game.py

import random


def inputPlayerLetter():
    letter = ''
    while not (letter == 'X' or letter == 'O'):
        print('Do you want to be X or O?')
        letter = input().upper()

    if letter == 'X':
        return ['X', 'O']
    else:
        return ['O', 'X']


def whoGoesFirst():

    if random.randint(0, 1) == 0:
        return 'computer'
    else:
        return 'player'


def playAgain():

    print('Do you want to play again? (yes or no)')
    return input().lower().startswith('y')


def makeMove(board, letter, move):
    board[move] = letter


def isWinner(bo, le):
    return ((bo[7] == le and bo[8] == le and bo[9] == le) or  # across the top
            (bo[4] == le and bo[5] == le and bo[6] == le) or  # across the middle
            (bo[1] == le and bo[2] == le and bo[3] == le) or  # across the bottom
            (bo[7] == le and bo[4] == le and bo[1] == le) or  # down the left side
            (bo[8] == le and bo[5] == le and bo[2] == le) or  # down the middle
            # down the right side
            (bo[9] == le and bo[6] == le and bo[3] == le) or
            (bo[7] == le and bo[5] == le and bo[3] == le) or  # diagonal
            (bo[9] == le and bo[5] == le and bo[1] == le))  # diagonal


def getBoardCopy(board):
    dupeBoard = []

    for i in board:
        dupeBoard.append(i)

    return dupeBoard


def isSpaceFree(board, move):
    return board[move] == ' '


def getPlayerMove(board):
    move = ' '
    while move not in '1 2 3 4 5 6 7 8 9'.split() or not isSpaceFree(board, int(move)):
        print('What is your next move? (1-9)')
        move = input()
    return int(move)


def chooseRandomMoveFromList(board, movesList):
    possibleMoves = []
    for i in movesList:
        if isSpaceFree(board, i):
            possibleMoves.append(i)

    if len(possibleMoves) != 0:
        return random.choice(possibleMoves)
    else:
        return None


def getComputerMove(board, computerLetter):
    if computerLetter == 'X':
        playerLetter = 'O'
    else:
        playerLetter = 'X'

    for i in range(1, 10):
        copy = getBoardCopy(board)
        if isSpaceFree(copy, i):
            makeMove(copy, computerLetter, i)
            if isWinner(copy, computerLetter):
                return i

    for i in range(1, 10):
        copy = getBoardCopy(board)
        if isSpaceFree(copy, i):
            makeMove(copy, playerLetter, i)
            if isWinner(copy, playerLetter):
                return i

    move = chooseRandomMoveFromList(board, [1, 3, 7, 9])
    if move != None:
        return move

    if isSpaceFree(board, 5):
        return 5

    return chooseRandomMoveFromList(board, [2, 4, 6, 8])


def isBoardFull(board):
    for i in range(1, 10):
        if isSpaceFree(board, i):
            return False
    return True