import sys
import pygame
from time import sleep
from bullet import Bullet
from alien import Alien
def check_keydown_events(event,ai_settings,screen,ship,bullets):
	#响应按键
	if event.key==pygame.K_RIGHT:
		ship.moving_right=True
	if event.key==pygame.K_LEFT:
		ship.moving_left=True
	elif event.key==pygame.K_SPACE:
		#创建一颗子弹并将其加入到编组bullets中
		fire_bullet(ai_settings,screen,ship,bullets)
	elif event.key==pygame.K_q:
		sys.exit()
def fire_bullet(ai_settings,screen,ship,bullets):
	if len(bullets)<ai_settings.bullets_allowed:
		new_bullet=Bullet(ai_settings,screen,ship)
		bullets.add(new_bullet)
def check_keyup_events(event,ship):
	#响应松开
	if event.key==pygame.K_RIGHT:
		ship.moving_right=False
	if event.key==pygame.K_LEFT:
		ship.moving_left=False
def check_events(ai_settings,screen,stats,sb,play_button,ship,aliens,bullets):
	#响应按键和鼠标事件
	for event in pygame.event.get():
		if event.type==pygame.QUIT:
			sys.exit()
		elif event.type==pygame.KEYDOWN:
			check_keydown_events(event,ai_settings,screen,ship,bullets)
		elif event.type==pygame.KEYUP:
			check_keyup_events(event,ship)
		elif event.type==pygame.MOUSEBUTTONDOWN:
			mouse_x,mouse_y=pygame.mouse.get_pos()
			check_play_button(ai_settings,screen,stats,sb,play_button,ship,aliens,bullets,mouse_x,mouse_y)
def check_play_button(ai_settings,screen,stats,sb,play_button,ship,aliens,bullets,mouse_x,mouse_y):
	#在玩家单击play按钮时开始新游戏
	button_clicked=play_button.rect.collidepoint(mouse_x,mouse_y)
	if button_clicked and not stats.game_active:
		#重置游戏设置
		ai_settings.initialize_dynamic_settings()
		#隐藏光标
		pygame.mouse.set_visible(False)
		#重置游戏统计信息
		stats.reset_stats()
		stats.game_active=True
		#重置记分牌图像
		sb.prep_score()
		sb.prep_high_score()
		sb.prep_level()
		sb.prep_ships()
		#清空外星人列表和子弹列表
		aliens.empty()
		bullets.empty()
		#创建一群新的外星人，并让飞船居中
		create_fleet(ai_settings,screen,ship,aliens)
		ship.center_ship()
def check_high_score(stats,sb):
	#检查最高得分
	if stats.score>stats.high_score:
		stats.high_score=stats.score
		sb.prep_high_score()
			
def update_screen(ai_settings,screen, stats,sb,ship,aliens,bullets,play_button):
	#更新屏幕上的图像，并切换到新屏幕
	#每次循环都重绘屏幕
	screen.fill(ai_settings.bg_color)
	#在飞船和外星人后面重绘所有子弹
	for bullet in bullets.sprites():
		bullet.draw_bullet()
	ship.blitme()
	aliens.draw(screen)
	#显示得分
	sb.show_score()
	#如果游戏处于非活动状态，就显示play按钮
	if not stats.game_active:
		play_button.draw_button()
	#让最近绘制的屏幕可见
	pygame.display.flip()
def update_bullets(ai_settings,screen,stats,sb,ship,aliens,bullets):
	#更新子弹的位置，并删除已消失的子弹
	#更新子弹位置
	bullets.update()
	#删除已消失子弹
	for bullet in bullets.copy():
		if bullet.rect.bottom<=0:
			bullets.remove(bullet)
		check_bullet_alien_collisions(ai_settings,screen,stats,sb,ship,aliens,bullets)
def check_bullet_alien_collisions(ai_settings,screen,stats,sb,ship,aliens,bullets):
	#响应子弹和外星人的碰撞
	#删除发生碰撞的子弹和外形人
	collisions=pygame.sprite.groupcollide(bullets,aliens,True,True)
	if collisions:
		for aliens in collisions.values():
			stats.score +=ai_settings.alien_points*len(aliens)
			sb.prep_score()
			check_high_score(stats,sb)
	if len(aliens)==0:
		#删除现有的子弹,加快游戏节奏，并新建一群外星人
		bullets.empty()
		ai_settings.increase_speed()
		stats.level +=1
		sb.prep_level()
		create_fleet(ai_settings,screen,ship,aliens)

def get_number_aliens_x(ai_settings,alien_width):
	#计算每行可容纳多少个机器人
	available_space_x=ai_settings.screen_width-2*alien_width
	number_aliens_x=int(available_space_x/(2*alien_width))
	return number_aliens_x
def get_number_rows(ai_settings,ship_height,alien_height):
	#计算屏幕可容纳多少行外星人
	available_space_y=(ai_settings.screen_height-3*alien_height-ship_height)
	number_rows=int(available_space_y/(2*alien_height))
	return number_rows
def create_alien(ai_settings,screen,aliens,alien_number,row_number):
	#创建一个外星人并将其加入当前行
	alien=Alien(ai_settings,screen)
	alien_width=alien.rect.width
	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
	aliens.add(alien) 
def create_fleet(ai_settings,screen,ship,aliens):
	#创建外星人群
	#创建一个外星人并计算每行可容纳多少个外星人
	alien=Alien(ai_settings,screen)
	number_aliens_x=get_number_aliens_x(ai_settings,alien.rect.width)
	number_rows=get_number_rows(ai_settings,ship.rect.height,alien.rect.height)
	#创建外星人群
	for row_number in range(number_rows):
		for alien_number in range(number_aliens_x):
			create_alien(ai_settings,screen,aliens,alien_number,row_number)
def check_fleet_edges(ai_settings,aliens):
	#有外星人到达屏幕边缘时采取相应措施
	for alien in aliens.sprites():
		if alien.check_edges():
			change_fleet_direction(ai_settings,aliens)
			break
def change_fleet_direction(ai_settings,aliens):
	#将整群外星人下移，并改变移动方向
	for alien in aliens.sprites():
		alien.rect.y +=ai_settings.fleet_drop_speed
	ai_settings.fleet_direction *=-1
	
def ship_hit(ai_settings,stats,sb,screen,ship,aliens,bullets):
	#响应被外星人撞到的飞船
	if stats.ships_left > 0:
		#将ships_left 减1
		stats.ships_left -=1
		#更新记分牌
		sb.prep_ships()
		
	else:
		stats.game_active=False
		pygame.mouse.set_visible(True)
	#清空外星人列表和子弹列表
	aliens.empty()
	bullets.empty()
	#创建一群新的外星人，并将飞船放到屏幕底部中央
	create_fleet(ai_settings,screen,ship,aliens)
	ship.center_ship()
	#暂停
	sleep(0.5)

def check_aliens_bottom(ai_settings,stats,sb,screen,ship,aliens,bullets):
	#检查是否有外星人到达屏幕底部
	screen_rect=screen.get_rect()
	for alien in aliens.sprites():
		if alien.rect.bottom>=screen_rect.bottom:
			#像飞船被撞到一样处理
			ship_hit(ai_settings, screen, stats, sb, ship, aliens, bullets)
		break	

def update_aliens(ai_settings,sb,stats,screen,ship,aliens,bullets):
	#检查是否有外星人位于屏幕边缘，并更新整群外星人位置
	check_fleet_edges(ai_settings,aliens)
	aliens.update()
	#检测外星人和飞船之间的碰撞
	if pygame.sprite.spritecollideany(ship,aliens):
		ship_hit(ai_settings,stats,screen,sb,ship,aliens,bullets)
	#检查是否有外星人抵达屏幕底部
	check_aliens_bottom(ai_settings, screen, stats, sb, ship, aliens, bullets)
	



	



