"use client";

import { useRouter } from "next/navigation";
import { useEffect, useState, type ReactNode } from "react";

import { AdminAuthCheckingScreen } from "@/components/admin/admin-auth-checking";
import { verifyStoredAdminSession } from "@/lib/admin-session-verify";
import { useAdminSessionStore } from "@/stores/admin-session";
import { readToken } from "@/stores/admin-token";

type ShellAuthGateProps = {
  children: ReactNode;
};

type GateStatus = "pending" | "authed" | "guest";

function hasAdminToken(bearerToken: string | null): boolean {
  const token = bearerToken ?? readToken();
  return token != null && token.trim() !== "";
}

/**
 * Shell 路由守卫：无 Token 或 `/auth/me` 校验失败时跳转登录页。
 */
export function ShellAuthGate({ children }: ShellAuthGateProps) {
  const router = useRouter();
  const bearerToken = useAdminSessionStore((s) => s.bearerToken);
  const [status, setStatus] = useState<GateStatus>("pending");

  const setShellAuthPending = useAdminSessionStore((s) => s.setShellAuthPending);

  useEffect(() => {
    let cancelled = false;
    setShellAuthPending(true);

    async function run() {
      if (!hasAdminToken(bearerToken)) {
        if (!cancelled) {
          setStatus("guest");
        }
        return;
      }

      if (!cancelled) {
        setStatus("pending");
      }

      const ok = await verifyStoredAdminSession();
      if (cancelled) {
        return;
      }

      if (ok) {
        setStatus("authed");
        return;
      }

      setStatus("guest");
    }

    void run().finally(() => {
      if (!cancelled) {
        setShellAuthPending(false);
      }
    });

    return () => {
      cancelled = true;
      setShellAuthPending(false);
    };
  }, [bearerToken, setShellAuthPending]);

  useEffect(() => {
    if (status === "guest") {
      router.replace("/admin/login");
    }
  }, [status, router]);

  if (status === "pending") {
    return <AdminAuthCheckingScreen variant="shell" />;
  }

  if (status === "guest") {
    return null;
  }

  return children;
}