Tic Tac Toe

tictactoe

#########################################
# A simple Tic-Tac-Toe game in Ruby  	
# Author: Will Hudgins					
#########################################

#### Todos:
# => Abstract out methods, refactor, clean up
# => Clean up AI code: Definitely a more beautiful way to elaborate the strategies
# => Implement something based on this: http://www.neverstopbuilding.com/minimax

@board_position = {"1" => [0,0], "2" => [0,1], "3" => [0,2], "4" => [1,0], "5" => [1,1], "6" => [1,2], "7" => [2,0], "8" => [2,1], "9" => [2,2]}
@move_message = ["Good move.", "Well played, sir or madam.", "Bold strategy Cotton, we'll see how that one plays out for them.", "Bravo.", "Are you sure about that?", "Not what I would have done...", "Well that's certainly one way of going about it."]
@lose_message = ["Baha! You lost to a machine.", "Better luck next time, I guess.", "Is that how it feels to lose? I wouldn't know.", "Amateur.", "Try again... if you dare."]
@win_message = ["What! I never lose. Must be a bug...", "You win. This must be a mistake...", "Game, set, match. Well done", "Well then... Hail to my human overlord.", "Enjoy your victory, it'll be your last."]
@ai_play_message = ["Here goes nothing.", "Prepare for domination.", "Feast your eyes upon this beauty.", "Well then, here's my move."]

def start_game
	board = [[" "," "," "],[" "," "," "],[" "," "," "]]
	print_board(board)
	puts "Welcome to Tic-Tac-Toe!"
	return board
end

def play_game(board)
	if check_winning_board(board)
		puts @lose_message.sample
		return
	end
	if !check_winning_board(board) and !board_full(board)
		print "Make a move by entering a position on the board 1-9: "
		move = gets.chomp
		board = do_turn(move.to_i, board)
		if board_full(board)
			return
		end
		board = make_AI_move(board, move.to_i)
		print_board(board)
		puts @move_message.sample
		puts @ai_play_message.sample
		play_game(board)
	end
end

def do_turn(move, board)
	# error catching
	if move < 1 or move > 9
		puts "You've made an invalid move. Try again!"
		play_game(board)
	end
	x_spots = get_spots(board, "X")
	o_spots = get_spots(board, "O")
	if x_spots.include?(move.to_s) or o_spots.include?(move.to_s)
		puts "You've made an invalid move. Try again!"
		play_game(board)
	end
	position = get_board_position(move)
	board = place_move(position, board, "X")
	if check_winning_board(board)
		puts @win_message.sample
	end
	if board_full(board)
		print_board(board)
		puts "Game over. Until we meet again."
	end
	return board
end

def make_AI_move(board, move)
	puts
	puts @ai_play_message.sample
	ai_move = get_optimal_move(board)
	position = get_board_position(ai_move)
	board = place_move(position, board, "O")
	return board
end

def get_spots(board, char)
	spots = []
	i = 0
	while i < 3
		j = 0
		while j < 3
			if board[i][j] == char.to_s
				spots.push(@board_position.key([i,j]))
			end
			j += 1
		end
		i += 1
	end
	return spots
end

def place_move(position, board, char)
	x = position[0]
	y = position[1]
	board[x][y] = char.to_s
	return board
end

def get_board_position(move)
	position = @board_position[move.to_s]
	return position
end

def print_board(board)
	system "clear"
	print board[0]
	puts
	print board[1]
	puts
	print board[2]
	puts
	puts
end

def blank_board(board)
	empty_spots = get_spots(board, " ")
	return empty_spots == ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
end

def board_full(board)
	empty_spots = get_spots(board, " ")
	if empty_spots.any?
		return false
	end
	return true
end

def check_winning_board(board)
	if !blank_board(board)
		if check_horizontal_win(board) 
			return true
		elsif check_vertical_win(board)
			return true
		elsif check_diagonal_win(board)
			return true
		end	
	end
		
	return false
end

def check_diagonal_win(board)
	x_spots = get_spots(board, "X")
	o_spots = get_spots(board, "O")
	if x_spots.include?("1") and x_spots.include?("5") and x_spots.include?("9")
		return true
	elsif x_spots.include?("3") and x_spots.include?("5") and x_spots.include?("7")
		return true
	end
	if o_spots.include?("1") and o_spots.include?("5") and o_spots.include?("9")
		return true
	elsif o_spots.include?("3") and o_spots.include?("5") and o_spots.include?("7")
		return true
	end
		
	return false
end

def check_horizontal_win(board)
	i = 0
	while i < 3
		if board[i][0] != " " and board[i][0] == board[i][1] and board[i][1] == board[i][2]
			return true
		end
		i += 1
	end
	return false
end

def check_vertical_win(board)
	i = 0
	while i < 3
		if board[0][i] != " " and board[0][i] == board[1][i] and board[1][i] == board[2][i]
			return true
		end
		i += 1
	end
	return false
end


def get_optimal_move(board)
	empty_spots = get_spots(board, " ")
	x_spots = get_spots(board, "X")
	o_spots = get_spots(board, "O")

	defensive_move = search_move(x_spots, empty_spots)

	if defensive_move != nil
		return defensive_move
	end

	offensive_move = search_move(o_spots, empty_spots)
	if offensive_move != nil
		return offensive_move
	end	

	# best move in the game. if its open, take it!
	if empty_spots.include?("5")
		return "5"
	# none met. pick a random empty spot.
	else
		ai_move = empty_spots.sample
		return ai_move
	end
end

def search_move(spots, empty_spots)
	# clean this up!
	# all the horizontal cases. 
	if spots.include?("1") and spots.include?("2") and empty_spots.include?("3")
		return "3"
	elsif spots.include?("1") and spots.include?("3") and empty_spots.include?("2")
		return "2"
	elsif spots.include?("2") and spots.include?("3") and empty_spots.include?("1")
		return "1"
	elsif spots.include?("4") and spots.include?("5") and empty_spots.include?("6")
		return "6"
	elsif spots.include?("4") and spots.include?("6") and empty_spots.include?("5")
		return "5"
	elsif spots.include?("5") and spots.include?("6") and empty_spots.include?("4")
		return "4"
	elsif spots.include?("7") and spots.include?("8") and empty_spots.include?("9")
		return "9"
	elsif spots.include?("7") and spots.include?("9") and empty_spots.include?("8")
		return "8"
	elsif spots.include?("8") and spots.include?("9") and empty_spots.include?("7")
		return "7"

	# vertical cases
	elsif spots.include?("1") and spots.include?("4") and empty_spots.include?("7")
		return "7"
	elsif spots.include?("1") and spots.include?("7") and empty_spots.include?("4")
		return "4"
	elsif spots.include?("4") and spots.include?("7") and empty_spots.include?("1")
		return "1"
	elsif spots.include?("2") and spots.include?("5") and empty_spots.include?("8")
		return "8"
	elsif spots.include?("2") and spots.include?("8") and empty_spots.include?("5")
		return "5"
	elsif spots.include?("5") and spots.include?("8") and empty_spots.include?("2")
		return "2"
	elsif spots.include?("3") and spots.include?("6") and empty_spots.include?("9")
		return "9"
	elsif spots.include?("3") and spots.include?("9") and empty_spots.include?("6")
		return "6"
	elsif spots.include?("6") and spots.include?("9") and empty_spots.include?("3")
		return "3"

	# diagonal cases
	elsif spots.include?("1") and spots.include?("5") and empty_spots.include?("9")
		return "9"
	elsif spots.include?("9") and spots.include?("5") and empty_spots.include?("1")
		return "1"
	elsif spots.include?("3") and spots.include?("5") and empty_spots.include?("7")
		return "7"
	elsif spots.include?("7") and spots.include?("5") and empty_spots.include?("3")
		return "3"
	end
end

play_game(start_game)