tictactoe

tictactoe

sealed trait TicTacToePlayer
case object X extends TicTacToePlayer
case object Y extends TicTacToePlayer

case class TicTacToeBoard(moves: List[(Int,TicTacToePlayer)]) {
  val boardRange = 0 to 8
  val players = List(X,Y)

  lazy val movesMap = moves.toMap

  def lastPlayer = moves.headOption.map( _._2)

  def print = printBoard.foreach( println )

  def printBoard = {
    val t = boardRange.map(i => movesMap.get(i).map(_.toString).getOrElse("-"))
    t.grouped(3).map(_.mkString)
  }

  def win(is: Seq[Int]): Option[TicTacToePlayer] = {
    val played = is.flatMap(movesMap.get)
    if (played.size == 3 && played.toSet.size == 1)
      played.headOption
    else
      None
  }

  def winner = {
    val rows = boardRange.grouped(3)
    val columns = boardRange.take(3).map(x => List(0, 3, 6).map(_ + x))
    val diags = List(List(0, 4, 8), List(2, 4, 6))
    (rows ++ columns ++ diags).flatMap(win).toList.headOption
  }

  def move(column: Int, row: Int) = {
    val player = lastPlayer.flatMap( player => players.filterNot( _ == player ).headOption).getOrElse(players.head)
    val move = column + row * 3
    if (movesMap.contains(move))
      None
    else
      Some(this.copy( moves = (move,player) :: moves))
  }
}

object TicTacToeBoard {
  def apply(): TicTacToeBoard = TicTacToeBoard(List.empty)
}