import type { RequestEvent } from "@sveltejs/kit";

const DEFAULT_ROOM = "default";

export async function maybeHandleChatWebSocket({
  event,
  params,
}: {
  event: RequestEvent;
  params: Record<string, string>;
  routePathname: string;
}) {
  const env = event.platform?.env as Env | undefined;

  if (!env) {
    return null;
  }

  const room = sanitizeRoom(params.room ?? null);
  const id = env.DO_CHAT.idFromName(room);
  const stub = env.DO_CHAT.get(id);
  const forwardUrl = new URL(
    `https://chat-do/ws-chat/${encodeURIComponent(room)}`,
  );
  const requestUrl = event.url;
  const name = requestUrl.searchParams.get("name");

  if (name) {
    forwardUrl.searchParams.set("name", name);
  }

  return stub.fetch(new Request(forwardUrl, event.request));
}

function sanitizeRoom(value: string | null) {
  const room = value
    ?.trim()
    .toLowerCase()
    .replace(/[^a-z0-9-_]/g, "-")
    .slice(0, 48);

  return room || DEFAULT_ROOM;
}