import pygame

from pygame.locals import *

import random

pygame.init()

# create the game screen

width = 480

height = 480

screen_size = (width, height)

screen = pygame.display.set_mode(screen_size)

pygame.display.set_caption('Snake Game')

# grid variables

grid_size = 20

num_rows = width // grid_size

num_cols = height // grid_size

# directions

up = (0, -1)

down = (0, 1)

left = (-1, 0)

right = (1, 0)

# colors

black = (0, 0, 0)

blue = (25, 103, 181)

dark_green = (67, 160, 71)

light_green = (129, 199, 132)

red = (200, 0, 0)

white = (255, 255, 255)

# game variables

score = 0

gameover = False

# game clock

clock = pygame.time.Clock()

fps = 10

class Apple:

def __init__(self):

self.randomize_location()

def randomize_location(self):

random_x = random.randint(0, num_cols - 1) * grid_size

random_y = random.randint(0, num_rows - 1) * grid_size

self.location = (random_x, random_y)

def draw(self):

square = pygame.Rect(self.location, (grid_size, grid_size))

pygame.draw.rect(screen, red, square)

class Snake:

def __init__(self):

self.body = [(width / 2, height / 2)]

self.direction = right

self.head = self.body[0]

def turn(self, direction):

# snake can move in any direction if length is 1

if len(self.body) == 1:

self.direction = direction

else:

# if turning left or right, ensure that

# the first two body parts are not in the same y position

if direction == left or direction == right:

if self.body[0][1] != self.body[1][1]:

self.direction = direction

# if turning up or down, ensure that

# the first two body parts are not in the same x position

if direction == up or direction == down:

if self.body[0][0] != self.body[1][0]:

self.direction = direction

def move(self):

# determine the head's next location

x, y = self.direction

next_x = (self.head[0] + x * grid_size)

next_y = (self.head[1] + y * grid_size)

# if next location hits a wall, wrap to the opposite wall

next_x = next_x % width

next_y = next_y % height

next_location = (next_x, next_y)

# add new head location to front of list

self.body.insert(0, next_location)

self.head = self.body[0]

# check if apple is at the head's location

if self.head == apple.location:

# move the apple to another location

apple.randomize_location()

# make sure the apple's new location is not where the snake is

while apple.location in self.body:

apple.randomize_location()

else:

# remove the last body part from list

self.body.pop()

def check_collision(self):

# check if head collided with a body part

if self.head in self.body[1:]:

return True

else:

return False

def draw(self):

for body_part in self.body:

square = pygame.Rect(body_part, (grid_size, grid_size))

pygame.draw.rect(screen, blue, square)

pygame.draw.rect(screen, white, square, 1)

# create the apple

apple = Apple()

# create the snake

snake = Snake()

# game loop

running = True

while running:

clock.tick(fps)

# check for event actions

for event in pygame.event.get():

if event.type == QUIT:

running = False

elif event.type == KEYDOWN:

# use arrow keys to turn the snake

if event.key == K_UP:

snake.turn(up)

elif event.key == K_DOWN:

snake.turn(down)

elif event.key == K_LEFT:

snake.turn(left)

elif event.key == K_RIGHT:

snake.turn(right)

# draw the background

for x in range(num_cols):

for y in range(num_rows):

# create a single square for the grid

square = pygame.Rect((x * grid_size, y * grid_size), (grid_size, grid_size))

# alternate colors for a checkered background

if (x + y) % 2 == 0:

pygame.draw.rect(screen, dark_green, square)

else:

pygame.draw.rect(screen, light_green, square)

# draw the apple

apple.draw()

# move the snake

snake.move()

# draw the snake

snake.draw()

# display the score

font = pygame.font.SysFont('monoface', 16)

text = font.render("Score: {0}".format(len(snake.body)), 1, black)

screen.blit(text, (5, 10))

# check for collision

collision = snake.check_collision()

if collision:

gameover = True

# gameover state

while gameover:

clock.tick(fps)

# draw the gameover text

pygame.draw.rect(screen, black, (0, height / 2 - 50, width, 100))

text = font.render("Game over! Press SPACE to play again", 1, white)

text_rect = text.get_rect()

text_rect.center = (width / 2, height / 2)

screen.blit(text, text_rect)

pygame.display.update()

# check if the user exited or pressed the space bar

for event in pygame.event.get():

if event.type == QUIT:

gameover = False

running = False

elif event.type == KEYDOWN and event.key == K_SPACE:

# reset the game

gameover = False

score = 0

snake.body = [(width / 2, height / 2)]

snake.direction = right

snake.head = snake.body[0]

apple.randomize_location()

pygame.display.update()

pygame.quit()