using AcDream.App.Rendering.Scene;
using AcDream.App.Rendering.Selection;
using AcDream.App.Rendering.Vfx;
using AcDream.App.Streaming;
using AcDream.Core.Rendering;

namespace AcDream.App.Rendering;

internal interface IWorldScenePViewRenderer
{
    IReadOnlySet<uint> OutdoorSceneParticleEntityIds { get; }

    RetailPViewFrameResult DrawInside(RetailPViewFrameInput input);

    void AbortFrame();
}

internal sealed class WorldScenePViewRenderer : IWorldScenePViewRenderer
{
    private readonly RetailPViewRenderer _renderer;
    private readonly IRetailPViewPassExecutor _passes;
    private readonly IOutdoorSceneParticleOwnerSource _particles;

    public WorldScenePViewRenderer(
        RetailPViewRenderer renderer,
        IRetailPViewPassExecutor passes,
        IOutdoorSceneParticleOwnerSource particles)
    {
        _renderer = renderer ?? throw new ArgumentNullException(nameof(renderer));
        _passes = passes ?? throw new ArgumentNullException(nameof(passes));
        _particles = particles ?? throw new ArgumentNullException(nameof(particles));
    }

    public IReadOnlySet<uint> OutdoorSceneParticleEntityIds =>
        _particles.OutdoorSceneParticleEntityIds;

    public RetailPViewFrameResult DrawInside(RetailPViewFrameInput input) =>
        _renderer.DrawInside(input, _passes);

    public void AbortFrame() => _passes.AbortFrame();
}

/// <summary>
/// Owns the normal-world render transaction between shared frame-resource
/// preparation and private presentation. It preserves retail's one PView
/// decision: a resolved viewer root uses DrawInside; only an unresolved root
/// uses the flat safety path.
/// </summary>
internal sealed class WorldSceneRenderer : IWorldSceneFramePhase
{
    private readonly IRenderFrameFoundationSource _foundation;
    private readonly IRenderLoginStateSource _login;
    private readonly IWorldSceneSkyStateSource _sky;
    private readonly IWorldRenderFrameBuilder _frames;
    private readonly IWorldSceneEntitySource _entities;
    private readonly IWorldSceneSelectionFrame? _selection;
    private readonly IWorldSceneAlphaFrame _alpha;
    private readonly IWorldSceneParticleVisibility _particleVisibility;
    private readonly IWorldScenePViewRenderer _pview;
    private readonly IRetailPViewCellSource _pviewCells;
    private readonly IWorldScenePassExecutor _passes;
    private readonly IWorldRenderRangeSource _renderRange;
    private readonly IWorldSceneDiagnostics _diagnostics;
    private readonly IWorldGenerationAvailability _availability;
    private readonly RetailPViewFrameInput _pviewFrameInput = new();

    public WorldSceneRenderer(
        IRenderFrameFoundationSource foundation,
        IRenderLoginStateSource login,
        IWorldSceneSkyStateSource sky,
        IWorldRenderFrameBuilder frames,
        IWorldSceneEntitySource entities,
        IWorldSceneSelectionFrame? selection,
        IWorldSceneAlphaFrame alpha,
        IWorldSceneParticleVisibility particleVisibility,
        IWorldScenePViewRenderer pview,
        IRetailPViewCellSource pviewCells,
        IWorldScenePassExecutor passes,
        IWorldRenderRangeSource renderRange,
        IWorldSceneDiagnostics diagnostics,
        IWorldGenerationAvailability? availability = null)
    {
        _foundation = foundation ?? throw new ArgumentNullException(nameof(foundation));
        _login = login ?? throw new ArgumentNullException(nameof(login));
        _sky = sky ?? throw new ArgumentNullException(nameof(sky));
        _frames = frames ?? throw new ArgumentNullException(nameof(frames));
        _entities = entities ?? throw new ArgumentNullException(nameof(entities));
        _selection = selection;
        _alpha = alpha ?? throw new ArgumentNullException(nameof(alpha));
        _particleVisibility = particleVisibility
            ?? throw new ArgumentNullException(nameof(particleVisibility));
        _pview = pview ?? throw new ArgumentNullException(nameof(pview));
        _pviewCells = pviewCells ?? throw new ArgumentNullException(nameof(pviewCells));
        _passes = passes ?? throw new ArgumentNullException(nameof(passes));
        _renderRange = renderRange ?? throw new ArgumentNullException(nameof(renderRange));
        _diagnostics = diagnostics ?? throw new ArgumentNullException(nameof(diagnostics));
        _availability = availability ?? AlwaysAvailableWorldGeneration.Instance;
    }

    public WorldRenderFrameOutcome Render(RenderFrameInput input)
    {
        _ = input;
        bool selectionFrameStarted = _selection is not null;
        bool worldFrameStarted = false;
        bool pviewFrameStarted = false;
        try
        {
            _selection?.BeginFrame();
            if (!_availability.IsWorldAvailable)
            {
                _selection?.CompleteFrame();
                selectionFrameStarted = false;
                return default;
            }

            RenderFrameFoundation foundation = _foundation.Foundation;
            if (foundation.PortalViewportVisible)
            {
                _selection?.CompleteFrame();
                selectionFrameStarted = false;
                return default;
            }

            // Set before BeginFrame so an already-poisoned queue is recovered by
            // the same abort path instead of making every later frame fail.
            worldFrameStarted = true;
            _alpha.BeginFrame();
            WorldRenderFrame world = _frames.Build(
                in foundation,
                _login.IsWaitingForLogin,
                _sky.ActiveDayGroup);
            _passes.BeginFrame();

            WorldCameraFrame camera = world.Camera;
            WorldRootFrame roots = world.Roots;
            LoadedCell? clipRoot = world.ClipRoot;
            bool renderSky = roots.RenderSky;
            bool drawSkyThisFrame = false;
            bool terrainDrawn = false;
            bool skyDrawn = false;
            bool depthClear = false;
            bool outdoorSceneryDrawn = false;
            int liveDynamicDrawnCount = 0;
            string sceneParticles = "none";
            TerrainClipMode terrainClipMode = TerrainClipMode.Planes;
            RetailPViewFrameResult? pviewResult = null;

            if (clipRoot is null)
            {
                _passes.PrepareFlatWorldClip();
                drawSkyThisFrame = renderSky;
                skyDrawn = drawSkyThisFrame;
                if (drawSkyThisFrame)
                {
                    _passes.DrawFlatSky(
                        in camera,
                        in foundation,
                        _sky.ActiveDayGroup,
                        _sky.DayFraction);
                }

                // The former sky-only "waiting for login" skip lived here.
                // It is unreachable now: LocalPlayerTeleportRenderStateSource
                // folds IsWaitingForLogin into PortalViewportVisible (retail's
                // pre-player gameplay screen draws NO world — black, not sky),
                // so the portal-visible return above already covers every
                // waiting frame. One gate computes the frame's visibility;
                // this phase only enforces it.
                _passes.DrawFlatTerrain(in camera, roots.PlayerLandblockId);
                terrainDrawn = true;
            }
            else
            {
                terrainClipMode = TerrainClipMode.Skip;
            }

            if (clipRoot is not null)
            {
                pviewFrameStarted = true;
                pviewResult = _pview.DrawInside(
                    _pviewFrameInput.Reset(
                        clipRoot,
                        world.Buildings.NearbyBuildingCells,
                        roots.ViewerEyePosition,
                        camera.ViewProjection,
                        _pviewCells,
                        camera.Camera,
                        camera.Position,
                        camera.Frustum,
                        roots.PlayerLandblockId,
                        world.AnimatedEntityIds,
                        roots.RenderCenterLandblockX,
                        roots.RenderCenterLandblockY,
                        _renderRange.NearRadius,
                        _entities.LandblockEntries,
                        renderSky,
                        roots.PlayerSeenOutside,
                        _sky.DayFraction,
                        _sky.ActiveDayGroup,
                        foundation.Sky,
                        foundation.EnvironOverrideActive,
                        roots.ViewerCellId,
                        roots.PlayerCellId,
                        roots.PlayerViewPosition,
                        camera.Camera.View,
                        _diagnostics.CameraCellResolution));

                _particleVisibility.MarkVisibleCells(pviewResult.DrawableCells);
                _frames.ObserveDrawableCells(pviewResult.DrawableCells);
                _diagnostics.EmitPViewInput(
                    pviewResult.PortalFrame,
                    camera.ViewProjection,
                    clipRoot,
                    camera.Position,
                    roots.PlayerViewPosition);

                bool hasOutsideSlice = pviewResult.ClipAssembly.OutsideViewSlices.Length > 0;
                terrainDrawn = hasOutsideSlice;
                skyDrawn = renderSky && hasOutsideSlice;
                // This mirrors the established diagnostic meaning, including
                // outdoor roots whose PView executor does not issue an interior
                // depth clear.
                depthClear = hasOutsideSlice;
                RenderProjectionCounts sourceCounts =
                    pviewResult.SourceCounts;
                if (sourceCounts.IndoorCellStatic > 0 || hasOutsideSlice)
                    sceneParticles = "pviewScoped";
                outdoorSceneryDrawn =
                    sourceCounts.OutdoorStatic > 0
                    && hasOutsideSlice;
                liveDynamicDrawnCount =
                    sourceCounts.LiveDynamicRoot;
            }
            else
            {
                _passes.DrawFlatEntities(
                    in camera,
                    _entities.LandblockEntries,
                    roots.PlayerLandblockId,
                    world.AnimatedEntityIds);
                _frames.ClearDrawableCells();
            }

            _passes.DisableClipDistances();
            sceneParticles = _passes.DrawPostWorldParticles(
                clipRoot,
                pviewResult?.ClipAssembly,
                in camera,
                _pview.OutdoorSceneParticleEntityIds,
                sceneParticles);

            if (clipRoot is null && drawSkyThisFrame)
            {
                skyDrawn = true;
                _passes.DrawFlatWeather(
                    in camera,
                    in foundation,
                    _sky.ActiveDayGroup,
                    _sky.DayFraction);
            }

            _diagnostics.EmitRenderSignature(
                clipRoot is null ? "OutdoorRoot" : "RetailPViewInside",
                clipRoot,
                roots.ViewerRoot,
                roots.PlayerRoot,
                roots.ViewerCellId,
                roots.PlayerCellId,
                roots.PlayerIndoorGate,
                roots.CameraInsideCell,
                renderSky,
                drawSkyThisFrame,
                terrainDrawn,
                terrainClipMode,
                skyDrawn,
                depthClear,
                outdoorSceneryDrawn,
                liveDynamicDrawnCount,
                sceneParticles,
                pviewResult,
                camera.Position,
                roots.PlayerViewPosition);

            WorldSceneDiagnosticOutcome diagnostic = _diagnostics.DrawAndPublish(
                in camera,
                _entities.LandblockBounds);
            CompleteWorldFrame();
            worldFrameStarted = false;
            pviewFrameStarted = false;
            _selection?.CompleteFrame();
            selectionFrameStarted = false;
            return new WorldRenderFrameOutcome(
                diagnostic.VisibleLandblocks,
                diagnostic.TotalLandblocks,
                NormalWorldDrawn: true);
        }
        catch (Exception renderFailure)
        {
            List<Exception>? abortFailures = AbortFrame(
                worldFrameStarted,
                pviewFrameStarted,
                selectionFrameStarted);
            if (abortFailures is { Count: > 0 })
            {
                abortFailures.Insert(0, renderFailure);
                throw new AggregateException(
                    "World rendering failed and the incomplete frame could not be fully aborted.",
                    abortFailures);
            }
            throw;
        }
    }

    private void CompleteWorldFrame()
    {
        _alpha.EndFrame();
        if (_passes.TerrainVisibleCellIds is { } visibleTerrainCells)
            _particleVisibility.MarkVisibleCells(visibleTerrainCells);
        _particleVisibility.CompleteFrame();
    }

    private List<Exception>? AbortFrame(
        bool worldFrameStarted,
        bool pviewFrameStarted,
        bool selectionFrameStarted)
    {
        List<Exception>? failures = null;
        if (worldFrameStarted)
        {
            if (pviewFrameStarted)
                TryAbort(_pview.AbortFrame);
            TryAbort(_passes.AbortFrame);
            TryAbort(_particleVisibility.AbortFrame);
            TryAbort(_alpha.AbortFrame);
        }
        if (selectionFrameStarted && _selection is not null)
            TryAbort(_selection.AbortFrame);
        return failures;

        void TryAbort(Action abort)
        {
            try
            {
                abort();
            }
            catch (Exception error)
            {
                (failures ??= []).Add(error);
            }
        }
    }
}