import { io, type Socket } from 'socket.io-client';
import type { GameSessionAuth } from '../shared/p2p-types.js';
import { PRESENCE_RETRY_MS } from '../../constants/presence.js';

export function createPresence(counter: HTMLElement) {
  let socket: Socket | undefined, sessionId = '';
  let retry: ReturnType<typeof setTimeout> | undefined;
  const unknown = () => { counter.textContent = '접속 확인 중'; };
  window.addEventListener('pagehide', () => { clearTimeout(retry); socket?.disconnect(); unknown(); });
  window.addEventListener('pageshow', () => { socket?.connect(); });
  return {
    connect(auth: GameSessionAuth) {
      if (socket && sessionId === auth.gameSessionId) { socket.connect(); return; }
      clearTimeout(retry); socket?.removeAllListeners(); socket?.disconnect(); unknown();
      sessionId = auth.gameSessionId;
      socket = io('/presence', { auth: { gameSessionId: auth.gameSessionId, token: auth.token }, forceNew: true, autoConnect: false });
      socket.on('presence:count', (count: unknown) => {
        if (Number.isSafeInteger(count) && (count as number) >= 0) counter.textContent = `현재 ${count}명 접속 중`;
      });
      socket.on('connect', () => clearTimeout(retry));
      socket.on('disconnect', unknown);
      socket.on('connect_error', error => {
        unknown(); clearTimeout(retry);
        // Middleware errors do not trigger Socket.IO's transport reconnection loop.
        if (error.message !== 'INVALID_SESSION') retry = setTimeout(() => socket?.connect(), PRESENCE_RETRY_MS);
      });
      socket.connect();
    },
  };
}