fig fig

object Start extends App {

  val fieldSize = 8

  case class Figure(point: (Int, Int), config: FigureConfig) {

    private def withinBounds(p: (Int, Int)): Boolean = {
      def within(i: Int) = i > 0 || i <= fieldSize
      within(p._1) && within(p._2)
    }

    def beats(cell: (Int, Int)): Boolean = {
      withinBounds(cell) && (cell == point || config.beatsCell(cell, point))
    }

  }

  trait FigureConfig {
    def beatsCell(cell: (Int, Int), point: (Int, Int)): Boolean = false
  }

  trait DiagonalFigureConfig extends FigureConfig {
    override def beatsCell(cell: (Int, Int), point: (Int, Int)): Boolean = Math.abs(point._1 - cell._1) == Math.abs(point._2 - cell._2) || super.beatsCell(cell, point)
  }

  trait LineFigureConfig extends FigureConfig {
    override def beatsCell(cell: (Int, Int), point: (Int, Int)): Boolean = (cell._1 == point._1) || (cell._2 == point._2) || super.beatsCell(cell, point)
  }

  case object QueenConfig extends DiagonalFigureConfig with LineFigureConfig

  case object BishopConfig extends DiagonalFigureConfig

  case object RockConfig extends LineFigureConfig

  def solveWithOpenedCells(openCells: List[(Int, Int)], figs: List[FigureConfig]): List[List[Figure]] = {
    if (figs.isEmpty) {
      List(Nil)
    } else {
      for (
        openCell <- openCells;
        r = Figure(openCell, figs.head);
        rest <- solveWithOpenedCells(openCells.filterNot(r.beats), figs.tail)
      ) yield r :: rest
    }
  }

  def solve(figs: List[FigureConfig]): List[List[Figure]] = {
    val opened = for (x <- 1 until fieldSize + 1; y <- 1 until fieldSize + 1) yield (x, y)
    solveWithOpenedCells(opened.toList, figs)
  }

  val figures = List(QueenConfig, QueenConfig, RockConfig)

  solve(figures).foreach(println)

}