import pygame
import math


class Shield(pygame.sprite.Sprite):
    def __init__(self, player):
        super().__init__()
        self.player = player
        self.radius = 16
        self.arc_angle = 90
        self.start_angle = 0
        self.shield_image = pygame.Surface(
            (self.radius*2, self.radius*2), pygame.SRCALPHA)
        self.color = (0, 255, 0)
        self.update_shield_image()

    def update_shield_image(self):
        self.shield_image.fill((0, 0, 0, 0))  # 透明背景
        pygame.draw.arc(self.shield_image, self.color, self.shield_image.get_rect(), math.radians(
            self.start_angle), math.radians(self.start_angle + self.arc_angle), self.radius)

    def generate(self):
        self.player_group = pygame.sprite.Group()
        self.player_group.add(self.player)

        # 根据玩家的位置和护盾角度调整护盾的位置和角度
        self.rect = self.shield_image.get_rect(center=self.player.rect.center)
        self.rect.x -= self.radius
        self.rect.y -= self.radius
        self.rotate_shield()

    def rotate_shield(self):
        rotated_image = pygame.transform.rotate(
            self.shield_image, self.player.toword_angle)
        self.image = pygame.Surface(rotated_image.get_size(), pygame.SRCALPHA)
        self.image.blit(rotated_image, (0, 0))
        self.mask = pygame.mask.from_surface(self.image)

    def damage(self):
        self.arc_angle -= 90
        self.start_angle += 90
        if self.arc_angle <= 0:
            self.kill()
        else:
            self.update_shield_image()
            self.rotate_shield()