import pygame
from pygame.sprite import Sprite


class Alien(Sprite):
    """A class to represent a single alien in the fleet"""

    def __init__(self, si_game):
        """Initialize the alien and set its starting position"""
        super().__init__()
        self.screen = si_game.screen
        self.settings = si_game.settings

        # Lädtdas bild des Invasionsschiffs und legt das rect-Attribut fest
        self.image = pygame.image.load('images/alien.png')
        self.rect = self.image.get_rect()

        # Platziert jedes neue Invasionsschiff oben links auf dem Bildschirm
        self.rect.x = self.rect.width
        self.rect.y = self.rect.height

        # Speichert die genaue Position des Invasionsschiffes
        self.x = float(self.rect.x)
    
    def check_edges(self):
        """Return True if alien is at the edge of screen"""
        screen_rect = self.screen.get_rect()
        if self.rect.right >= screen_rect.right or self.rect.left <= 0:
            return True

    def update(self):
        """Move the alien right or left"""
        self.x += (self.settings.alien_speed * self.settings.fleet_direction)
        self.rect.x = self.x