from pygame import *
from random import randint


#background music
mixer.init()
mixer.music.load('space.ogg')
mixer.music.play()
fire_sound = mixer.Sound('fire.ogg')


#fonts and captions
font.init()
font2 = font.Font(None, 36)


#we need the following images:
img_back = "galaxy.jpg" # game background
img_hero = "rocket.png" # hero
img_enemy = "ufo.png" # enemy


score = 0 #ships destroyed
lost = 0 #ships missed


#parent class for other sprites
class GameSprite(sprite.Sprite):
 #class constructor
   def __init__(self, player_image, player_x, player_y, size_x, size_y, player_speed):
       #Call for the class (Sprite) constructor:
       sprite.Sprite.__init__(self)


       #every sprite must store the image property
       self.image = transform.scale(image.load(player_image), (size_x, size_y))
       self.speed = player_speed


       #every sprite must have the rect property that represents the rectangle it is fitted in
       self.rect = self.image.get_rect()
       self.rect.x = player_x
       self.rect.y = player_y
 #method drawing the character on the window
   def reset(self):
       window.blit(self.image, (self.rect.x, self.rect.y))


#main player class
class Player(GameSprite):
   #method to control the sprite with arrow keys
   def update(self):
       keys = key.get_pressed()
       if keys[K_LEFT] and self.rect.x > 5:
           self.rect.x -= self.speed
       if keys[K_RIGHT] and self.rect.x < win_width - 80:
           self.rect.x += self.speed
 #method to "shoot" (use the player position to create a bullet there)
   def fire(self):
       pass


#enemy sprite class  
class Enemy(GameSprite):
   #enemy movement
   def update(self):
       self.rect.y += self.speed
       global lost
       #disappears upon reaching the screen edge
       if self.rect.y > win_height:
           self.rect.x = randint(80, win_width - 80)
           self.rect.y = 0
           lost = lost + 1


#create a small window
win_width = 700
win_height = 500
display.set_caption("Shooter")
window = display.set_mode((win_width, win_height))
background = transform.scale(image.load(img_back), (win_width, win_height))


#create sprites
ship = Player(img_hero, 5, win_height - 100, 80, 100, 10)


monsters = sprite.Group()
for i in range(1, 6):
   monster = Enemy(img_enemy, randint(80, win_width - 80), -40, 80, 50, randint(1, 5))
   monsters.add(monster)


#the "game is over" variable: as soon as True is there, sprites stop working in the main loop
finish = False
#Main game loop:
run = True #the flag is reset by the window close button
while run:
   #"Close" button press event
   for e in event.get():
       if e.type == QUIT:
           run = False


   if not finish:
       #update the background
       window.blit(background,(0,0))


       #write text on the screen
       text = font2.render("Score: " + str(score), 1, (255, 255, 255))
       window.blit(text, (10, 20))


       text_lose = font2.render("Missed: " + str(lost), 1, (255, 255, 255))
       window.blit(text_lose, (10, 50))


       #launch sprite movements
       ship.update()
       monsters.update()


       #update them in a new location in each loop iteration
       ship.reset()
       monsters.draw(window)


       display.update()
   #the loop is executed each 0.05 sec
   time.delay(50)