/**
 * Format a Date as YYYY-MM-DD in an IANA timezone.
 *
 * Uses "en-CA" because that locale natively produces ISO-style dates,
 * so we don't have to reassemble parts.
 */
export function formatLocalDate(d: Date, tz: string): string {
  return new Intl.DateTimeFormat("en-CA", {
    timeZone: tz,
    year: "numeric",
    month: "2-digit",
    day: "2-digit",
  }).format(d);
}

/**
 * Format a Date as HH:MM (24-hour) in an IANA timezone.
 */
export function formatLocalTime(d: Date, tz: string): string {
  const parts = new Intl.DateTimeFormat("en-GB", {
    timeZone: tz,
    hour: "2-digit",
    minute: "2-digit",
    hour12: false,
  }).formatToParts(d);
  const h = parts.find((p) => p.type === "hour")?.value ?? "00";
  const m = parts.find((p) => p.type === "minute")?.value ?? "00";
  return `${h}:${m}`;
}