gistfile1.txt

import scala.annotation.tailrec
import scala.concurrent.{Await, Future}
import scala.concurrent.duration._
import scala.util.Try


object Main extends App {
  import scala.concurrent.ExecutionContext.Implicits.global

  implicit val board = GameBoard(Vector(40,20))

  var dir: Vector = Vector(1,0)
  var quit: Boolean = false

  @tailrec
  def play(data: GameData)(implicit board: GameBoard): Boolean = {
//    readInput()
    println()
    println()
    println("Score: " + data.score)
    val newSnake = data.snake.move(dir)
    val boardData = newSnake.segments.map((_,'#')).toMap
    board.render(boardData)
    Try{Await.result(Future(readInput()), 300 millis)}
    if(quit) false else play(data.copy(snake = newSnake))
  }

  def readInput() = {
    java.lang.System.in.read().toChar match {
      case 0 =>
      case readValue =>
        val newDir = readValue match {
          case 'w' => Vector(0, 1)
          case 'a' => Vector(-1, 0)
          case 's' => Vector(0, -1)
          case 'd' => Vector(1, 0)
          case 'x' =>
            quit = true
            Vector(0, 0)
          case _ => dir
        }

        if(newDir != Vector(dir.x* -1, dir.y* -1))
          dir = newDir
      }
  }

  play(GameData(Snake(List(Point(20,10), Point(21,10),Point(22,10),Point(23,10))),Point(5,5), 0))

}

case class Point(x: Int, y: Int) {
  def move(vel: Vector, steps: Int = 1)(implicit gameBoard: GameBoard) = Point(
    (x + vel.x * steps)      % gameBoard.size.x,
    (y + vel.y * steps * -1) % gameBoard.size.y // Invert X/Y movement
  )
}

case class Vector(x: Int, y: Int)

case class GameData(snake: Snake, foodPosition: Point, score: Int)

case class Snake(segments: List[Point]){
  def move(dir: Vector, steps: Int = 1)(implicit gameBoard: GameBoard): Snake = Snake(
      segments.foldLeft((List.empty[Point],Option.empty[Point])){
        (data, curPoint) => (data._1 :+ data._2.getOrElse(curPoint.move(dir)), Some(curPoint))
      }._1
    )

}

case class GameBoard(size: Vector) {
  def render(boardData: Map[Point, Char]): Unit =
    print((for (
      y <- 0 to size.y;
      x <- 0 to size.x + 1
    )
    yield {
      val curPos = Point(x, y)
      if (x == size.x + 1) '\n'
      else if ((y == size.y && x == 0) || (y == size.y && x == size.x) || (y == 0 && x == 0)) '+'
      else if (y == 0 && x == size.x) '+'
      else if (y == 0 || y == size.y) '-'
      else if (x == 0 || x == size.x) '|'
      else boardData.getOrElse(curPos, ' ')
    }).mkString)

}