alien_invasion.py

import sys
from time import sleep
import pygame
from pygame import mixer
import json

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:
    '''Overall Class to manage game'''

    def __init__(self):

        pygame.init() #initialize the game and create game resources

        self.settings = Settings()

        # to create display window of 1200W X 800H
        self.screen = pygame.display.set_mode((self.settings.screen_width, self.settings.screen_height))

        #For Fullscreen :
        # 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") #set title of the game

        #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):
        while 1: 
            self._check_events() # hleper Method (doesn't require instance to call)
            if self.stats.game_active:
                self.ship.update()
                self._update_bullets()
                self._update_aliens()
            self._update_screen()


    def _check_events(self):

        for event in pygame.event.get(): #Event Loop(wtach for keyboard, mouse)
            if event.type == pygame.QUIT: #to Exit
                with open('high_score.json', 'w') as f: #to Store the high score
                    json.dump(self.stats.high_score, f)
                sys.exit()

            elif event.type == pygame.KEYDOWN: # each key press is registered as KEYDOWN event
                self._check_keydown_events(event)

            elif event.type == pygame.KEYUP: # each key release is registered as KEYUP event
                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):
        if event.key == pygame.K_RIGHT: #to move the ship right
            self.ship.moving_right = True
        elif event.key ==  pygame.K_LEFT: #to move the ship left
            self.ship.moving_left = True
        elif event.key == pygame.K_d:
            self.ship.moving_right = True
        elif event.key ==  pygame.K_a:
            self.ship.moving_left = True
        elif event.key == pygame.K_q: #to Quit the game
            with open('high_score.json', 'w') as f: #to Store the high score
                    json.dump(self.stats.high_score, f)
            sys.exit()
        elif event.key == pygame.K_SPACE or event.key == pygame.K_KP_ENTER:
            self._fire_bullet()
            mixer.music.load("sounds/gun_shot.mp3")
            mixer.music.play()
            

    def _check_keyup_events(self, event):
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = False
        elif event.key ==  pygame.K_LEFT:
            self.ship.moving_left = False
        elif event.key == pygame.K_d:
            self.ship.moving_right = False
        elif event.key ==  pygame.K_a:
            self.ship.moving_left = False
        elif event.key == pygame.K_SPACE or event.key == pygame.K_KP_ENTER:
            mixer.music.stop()


    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:
            self.settings.initialize_dynamic_settings()
            self.stats.reset_stats()
            self.stats.game_active = True
            self.sb.prep_score()
            self.sb.prep_level()
            self.sb.prep_ships()

            #Get rid of the remaining alien 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)


    def _fire_bullet(self):
        #create a new bullet and add it to the bullets group
        if len(self.bullets) < self.settings.bullets_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)


    def _update_bullets(self):
        '''Update the bullet position and get rid of old bullets'''

        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_collisoins()

    def _check_bullet_alien_collisoins(self):
        #check for any bullets that have hit aliens
        # If so, get rid of the bullet and alien
        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_aliens(self):
        '''Check if the fleet is at an edge
                Update position 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()

        #Look for aliens hitting the bottom of the screen
        self._check_aliens_bottom()

    def _create_fleet(self):
        #Create fleet of Aliens
        #Create a alien and find the number of aliens in a row
        # Spacing between each alien 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 the 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 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_height + 2 * alien.rect.height * row_number
        self.aliens.add(alien)

    def _check_fleet_edges(self):
        '''Respond appropriately if any aliens have reached an edge'''
        for alien in self.aliens.sprites():
            if alien.check_edges():
                self._change_fleet_direction()
                break

    def _change_fleet_direction(self):
        '''Drop the entire 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 an alien'''

        if self.stats.ship_left > 0 :
            # Decrement ships_left and update scoreboard
            self.stats.ship_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()

            sleep(1.5) #pause

        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:
                self._ship_hit()
                break


    def _update_screen(self):
        '''Update images on the screen and flip to the new screen'''
        self.screen.fill(self.settings.bg_color) #Redraw the screen during each pass through the loop
        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() #make most recently drawn screen visible





if __name__ == '__main__':
    ai = AlienInvasion()
    ai.run_game()