import { useEffect, useRef, useState } from 'react';
import { io } from 'socket.io-client';
import { api } from './api.js';

let shared = null;
export function getSocket() {
  if (!shared) shared = io({ path: '/socket.io', transports: ['websocket', 'polling'] });
  return shared;
}

/** Abonniert den Live-Zustand eines Matches. Meldet sich nach jedem Reconnect neu an. */
export function useMatch(matchId, token) {
  const [state, setState] = useState(null);
  const [error, setError] = useState(null);
  const [connected, setConnected] = useState(false);
  const tokenRef = useRef(token);
  tokenRef.current = token;

  useEffect(() => {
    const socket = getSocket();
    const subscribe = () => socket.emit('match:subscribe', { matchId, token: tokenRef.current });
    const onState = (s) => {
      if (s.id !== matchId) return;
      setState(s);
      setError(null);
    };
    const onError = (e) => setError(e);
    const onConnect = () => {
      setConnected(true);
      subscribe();
    };
    const onDisconnect = () => setConnected(false);

    socket.on('match:state', onState);
    socket.on('match:error', onError);
    socket.on('connect', onConnect);
    socket.on('disconnect', onDisconnect);
    if (socket.connected) onConnect();

    // Erster Stand per REST, falls der Socket noch verbindet; neuere Socket-Stände haben Vorrang.
    let active = true;
    api(`/matches/${matchId}`, { token })
      .then((s) => active && setState((prev) => (prev && prev.updatedAt >= s.updatedAt ? prev : s)))
      .catch((e) => active && setError({ error: e.message, code: e.code }));

    return () => {
      active = false;
      socket.off('match:state', onState);
      socket.off('match:error', onError);
      socket.off('connect', onConnect);
      socket.off('disconnect', onDisconnect);
    };
  }, [matchId, token]);

  return { state, error, connected };
}

export function useOverview() {
  const [matches, setMatches] = useState(null);
  const [connected, setConnected] = useState(false);
  useEffect(() => {
    const socket = getSocket();
    const onConnect = () => {
      setConnected(true);
      socket.emit('overview:subscribe');
    };
    const onOverview = (d) => setMatches(d.matches);
    const onDisconnect = () => setConnected(false);
    socket.on('overview', onOverview);
    socket.on('connect', onConnect);
    socket.on('disconnect', onDisconnect);
    if (socket.connected) onConnect();
    return () => {
      socket.off('overview', onOverview);
      socket.off('connect', onConnect);
      socket.off('disconnect', onDisconnect);
    };
  }, []);
  return { matches, connected };
}