import random
import time

import pygame


class Star:
    def __init__(self,visible,pos):
        self.visible = visible
        self.pos = pos
        self.size = random.randint(1,3)
    def set_visible(self):
        self.visible = True
    def star_appear(self,screen):
        pygame.draw.circle(screen, WHITE, self.pos, self.size)

stars = []
width = 640
height = 600
SIZE = (width, height)
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)

def main():
    screen = init_game()
    game_loop(screen)
    exit_game()

def init_game():
    pygame.init()
    screen = pygame.display.set_mode(SIZE)
    return screen

def game_loop(screen):
    while True:
        if not event_handling():
            break
        if not update_game(screen):
            break
        event = event_handling()
        update_game(screen)
        draw_screen(screen)
        time.sleep(0.5)

def event_handling():
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            return False
    return True

def update_game(screen):
    for _ in range (2):
        night_sky(screen)
    random.choice(stars).set_visible()
    return True

def draw_screen(screen):
    screen.fill(BLACK)
    x = 0
    for _ in stars:
        if stars[x].visible:
            stars[x].star_appear(screen)
        x+=1
    pygame.display.flip()

def night_sky(screen):
        pos = (random.randint(0, SIZE[0]), random.randint(0, SIZE[1]))
        stars.append(Star(False, pos))

def exit_game():
    pygame.quit()

main()