import { parseCookie } from "cookie";
import type { Socket } from "socket.io";
import { env } from "../config/env.js";
import { resolveAdminFromToken } from "./require-admin.js";

/**
 * `socket.io` handshake middleware guarding the admin WebSocket surface —
 * the connection-level equivalent of {@link requireAdmin} (`require-
 * admin.ts`). A `socket.io` handshake is a plain HTTP request that never
 * runs through Express's own middleware stack (`cookie-parser` included),
 * so the raw `Cookie` header has to be parsed by hand here with the
 * `cookie` package (the same one `cookie-parser` itself wraps).
 *
 * Registered via `io.use(requireAdminSocket)` — `socket.io` calls every
 * `io.use` middleware once per connection attempt, before `"connection"`
 * fires, exactly like Express's per-request middleware chain. Calling
 * `next()` with no argument admits the connection; calling it with an
 * `Error` rejects it, which the client sees as a `connect_error` event
 * (`socket.io-client` never even fires `"connect"` for it).
 *
 * On success, stashes the resolved admin on `socket.data.adminUser` —
 * `socket.io`'s per-connection storage bag, the WebSocket equivalent of
 * `res.locals` — for any handler that ends up needing it later.
 */
export async function requireAdminSocket(
  socket: Socket,
  next: (err?: Error) => void,
): Promise<void> {
  try {
    const cookieHeader = socket.handshake.headers.cookie;
    const token = cookieHeader ? parseCookie(cookieHeader)[env.ADMIN_COOKIE_NAME] : undefined;
    if (typeof token !== "string") {
      throw new Error("Not authenticated");
    }

    socket.data.adminUser = await resolveAdminFromToken(token);
    next();
  } catch {
    // Covers everything resolveAdminFromToken can throw, plus a missing
    // cookie — same "never distinguish the reason" posture as requireAdmin.
    next(new Error("Not authenticated"));
  }
}