import sys

import pygame

from settings import Settings

class AlienInvasion:
	""" Overall class to manage game assets and behavior."""

	def __init__(self):
		"""Initialize the game, and create game resources."""
		pygame.init()
		self.settings = Settings()

		self.screen = pygame.display.set_mode(
			(self.settings.screen_width, self.settings.screen_height))
		pygame.display.set_caption("Alien Invasion")

		self.ship = Ship(self)

		# set the background color.
		self.bg_color = (230, 230, 230)

	def run_game(self):
		"""Start the main loop for the game."""
		while True:
			self._check_events()
			self._update_screen()

	def _check_events(self):
		"""Respond to a keypresses and mouse events."""
		for event in pygame.event.get():
			if event.type == pygame.QUIT:
				sys.exit()
			elif event.type == pygame.KEYDOWN:
				if event.key == pygame.K_RIGHT:
					# Move the ship to the right.
					self.ship_rect.x += 1

	def _update_screen(self):
		"""Updates imgaes on the screen, and flip to the new screen."""
		self.screen.fill(self.settings.bg_color)
		self.ship.blitme()

		# make the most recently drawn screen visible.
		pygame.display.flip()

if __name__ == '__main__':
	#make a game instance, and run the game
	ai = AlienInvasion()
	ai.run_game()