import { useEffect, useState } from "react";

const ADMIN_TOKEN_KEY = "topobench:admin-token";
const ADMIN_CHANGE_EVENT = "topobench:admin-change";

export function getAdminToken(): string | null {
  if (typeof window === "undefined") {
    return null;
  }
  return window.sessionStorage.getItem(ADMIN_TOKEN_KEY);
}

function emitChange(): void {
  if (typeof window !== "undefined") {
    window.dispatchEvent(new Event(ADMIN_CHANGE_EVENT));
  }
}

export async function validateAdminToken(token: string): Promise<boolean> {
  try {
    const response = await fetch("/api/admin/check", {
      headers: { Authorization: `Bearer ${token}` },
    });
    return response.ok;
  } catch {
    return false;
  }
}

export async function unlockAdmin(token: string): Promise<boolean> {
  const trimmed = token.trim();
  if (!trimmed) {
    return false;
  }
  const ok = await validateAdminToken(trimmed);
  if (!ok) {
    return false;
  }
  window.sessionStorage.setItem(ADMIN_TOKEN_KEY, trimmed);
  emitChange();
  return true;
}

export function lockAdmin(): void {
  if (typeof window !== "undefined") {
    window.sessionStorage.removeItem(ADMIN_TOKEN_KEY);
    emitChange();
  }
}

export function useAdmin(): { enabled: boolean; token: string | null } {
  const [token, setToken] = useState<string | null>(getAdminToken);
  useEffect(() => {
    const handler = () => setToken(getAdminToken());
    window.addEventListener(ADMIN_CHANGE_EVENT, handler);
    return () => window.removeEventListener(ADMIN_CHANGE_EVENT, handler);
  }, []);
  return { enabled: Boolean(token), token };
}

export async function adminFetch(
  input: string,
  init: RequestInit = {},
): Promise<Response> {
  const token = getAdminToken();
  const headers = new Headers(init.headers);
  if (token) {
    headers.set("Authorization", `Bearer ${token}`);
  }
  return fetch(input, { ...init, headers });
}