/** Client-side image compression for card uploads (data URL). */

export async function compressImageFile(
  file: File,
  opts: { maxEdge?: number; quality?: number } = {},
): Promise<string> {
  const maxEdge = opts.maxEdge ?? 640;
  const quality = opts.quality ?? 0.78;

  if (!file.type.startsWith("image/")) {
    throw new Error("Please choose an image file");
  }
  if (file.size > 8 * 1024 * 1024) {
    throw new Error("Image must be under 8MB");
  }

  const bitmap = await createImageBitmap(file);
  const scale = Math.min(1, maxEdge / Math.max(bitmap.width, bitmap.height));
  const w = Math.max(1, Math.round(bitmap.width * scale));
  const h = Math.max(1, Math.round(bitmap.height * scale));

  const canvas = document.createElement("canvas");
  canvas.width = w;
  canvas.height = h;
  const ctx = canvas.getContext("2d");
  if (!ctx) throw new Error("Could not process image");
  ctx.drawImage(bitmap, 0, 0, w, h);
  bitmap.close();

  const dataUrl = canvas.toDataURL("image/jpeg", quality);
  if (dataUrl.length > 850_000) {
    // Retry smaller
    return compressImageFile(file, { maxEdge: Math.floor(maxEdge * 0.7), quality: quality * 0.85 });
  }
  return dataUrl;
}