Queen Attack Solution

queen_attack.rb

class Queens
  attr_reader :white, :black

  def initialize(white: [0, 3], black: [7, 3])
    @white, @black = white, black
    fail ArgumentError, "Queens cannot occupy the same position." if white == black
  end

  def to_s
    mark_board.map { |row| row.join(" ") }.join("\n")
  end

  def attack?
    queens_on_same_row? || queens_on_same_column? || queens_on_diagonal?
  end

  private

  def initialize_board
    board = []
    8.times { board << %w(_ _ _ _ _ _ _ _) }
    board
  end

  def white_queen_row
    white.first
  end

  def white_queen_column
    white.last
  end

  def black_queen_row
    black.first
  end

  def black_queen_column
    black.last
  end

  def mark_board
    board = initialize_board
    board.fetch(white_queen_row)[white_queen_column] = "W"
    board.fetch(black_queen_row)[black_queen_column] = "B"
    board
  end

  def queens_on_same_row?
    white_queen_row == black_queen_row
  end

  def queens_on_same_column?
    white_queen_column == black_queen_column
  end

  def queens_on_diagonal?
    (white_queen_row - white_queen_column).abs == (black_queen_row - black_queen_column).abs
  end
end