给你一段代码，请你帮我加上自动复原的功能代码：import pygame, sys, random
from pygame.locals import *

# 一些常量
WINDOWWIDTH = 500
WINDOWHEIGHT = 500
BACKGROUNDCOLOR = (255, 255, 255)
BLUE = (0, 0, 255)
BLACK = (0, 0, 0)
FPS = 40

VHNUMS = 3
CELLNUMS = VHNUMS * VHNUMS
MAXRANDTIME = 100


# 退出
def terminate():
    pygame.quit()
    sys.exit()


# 随机生成游戏盘面
def newGameBoard():
    board = []
    for i in range(CELLNUMS):
        board.append(i)
    blackCell = CELLNUMS - 1
    board[blackCell] = -1

    for i in range(MAXRANDTIME):
        direction = random.randint(0, 3)
        if (direction == 0):
            blackCell = moveLeft(board, blackCell)
        elif (direction == 1):
            blackCell = moveRight(board, blackCell)
        elif (direction == 2):
            blackCell = moveUp(board, blackCell)
        elif (direction == 3):
            blackCell = moveDown(board, blackCell)
    return board, blackCell


# 若空白图像块不在最左边，则将空白块左边的块移动到空白块位置
def moveRight(board, blackCell):
    if blackCell % VHNUMS == 0:
        return blackCell
    board[blackCell - 1], board[blackCell] = board[blackCell], board[blackCell - 1]
    return blackCell - 1


# 若空白图像块不在最右边，则将空白块右边的块移动到空白块位置
def moveLeft(board, blackCell):
    if blackCell % VHNUMS == VHNUMS - 1:
        return blackCell
    board[blackCell + 1], board[blackCell] = board[blackCell], board[blackCell + 1]
    return blackCell + 1


# 若空白图像块不在最上边，则将空白块上边的块移动到空白块位置
def moveDown(board, blackCell):
    if blackCell < VHNUMS:
        return blackCell
    board[blackCell - VHNUMS], board[blackCell] = board[blackCell], board[blackCell - VHNUMS]
    return blackCell - VHNUMS


# 若空白图像块不在最下边，则将空白块下边的块移动到空白块位置
def moveUp(board, blackCell):
    if blackCell >= CELLNUMS - VHNUMS:
        return blackCell
    board[blackCell + VHNUMS], board[blackCell] = board[blackCell], board[blackCell + VHNUMS]
    return blackCell + VHNUMS


# 是否完成
def isFinished(board, blackCell):
    for i in range(CELLNUMS - 1):
        if board[i] != i:
            return False
    return True


# 初始化
pygame.init()
mainClock = pygame.time.Clock()

# 加载图片
gameImage = pygame.image.load('1.jpg')
gameRect = gameImage.get_rect()

# 设置窗口，窗口的宽度和高度取决于图片的宽高
windowSurface = pygame.display.set_mode((gameRect.width, gameRect.height))
pygame.display.set_caption('拼图')

cellWidth = int(gameRect.width / VHNUMS)
cellHeight = int(gameRect.height / VHNUMS)

finish = False

gameBoard, blackCell = newGameBoard()

# 游戏主循环
while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            terminate()
        if finish:
            continue
        if event.type == KEYDOWN:
            if event.key == K_LEFT or event.key == ord('a'):
                blackCell = moveLeft(gameBoard, blackCell)
            if event.key == K_RIGHT or event.key == ord('d'):
                blackCell = moveRight(gameBoard, blackCell)
            if event.key == K_UP or event.key == ord('w'):
                blackCell = moveUp(gameBoard, blackCell)
            if event.key == K_DOWN or event.key == ord('s'):
                blackCell = moveDown(gameBoard, blackCell)
        if event.type == MOUSEBUTTONDOWN and event.button == 1:
            x, y = pygame.mouse.get_pos()
            col = int(x / cellWidth)
            row = int(y / cellHeight)
            index = col + row * VHNUMS
            if (
                    index == blackCell - 1 or index == blackCell + 1 or index == blackCell - VHNUMS or index == blackCell + VHNUMS):
                gameBoard[blackCell], gameBoard[index] = gameBoard[index], gameBoard[blackCell]
                blackCell = index

    if (isFinished(gameBoard, blackCell)):
        gameBoard[blackCell] = CELLNUMS - 1
        finish = True

    windowSurface.fill(BACKGROUNDCOLOR)

    for i in range(CELLNUMS):
        rowDst = int(i / VHNUMS)
        colDst = int(i % VHNUMS)
        rectDst = pygame.Rect(colDst * cellWidth, rowDst * cellHeight, cellWidth, cellHeight)

        if gameBoard[i] == -1:
            continue

        rowArea = int(gameBoard[i] / VHNUMS)
        colArea = int(gameBoard[i] % VHNUMS)
        rectArea = pygame.Rect(colArea * cellWidth, rowArea * cellHeight, cellWidth, cellHeight)
        windowSurface.blit(gameImage, rectDst, rectArea)

    for i in range(VHNUMS + 1):
        pygame.draw.line(windowSurface, BLACK, (i * cellWidth, 0), (i * cellWidth, gameRect.height))
    for i in range(VHNUMS + 1):
        pygame.draw.line(windowSurface, BLACK, (0, i * cellHeight), (gameRect.width, i * cellHeight))

    pygame.display.update()

    mainClock.tick(FPS)