nuxt-app/app/composables/useAuth.ts

interface User {
  id: number;
  username: string;
  email: string | null;
  nickname: string | null;
  avatar: string | null;
  role: string;
  createdAt?: number;
}

interface CaptchaData {
  token: string;
  image: string;
}

interface ApiResponse<T> {
  code: number;
  message: string;
  data: T | null;
}

export function useAuth() {
  const user = useState<User | null>("auth-user", () => null);
  const loading = ref(false);

  async function loadUser() {
    try {
      const res = await $fetch<ApiResponse<{ user: User }>>("/api/auth/me", {
        headers: process.server ? useRequestHeaders(["cookie"]) : {},
      });
      if (res.code === 0 && res.data?.user) {
        user.value = res.data.user;
      }
    } catch {
      // 未登录时静默处理
    }
  }

  async function register(username: string, password: string, captchaToken: string, captchaCode: string) {
    loading.value = true;
    try {
      const res = await $fetch<ApiResponse<{ user: User }>>("/api/auth/register", {
        method: "POST",
        body: { username, password, captchaToken, captchaCode },
      });
      if (res.code !== 0) {
        return { success: false as const, message: res.message || "注册失败" };
      }
      await loadUser();
      return { success: true as const };
    } catch {
      return { success: false as const, message: "网络错误，请重试" };
    } finally {
      loading.value = false;
    }
  }

  async function login(username: string, password: string, captchaToken: string, captchaCode: string) {
    loading.value = true;
    try {
      const res = await $fetch<ApiResponse<{ user: User }>>("/api/auth/login", {
        method: "POST",
        body: { username, password, captchaToken, captchaCode },
      });
      if (res.code !== 0) {
        return { success: false as const, message: res.message || "登录失败" };
      }
      await loadUser();
      return { success: true as const };
    } catch {
      return { success: false as const, message: "网络错误，请重试" };
    } finally {
      loading.value = false;
    }
  }

  async function logout() {
    await $fetch("/api/auth/logout", { method: "POST" });
    user.value = null;
  }

  async function fetchCaptcha(): Promise<CaptchaData | null> {
    const res = await $fetch<ApiResponse<CaptchaData>>("/api/auth/captcha", {
      method: "POST",
    });
    if (res.code === 0 && res.data) {
      return res.data;
    }
    return null;
  }

  const isLoggedIn = computed(() => !!user.value);

  return { user, loading, isLoggedIn, loadUser, register, login, logout, fetchCaptcha };
}