const dateFormat = new Intl.DateTimeFormat("sv", {
  timeZone: "EST",
  year: "numeric",
  month: "2-digit",
  hour: "2-digit",
  day: "2-digit",
  minute: "2-digit",
});

// YYYY-MM-DD HH:MM
export function formatQuestionTimestamp(date: Date) {
  return dateFormat.format(date);
}

// YYYY-MM-DDTHH:MM:00Z
export function formatQuestionISOTimestamp(date: Date) {
  const str = dateFormat.format(date);
  return `${str.slice(0, 10)}T${str.slice(11)}-05:00`;
}

// YYMMDDHHMM
export function formatQuestionId(date: Date) {
  return formatQuestionTimestamp(date).replace(/[^\d]/g, "").slice(2, 12);
}

export function questionIdToTimestamp(id: string) {
  if (id.length !== 10 || !/^\d+$/.test(id)) {
    return null;
  }
  const date = new Date(
    `20${id.slice(0, 2)}-${id.slice(2, 4)}-${id.slice(4, 6)} ${
      id.slice(6, 8)
    }:${id.slice(8, 10)}:00 EST`,
  );
  if (isNaN(date.getTime())) {
    return null;
  }
  return date;
}