filter.scala

  trait DateRepr {
    def dt: DateTime
  }

  trait HasYear extends DateRepr {
    def year = dt.getYear
  }

  trait HasMonth extends DateRepr {
    def month = dt.getMonthOfYear

    def maxMonthOfYear(dt: DateTime): Int = {
      dt.monthOfYear().withMaximumValue().getMonthOfYear
    }
  }

  trait HasDay extends DateRepr {
    def day = dt.getDayOfMonth

    def maxDayOfMonth(dt: DateTime): Int = {
      dt.dayOfMonth().withMaximumValue().getDayOfMonth
    }
  }

  case class Year(dt: DateTime) extends HasYear
  case class YearMonth(dt: DateTime) extends HasYear with HasMonth
  case class YearMonthDay(dt: DateTime) extends HasYear with HasMonth with HasDay
  case class YearMonthDayHour(dt: DateTime) extends DateRepr

  implicit class DateReprGen(val s: String) extends AnyVal {

    def toDR: DateRepr = {
      s.length match {
        case 4 => Year(DateTime.parse(s, DateTimeFormat.forPattern("yyyy")))
        case 6 => YearMonth(DateTime.parse(s, DateTimeFormat.forPattern("yyyyMM")))
        case 8 => YearMonthDay(DateTime.parse(s, DateTimeFormat.forPattern("yyyyMMdd")))
        case 10 => YearMonthDayHour(DateTime.parse(s, DateTimeFormat.forPattern("yyyyMMddHH")))
      }
    }
  }

  def seqGlob(a: Int, b: Int): String =
    a to b map (i => "%02d".format(i)) mkString("{", ",", "}")

  def computeFilter(repr1: DateRepr, repr2: DateRepr): Seq[String] = {
    (repr1, repr2) match {
      case (a: Year, b: Year) => Seq(seqGlob(a.year, b.year) + "/*")
      case (a: YearMonth, b: YearMonth) =>
        if (b.year == a.year) {
          Seq(s"${a.year}/${seqGlob(a.month, b.month)}/*")
        } else if (b.year - a.year > 1) {
          Seq(
            s"${a.year}/${seqGlob(a.month, )}/*",
            computeFilter(Year(a.dt.plusYears(1)), Year(b.dt.minusYears(1))).head,
            s"${b.year}/${seqGlob(01, b.month)}/*")
        } else {
          Seq(
            s"${a.year}/${seqGlob(a.month, 12)}/*",
            s"${b.year}/${seqGlob(01, b.month)}/*")
        }
      case (a: YearMonthDay, b: YearMonthDay) =>
        if (a.year == b.year) {
          if (a.month == b.month)
            Seq(s"${a.year}/${a.month}/${seqGlob(a.day, b.day)}/*")
          else if (b.month - a.month > 1) {
            Seq(s"${a.year}/${a.month}/${seqGlob(a.day, b.day)}/*")
          }
        }

    }
  }

  //computeFilter("2013".toDR, "2015".toDR) foreach println

  computeFilter("201504".toDR, "201510".toDR) foreach println