export function parsePdfPageLocator(locator?: string | null): number | null {
  if (!locator?.startsWith("pdf:page:")) return null;
  const value = Number(locator.split(":").at(-1));
  return Number.isInteger(value) && value > 0 ? value : null;
}

export function pdfPagePercent(page: number, pages: number): number {
  if (!Number.isFinite(page) || !Number.isFinite(pages) || pages < 1) return 0;
  return Math.max(0, Math.min(100, Math.round((page / pages) * 100)));
}