bla.scala

package advent

import adventutil.io._

import scala.annotation.tailrec


object Day2 {

    def splitInstruction(instruction: String): (String, Int) = {
        val splitted = instruction.split("\\s")
        return (splitted(0), splitted(1).toInt)
    }

    def calcPosition(instructions: List[(String, Int)]): Int = {
        val (horizontal, depth) = calcPositionRec(instructions, 0, 0)
        return horizontal * depth
    }

    @tailrec
    def calcPositionRec(instructions: List[(String, Int)], horizontal: Int, depth: Int): (Int, Int) = {
        instructions match {
            case Nil => (horizontal, depth)
            case ("forward", v) :: rest => 
                calcPositionRec(rest, horizontal+v, depth)
            case ("down", v) :: rest => 
                calcPositionRec(rest, horizontal, depth+v)
            case ("up", v) :: rest => 
                calcPositionRec(rest, horizontal, depth-v)
            case _ => (0,0)
        }
    }

    def main(args: Array[String]) = {
        val lines = io.readFile(args(0)).map(splitInstruction(_))

        val res = calcPosition(lines)
        println(res)

    }
}