Turtle.scala

object OOWay extends App {

  object PenState extends Enumeration {
    type PenState = Value
    val Up, Down = Value
  }

  object PenColor extends Enumeration {
    type PenColor = Value
    val Black, Red, Blue = Value
  }

  case class Position(x:Double, y:Double)

  class Log {
    def log(line:String) = { Console.println(line) }
  }

  def dummyDrawLine(log:Log, oldPos:Position, newPos:Position, color:PenColor.Value) = {
    log.log(f"...Draw line from (${oldPos.x},${oldPos.y}) to (${newPos.x},${newPos.x}) using $color")
  }

  def round2(d:Double):Double = {
    Math.round(d * 100) / 100.0
  }

  def calcNewPosition(distance:Double)(angle:Double)(currentPos:Position) = {
    val angleInRads = math.toRadians(angle)
    val x0 = currentPos.x
    val y0 = currentPos.y

    val x1 = x0 + (distance * Math.cos(angleInRads))
    val y1 = y0 + (distance * Math.sin(angleInRads))

    Position(round2(x1), round2(y1))
  }

  class Turtle(log:Log) {
    var curPosition: Position = Position(0, 0)
    var currentAngle: Double = 0.0
    var curColor: PenColor.Value = PenColor.Black
    var curState: PenState.Value = PenState.Down

    def penUp() = {
      log.log("Pen Up")
      curState = PenState.Up
    }

    def penDown() = {
      log.log("Pen Down")
      curState = PenState.Down
    }

    def turn(angle: Double) = {
      log.log(f"Turn $angle")

      val newAngle = (currentAngle + angle) % 360.0
      currentAngle = newAngle
    }

    def setColor(penColor: PenColor.Value) = {
      log.log(String.format("Set Color : %s", penColor.toString))
      this.curColor = penColor
    }

    def move(distance: Double) = {
      log.log(f"Move $distance")

      val newPosition = calcNewPosition(distance)(currentAngle)(curPosition)

      if (curState == PenState.Down) {
        dummyDrawLine(log, curPosition, newPosition, curColor)
      }

      curPosition = newPosition
    }
  }

/*  let drawPolygon n =
    let angle = 180.0 - (360.0/float n)
  let angleDegrees = angle * 1.0<Degrees>
    let turtle = Turtle(log)

  // define a function that draws one side
  let drawOneSide() =
    turtle.Move 100.0
  turtle.Turn angleDegrees

  // repeat for all sides
  for i in [1..n] do
    drawOneSide()*/


  def drawPolygon(n: Int):Unit = {

    def angle = 180.0 - (360.0/n)

    val log = new Log()
    val turtle = new Turtle(log)

    def drawOneSide():Unit = {
      turtle move 100.0
      turtle turn angle
    }

    for ( i <- 1 to n) {

      drawOneSide()
    }

  }

  val log = new Log()
  val turtle = new Turtle(log)
//
//  turtle move 100.0
//  turtle turn 120.0
//  turtle move 100.0
//  turtle turn 120.0
//  turtle move 100.0
//  turtle turn 120.0

  drawPolygon(8)
}