import pygame
import sys
from pygame.sprite import Sprite
from pygame.sprite import Group
from time import sleep
import pygame.font
# 修改游戏的一些新设置
class Settings():
  """存储《外星人入侵》的所有设置的类"""
  def __init__(self):
    """初始化游戏的设置"""
    # 屏幕设置
    self.screen_width = 1200
    self.screen_height = 800
    self.bg_color = (230, 230, 230) # 浅灰色
    # 飞船的设置，移动1.5像素
    self.ship_limit = 3
    # 子弹设置---创建宽3像素、高15像素的深灰色子弹
    self.bullet_speed_factor = 3
    self.bullet_width = 3
    self.bullet_height = 15
    self.bullet_color = 60, 60, 60
    self.bullets_allowed = 3
    # 外星人设置
    self.fleet_drop_speed = 10
    # 以什么样的速度加快游戏节奏
    self.speedup_scale = 1.1
    # 外星人点数的提高速度
    self.score_scale = 1.5
    self.initialize_dynamic_settings()
  def initialize_dynamic_settings(self):
    """初始化随游戏进行而变化的设置"""
    self.ship_speed_factor = 1.5
    self.bullet_speed_factor = 3
    self.alien_speed_factor = 1
    # fleet_direcction为1表示向右，为-1表示向左
    self.fleet_direction = 1
    # 计分
    self.alien_points = 50
  def increase_speed(self):
    """提高速度设置和外星人点数"""
    self.ship_speed_factor *= self.speedup_scale
    self.bullet_speed_factor *= self.speedup_scale
    self.alien_speed_factor *= self.speedup_scale
    self.alien_points = int(self.alien_points * self.score_scale)


# 创建一个ship类
class Ship(Sprite):
  def __init__(self, ai_settings, screen):
    """初始化飞船并设置其起始位置"""
    super(Ship, self).__init__()
    self.screen = screen
    self.ai_settings = ai_settings
    # 加载飞船图像并获取其外接矩形
    self.image = pygame.image.load('images/ship.bmp')
    self.rect = self.image.get_rect() # 以矩形形式来获取相应的surface属性
    self.screen_rect = screen.get_rect()
    # 将每艘新飞船放在屏幕底部中央
    self.rect.centerx = self.screen_rect.centerx
    self.rect.bottom = self.screen_rect.bottom
    # 在飞船的属性center中存储小数值----在后面加快游戏节奏时更细致地控制飞船的速度
    self.center = float(self.rect.centerx)
    # 移动标志
    self.moving_right = False
    self.moving_left = False
  def update(self):
    """根据移动标志调整飞船的位置"""
    # 更新飞船的center值，而不是rect
    if self.moving_right and self.rect.right < self.screen_rect.right:
      self.center += self.ai_settings.ship_speed_factor
    if self.moving_left and self.rect.left > 0:
      self.center -= self.ai_settings.ship_speed_factor
    # 根据self.center更新rect对象
    self.rect.centerx = self.center
  def center_ship(self):
    """将飞船在屏幕居中"""
    self.center = self.screen_rect.centerx
  def blitme(self):
    """在指定位置绘制飞船"""
    self.screen.blit(self.image, self.rect)


# 创建一个Alien类
class Alien(Sprite):
  """表示单个外星人的类"""
  def __init__(self, ai_settings, screen):
    """初始化外星人并设置其起始位置"""
    super(Alien, self).__init__()
    self.screen = screen
    self.ai_settings = ai_settings
    # 加载外星人图像，并设置其rect属性
    self.image = pygame.image.load('images/alien.bmp')
    self.rect = self.image.get_rect()
    # 每个外星人最初都在屏幕左上角附近
    self.rect.x = self.rect.width
    self.rect.y = self.rect.height
    # 存储外星人的准确位置
    self.x = float(self.rect.x)
  def check_edges(self):
    """如果外星人位于屏幕边缘，就返回True"""
    screen_rect = self.screen.get_rect()
    if self.rect.right >= screen_rect.right:
      return True
    elif self.rect.left <= 0:
      return True
  def update(self):
    """向左或向右移动外星人"""
    self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)
    self.rect.x = self.x
  def blitme(self):
    """在指定位置绘制外星人"""
    self.screen.blit(self.image, self.rect)


def get_number_aliens_x(ai_settings, alien_width):
  """计算每行可容纳多少个外星人"""
  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放在当前行"""
  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，并计算一行可容纳多少个外星人
  # 外星人间距为外星人宽度
  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):
      # 创建一个外星人并将其加入当前行
      create_alien(ai_settings, screen, aliens, alien_number, row_number)


class Bullet(Sprite):
  """一个对飞船发射的子弹进行管理的类"""
  def __init__(self, ai_settings, screen, ship):
    """在飞船所处的位置创建一个子弹对象"""
    super(Bullet, self).__init__()
    self.screen = screen
    # 在(0, 0)处创建一个表示子弹的矩形，再设置正确的位置
    self.rect = pygame.Rect(0, 0, ai_settings.bullet_width, ai_settings.bullet_height)
    self.rect.centerx = ship.rect.centerx
    self.rect.top = ship.rect.top
    # 存储用小数表示的子弹位置
    self.y = float(self.rect.y)
    # 设置子弹射出的颜色和速度
    self.color = ai_settings.bullet_color
    self.speed_factor = ai_settings.bullet_speed_factor
  def update(self):
    """向上移动子弹"""
    # 更新表示子弹位置的小数值
    self.y -= self.speed_factor
    # 更新表示子弹的rect位置
    self.rect.y = self.y
  def draw_bullet(self):
    """在屏幕上绘制子弹"""
    pygame.draw.rect(self.screen, self.color, self.rect)


# 管理事件，设置两个函数，一个处理KEYDOWN事件，一个处理KEYUP事件
def check_keydown_events(event, ai_settings, screen, ship, bullets):
  """响应按键"""
  if event.key == pygame.K_RIGHT:
    ship.moving_right = True
  elif event.key == pygame.K_LEFT:
    ship.moving_left = True
  elif event.key == pygame.K_SPACE:
    fire_bullets(ai_settings, screen, ship, bullets)
  elif event.key == pygame.K_q:
    sys.exit()


def check_keyup_events(event, ship):
  """响应松开"""
  if event.key == pygame.K_RIGHT:
    ship.moving_right = False
  elif 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 fire_bullets(ai_settings, screen, ship, bullets):
  """如果还没有到达限制，就发射一颗子弹"""
  # 创建一颗子弹，并将其加入到编组bullets中
  if len(bullets) < ai_settings.bullets_allowed:
    new_bullet = Bullet(ai_settings, screen, ship)
    bullets.add(new_bullet)



def check_bullet_alien_collisions(ai_settings, screen, stats, sb, ship, aliens, bullets):
  """响应子弹和外星人的碰撞"""
  # 如果是这样，就删除相应的子弹和外星人
  collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
  if len(aliens) == 0:
    # 消除已有的子弹，加快游戏节奏，并创建一群新的外星人
    # 如wan果整群外星人都被消灭，就提高一个等级
    bullets.empty()
    ai_settings.increase_speed()
    # 提高等级
    stats.level += 1
    sb.prep_level()
    create_fleet(ai_settings, screen, ship, aliens)
  if collisions:
    for aliens in collisions.values():
      stats.score += ai_settings.alien_points * len(aliens)
      sb.prep_score()
    check_high_score(stats, sb)


def update_bullets(ai_settings, screen, stats, sb, ship, aliens, bullets):
  """更新子弹位置，并删除已消失的子弹"""
  # 更新子弹位置
  bullets.update()
  # 删除已消失的子弹
  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 change_fleet_direction(ai_settings, aliens):
  """将整群外星人向下移，并改变它们的方向"""
  for alien in aliens.sprites():
    alien.rect.y += ai_settings.fleet_drop_speed
  ai_settings.fleet_direction *= -1


def check_fleet_edges(ai_settings, aliens):
  """有外星人到达边缘时采取响应的措施"""
  for alien in aliens.sprites():
    if alien.check_edges():
      change_fleet_direction(ai_settings, aliens)
      break


def ship_hit(ai_settings, screen, stats, sb, 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()
    # 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端中央
    create_fleet(ai_settings, screen, ship, aliens)
    ship.center_ship()
    # 暂停
    sleep(0.5)
  else:
    stats.game_active = False
    pygame.mouse.set_visible(True)


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


def update_aliens(ai_settings, screen, stats, sb, ship, aliens, bullets):
  """检查是否有外星人位于屏幕边缘，并更新整群外星人的位置"""
  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, screen, stats, sb, ship, aliens, bullets)
  # 检查是否有外星人到达屏幕底端
  check_aliens_bottom(ai_settings, screen, stats, sb, ship, aliens, bullets)


class GameStats():
  """跟踪游戏的统计信息"""
  def __init__(self, ai_settings):
    """初始化统计信息"""
    self.ai_settings = ai_settings
    self.reset_stats()
    # 游戏刚启动时处于非活跃状态，为了添加Play按钮
    self.game_active = False
    # 在任何情况下都不应重置最高得分
    self.high_score = 0
  def reset_stats(self):
    """初始化在游戏运行期间可能变化的统计信息"""
    self.ships_left = self.ai_settings.ship_limit
    self.score = 0
    self.level = 1


class Scoreboard():
  """显示得分信息的类"""
  def __init__(self, ai_settings, screen, stats):
    """初始化显示得分涉及的属性"""
    self.screen = screen
    self.screen_rect = screen.get_rect()
    self.ai_settings = ai_settings
    self.stats = stats
    # 显示得分信息时使用的字体设置
    self.text_color = (30, 30, 30)
    self.font = pygame.font.SysFont(None, 48)
    # 准备包含最高得分和当前得分的图像
    self.prep_score()
    self.prep_high_score()
    self.prep_level()
    self.prep_ships()
  def prep_score(self):
    """将得分转换为一幅渲染的图像"""
    rounded_score = int(round(self.stats.score, -1))
    score_str = "{:,}".format(rounded_score)
    self.score_image = self.font.render(score_str, True, self.text_color, self.ai_settings.bg_color)
    # 将得分放在屏幕右上角
    self.score_rect = self.score_image.get_rect()
    self.score_rect.right = self.screen_rect.right - 20
    self.score_rect.top = 20
  def prep_high_score(self):
    """将最高得分转换为渲染的图像"""
    high_score = int(round(self.stats.high_score, -1))
    high_score_str = "{:,}".format(high_score)
    self.high_score_image = self.font.render(high_score_str, True, self.text_color, self.ai_settings.bg_color)
    # 将最高得分放在屏幕中央
    self.high_score_rect = self.high_score_image.get_rect()
    self.high_score_rect.centerx = self.screen_rect.centerx
    self.high_score_rect.top = self.score_rect.top
  def prep_level(self):
    """将等级转换为渲染的图像"""
    self.level_image = self.font.render(str(self.stats.level), True, self.text_color, self.ai_settings.bg_color)
    # 将等级放在得分下方
    self.level_rect = self.level_image.get_rect()
    self.level_rect.right = self.score_rect.right
    self.level_rect.top = self.score_rect.bottom + 10
  def prep_ships(self):
    """显示还余下多少艘飞船"""
    self.ships = Group()
    for ship_number in range(self.stats.ships_left):
      ship = Ship(self.ai_settings, self.screen)
      ship.rect.x = 10 + ship_number * ship.rect.width
      ship.rect.y = 10
      self.ships.add(ship)
  def show_score(self):
    """在屏幕上显示得分和飞船"""
    self.screen.blit(self.score_image, self.score_rect)
    self.screen.blit(self.high_score_image, self.high_score_rect)
    self.screen.blit(self.level_image, self.level_rect)
    # 绘制飞船
    self.ships.draw(self.screen)


def check_high_score(stats, sb):
  """检查是否诞生了新的最高得分"""
  if stats.score > stats.high_score:
    stats.high_score = stats.score
    sb.prep_high_score()


class Button():
  def __init__(self, ai_settings, screen, msg):
    """初始化按钮的属性"""
    self.screen = screen
    self.screen_rect = screen.get_rect()
    # 设置按钮的尺寸和其他属性
    self.width, self.height = 200, 50
    self.button_color = (0, 255, 0) # 亮绿色
    self.text_color = (255, 255, 255) # 白色
    self.font = pygame.font.SysFont(None, 48) # 使用默认、48号字体
    # 创建按钮的rect对象，并使其居中
    self.rect = pygame.Rect(0, 0, self.width, self.height)
    self.rect.center = self.screen_rect.center
    # 按钮的标签只需创建一次
    self.prep_msg(msg)
  def prep_msg(self, msg):
    """将msg渲染为图像，并使其在按钮上居中"""
    self.msg_image = self.font.render(msg, True, self.text_color, self.button_color)
    self.msg_image_rect = self.msg_image.get_rect()
    self.msg_image_rect.center = self.rect.center
  def draw_button(self):
    # 绘制一个用颜色填充的按钮，再绘制文本
    self.screen.fill(self.button_color, self.rect)
    self.screen.blit(self.msg_image, self.msg_image_rect)


# 更新屏幕上的图像，并切换到新屏幕
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"""
  # 每次循环时都重新绘制屏幕
  screen.fill(ai_settings.bg_color)
  # 在飞船和外星人后面重新绘制所有子弹
  for bullet in bullets.sprites():
    bullet.draw_bullet()
  ship.blitme()
  aliens.draw(screen)
  # 显示得分
  sb.show_score()
  # 如果游戏处于非活跃状态，就绘制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 run_game():
  # 初始化游戏并创建一个屏幕对象
  pygame.init()
  ai_settings = Settings()
  screen = pygame.display.set_mode((ai_settings.screen_width, ai_settings.screen_height))
  pygame.display.set_caption("Alien Invation")
  # 创建一艘飞船
  ship = Ship(ai_settings, screen)
  # 创建一个外星人
  alien = Alien(ai_settings, screen)
  # 创建一个用于存储子弹的编组
  bullets = Group()
  # 创建一个外星人编组
  aliens = Group()
  # 创建一个外星人群
  create_fleet(ai_settings, screen, ship, aliens)
  # 创建存储游戏统计信息的实例，并创建记分牌
  stats = GameStats(ai_settings)
  sb = Scoreboard(ai_settings, screen, stats)
  # 创建Play按钮
  play_button = Button(ai_settings, screen, "Play")
  # 开始游戏的主循环
  while True:
    check_events(ai_settings, screen, stats, sb, play_button, ship, aliens, bullets)
    if stats.game_active:
      ship.update()
      update_bullets(ai_settings, screen, stats, sb, ship, aliens, bullets)
      update_aliens(ai_settings, screen, stats, sb, ship, aliens, bullets)
    update_screen(ai_settings, screen, stats, sb, ship, aliens, bullets, play_button)


run_game()