import { useEffect, useState } from 'react';
import { Link, useNavigate, useParams } from 'react-router-dom';
import { api } from '../lib/api.js';
import { getAccess, setAccess, setPlayerToken } from '../lib/session.js';

function useCode() {
  const { code } = useParams();
  const [info, setInfo] = useState(null);
  const [error, setError] = useState(null);
  useEffect(() => {
    api('/access', { method: 'POST', body: { code } }).then(setInfo).catch((e) => setError(e.message));
  }, [code]);
  return { code, info, error };
}

function alreadyPlayer(access) {
  if (!access) return false;
  if (access.kind === 'organizer') return Boolean(access.playerToken);
  return access.kind === 'player';
}

export function JoinPage() {
  const { code, info, error } = useCode();
  const navigate = useNavigate();
  const [nickname, setNickname] = useState('');
  const [steamId, setSteamId] = useState('');
  const [submitError, setSubmitError] = useState(null);
  const [busy, setBusy] = useState(false);

  useEffect(() => {
    if (!info) return;
    if (info.access === 'spectator') navigate(`/watch/${code}`, { replace: true });
    // Schon als Spieler dabei? Dann direkt zur Lobby. Organisator ohne Team und Zuschauer dürfen beitreten.
    else if (alreadyPlayer(getAccess(info.matchId))) navigate(`/m/${info.matchId}`, { replace: true });
  }, [info, code, navigate]);

  if (error) return <AccessError message={error} />;
  if (!info) return <p className="muted">Prüfe Code …</p>;

  const submit = async (e) => {
    e.preventDefault();
    setBusy(true);
    setSubmitError(null);
    try {
      const res = await api(`/matches/${info.matchId}/join`, { method: 'POST', body: { code, nickname, steamId } });
      const existing = getAccess(info.matchId);
      // Der Organisator behält seinen Zugang und bekommt den Spieler-Zugang dazu.
      if (existing?.kind === 'organizer') setPlayerToken(info.matchId, res.playerToken);
      else setAccess(info.matchId, { token: res.playerToken, kind: 'player' });
      navigate(`/m/${info.matchId}`);
    } catch (err) {
      setSubmitError(err.message);
      setBusy(false);
    }
  };

  return (
    <form className={`join-card team-${info.team}`} onSubmit={submit}>
      <p className="muted">{info.title}</p>
      <h1>Beitreten als {info.teamName}</h1>
      <label className="field">
        <span>Spielername</span>
        <input value={nickname} onChange={(e) => setNickname(e.target.value)} required minLength={2} maxLength={24} autoFocus />
      </label>
      <label className="field">
        <span>SteamID64 (optional)</span>
        <input value={steamId} onChange={(e) => setSteamId(e.target.value)} inputMode="numeric" placeholder="7656119…" pattern="\d{17}" />
        <small className="hint">Hilft dem Organisator, dich auf dem Server zuzuordnen.</small>
      </label>
      {submitError && <div className="alert alert-error">{submitError}</div>}
      <button className="btn btn-primary btn-lg" disabled={busy}>{busy ? 'Trete bei …' : `${info.teamName} beitreten`}</button>
    </form>
  );
}

export function WatchPage() {
  const { code, info, error } = useCode();
  const navigate = useNavigate();
  useEffect(() => {
    if (!info) return;
    if (info.access !== 'spectator') {
      navigate(`/join/${code}`, { replace: true });
      return;
    }
    // Spieler oder Organisator behalten ihren stärkeren Zugang.
    if (!getAccess(info.matchId)) setAccess(info.matchId, { token: code, kind: 'spectator' });
    navigate(`/m/${info.matchId}`, { replace: true });
  }, [info, code, navigate]);
  if (error) return <AccessError message={error} />;
  return <p className="muted">Öffne Zuschauerzugang …</p>;
}

function AccessError({ message }) {
  return (
    <div className="empty">
      <h2>Code nicht gültig</h2>
      <p className="muted">{message}. Prüfe den Link oder frag den Organisator nach einem neuen Code.</p>
      <Link to="/" className="btn">Zur Übersicht</Link>
    </div>
  );
}