectionAdapter(dats);
        return true;
    }

    private sealed class FakeChargenRenderer : IChargenPreviewRenderer
    {
        public WorldEntity? LastEntity { get; private set; }
        public int SetPreviewCallCount { get; private set; }
        public int RenderCallCount { get; private set; }

        /// <summary>Batch D (GF-7/GF-14): last value passed to <see cref="SetBackdrop"/>.
        /// Null both before the first call AND after an explicit clear — tests
        /// distinguish the two via <see cref="SetBackdropCallCount"/>.</summary>
        public WorldEntity? LastBackdropEntity { get; private set; }
        public int SetBackdropCallCount { get; private set; }

        public void SetPreview(WorldEntity? entity)
        {
            LastEntity = entity;
            SetPreviewCallCount++;
        }

        public void SetBackdrop(WorldEntity? entity)
        {
            LastBackdropEntity = entity;
            SetBackdropCallCount++;
        }

        public uint Render(int width, int height)
        {
            RenderCallCount++;
            return 42u;
        }
    }

    private sealed class FakeChargenView : IChargenPreviewFrameView
    {
        public bool Visible { get; set; } = true;
        public int Width { get; set; } = 128;
        public int Height { get; set; } = 128;
        public uint? LastTextureHandle { get; private set; }

        public bool TryGetVisibleSize(out int width, out int height)
        {
            width = Width;
            height = Height;
            return Visible;
        }

        public void SetTextureHandle(uint textureHandle) => LastTextureHandle = textureHandle;
    }
}