using System;

namespace AcDream.Core.Rendering;

/// <summary>
/// 2026-05-19 — runtime-toggleable diagnostic flags for the indoor cell
/// rendering pipeline. Initialized from env vars at process start;
/// flippable at runtime via the DebugPanel mirror. Log call sites read
/// these statics so a checkbox toggle takes effect on the next frame
/// without relaunching.
///
/// <para>
/// Mirrors the L.2a <see cref="AcDream.Core.Physics.PhysicsDiagnostics"/>
/// pattern. The master <see cref="IndoorAll"/> toggle is the user's
/// common case — flipping it cascades to all five probe flags.
/// </para>
///
/// <para>
/// Spec: <c>docs/superpowers/specs/2026-05-19-indoor-cell-rendering-fix-design.md</c>.
/// </para>
/// </summary>
public static class RenderingDiagnostics
{
    /// <summary>
    /// When true, <c>WbDrawDispatcher.WalkVisibleEntities</c> emits one
    /// <c>[indoor-walk]</c> line per visible cell entity per second:
    /// entity id, world position, parent cell id, landblock visible flag,
    /// AABB-visible flag, "in visible cells" flag, drew flag.
    /// Initial state from <c>ACDREAM_PROBE_INDOOR_WALK=1</c>.
    /// </summary>
    public static bool ProbeIndoorWalkEnabled { get; set; } =
        Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_WALK") == "1"
        || Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_ALL") == "1";

    /// <summary>
    /// When true, <c>WbDrawDispatcher</c> emits one <c>[indoor-lookup]</c>
    /// line per visible cell entity per second: render-data hit/miss,
    /// IsSetup flag, SetupParts count, parts-hit / parts-miss tallies.
    /// Initial state from <c>ACDREAM_PROBE_INDOOR_LOOKUP=1</c>.
    /// </summary>
    public static bool ProbeIndoorLookupEnabled { get; set; } =
        Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_LOOKUP") == "1"
        || Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_ALL") == "1";

    /// <summary>
    /// When true, <c>WbMeshAdapter</c> emits two lines per EnvCell id:
    /// <c>[indoor-upload] requested</c> on first IncrementRefCount and
    /// <c>[indoor-upload] completed</c> when WB's staged drain produces
    /// its <c>ObjectMeshData</c>. Missing "completed" lines indicate WB
    /// silently returned null (hypothesis H1).
    /// Initial state from <c>ACDREAM_PROBE_INDOOR_UPLOAD=1</c>.
    /// </summary>
    public static bool ProbeIndoorUploadEnabled { get; set; } =
        Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_UPLOAD") == "1"
        || Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_ALL") == "1";

    /// <summary>
    /// When true, <c>WbDrawDispatcher</c> emits one <c>[indoor-xform]</c>
    /// line per visible cell entity per second: cell-geometry SetupPart's
    /// composed world matrix translation. Disambiguates transform
    /// double-apply (hypothesis H5).
    /// Initial state from <c>ACDREAM_PROBE_INDOOR_XFORM=1</c>.
    /// </summary>
    public static bool ProbeIndoorXformEnabled { get; set; } =
        Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_XFORM") == "1"
        || Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_ALL") == "1";

    /// <summary>
    /// When true, <c>WbDrawDispatcher.WalkVisibleEntities</c> emits one
    /// <c>[indoor-cull]</c> line per cell entity that gets culled, with
    /// the reason (visibleCellIds-miss, frustum, landblock). Disambiguates
    /// cull bugs (hypothesis H3).
    /// Initial state from <c>ACDREAM_PROBE_INDOOR_CULL=1</c>.
    /// </summary>
    public static bool ProbeIndoorCullEnabled { get; set; } =
        Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_CULL") == "1"
        || Environment.GetEnvironmentVariable("ACDREAM_PROBE_INDOOR_ALL") == "1";

    /// <summary>
    /// Master toggle. Reading reflects the AND of all five flags
    /// (true only when every probe is on). Writing cascades — setting
    /// to <see langword="true"/> turns ALL five flags on; setting to
    /// <see langword="false"/> turns ALL five off.
    /// </summary>
    public static bool IndoorAll
    {
        get => ProbeIndoorWalkEnabled
            && ProbeIndoorLookupEnabled
            && ProbeIndoorUploadEnabled
            && ProbeIndoorXformEnabled
            && ProbeIndoorCullEnabled;
        set
        {
            ProbeIndoorWalkEnabled   = value;
            ProbeIndoorLookupEnabled = value;
            ProbeIndoorUploadEnabled = value;
            ProbeIndoorXformEnabled  = value;
            ProbeIndoorCullEnabled   = value;
        }
    }

    /// <summary>
    /// Helper for probe call sites. Returns <see langword="true"/> when
    /// the low 16 bits of <paramref name="id"/> are ≥ 0x0100 — the AC
    /// convention for EnvCell (indoor) cells, as opposed to outdoor cells
    /// in the 8×8 landblock grid (0x0001–0x0040).
    /// </summary>
    public static bool IsEnvCellId(ulong id) => (id & 0xFFFFu) >= 0x0100u;
}