/** OTP expiry is stored as epoch milliseconds on user documents. */
export function otpExpireToEpochMs(value: unknown): number {
  if (value == null) return 0;
  if (typeof value === "number" && Number.isFinite(value)) {
    if (value >= 1_000_000_000_000) return value;
    if (value >= 1_000_000_000 && value < 1_000_000_000_000) {
      return value * 1000;
    }
    return value;
  }
  if (value instanceof Date) {
    return value.getTime();
  }
  if (typeof value === "string") {
    const asNum = Number(value);
    if (Number.isFinite(asNum)) return asNum;
    const parsed = Date.parse(value);
    if (Number.isFinite(parsed)) return parsed;
  }
  return 0;
}

export function isOtpExpiryActive(
  otpExpire: unknown,
  nowMs: number = Date.now(),
): boolean {
  const exp = otpExpireToEpochMs(otpExpire);
  return exp > nowMs;
}

export function computeOtpExpireMs(
  expireMinutes: number,
  nowMs: number = Date.now(),
): number {
  const minutes =
    Number.isFinite(expireMinutes) && expireMinutes > 0 ? expireMinutes : 2;
  return nowMs + minutes * 60 * 1000;
}

export function readOtpExpireMinutesFromEnv(): number {
  const raw = Number(process.env.EXP_OTP_TIME ?? "2");
  return Number.isFinite(raw) && raw > 0 ? raw : 2;
}