computer class for tic tac toe

comp_class.rb

class ComputerPlayer
  def initialize(name, mark=0)
    @name = name
    @mark = mark
  end
  
  def name
    @name
  end
  
  def mark
    @mark
  end
  
  def board
    grid
  end
  
  def choose_mark(symbol)
    move = []
    row_set = []
    if board.any?{|row| row.count(symbol) == 2}
      row_set = board.select{|row| row.count(symbol) == 2}
      row_index = board.index(row_set)
      column = row_set.index(nil)
    end
    move = [row_index, column]
    return move unless move.empty?
    
    first_column = []
    second_column = []
    third_column = []

    board.each do |row|
      first_column << row[0]
      second_column << row[1]
      third_column << row[2]
    end
    
    diagonal_set_backslash = [board[0][0], board[1][1], board[2][2]]
    diagonal_set_forward = [board[0][2], board[1][1], board[2][0]]
    
    if first_column.count(symbol) == 2 
      move = [0, first_column.index(nil)]
    elsif second_column.count(symbol) == 2 
      move = [1, first_column.index(nil)]
    elsif third_column.count(symbol) == 2 
      move = [2, first_column.index(nil)]
    elsif diagonal_set_backslash.count(symbol) == 2
      location = diagonal_set_backslash.index(nil)
      if location == 0
        move = [0,0] 
      elsif location == 1
        move = [1,1]
      elsif location == 2
        move = [2,2]
      end
    elsif diagonal_set_forward.count(symbol) == 2
      location = diagonal_set_forward.index(nil)
      if location == 0
        move = [0,2]
      elsif location == 1
        move = [1,1]
      elsif location == 2
        move = [2,0]
      end
    end
    move
  end
  
  def choose_random_move
    board = display(board)
    options = []
    board.each_with_index do |row, i|
      row.each_with_index do |column, j|
        if column.nil?
          options << [i,j]
        end
      end
    end
    max = options.length
    options[rand(0..max)]
  end
  
  def get_move
    move = choose_mark(mark)
    move = choose_random_move if move.empty?
  end
end