/**
 * How long ago, in the product's words - **one spelling, everywhere something says how long it has been.**
 *
 * MOVED HERE 2026-08-22 from `ReceptionistHomePage/frontDeskQueues.ts`, which is where it was written
 * and which re-exports it so every existing import keeps working unchanged. Its own note there gave the
 * reason it exists, and that reason applies past the front desk: *"the elapsed column, the late toast and
 * the row's own state label all say how long something has been true, and three spellings of that is
 * three answers to one question."*
 *
 * **Spencer, 2026-08-22:** *"405m should show in hours."* The clinician overview's in-progress badge
 * was rendering raw minutes with no hour rollover at all, so a visit open since the morning read **405m**.
 * It is the fourth spelling of this in the codebase; it is now the first caller of the shared one
 * rather than the fourth copy.
 *
 * The ladder, and each step is a deliberate choice about what the reader needs:
 * | elapsed | reads |
 * |---|---|
 * | under a minute | `now` - a number that changes while you look at it is noise |
 * | under an hour | `12m` |
 * | under a day | `6h 45m`, or `6h` on the hour - minutes still matter inside a working day |
 * | a day or more | `2d 3h`, or `2d` - minutes have stopped meaning anything by then |
 *
 * `now` is injectable ONLY so this can be asserted at a fixed instant. Every caller passes nothing.
 */
export const formatElapsedSince = (timestamp: number, now = Date.now()): string => {
  const elapsedMinutes = Math.floor(Math.max(0, now - timestamp) / 60_000);
  if (elapsedMinutes < 1) return 'now';
  if (elapsedMinutes < 60) return `${elapsedMinutes}m`;

  const elapsedHours = Math.floor(elapsedMinutes / 60);
  if (elapsedHours < 24) {
    const remainingMinutes = elapsedMinutes % 60;
    return remainingMinutes > 0 ? `${elapsedHours}h ${remainingMinutes}m` : `${elapsedHours}h`;
  }

  const elapsedDays = Math.floor(elapsedHours / 24);
  const remainingHours = elapsedHours % 24;
  return remainingHours > 0 ? `${elapsedDays}d ${remainingHours}h` : `${elapsedDays}d`;
};