import pygame, sys
import random

pygame.init()                                                         
screen = pygame.display.set_mode([640,480])                           
background = pygame.Surface(screen.get_size())                        
background.fill([0, 0, 0])                                      
clock = pygame.time.Clock()                                           

class Bullet(pygame.sprite.Sprite):                               
    def __init__(self, image_file, location):                                        
        pygame.sprite.Sprite.__init__(self) #call Sprite initializer  
        self.image = pygame.image.load(image_file)                    
        self.rect = self.image.get_rect()                             
        self.rect.left, self.rect.top = location

    def fire(self):
        if self.rect.top >= -30:
            self.rect.top -= 30
            
class Explosion(pygame.sprite.Sprite):                               
    def __init__(self, image_file, location):                                        
        pygame.sprite.Sprite.__init__(self) #call Sprite initializer  
        self.image = pygame.image.load(image_file)                    
        self.rect = self.image.get_rect()                             
        self.rect.left, self.rect.top = location
        
class Fighter(pygame.sprite.Sprite):                                     
   def __init__(self, image_file, speed, location):                   
        pygame.sprite.Sprite.__init__(self) #call Sprite initializer  
        self.image = pygame.image.load(image_file)                    
        self.rect = self.image.get_rect()                             
        self.rect.left, self.rect.top = location                      
        self.speed = speed                                            
    
class Enemy(pygame.sprite.Sprite):                                     
   def __init__(self, image_file, speed, location):                   
        pygame.sprite.Sprite.__init__(self) #call Sprite initializer  
        self.image = pygame.image.load(image_file)                    
        self.rect = self.image.get_rect()                             
        self.rect.left, self.rect.top = location                      
        self.speed = speed                                            
  
   def move(self):                                                    
        if self.rect.left <= screen.get_rect().left or \
                 self.rect.right >= screen.get_rect().right:          
            self.speed[0] = - self.speed[0]                           
        newpos = self.rect.move(self.speed)
        self.rect = newpos
        
        if self.rect.bottom < 0:
            self.rect.top = screen.get_rect().bottom

        if self.rect.top > screen.get_rect().bottom:
            self.rect.bottom = 0        

class Energy(pygame.sprite.Sprite):                                     
   def __init__(self, image_file, speed, location):                   
        pygame.sprite.Sprite.__init__(self) #call Sprite initializer  
        self.image = pygame.image.load(image_file)                    
        self.rect = self.image.get_rect()                             
        self.rect.left, self.rect.top = location                      
        self.speed = speed                                            
  
   def move(self):                                                    
        if self.rect.left <= screen.get_rect().left or \
                 self.rect.right >= screen.get_rect().right:          
            self.speed[0] = - self.speed[0]                           
        newpos = self.rect.move(self.speed)
        self.rect = newpos
        
        if self.rect.bottom < 0:
            self.rect.top = screen.get_rect().bottom

        if self.rect.top > screen.get_rect().bottom:
            self.rect.bottom = 0

myFighter = Fighter('fighter.png', [20, 20], [270,360])
screen.blit(myFighter.image, myFighter.rect)
enemies = pygame.sprite.Group()
for i in range(5):
    enemies.add(Enemy('spaceship.png', [20, 1], [100+i*100, 20+i*5]))

myBullet = Bullet('missile.png', [0,-40])                         

expoSprite = [Explosion('explosion-0.png', [0, -400]),
              Explosion('explosion-1.png', [0, -400]),
              Explosion('explosion-2.png', [0, -400]),
              Explosion('explosion-3.png', [0, -400]),
              Explosion('explosion-4.png', [0, -400]),
              Explosion('explosion-5.png', [0, -400]),
              Explosion('explosion-6.png', [0, -400]),
              Explosion('explosion-7.png', [0, -400])]
expoLocations = []

energies = pygame.sprite.Group()

delay = 100
interval = 50
pygame.key.set_repeat(delay, interval)

enemyInterval = 50
score = 0
scoreFont = pygame.font.Font(None, 20)

while True:                                                           
    for event in pygame.event.get():                                  
        if event.type == pygame.QUIT:                                 
            pygame.display.quit()
            sys.exit()                                                
##        elif event.type == pygame.KEYDOWN:                            
##            if event.key == pygame.K_UP:                              
##                myFighter.rect.top = myFighter.rect.top - 10              
##            elif event.key == pygame.K_DOWN:                          
##                myFighter.rect.top = myFighter.rect.top + 10              

##        elif event.type == pygame.MOUSEBUTTONDOWN:
##            if myBullet.rect.top <= 0:
##                myBullet.rect.top = myFighter.rect.top
##                myBullet.rect.centerx = myFighter.rect.centerx

    clock.tick(30)
    screen.blit(background, (0, 0))

    if True in pygame.mouse.get_pressed():
        if myBullet.rect.top <= 0:
                myBullet.rect.top = myFighter.rect.top
                myBullet.rect.centerx = myFighter.rect.centerx

    # add more enemies
    enemyInterval -= 1
    if enemyInterval == 0:
        enemies.add(Enemy('spaceship.png', [10, 1],
                          [random.randint(20, 500), 20]))
        enemyInterval = 50
    
    myBullet.fire()
    screen.blit(myBullet.image, myBullet.rect)

    # use the following code instead of pygame.MOUSEMOTION for acceleration effect
    if abs(myFighter.rect.centerx - pygame.mouse.get_pos()[0]) > 1:
        myFighter.rect.centerx += int((pygame.mouse.get_pos()[0] - myFighter.rect.centerx)/10)  
    if abs(myFighter.rect.centery - pygame.mouse.get_pos()[1]) > 1:
        myFighter.rect.centery += int((pygame.mouse.get_pos()[1] - myFighter.rect.centery)/10)

    for enemy in enemies:
        enemy.move()

    for enemy in enemies:
        hitList = pygame.sprite.spritecollide(myBullet, enemies, True)
        if len(hitList) > 0:
            myBullet.rect.top = -400
            for hit in hitList:
                expoLocations.append([(hit.rect.left-65, hit.rect.top-42), 0])
                energies.add(Energy('energy.png',
                                    [random.randint(1, 4), random.randint(1, 2)],
                                    (hit.rect.left+21, hit.rect.top+18)))
                                    
        screen.blit(enemy.image, enemy.rect)

    for expo in expoLocations:
        if expo[1] < 7:
            screen.blit(expoSprite[expo[1]].image, expo[0])
            expo[1] += 1
        else:
            expoLocations.remove(expo)

    for energy in energies:
        energy.move()
        score += len(pygame.sprite.spritecollide(myFighter, energies, True))
        screen.blit(energy.image, energy.rect)

    scoreText = "Score: " + str(score)
    scoreSurf = scoreFont.render(scoreText, 1, (100, 100, 255))
    screen.blit(scoreSurf, [20, 5])
    screen.blit(myFighter.image, myFighter.rect)
    pygame.display.flip()