Module: Evaluator

Included in:
Game
Defined in:
lib/capim_tictactoe/evaluator.rb

Instance Method Summary collapse

Instance Method Details

#eval_board(board, human_marker, computer_marker, game_mode) ⇒ Object 



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# File 'lib/capim_tictactoe/evaluator.rb', line 4

def eval_board(board, human_marker, computer_marker, game_mode)
  # EASY behavior:
  # 1 - Mark center if available
  # 2 - Go through all available moves and checks if one of them is the winning move.
  # 3 - If not, mark a random spot.
  #
  # HARD behavior:
  # 1 - Mark center if available.
  # 2 - Go through all available moves and checks if one of them is the winning move for both the machine or the player.
  # 3 - If not, mark a random spot.

  unless board.center_marked?
    board.mark_center(computer_marker)
    return
  end

  spot = get_best_move(board, human_marker, computer_marker, game_mode)
  board.grid.marked?(spot) ? nil : board.grid.spot_marker(spot, computer_marker)
end

#get_best_move(board, human_marker, computer_marker, game_mode) ⇒ Object 



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# File 'lib/capim_tictactoe/evaluator.rb', line 24

def get_best_move(board, human_marker, computer_marker, game_mode)
  best_move = nil

  board.available_spots.each do |available_spot|
    if winning_move?(board, computer_marker, available_spot.to_i)
      best_move = available_spot.to_i
      return best_move
    end

    best_move = available_spot.to_i if game_mode == :hard && winning_move?(board, human_marker, available_spot.to_i)
  end
  return best_move if best_move

  board.available_spots.sample.to_i
end

#winning_move?(board, marker, spot) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/capim_tictactoe/evaluator.rb', line 40

def winning_move?(board, marker, spot)
  # A tmp board is used to avoid mutating the board instance variable spots.
  tmp_board = board.grid.spots.dup
  tmp_board[spot] = marker

  board.game_over?(tmp_board)
end