/** Validate portable model containers before allowing renderer-side resource loads. */
export function modelDocument(bytes: Uint8Array, name: string) {
  if (bytes.byteLength < 12 || bytes.byteLength > 25 * 1024 * 1024)
    throw Error("Размер модели: 12 байт — 25 МБ");
  let gltf: any;
  if (name.toLowerCase().endsWith(".gltf"))
    gltf = JSON.parse(new TextDecoder().decode(bytes));
  else {
    const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
    if (
      view.getUint32(0, true) !== 0x46546c67 ||
      view.getUint32(4, true) !== 2 ||
      view.getUint32(8, true) !== bytes.byteLength
    )
      throw Error("Некорректный GLB v2");
    if (bytes.byteLength < 20 || view.getUint32(16, true) !== 0x4e4f534a)
      throw Error("GLB не содержит JSON");
    const length = view.getUint32(12, true);
    if (length > bytes.byteLength - 20) throw Error("Повреждён JSON GLB");
    gltf = JSON.parse(
      new TextDecoder()
        .decode(bytes.subarray(20, 20 + length))
        .replace(/\0+$/, ""),
    );
  }
  if (gltf.asset?.version !== "2.0") throw Error("Поддерживается glTF 2.0");
  return gltf;
}
export function inspectModel(bytes: Uint8Array, name: string) {
  const gltf = modelDocument(bytes, name);
  if (gltf.asset?.version !== "2.0") throw Error("Поддерживается glTF 2.0");
  if (
    [...(gltf.buffers || []), ...(gltf.images || [])].some(
      (r: any) => r.uri && !r.uri.startsWith("data:"),
    )
  )
    throw Error("Экспортируй GLB со встроенными текстурами и буферами");
  const compressed = [
    "KHR_draco_mesh_compression",
    "EXT_meshopt_compression",
    "KHR_texture_basisu",
  ];
  if (
    [...(gltf.extensionsUsed || []), ...(gltf.extensionsRequired || [])].some(
      (x) => compressed.includes(x),
    )
  )
    throw Error(
      "Используй экспорт без Draco, Meshopt и KTX2: автономные декодеры не включены",
    );
  return {
    clips: (gltf.animations || []).map(
      (a: any, i: number) => a.name || "Animation " + i,
    ),
    skeletons: (gltf.skins || []).length,
    nodes: (gltf.nodes || []).length,
    meshes: (gltf.meshes || []).length,
    materials: (gltf.materials || []).map((m: any, i: number) => m.name || `Material ${i}`),
    cameras: (gltf.cameras || []).map((c: any, i: number) => c.name || `Camera ${i}`),
    activeCamera: typeof gltf.extras?.forma?.activeCamera === "string" ? gltf.extras.forma.activeCamera : null,
    lights: (gltf.extensions?.KHR_lights_punctual?.lights || []).length + (gltf.extensions?.EXT_lights_area?.lights || []).length,
    morphTargets: (gltf.meshes || []).reduce((sum: number, m: any) => sum + Math.max(0, ...(m.primitives || []).map((p: any) => p.targets?.length || 0)), 0),
    animatedProperties: [...new Set<string>((gltf.animations || []).flatMap((a: any) => (a.channels || []).map((c: any) => c.target?.extensions?.KHR_animation_pointer?.pointer).filter(Boolean)))],
    extensions: gltf.extensionsUsed || [],
    warnings: (Array.isArray(gltf.extras?.forma?.warnings) ? gltf.extras.forma.warnings : []).filter((w: any) => typeof w === "string").slice(0, 100),
  };
}