gistfile1.txt

object Day7 extends Challenge {
  val ips = loadFile("day7.txt").getLines().toList

  override def runFirst(): Unit = {
    println(ips.count(supportsTLS))
  }

  override def runSecond(): Unit = {
    println(ips.count(supportsSSL))
  }

  def supportsTLS(ip: String): Boolean = {
    def hasAbba(part: String) = part.matches(""".*([a-z])((?:(?!\1).))(\2)\1.*""")

    val abbaParts = splitParts(ip).map {
      case (part, true) =>
        true -> hasAbba(part)
      case (part, false) =>
        false -> hasAbba(part)
    }

    abbaParts.contains((true, true)) && !abbaParts.contains((false, true))
  }

  def supportsSSL(ip: String): Boolean = {
    val abaRegex = """([a-z])((?:(?!\1).))\1""".r

    def getAbaList(part: String) = part.sliding(3).flatMap(abaRegex.findFirstIn).toList

    def createBab(aba: String) = new StringBuilder().append(aba(1)).append(aba(0)).append(aba(1)).toString()

    val parts = splitParts(ip)
    val babs = parts
      .filter(_._2)
      .flatMap(a => getAbaList(a._1))
      .map(createBab)

    parts.filter(!_._2).exists(p => babs.exists(bab => p._1.contains(bab)))
  }

  private def splitParts(ip: String) = {
    val parts = ip.split("""\[|\]""")
    parts.zipWithIndex.map(p => p._1 -> (p._2 % 2 == 0))
  }
}