namespace AcDream.Plugin.Abstractions.Rendering;

/// <summary>Prerequisite tier reached by a pack.</summary>
public enum RenderPackTier
{
    Tier1 = 1,
    Tier2 = 2,
    Tier2Plus = 3,
}

/// <summary>
/// Renderer-owned facilities a pack may require or use opportunistically.
/// These are semantic capabilities, not Vulkan extension or feature names.
/// </summary>
public enum RenderCapability
{
    MainWorldColorIntermediate,
    FullscreenPasses,
    SceneDepthSampling,
    SceneNormalSampling,
    AuthoredSunDirection,
    AuthoredSunScreenPosition,
    AuthoredWeather,
    DirectionalShadowMaps,
    OutdoorDirectionalShadowCasterReplay,
    AnimatedCasterTransforms,
    AlphaCutoutShadowCasters,
    GpuTimestampQueries,
    /// <summary>One layered directional-depth pass may address multiple cascade views.</summary>
    MultiviewDirectionalShadowCascades,
    /// <summary>One renderer-selected authored sun-or-moon shadow direction.</summary>
    AuthoredCelestialDirectionalLight,
}

/// <summary>Fixed renderer-owned positions at which a declared pass may run.</summary>
public enum RenderPassHook
{
    ShadowDepthBeforeWorld,
    AtmosphereBeforeToneMap,
    ToneMap,
    AfterToneMapBeforePrivateViewports,
}

/// <summary>Immutable frame facts the renderer may bind for a pack.</summary>
public enum RenderSemanticInput
{
    WorldColor,
    SceneDepth,
    SceneNormals,
    SunDirection,
    SunScreenPosition,
    ActiveDayGroup,
    Weather,
    CameraMatrices,
    ShadowCasterTransforms,
    DirectionalShadowMaps,
    FrameTime,
    /// <summary>Selected surface-to-sun-or-moon direction for shadow work.</summary>
    SelectedCelestialDirectionalLight,
}

/// <summary>Renderer-owned replay operations available to a declaration.</summary>
public enum RenderSceneReplaySemantic
{
    OutdoorDirectionalShadowCasters,
}

/// <summary>Existing retained-scene classes eligible for a scene replay.</summary>
[Flags]
public enum RenderCasterClass
{
    None = 0,
    Terrain = 1 << 0,
    OpaqueWorld = 1 << 1,
    AlphaCutoutWorld = 1 << 2,
    AnimatedOpaque = 1 << 3,
    AnimatedAlphaCutout = 1 << 4,
}

/// <summary>Base renderer pipeline a pack may specialize.</summary>
public enum RenderPipelineBaseSemantic
{
    Terrain,
    WorldMesh,
    EnvCell,
}

/// <summary>Material classifications accepted by a pipeline variant.</summary>
[Flags]
public enum RenderMaterialClass
{
    None = 0,
    Opaque = 1 << 0,
    AlphaCutout = 1 << 1,
    AnimatedOpaque = 1 << 2,
    AnimatedAlphaCutout = 1 << 3,
}

/// <summary>Kind of renderer-owned intermediate resource.</summary>
public enum RenderResourceKind
{
    Image2D,
    Image2DArray,
    Buffer,
}

/// <summary>Portable format families resolved by the renderer.</summary>
public enum RenderFormatClass
{
    LdrColor,
    HdrColor,
    SingleChannel,
    DirectionalDepth,
    StructuredData,
}

/// <summary>How declared image dimensions are interpreted.</summary>
public enum RenderExtentMode
{
    AbsolutePixels,
    RelativeToMainWorld,
    RelativeToOutput,
}

/// <summary>Permitted uses of a declared resource.</summary>
[Flags]
public enum RenderResourceUsage
{
    None = 0,
    Sampled = 1 << 0,
    ColorAttachment = 1 << 1,
    DepthAttachment = 1 << 2,
    Storage = 1 << 3,
    TransferSource = 1 << 4,
    TransferDestination = 1 << 5,
}

/// <summary>Lifetime class used by the renderer's frame-flight allocator.</summary>
public enum RenderResourceLifetime
{
    TransientPass,
    FrameFlight,
    ActivePack,
}

/// <summary>
/// Renderer-owned meaning of a declared resource. <see cref="Custom"/> is
/// available to ordinary declarative fullscreen graphs; the remaining values
/// let a pack request host executors without relying on magic resource IDs.
/// </summary>
public enum RenderResourceSemantic
{
    Custom,
    MainWorldHdr,
    BloomPing,
    BloomPong,
    SunOcclusionMask,
    SunRays,
    DirectionalShadowDepth,
    VolumetricShafts,
}

/// <summary>Shape of one image declaration.</summary>
/// <param name="Mode">Absolute pixels or a scale relative to a renderer surface.</param>
/// <param name="Width">Pixel width for absolute mode; horizontal scale otherwise.</param>
/// <param name="Height">Pixel height for absolute mode; vertical scale otherwise.</param>
/// <param name="Layers">Array layers; one for an ordinary 2-D image.</param>
public sealed record RenderExtentDeclaration(
    RenderExtentMode Mode,
    double Width,
    double Height,
    int Layers = 1);

/// <summary>One renderer-owned intermediate image or buffer.</summary>
public sealed record RenderResourceDeclaration(
    string Id,
    RenderResourceKind Kind,
    RenderFormatClass Format,
    RenderExtentDeclaration? Extent,
    long SizeBytes,
    RenderResourceUsage Usage,
    RenderResourceLifetime Lifetime,
    long EstimatedResidentBytes)
{
    public RenderResourceSemantic Semantic { get; init; } = RenderResourceSemantic.Custom;
}

/// <summary>
/// Renderer-owned execution meaning of a pass. IDs remain pack-owned stable
/// identifiers; semantic execution never depends on a particular ID string.
/// </summary>
public enum RenderPassSemantic
{
    CustomFullscreen,
    DirectionalShadowDepth,
    BloomDownsample,
    BloomBlurHorizontal,
    BloomBlurVertical,
    SunOcclusion,
    SunRays,
    VolumetricShafts,
    FilmicComposite,
}

/// <summary>One declarative full-screen, atmosphere, or tone-map pass.</summary>
public sealed record RenderPassDeclaration(
    string Id,
    RenderPassHook Hook,
    string VertexShaderAsset,
    string FragmentShaderAsset,
    IReadOnlyList<RenderSemanticInput> SemanticInputs,
    IReadOnlyList<string> ResourceReads,
    IReadOnlyList<string> ResourceWrites)
{
    public RenderPassSemantic Semantic { get; init; } = RenderPassSemantic.CustomFullscreen;
}

/// <summary>A renderer-owned replay of retained scene geometry.</summary>
public sealed record SceneReplayDeclaration(
    string Id,
    RenderSceneReplaySemantic Semantic,
    RenderCasterClass CasterClasses,
    int ViewCount);

/// <summary>A shader specialization of an existing renderer pipeline.</summary>
public sealed record PipelineVariantDeclaration(
    string Id,
    RenderPipelineBaseSemantic BaseSemantic,
    string VertexShaderAsset,
    string FragmentShaderAsset,
    RenderMaterialClass CompatibleMaterials,
    IReadOnlyList<RenderSemanticInput> SemanticInputs)
{
    public RenderPipelineVariantSemantic Semantic { get; init; } =
        RenderPipelineVariantSemantic.Custom;
}

/// <summary>Renderer-owned role of a fixed retained-scene pipeline variant.</summary>
public enum RenderPipelineVariantSemantic
{
    Custom,
    TerrainDirectionalShadowCaster,
    WorldOpaqueDirectionalShadowCaster,
    WorldAlphaCutoutDirectionalShadowCaster,
    TerrainDirectionalShadowReceiver,
    WorldDirectionalShadowReceiver,
    TerrainMultiviewDirectionalShadowCaster,
    WorldOpaqueMultiviewDirectionalShadowCaster,
    WorldAlphaCutoutMultiviewDirectionalShadowCaster,
}

/// <summary>Per-preset replacement for one resource's size.</summary>
public sealed record RenderQualityResourceOverride(
    string ResourceId,
    RenderExtentDeclaration? Extent,
    long SizeBytes,
    long EstimatedResidentBytes);

/// <summary>Per-preset value for a declared user setting.</summary>
public sealed record RenderQualitySettingOverride(
    string SettingId,
    string Value);

/// <summary>One user-selectable, independently capability-gated preset.</summary>
public sealed record RenderQualityPreset(
    string Id,
    string DisplayName,
    IReadOnlyList<RenderCapability> RequiredCapabilities,
    IReadOnlyList<RenderQualityResourceOverride> ResourceOverrides,
    IReadOnlyList<RenderQualitySettingOverride> SettingOverrides,
    long MaxResidentGpuBytes,
    double MaxIncrementalGpuMillisecondsP50,
    double MaxIncrementalGpuMillisecondsP99,
    double MaxIncrementalCpuMillisecondsP50,
    double MaxIncrementalCpuMillisecondsP99,
    bool AutoEligible = true)
{
    public RenderQualitySemantic Semantic { get; init; } = RenderQualitySemantic.Custom;

    /// <summary>
    /// Optional renderer-owned execution optimizations whose shader ABI the
    /// pack explicitly implements. The host never infers these from a pack ID.
    /// </summary>
    public RenderQualityExecutionHints ExecutionHints { get; init; } =
        RenderQualityExecutionHints.None;
}

/// <summary>
/// Opt-in execution forms for renderer-owned atmospheric work. These hints
/// may fuse passes or compatible submissions; they do not remove declared
/// effects or caster classes from the final image.
/// </summary>
[Flags]
public enum RenderQualityExecutionHints
{
    None = 0,

    /// <summary>
    /// The sun-rays shader accepts scene depth directly and filmic composite
    /// evaluates the declared bloom extraction/filter while composing the
    /// image. See the standard PackPass ABI flags.
    /// </summary>
    FusedAtmosphericPostProcess = 1 << 0,

    /// <summary>
    /// The three multiview caster variants select the exact cascade matrix with
    /// the renderer-owned view index and render every declared Low cascade in
    /// one layered depth pass.
    /// </summary>
    MultiviewDirectionalShadowCascades = 1 << 1,
}

/// <summary>
/// Optional host quality role. Pack-owned IDs remain persisted; this semantic
/// is used only when a pack opts into the host's automatic-quality controller.
/// </summary>
public enum RenderQualitySemantic
{
    Custom,
    Low,
    Medium,
    High,
    Automatic,
}

/// <summary>Storage and presentation kind for a pack-defined setting.</summary>
public enum RenderSettingKind
{
    Boolean,
    Integer,
    Float,
    Choice,
}

/// <summary>A bounded, user-visible pack setting.</summary>
public sealed record RenderSettingDeclaration(
    string Id,
    string DisplayName,
    RenderSettingKind Kind,
    string DefaultValue,
    double? Minimum,
    double? Maximum,
    double? Step,
    IReadOnlyList<string> Choices)
{
    public RenderSettingSemantic Semantic { get; init; } = RenderSettingSemantic.Custom;
}

/// <summary>
/// Optional host meaning for settings consumed by a renderer-owned atmospheric
/// executor. Ordinary pack settings use <see cref="Custom"/>.
/// </summary>
public enum RenderSettingSemantic
{
    Custom,
    BloomStrength,
    FilmicStrength,
    Exposure,
    GradeSaturation,
    GradeContrast,
    VignetteStrength,
    SunRayStrength,
    DirectionalShadowStrength,
    DirectionalShadowReachMetres,
    DirectionalShadowPcfTaps,
    VolumetricStrength,
    VolumetricRayMarchSteps,
    AutomaticQuality,
    // Campaign VM VM6: foliage wind.
    WindEnabled,
    WindStrength,
    WindDirectionDegrees,
    WindLeanMetres,
    WindBranchMetres,
    WindFlutterMetres,
    WindCanopyHeightMetres,
}

/// <summary>One point on a declared sun-elevation response curve.</summary>
public sealed record SunElevationResponsePoint(
    double ElevationDegrees,
    double Multiplier);

/// <summary>Explicit mapping from an authored AC day group to an effect multiplier.</summary>
public sealed record ActiveDayGroupMultiplier(
    int ActiveDayGroup,
    double Multiplier);

/// <summary>
/// Explicit mapping from a DAT-classified weather kind to the foliage-wind
/// mean and gust strength for that weather (both in the declared [0,1] range
/// before the pack's global wind-strength setting scales them). Campaign VM
/// VM6, corrected in the fix round: the day-group's raw <c>activeDayGroup</c>
/// INDEX carries no weather meaning by itself — <c>WeatherState.cs</c>'s
/// existing name classification is what turns a day group's DAT name into
/// one of the five real weather kinds, and that is what the host already
/// threads through <c>AtmosphericFrameInputs.Weather</c> / <c>uAtmosphereWeather.x</c>.
/// This is the same fact, keyed correctly instead of by index.
/// </summary>
/// <param name="WeatherKind">
/// The exact member name of <c>AcDream.Core.World.WeatherKind</c> — one of
/// <c>"Clear"</c>, <c>"Overcast"</c>, <c>"Rain"</c>, <c>"Snow"</c>,
/// <c>"Storm"</c>. A plain string because this project (Plugin.Abstractions)
/// is BCL-only and cannot reference the Core enum; the host converts with
/// <c>WeatherKind.ToString()</c> (ordinal) when resolving.
/// </param>
public sealed record FoliageWindWeatherPoint(
    string WeatherKind,
    double Mean,
    double Gust);

/// <summary>Visible authored-atmosphere interpretation owned by the pack.</summary>
public sealed record AtmospherePolicyDeclaration(
    IReadOnlyList<SunElevationResponsePoint> SunElevationResponse,
    IReadOnlyList<ActiveDayGroupMultiplier> ActiveDayGroupMultipliers)
{
    /// <summary>
    /// Optional selected-light elevation curve for directional shadows. The host
    /// linearly interpolates adjacent points in sine-of-elevation space and
    /// clamps beyond the endpoints.
    /// The resolved multiplier must be zero at and below the authored
    /// 0-degree horizon: every non-positive control point must be zero and,
    /// when no exact 0-degree point is declared, the first positive control
    /// point must also be zero.
    /// A pack using the directional-shadow semantic must declare this curve.
    /// </summary>
    public IReadOnlyList<SunElevationResponsePoint> DirectionalShadowLightElevationResponse
        { get; init; } = [];

    /// <summary>
    /// Optional moving-sun strength curve for volumetric shafts. The host
    /// smoothstep-interpolates adjacent points in elevation-degree space and
    /// clamps beyond the endpoints.
    /// A pack using the volumetric-shaft semantic must declare this curve.
    /// </summary>
    public IReadOnlyList<SunElevationResponsePoint> VolumetricShaftSunElevationResponse
        { get; init; } = [];

    /// <summary>
    /// Campaign VM VM6: exact per-weather-kind foliage-wind mean/gust
    /// targets, looked up by the DAT-classified
    /// <c>AcDream.Core.World.WeatherKind</c> (an exact match, not an
    /// interpolation — the five kinds are not ordered by "how windy"). The
    /// host smooths the resolved (mean, gust) target toward whatever this
    /// table returns over time using the existing weather delta-seconds
    /// clock, so a weather change never snaps. A kind absent from this table
    /// falls back to the declared Clear row, then to (0, 0) if Clear itself
    /// is undeclared. Each declared <see cref="FoliageWindWeatherPoint.WeatherKind"/>
    /// must be one of the five real kind names and must appear at most once.
    /// </summary>
    public IReadOnlyList<FoliageWindWeatherPoint> FoliageWindByWeather
        { get; init; } = [];

    /// <summary>
    /// Campaign VM VM6: object/GfxObj ids excluded from foliage-wind sway
    /// even though their entity id falls in the procedural-scenery
    /// namespace and their subset classification would otherwise qualify —
    /// the rare scenery object that is cutout-material but not actually
    /// foliage (e.g. a cutout rock or fence prop drawn from the scenery
    /// table). There is no include list: outside this exclusion set, the
    /// classification rule in <c>WbDrawDispatcher</c> is the rule.
    /// </summary>
    public IReadOnlyList<uint> FoliageExclusions { get; init; } = [];
}

/// <summary>
/// Complete immutable declaration for one render pack. Packs describe what
/// they need; the renderer validates and owns every concrete resource, pass,
/// pipeline, barrier, and scene replay.
/// </summary>
public sealed record RenderPackDescriptor(
    string Id,
    string DisplayName,
    Version PackVersion,
    int PackApiVersion,
    RenderPackTier HighestTier,
    IReadOnlyList<RenderCapability> RequiredCapabilities,
    IReadOnlyList<RenderCapability> OptionalCapabilities,
    IReadOnlyList<RenderResourceDeclaration> Resources,
    IReadOnlyList<RenderPassDeclaration> Passes,
    IReadOnlyList<SceneReplayDeclaration> SceneReplays,
    IReadOnlyList<PipelineVariantDeclaration> PipelineVariants,
    IReadOnlyList<RenderQualityPreset> QualityPresets,
    IReadOnlyList<RenderSettingDeclaration> Settings,
    AtmospherePolicyDeclaration? AtmospherePolicy)
{
    /// <summary>Short user-facing description shown beside compatibility and cost.</summary>
    public string FeatureSummary { get; init; } = string.Empty;
}