trait Rule {}

object ALPHA extends Rule

object DIGIT extends Rule

object OCTET extends Rule

case class Alternative(rules: Rule*) extends Rule

case class Concatenation(rules: Rule*) extends Rule

case class SpecificRepetition(rule: Rule, n: Int) extends Rule

case class VariableRepetition(rule: Rule, lower: Option[Int] = None, upper: Option[Int] = None) extends Rule

case class Terminal(value: String) extends Rule

case class Range(lower: Char, upper: Char) extends Rule

case class Single(c: Char) extends Rule

object CookieDateParser {
  val timefield = VariableRepetition(DIGIT, Some(1), Some(2))
  val hmsTime = Concatenation(timefield, Terminal(":"), timefield, Terminal(":"), timefield)
  val nonDigit = Alternative(Range(0x00, 0x2f), Range(0x3a, 0xff))
  val time = Concatenation(hmsTime, Concatenation(nonDigit, VariableRepetition(OCTET)))
  val year = Concatenation(
    VariableRepetition(DIGIT, Some(2), Some(4)),
    Concatenation(nonDigit, VariableRepetition(OCTET))
  )
  val month = Concatenation(
    Alternative(
      Terminal("jan"), Terminal("feb"), Terminal("mar"), Terminal("apr"), Terminal("may"), Terminal("jun"),
      Terminal("jul"), Terminal("aug"), Terminal("sep"), Terminal("oct"), Terminal("nov"), Terminal("dev")
    ),
    VariableRepetition(OCTET)
  )
  val dayOfMonth = Concatenation(
    VariableRepetition(DIGIT, Some(1), Some(2)),
    Concatenation(nonDigit, VariableRepetition(OCTET))
  )
  val nonDelimiter = Alternative(
    Range(0x00, 0x08),
    Range(0x0a, 0x1f),
    DIGIT,
    Terminal(":"),
    ALPHA,
    Range(0x7f, 0xff)
  )
  val delimiter = Alternative(
    Single(0x09),
    Range(0x20, 0x2f),
    Range(0x3b, 0x40),
    Range(0x5b, 0x60),
    Range(0x7b, 0x7e)
  )
  val dateToken = VariableRepetition(nonDelimiter, Some(1))
  val dateTokenList = Concatenation(
    dateToken,
    VariableRepetition(Concatenation(VariableRepetition(delimiter, Some(1)), dateToken))
  )
}