type Unit = "ms" | "s" | "m" | "h" | "d";

export type Duration = `${number} ${Unit}` | `${number}${Unit}`;

/**
 * Convert a human readable duration to milliseconds
 */
export function ms(d: Duration): number {
  const match = d.match(/^(\d+)\s?(ms|s|m|h|d)$/);
  if (!match) {
    throw new Error(`Unable to parse window size: ${d}`);
  }
  const time = parseInt(match[1]);
  const unit = match[2] as Unit;

  switch (unit) {
    case "ms":
      return time;
    case "s":
      return time * 1000;
    case "m":
      return time * 1000 * 60;
    case "h":
      return time * 1000 * 60 * 60;
    case "d":
      return time * 1000 * 60 * 60 * 24;

    default:
      throw new Error(`Unable to parse window size: ${d}`);
  }
}