Bowling.scala

object Bowling {
  type Coef = (Int, Int)

  implicit class Tuple2Ops[A, B](val t: (A, B)) extends AnyVal {
    def map_1[C](f: A => C): (C, B) = (f(t._1), t._2)

    def map_2[C](f: B => C): (A, C) = (t._1, f(t._2))
  }

  case class TempScore(scoreTotal: Int, coef: Coef, isNewTurn: Boolean, nbTurn: Int, lastShot: Option[Int]) {
    def addShot(shot: Int): TempScore = {
      (isNewTurn, lastShot.getOrElse(0) + shot == 10) match {
          //STRIKE
        case (true, true) => updateScore(shot).incNextShot.incSecondShot.nextTurn
          //SPARE
        case (false, true) => updateScore(shot).incNextShot.nextTurn
          //A Shot
        case (true, false) => updateScore(shot)
          //END OF TURN
        case (false, false) => updateScore(shot).nextTurn
      }
    }

    private def incSecondShot: TempScore = copy(coef = coef.map_1(_ + 1))

    private def incNextShot: TempScore = copy(coef = coef.map_2(_ + 1))

    private def updateScore(shot: Int): TempScore = copy(scoreTotal = scoreTotal + shot * coef._1, coef = (coef._2, 1), lastShot = Some(shot), isNewTurn = false)

    private def nextTurn: TempScore = copy(isNewTurn = true, nbTurn = nbTurn + 1, lastShot = None)
  }

  val init: TempScore = TempScore(scoreTotal = 0, coef = (1, 1), isNewTurn = true, nbTurn = 0, lastShot = None)

  def score(shots: Integer*): Integer = {
    shots.foldLeft(init)(_ addShot _).scoreTotal
  }
}