# Tic Tac Toe


import random


def drawBoard(board):
    # 列印棋盤


    # "board"是長度為10的列表，為了方便輸入，忽略第一個元素board[0]


    print('\n\n\n\n')
    print('\t\t\t┌─┬─┬─┐')
    print('\t\t\t│'+board[7]+' │'+board[8]+' │'+board[9]+' │')
    print('\t\t\t├─┼─┼─┤')
    print('\t\t\t│'+board[4]+' │'+board[5]+' │'+board[6]+' │')
    print('\t\t\t├─┼─┼─┤')
    print('\t\t\t│'+board[1]+' │'+board[2]+' │'+board[3]+' │')
    print('\t\t\t└─┴─┴─┘')


def inputPlayerLetter():
    # 讓玩家選擇棋子
    # 返回一個列表，第一個是玩家的棋子，第二個是電腦的
    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():
    # 隨機產生誰先走
    if random.randint(0, 1) == 0:
        return 'computer'
    else:
        return 'player'


def playAgain():
    # 再玩一次？輸入yes或y返回True
    print('Do you want to play again? (yes or no)')
    return input().lower().startswith('y')


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


def isWinner(bo, le):
    # 判斷所給的棋子是否獲勝
    # 引數為棋盤上的棋子（列表）和棋子符號
    # 以下是所有可能勝利的情況，共8種
    return ((bo[7] == le and bo[8] == le and bo[9] == le) or 
    (bo[4] == le and bo[5] == le and bo[6] == le) or 
    (bo[1] == le and bo[2] == le and bo[3] == le) or 
    (bo[7] == le and bo[4] == le and bo[1] == le) or 
    (bo[8] == le and bo[5] == le and bo[2] == le) or 
    (bo[9] == le and bo[6] == le and bo[3] == le) or
    (bo[7] == le and bo[5] == le and bo[3] == le) or
    (bo[9] == le and bo[5] == le and bo[1] == le)) 


def getBoardCopy(board):
    # 複製一份棋盤，供電腦落子時使用
    dupeBoard = []


    for i in board:
        dupeBoard.append(i)


    return dupeBoard


def isSpaceFree(board, move):
    # 判斷這個位置是否有子，沒子返回True
    return board[move] == ' '


def getPlayerMove(board):
    # 玩家落子
    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):
    # 隨機返回一個可以落子的座標
    # 如果沒有所給的movesList中沒有可以落子的，返回None
    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):
    # 確定電腦的落子位置
    if computerLetter == 'X':
        playerLetter = 'O'
    else:
        playerLetter = 'X'


    # Tic Tac Toe AI核心演算法:
    # 首先判斷電腦方能否通過一次落子直接獲得遊戲勝利
    for i in range(1, 10):
        copy = getBoardCopy(board)
        if isSpaceFree(copy, i):
            makeMove(copy, computerLetter, i)
            if isWinner(copy, computerLetter):
                return i


    # 判斷玩家下一次落子能否獲得勝利，如果能，給它堵上
    for i in range(1, 10):
        copy = getBoardCopy(board)
        if isSpaceFree(copy, i):
            makeMove(copy, playerLetter, i)
            if isWinner(copy, playerLetter):
                return i


    # 如果角上能落子的話，在角上落子
    move = chooseRandomMoveFromList(board, [1, 3, 7, 9])
    if move != None:
        return move


    # 如果能在中心落子的話，在中心落子
    if isSpaceFree(board, 5):
        return 5


    # 在邊上落子
    return chooseRandomMoveFromList(board, [2, 4, 6, 8])


def isBoardFull(board):
    # 如果棋盤滿了，返回True
    for i in range(1, 10):
        if isSpaceFree(board, i):
            return False
    return True




print('Welcome to Tic Tac Toe!')


while True:
    # 更新棋盤
    theBoard = [' '] * 10
    playerLetter, computerLetter = inputPlayerLetter()
    turn = whoGoesFirst()
    print('The ' + turn + ' will go first.')
    gameIsPlaying = True


    while gameIsPlaying:
        if turn == 'player':
            # 玩家回合
            drawBoard(theBoard)
            move = getPlayerMove(theBoard)
            makeMove(theBoard, playerLetter, move)


            if isWinner(theBoard, playerLetter):
                drawBoard(theBoard)
                print('Hooray! You have won the game!')
                gameIsPlaying = False
            else:
                if isBoardFull(theBoard):
                    drawBoard(theBoard)
                    print('The game is a tie!')
                    break
                else:
                    turn = 'computer'


        else:
            # 電腦回合
            move = getComputerMove(theBoard, computerLetter)
            makeMove(theBoard, computerLetter, move)


            if isWinner(theBoard, computerLetter):
                drawBoard(theBoard)
                print('The computer has beaten you! You lose.')
                gameIsPlaying = False
            else:
                if isBoardFull(theBoard):
                    drawBoard(theBoard)
                    print('The game is a tie!')
                    break
                else:
                    turn = 'player'


    if not playAgain():
        break