import sharp from "sharp";

import { HttpError } from "@/lib/security/http";
import { hasValidImageSignature, MAX_MEDIA_BYTES, type IMAGE_MIME_TYPES } from "./validation";

export const MAX_IMAGE_PIXELS = 40_000_000;

export async function inspectImage(bytes: Uint8Array, mimeType: (typeof IMAGE_MIME_TYPES)[number]) {
  if (bytes.byteLength > MAX_MEDIA_BYTES) throw new HttpError(413, "image-too-large");
  if (!hasValidImageSignature(bytes.subarray(0, 16), mimeType)) throw new HttpError(422, "invalid-image");
  try {
    const image = sharp(bytes, { limitInputPixels: MAX_IMAGE_PIXELS, failOn: "warning", animated: true });
    const metadata = await image.metadata();
    const width = metadata.autoOrient.width || metadata.width;
    const height = metadata.autoOrient.height || metadata.height;
    if (!width || !height || width * height > MAX_IMAGE_PIXELS) throw new Error("invalid dimensions");
    // Metadata alone accepts truncated images; decode pixels before publishing.
    await image.stats();
    return { width, height };
  } catch {
    throw new HttpError(422, "invalid-image");
  }
}