one-file-projects/tictactoe.py

import random

class Player(object):

    def __init__(self,rep):
        self.rep = rep

    def __repr__(self):
        return self.rep

    def count_win_chances(self, board):
        chances = 0
        for line in board.get_all_lines():
            if all( map( lambda v: v == self or v == Board.empty, line) ):
                chances += 1
        return chances

class Board(object):
    draw = object()
    empty = Player(" ")
    def __init__(self,size=3):
        self.board = [ [Board.empty] * size for i in range(size) ]
        self.size = size

    def set(self, x, y, value):
        if x < 0 or x >= self.size or y < 0 or y >= self.size:
            raise Exception("Out of bounds!")
        if value == Board.empty or isinstance(value,Player):
            self.board[x][y] = value
        else:
            raise Exception("Invalid value %s" % str(value))

    def get(self, x, y):
        if x < 0 or x >= self.size or y < 0 or y >= self.size:
            raise Exception("Out of bounds!")
        else:
            return self.board[x][y]

    def get_all_lines(self):
        lines = []
        #diagonals
        lines.append( [ self.board[xy][xy] for xy in range(self.size) ] )
        lines.append( [ self.board[x][self.size-x-1] for x in range(self.size) ] )

        #rows
        lines += self.board

        #cols
        lines += [ [ self.board[x][y] for x in range(self.size) ] for y in range(self.size) ]

        return lines

    def get_empty_fields(self):
        for x in range(self.size):
            for y in range(self.size):
                if self.board[x][y] == Board.empty:
                    yield (x,y)

    def get_winner(self):
        for line in self.get_all_lines():
            if line[0] != self.empty and all(map(lambda v: v == line[0],line)):
                return line[0]
        for field in self.get_empty_fields():
            return None
        return Board.draw

    def copy(self):
        c = Board(size=self.size)
        for x in range(self.size):
            for y in range(self.size):
                c.set(x,y, self.get(x,y))
        return c

    def __str__(self):
        return ("\n-"+("*-"*(self.size-1)) +"\n").join( [ "|".join( [ str(pos) for pos in line ] ) for line in self.board ] )


class AI(Player):
    def play(self,enemy, board):
        if board.get_winner() is not None:
            raise Exception("Game over!")
        boardcopy = board.copy()

        moves = []

        #Check for win chance
        for x,y in board.get_empty_fields():
            boardcopy.set(x,y,self)
            # Check for win
            if boardcopy.get_winner() == self:
                return (x,y)

            # Check for chance
            chance = self.count_win_chances(boardcopy) - enemy.count_win_chances(boardcopy)

            moves.append( (chance,(x,y)) )


            # Check if enemy win
            boardcopy.set(x,y,enemy)

            if boardcopy.get_winner() == enemy:
                return (x,y)

            boardcopy.set(x,y,Board.empty)

        moves.sort(key=lambda x: -x[0])

        best_move = moves[0]

        good_moves = []

        for move in moves:
            if move[0] == best_move[0]:
                good_moves.append(move)

        return random.choice(good_moves)[1]

class Human(Player):
    def play(self, enemy, board):
        while True:
            s = input("Player %s's turn:")
            try:
                (x,y) = map(int, s.split(","))
                return (x,y)
            except Exception:
                print("Try again?")

def rotate(l):
    return l[1:] + l[:1]

if __name__ == "__main__":
    board = Board(size=6)
    players = [ AI("X"), AI("O") ]

    print(str(board))

    while board.get_winner() is None:
        (x,y) = players[0].play(players[1],board)
        while board.get(x,y) != Board.empty:
            print("Try again!")
            (x,y) = players[0].play(players[1],board)

        board.set(x,y,players[0])
        players = rotate(players)

        print()
        print(str(board))

    winner = board.get_winner()

    if winner == Board.draw:
        print("Round draw!")
    else:
        print("%s has won!" % str(winner) )