Bowling Kata

bowling_scorer.scala

import scala.collection.mutable.ArrayBuffer

object BowlingScorer extends App {
	val testFrame = "XXXXXXXXXXXX"
	//val testFrame = "9-9-9-9-9-9-9-9-9-9-"
	//val testFrame = "5/5/5/5/5/5/5/5/5/5/5"
	val frames = new ArrayBuffer[Frame]()
	var frameCount = 0
	
	for( roll <- testFrame ){
	  if(frames.length == 0 || frames.last.complete()){
	    frames += new Frame(roll, frameCount)
	  	frameCount+=1
	  }
	  else 
	    frames.last.addPins(roll)
	}
	val score = frames.foldLeft(0){(sum, frame) => sum + frame.score(testFrame)}
	println( score )
}

class Frame(initialPins:Char, frameCount:Int){
  var isSpare = false
  var isStrike = initialPins == 'X'
  var pins = new ArrayBuffer[Int]() 
  pins += pinCount(initialPins)
  var rolls = 1
  val frame = frameCount
  
  def pinCount(initialPins:Char): Int = {
    initialPins match{
	    case 'X' => 10
	    case '-' => 0
	    case '/' => 10 - pins.first
	    case _ => Integer.parseInt(initialPins.toString())
	  }
  }   
  
  def complete() : Boolean = {    
    frame < 9 && (rolls  == 2 || pinSum() == 10)    
  }
  
  def addPins(p:Char) {
    if(rolls < 2)
      isSpare = p == '/' 
    pins += pinCount(p)
    rolls += 1
  }
  
  def pinSum(): Int = {
    if(isStrike || isSpare)
      10
    else
      pins(0) + (if(pins.length == 1) 0 else pins(1))
  }
  
  def score(rolls:String) : Int = {
    var score = pinSum()    
    if(isStrike){
      score += pinCount(rolls(frame+1)) + pinCount(rolls(frame+2))
    }
    if(isSpare){      
      score += pinCount(rolls(frame+1))
    }   
    score
  }
 
}