docs: private String getUpfrontReservationTime(Long dateInMillis) {
          DateTime now = new DateTime(DateTimeZone.forTimeZone(TimeZone.getTimeZone("UTC")));
          DateTime event = new DateTime(dateInMillis, DateTimeZone.forTimeZone(TimeZone.getTimeZone("UTC")));
          Duration duration = new Duration(now, event);
  
          if (duration.getMillis() < 0) {
              return "-1";
          } else if (duration.getStandardSeconds() < 86400) {
              return "1d";
          } else if (duration.getStandardDays() < 4) {
              return "4d";
          } else if (duration.getStandardDays() < 7) {
              return "1w";
          } else if (duration.getStandardDays() < 14) {
              return "2w";
          } else if (duration.getStandardDays() < 28) {
              return "4w";
          } else if (duration.getStandardDays() < 56) {
              return "8w";
          } else {
              return "-";
          }
      }