alien_invasion.py

import sys

from time import sleep

import pygame

from settings import Settings

from game_stats import GameStats

from scoreboard import Scoreboard

from button import Button

from ship import Ship

from bullet import Bullet

from alien import Alien




class AlienInvasion:
    #class to manage the resources and behaviour.

    def __init__(self):
        #initialize the game.
        pygame.init()

        self.settings = Settings()

        self.screen = pygame.display.set_mode((0, 0), pygame.FULLSCREEN)
        self.settings.screen_width = self.screen.get_rect().width
        self.settings.screen_height = self.screen.get_rect().height

        pygame.display.set_caption("Alien Invasion")

        #create an instance to store game statistics.
        #And create a scoreboard.
        self.stats = GameStats(self)
        self.sb = Scoreboard(self)

        self.ship = Ship(self)
        self.bullets = pygame.sprite.Group()
        self.aliens = pygame.sprite.Group()

        self._create_fleet()

        #make the play button.
        self.play_button = Button(self, "PLAY")

        
    
    def run_game(self):
        #Start main loop for game.

        while True:
            self._check_events()

            if self.stats.game_active:
                self.ship.update()
               # self.bullets.update()
                self._update_bullet()
                self._update_aliens()

            self._update_screen()



    def _check_events(self):
        """Respond to keypresses and mouse events."""

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()
            elif event.type == pygame.KEYDOWN:
                self._check_keydown_events(event)
            elif event.type == pygame.KEYUP:
                self._check_keyup_events(event)
            elif event.type == pygame.MOUSEBUTTONDOWN:
                mouse_pos = pygame.mouse.get_pos()
                self._check_play_button(mouse_pos)

    def _check_keydown_events(self,event):
        """Respond key keypresses"""         
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = True
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = True
        elif event.key == pygame.K_q:
            sys.exit()
        elif event.key == pygame.K_SPACE:
            self._fire_bullet()

    def _check_keyup_events(self,event):
        """Respond key releases"""         
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = False
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = False

    def _fire_bullet(self):
        """Create a new bullet and add it to the bullet group."""
        if len(self.bullets) < self.settings.bullets_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)
    
    def _update_bullet(self):
        """Update position of  bullet and get rid of old bullets."""
        #update bullet positions.
        self.bullets.update()

        #Get rid of bullets that have disappeared.
        for bullet in self.bullets.copy():
            if bullet.rect.bottom <= 0:
                self.bullets.remove(bullet)
        
        self._check_bullet_alien_collisions()

    def _check_bullet_alien_collisions(self):
        """Respond to bullet-Aliencollisions."""
        #remove any bullets and aliens that have collided.
          
        collisions = pygame.sprite.groupcollide(self.bullets, self.aliens, True, True)

        if collisions:
            for aliens in collisions.values():
                self.stats.score += self.settings.alien_points * len(aliens)
            self.sb.prep_score()
            self.sb.check_high_score()

        if not self.aliens:
            #Destroy existing bullets and create new fleet.
            self.bullets.empty()
            self._create_fleet()
            self.settings.increase_speed()

            #Increase Level.
            self.stats.level += 1
            self.sb.prep_level()


    def _update_screen(self):
        """update the images on the screen,and flip to new screen."""

        self.screen.fill(self.settings.bg_color)
        self.ship.blitme()

        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        
        self.aliens.draw(self.screen)

        #draw the score information.
        self.sb.show_score()

        #Draw the play button if the game is inactive.
        if not self.stats.game_active:
            self.play_button.draw_button()

        pygame.display.flip()
    
    def _create_fleet(self):
        """Create the fleet of aliens."""
        #create an alien and find the number of aliens in a row.
        #spacing between each line is equal to one alien width.

        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        available_space_x = self.settings.screen_width - (2 * alien_width)
        number_aliens_x = available_space_x // (2 * alien_width)

        #Determine the number of rows of aliens that fit on the screen.
        
        ship_height = self.ship.rect.height
        available_space_y = (self.settings.screen_height - (3 * alien_height) - ship_height)
        number_rows = available_space_y // (2 * alien_height)

        #Create full fleet of aliens.
        for row_number in range(number_rows):
            for alien_number in range(number_aliens_x):
                self._create_alien(alien_number, row_number)
            

    def _create_alien(self, alien_number,row_number):
        """Create an alien and place it in the row"""
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        alien.x =alien_width + 2  * alien_width * alien_number
        alien.rect.x=alien.x
        alien.rect.y = alien.rect.height + 2 * alien.rect.height * row_number
        self.aliens.add(alien)
    
    def _update_aliens(self):
        """
        check if the fleet is at an edge, then
        update the positions of all aliens in the fleet
        """
        self._check_fleet_edges()
        self.aliens.update()

        #Look for alien ship collisions.
        if pygame.sprite.spritecollideany(self.ship, self.aliens):
            self._ship_hit()
            print("Ship hit!!!!!!")
    
    def _check_fleet_edges(self):
        """Respond appropriately if any aliens have reaced an edge."""
        for alien in self.aliens.sprites():
            if alien.check_edges():
                self._change_fleet_direction()
                break
    
    def _change_fleet_direction(self):
        """Drop the entrie fleet and change the fleet's direction."""
        for alien in self.aliens.sprites():
            alien.rect.y += self.settings.fleet_drop_speed
        self.settings.fleet_direction *= -1

    def _ship_hit(self):
        """Respond to the ship being hit by alien."""

        if self.stats.ships_left > 0:
            #Decrement ships_left, and update scoreboard
            self.stats.ships_left -= 1
            self.sb.prep_ships()

            #Get rid of any remaining aliens and bullets.
            self.aliens.empty()
            self.bullets.empty()

            #Create a new fleet and center the ship.
            self._create_fleet()
            self.ship.center_ship()

            #pause
            sleep(0.5)
        else:
            self.stats.game_active = False
            pygame.mouse.set_visible(True)
    
    def _check_aliens_bottom(self):
        """Check if any aliens have reached the bottom of the screen"""

        screen_rect = self.screen.get_rect()
        for alien in self.aliens.sprites():
            if alien.rect.bottom >= screen_rect.bottom:
                #Treat this same as the ship got hit.
                self._ship_hit()

                #Look for aliens hitting the bottom of the screen

            self._check_aliens_bottom()

    def _check_play_button(self, mouse_pos):
        """Start a new game when the player clicks play"""
        button_clicked = self.play_button.rect.collidepoint(mouse_pos)
        if button_clicked and not self.stats.game_active:

            #Reset the game settings
            self.settings.initialize_dynamic_settings()

            #Reset the game statistics.
            self.stats.reset_stats()
            self.stats.game_active = True
            self.sb.prep_score()
            self.sb.prep_level()

            #get rid of any remaining aliens and bullets.
            self.aliens.empty()
            self.bullets.empty()

            #Create a new fleet and center the ship.
            self._create_fleet()
            self.ship.center_ship()

            #Hide the mouse cursor
            pygame.mouse.set_visible(False) 


if __name__=='__main__':
    #Make a game object or instance,and run the game

    ai=AlienInvasion()
    ai.run_game()