/**
 * Goods Received Note number: `GRN-<DIRECTION>-<YYYYMMDD>-<OWNER>-<REF8>`.
 *
 * The GRN is mapped to the goods OWNER (the booking's customer / consignee) for
 * both import and export, so a note is identifiable by who owns the cargo
 * without opening it. The trailing reference slice stays as the uniqueness
 * anchor — one owner can have several bookings received on the same day.
 * Owner-less receipts (manual walk-ins with no booking) fall back to the
 * original `GRN-<DIRECTION>-<YYYYMMDD>-<REF8>` form.
 *
 * Shared so a GRN raised at a load/unload facility is indistinguishable from one
 * raised in a warehouse — the two live in different tables
 * (facility_handling_events vs warehouse_inventory), and a second generator would
 * eventually let their formats drift apart.
 */
export function generateGrnNumber(
  direction: string,
  referenceId: string,
  date: Date,
  ownerName?: string | null,
): string {
  const stamp = date.toISOString().slice(0, 10).replace(/-/g, '');
  const suffix = referenceId.replace(/-/g, '').slice(0, 8).toUpperCase();
  const owner = grnOwnerSlug(ownerName);
  const base = `GRN-${direction.toUpperCase()}-${stamp}`;
  return owner ? `${base}-${owner}-${suffix}` : `${base}-${suffix}`;
}

/**
 * Owner name → GRN-safe token: letters/digits only, upper-cased, capped so a
 * long company name can't run away with the number. Null when there is nothing
 * usable, which drops the segment rather than emitting an empty `--`.
 */
export function grnOwnerSlug(ownerName?: string | null): string | null {
  const slug = (ownerName ?? '')
    .normalize('NFKD')
    .replace(/[^a-zA-Z0-9]+/g, '')
    .toUpperCase()
    .slice(0, 12);
  return slug || null;
}