tictactoe.py

import random

class TicTacToeNode:
    def __init__(self):
        self.board = ['.'] * 9
        self.win_states = (\
            [0,1,2], [3,4,5], [6,7,8],\
            [0,3,6], [1,4,7], [2,5,8],\
            [0,4,8], [2,4,6]\
        )
        
        self.allocations = {'X': 'Human', 'O': 'Cpu'}
        self.turn = self.allocations['X']
        self.empty = 9
        
    def reset(self):
        self.board = ['.'] * 9
        self.turn = self.allocations['X']
        self.empty = 9
        
    def render(self):
        print self.board[0], self.board[1], self.board[2]
        print self.board[3], self.board[4], self.board[5]
        print self.board[6], self.board[7], self.board[8]
        
    def place(self, x, y):
        position = x + 3*y
        return self.place(position)
    
    def place(self, position):
        if self.empty <= 0:
            return False
            
        if self.board[position] != '.':
            return False
        else:
            self.empty -= 1
            if self.turn == 'Human':
                self.turn = 'Cpu'
                piece = 'X'
            else:
                self.turn = 'Human'
                piece = 'O'
            self.board[position] = piece
            return True
            
    def whoWon(self):
        for state in self.win_states:
            piece = self.board[state[0]]
            if piece == '.':
                continue
                
            for position in state:
                if self.board[position] != piece:
                    break
            else: # if the loop breaks, else doesn't happen
                return self.allocations[piece]
        
        if self.empty <= 0:
            return "Draw"
        else:
            return "No one"
        
    def makeCopy(self):
        copy = TicTacToeNode()
        for i, tile in enumerate(self.board):
            copy.board[i] = tile
        copy.turn = self.turn
        copy.empty = self.empty
        return copy
        
    # Return a list with the game state after each possible move
    def children(self):
        child_nodes = []
        
        for i, tile in enumerate(self.board):
            if tile == '.':
                child = self.makeCopy()
                child.place(i)
                child_nodes.append(child)
        
        return child_nodes
                
    def heuristic(self):
        return 0
        
    def makeAIMove(self):
        moves = []
        for i, tile in enumerate(self.board):
            if tile == '.':
                moves.append(i)
        return game.place(random.choice(moves))
    

game = TicTacToeNode()         
while True:
    game.render()
    move = int(raw_input('What is your move? (0 - 8): '))
    worked = game.place(move)
    if worked:
        game.makeAIMove()
    else:
        print 'That is not a legal move!'
        
    victory = game.whoWon()
    if victory == 'No one':
        continue
    else:
        game.render()
        game.reset()
        if victory == 'Human':
            print 'Human Wins'
        elif victory == 'Cpu':
            print 'Computer Wins'
        else:
            print 'It is a draw'