import { md5 } from './md5';

/**
 * The exact Accept header the reader app sends when fetching a PDF.
 * It is part of the media CDN hash, so it must match byte for byte.
 */
export const PDF_ACCEPT =
  'application/pdf, image/webp, image/jpeg, image/png, image/gif, image/svg';

/**
 * The media CDN "hotlink" hash, computed by the reader app as
 * md5("<Accept header>|<origin>|<client-authorize header, always empty>").
 * Verified against real traffic (download.har): the PDF Accept header and the
 * origin "https://etidning.vf.se" produce the h value seen in the wild.
 */
export function mediaHash(origin: string): string {
  return md5(`${PDF_ACCEPT}|${origin}|`);
}

/** Appends the h parameter to a media URL. */
export function withMediaHash(url: string, origin: string): string {
  const parsed = new URL(url, origin);
  parsed.searchParams.set('h', mediaHash(origin));
  return parsed.toString();
}