/** e.g. "Aug 12, 2026, 3:45 PM" -- absolute, not relative, so it doesn't
 * need to be re-rendered on a timer just to stay accurate. */
export function formatDateTime(iso: string): string {
  return new Date(iso).toLocaleString(undefined, {
    year: "numeric",
    month: "short",
    day: "numeric",
    hour: "numeric",
    minute: "2-digit",
  });
}

/** e.g. "Monday, Aug 17" from a "YYYY-MM-DD" date key. Forces UTC
 * interpretation -- these keys are calendar dates, not instants, so
 * rendering them in the viewer's local timezone could shift midnight UTC
 * to the wrong day (e.g. showing "Sunday" for a Monday date key west of
 * UTC). */
export function formatWeekdayDate(dateKey: string): string {
  return new Date(`${dateKey}T00:00:00Z`).toLocaleDateString(undefined, {
    weekday: "long",
    month: "short",
    day: "numeric",
    timeZone: "UTC",
  });
}