import scala.io.Source

object Day4 extends App:

  val input = Source
    .fromURL(getClass.getResource("day4Input.txt"))
    .mkString

  final case class Bingo(boards: Array[Board], playedNumbers: Seq[Int]):
    def playNumber(number: Int) =
      Bingo(
        boards.map(board => if (board.isWinner) board else board.mark(number)),
        playedNumbers.appended(number)
      )

    def winningBoards: Seq[Board] = boards
      .filter(_.isWinner)
      .map(board => (board, board.lastMarked.map(playedNumbers.indexOf(_))))
      .sortBy(_._2)
      .map(_._1)

    val gameOver = boards.forall(_.isWinner)

  object Bingo:
    def parse(input: Array[String]): Bingo =
      Bingo(input.map(Board.parse), Seq())

  final case class Board(
      val rows: Array[Array[Cell]],
      lastMarked: Option[Int] = None
  ):
    val isWinner: Boolean = rows.exists(_.forall(_.marked)) ||
      rows.transpose.exists(_.forall(_.marked))

    def mark(number: Int): Board =
      Board(
        rows.map(_.map(_.mark(number))),
        Some(number)
      )

    def score: Int =
      rows.flatMap(_.filterNot(_.marked).map(_.value)).sum *
        lastMarked.getOrElse(0)

  object Board:
    def parse(input: String) =
      Board(
        input
          .split('\n')
          .map(
            _.split(' ')
              .filter(_.nonEmpty)
              .map(Cell.parse)
          )
      )

  final case class Cell(value: Int, marked: Boolean = false):
    def mark(number: Int): Cell =
      if (number == value) Cell(value, true) else this

  object Cell:
    def parse(input: String) = Cell(input.toInt)

  val numbersAndBoardsInput = input.split("\n\n")
  val drawnNumbers = numbersAndBoardsInput.head.split(',').map(_.toInt)
  val initialState = Bingo.parse(numbersAndBoardsInput.tail)

  val finalState = drawnNumbers.foldLeft(initialState)(_.playNumber(_))

  val firstWinningBoard = finalState.winningBoards.head
  println(s"Part 1: ${firstWinningBoard.score}")

  val lastWinningBoard = finalState.winningBoards.last
  println(s"Part 2: ${lastWinningBoard.score}")