Parsing (from and to) WCF DateTime json input to joda DateTime

wcf-datetime-parsing.scala

  private val microsoftDateWithTZ = """\/Date\(([0-9]+)([\-\+])([0-9]{2})([0-9]{2})\)\/""".r
  private val microsoftDateWithoutTZ = """\/Date\(([0-9]+)\)\/""".r
  implicit val jodaDateTimeReads = Reads[DateTime]({
    case JsString(microsoftDateWithoutTZ(ticks)) =>
      JsSuccess(new DateTime(ticks.toLong))

    case JsString(microsoftDateWithTZ(ticks, upOrDown, hours, minutes)) =>
      val hoursInt = hours.dropWhile(_ == '0').toIntOpt.getOrElse(0)
      val minutesInt = minutes.dropWhile(_ == '0').toIntOpt.getOrElse(0)

      val tz =
        if (upOrDown == "+") {
          DateTimeZone.forOffsetHoursMinutes(hoursInt, minutesInt)
        } else {
          DateTimeZone.forOffsetHoursMinutes(-hoursInt, minutesInt)
        }

      JsSuccess(new DateTime(ticks.toLong, tz))
    case JsString(text) => JsError(s"This is not a valid datetime: $text")
  })

  implicit val jodaDateTimeWrites = Writes[DateTime](x => {
    JsString("/Date(" + x.withZone(DateTimeZone.UTC).getMillis + "-0000)/")
  })