export function useApi() {
  async function api<T>(path: string, opts: RequestInit & { json?: unknown } = {}): Promise<T> {
    const headers = new Headers(opts.headers);
    if (opts.json !== undefined) headers.set("Content-Type", "application/json");
    const res = await fetch(path, {
      ...opts,
      headers,
      credentials: "include",
      body: opts.json !== undefined ? JSON.stringify(opts.json) : opts.body,
    });
    if (!res.ok) {
      const err = await res.json().catch(() => ({ error: res.statusText }));
      throw Object.assign(new Error(err.error || "Error"), { status: res.status, data: err });
    }
    const ct = res.headers.get("content-type") || "";
    if (ct.includes("application/json")) return await res.json() as T;
    return (await res.blob()) as T;
  }
  async function download(path: string, filename: string) {
    const blob = await api<Blob>(path);
    const url = URL.createObjectURL(blob);
    const a = document.createElement("a");
    a.href = url;
    a.download = filename;
    a.rel = "noopener";
    document.body.appendChild(a);
    a.click();
    a.remove();
    window.setTimeout(() => URL.revokeObjectURL(url), 2000);
  }
  return { api, download };
}

export const useAuth = () => {
  const user = useState<{
    id: number;
    username: string;
    display_name: string;
    company_id?: number | null;
    company_code?: string | null;
    company_name?: string | null;
    company_kind?: string | null;
    tenant_id?: number | null;
    role?: "platform_admin" | "tenant_admin" | "user";
    realm?: "app" | "platform";
    must_change_password?: boolean;
  } | null>("auth-user", () => null);
  const { api } = useApi();
  async function fetchMe() {
    try {
      const r = await api<{ user: NonNullable<typeof user.value> }>("/v1/auth/me");
      user.value = r.user;
    } catch {
      user.value = null;
    }
  }
  async function login(username: string, password: string) {
    const r = await api<{ user: NonNullable<typeof user.value> }>("/v1/auth/login", {
      method: "POST",
      json: { username, password },
    });
    user.value = r.user;
  }
  async function logout() {
    await api("/v1/auth/logout", { method: "POST" });
    user.value = null;
    await navigateTo("/login");
  }
  return { user, fetchMe, login, logout };
};