#!/usr/bin/env python
import pygame,sys,time,random
from pygame.locals import *
# 定义颜色变量
redColour = pygame.Color(255,0,0)
blackColour = pygame.Color(0,0,0)
whiteColour = pygame.Color(255,255,255)
greyColour = pygame.Color(150,150,150)

# @@@@@@@@把蛇头和那个点换成人物图片更有趣@@@@@@@@@@@@
# 定义gameOver函数
def gameOver(playSurface):
    gameOverFont = pygame.font.Font('arial.ttf',72)
    gameOverSurf = gameOverFont.render('Game Over', True, greyColour)
    gameOverRect = gameOverSurf.get_rect()
    gameOverRect.midtop = (320, 10)
    playSurface.blit(gameOverSurf, gameOverRect)
    pygame.display.flip()
    time.sleep(5)
    pygame.quit()
    sys.exit()

# 定义main函数
def main():
 # 初始化pygame
 pygame.init()
 fpsClock = pygame.time.Clock()
 # 创建pygame显示层
 playSurface = pygame.display.set_mode((640,480))
 pygame.display.set_caption('Raspberry Snake')

 # 初始化变量
 snakePosition = [100,100]
 snakeSegments = [[100,100],[80,100],[60,100]]
 raspberryPosition = [300,300]
 raspberrySpawned = 1
 direction = 'right'
 changeDirection = direction
 while True:
 # 检测例如按键等pygame事件
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == KEYDOWN:
 # 判断键盘事件
         if event.key == K_RIGHT or event.key == ord('d'):
            changeDirection = 'right'
         if event.key == K_LEFT or event.key == ord('a'):
            changeDirection = 'left'
         if event.key == K_UP or event.key == ord('w'):
            changeDirection = 'up'
         if event.key == K_DOWN or event.key == ord('s'):
            changeDirection = 'down'
         if event.key == K_ESCAPE:
            pygame.event.post(pygame.event.Event(QUIT))
 # 判断是否输入了反方向
        if changeDirection == 'right' and not direction == 'left':
            direction = changeDirection
        if changeDirection == 'left' and not direction == 'right':
            direction = changeDirection
        if changeDirection == 'up' and not direction == 'down':
            direction = changeDirection
        if changeDirection == 'down' and not direction == 'up':
            direction = changeDirection
 # 根据方向移动蛇头的坐标
        if direction == 'right':
            snakePosition[0] += 20
        if direction == 'left':
            snakePosition[0] -= 20
        if direction == 'up':
            snakePosition[1] -= 20
        if direction == 'down':
            snakePosition[1] += 20
 # 增加蛇的长度
    snakeSegments.insert(0,list(snakePosition))
 # 判断是否吃掉了树莓
    if snakePosition[0] == raspberryPosition[0] and snakePosition[1] == raspberryPosition[1]:
        raspberrySpawned = 0
    else:
        snakeSegments.pop()
 # 如果吃掉树莓，则重新生成树莓
    if raspberrySpawned == 0:
        x = random.randrange(1,32)
        y = random.randrange(1,24)
        raspberryPosition = [int(x*20),int(y*20)]
        raspberrySpawned = 1
 # 绘制pygame显示层
    playSurface.fill(blackColour)
    for position in snakeSegments:
        pygame.draw.rect(playSurface,whiteColour,Rect(position[0],position[1],20,20))
        pygame.draw.rect(playSurface,redColour,Rect(raspberryPosition[0], raspberryPosition[1],20,20))

 # 刷新pygame显示层
    pygame.display.flip()
 # 判断是否死亡
    if snakePosition[0] > 620 or snakePosition[0] < 0:
        gameOver(playSurface)
    if snakePosition[1] > 460 or snakePosition[1] < 0:
        for snakeBody in snakeSegments[1:]:
            if snakePosition[0] == snakeBody[0] and snakePosition[1] == snakeBody[1]:
                gameOver(playSurface)
 # 控制游戏速度
    fpsClock.tick(48)

if __name__ == "__main__":
    main()