import {default as parseDuration} from 'parse-duration';
import { fromUnixTime, parseISO } from 'date-fns';

const EPOCH_TIMESTAMP_REGEX = /^\d+$/;

export function parseDate(value: string): Date {
  const iso = parseISO(value);
  if (iso.getTime()) {
    return iso;
  } else if (EPOCH_TIMESTAMP_REGEX.test(value)) {
    return fromUnixTime(parseInt(value, 10));
  } else {
    return new Date(Date.now() - parseDuration(value)!);
  }
}

export function isValidDateOrEpochOrDurationString(value: string): boolean  {
  return EPOCH_TIMESTAMP_REGEX.test(value) ||
    parseISO(value).getTime() ||
    parseDuration(value) ? true : false;
}