import { useCallback, useEffect, useState } from 'react';
import { Link, useParams } from 'react-router-dom';
import { api } from '../lib/api.js';
import { FORMAT_LABEL, ROLE_LABEL, serverLabel } from '../lib/labels.js';
import { clearAccess, getPlayerToken, getToken, setAccess, setPlayerToken } from '../lib/session.js';
import { useMatch } from '../lib/useMatch.js';
import TeamCard from '../components/TeamCard.jsx';
import VetoBoard from '../components/VetoBoard.jsx';
import ServerPanel from '../components/ServerPanel.jsx';
import OrganizerPanel from '../components/OrganizerPanel.jsx';
import SeriesList from '../components/SeriesList.jsx';
import EventLog from '../components/EventLog.jsx';
import MapImage from '../components/MapImage.jsx';
import SelfJoin from '../components/SelfJoin.jsx';

export default function MatchPage() {
  const { id } = useParams();
  const [token, setToken] = useState(() => {
    // Organisator-Link für ein weiteres Gerät: /m/<id>#org=<token>
    const hash = new URLSearchParams(window.location.hash.slice(1));
    const org = hash.get('org');
    if (org) {
      setAccess(id, { token: org, kind: 'organizer' });
      window.history.replaceState(null, '', window.location.pathname);
    }
    return getToken(id);
  });
  // Spieler-Token des Organisators, wenn er im selben Browser selbst mitspielt
  const [playerToken, setPlayerTokenState] = useState(() => getPlayerToken(id));
  const { state, error, connected } = useMatch(id, token, playerToken);
  const [busy, setBusy] = useState(null);
  const [toast, setToast] = useState(null);

  // Gespeicherter Zugang ist ungültig geworden (z. B. aus dem Team entfernt)
  const lostAccess = state && token && state.viewer.role === 'public';
  useEffect(() => {
    if (lostAccess) {
      clearAccess(id);
      setToken(null);
      setToast({ tone: 'error', text: 'Dein gespeicherter Zugang ist nicht mehr gültig. Tritt mit deinem Teamcode erneut bei.' });
    }
  }, [lostAccess, id]);

  // Organisator war Spieler, ist es aber nicht mehr (Team verlassen oder entfernt)
  // justJoined: bis der erste Zustand mit Spieler ankommt, ist ein Zustand ohne Spieler noch veraltet
  const [justJoined, setJustJoined] = useState(false);
  useEffect(() => {
    if (state?.viewer.playerId) setJustJoined(false);
  }, [state]);
  const lostPlayer = state && playerToken && !justJoined && state.viewer.isOrganizer && !state.viewer.playerId;
  useEffect(() => {
    if (lostPlayer) {
      setPlayerToken(id, null);
      setPlayerTokenState(null);
    }
  }, [lostPlayer, id]);

  const joinAsOrganizer = useCallback((newPlayerToken) => {
    setJustJoined(true);
    setPlayerToken(id, newPlayerToken);
    setPlayerTokenState(newPlayerToken);
  }, [id]);

  useEffect(() => {
    if (!toast) return undefined;
    const t = setTimeout(() => setToast(null), 6000);
    return () => clearTimeout(t);
  }, [toast]);

  /** Führt eine Aktion aus; verhindert Doppelklicks, solange sie läuft. */
  const act = useCallback(async (path, body, success) => {
    if (busy) return;
    setBusy(path);
    try {
      await api(`/matches/${id}/${path}`, { method: 'POST', body: body ?? {}, token, playerToken });
      if (success) setToast({ tone: 'ok', text: success });
    } catch (err) {
      setToast({ tone: 'error', text: err.message });
    } finally {
      setBusy(null);
    }
  }, [busy, id, token, playerToken]);

  if (error && !state) {
    return (
      <div className="empty">
        <h2>{error.code === 'not_found' ? 'Match nicht gefunden' : 'Fehler'}</h2>
        <p className="muted">{error.error}</p>
        <Link to="/" className="btn">Zur Übersicht</Link>
      </div>
    );
  }
  if (!state) return <p className="muted">Verbinde mit Lobby …</p>;

  const { viewer } = state;
  const isOrg = viewer.isOrganizer;
  const server = serverLabel(state.server);
  const ctx = { state, act, busy, isOrg, viewer, matchId: id, onJoined: joinAsOrganizer };

  return (
    <div className="match">
      {connected === false && <div className="reconnect">Verbindung unterbrochen – stelle wieder her …</div>}
      {toast && <div className={`toast toast-${toast.tone}`} role="status">{toast.text}</div>}

      <header className="match-head">
        <div className="versus">
          <h1>
            <span className="team-a">{state.teams.A.name}</span>
            {state.series.length > 1 ? (
              <span className="series-total" title="Serienstand (gewonnene Maps)">
                {state.seriesScore.A}<span className="colon">:</span>{state.seriesScore.B}
              </span>
            ) : (
              <span className="vs">vs.</span>
            )}
            <span className="team-b">{state.teams.B.name}</span>
          </h1>
        </div>
        <dl className="match-facts">
          <div><dt>Modus</dt><dd>{state.modeLabel}</dd></div>
          <div><dt>Serie</dt><dd>{FORMAT_LABEL[state.format]}</dd></div>
          <div><dt>Status</dt><dd>{state.statusLabel}</dd></div>
          <div><dt>Server</dt><dd className={`tone-${server.tone}`}>{server.text}</dd></div>
          <div><dt>Du bist</dt><dd>{describeViewer(viewer, state.teams)}</dd></div>
        </dl>
      </header>

      {viewer.role === 'public' && <PublicNotice />}

      <div className={`match-grid ${state.status !== 'lobby' && viewer.role !== 'public' ? 'stage-wide' : ''}`}>
        <TeamCard team={state.teams.A} side="A" {...ctx} />
        <section className="stage">
          <Stage {...ctx} />
        </section>
        <TeamCard team={state.teams.B} side="B" {...ctx} />
      </div>

      {viewer.role !== 'public' && (
        <div className="match-lower">
          <ServerPanel {...ctx} />
          {isOrg && <OrganizerPanel {...ctx} token={token} />}
          <EventLog events={state.events} />
        </div>
      )}
    </div>
  );
}

/** z. B. "Organisator, Captain bei Nordlicht" oder "Spieler bei Hafenkante" */
function describeViewer(viewer, teams) {
  const team = viewer.team ? teams[viewer.team].name : null;
  const asPlayer = team ? `${viewer.isCaptain ? 'Captain' : 'Spieler'} bei ${team}` : null;
  if (viewer.isOrganizer) return asPlayer ? `Organisator, ${asPlayer}` : 'Organisator';
  return asPlayer ?? ROLE_LABEL[viewer.role];
}

function Stage(ctx) {
  const { state, isOrg, act, busy } = ctx;
  if (state.viewer.role === 'public') {
    return <div className="stage-note"><h2>{state.statusLabel}</h2><p className="muted">Details sehen nur Teilnehmer.</p></div>;
  }
  if (state.status === 'lobby') {
    const { A, B } = state.teams;
    const missing = [A, B].filter((t) => !t.readiness.ready);
    return (
      <div className="stage-note">
        <h2>{missing.length === 0 ? 'Beide Teams sind bereit' : 'Warten auf beide Teams'}</h2>
        {missing.length > 0 && (
          <ul className="missing-list">
            {missing.map((t) => <li key={t.key}><strong className={`team-${t.key.toLowerCase()}`}>{t.name}:</strong> {readinessGap(t, state.requireFullTeams)}</li>)}
          </ul>
        )}
        {isOrg ? (
          <>
            <button className="btn btn-primary btn-lg" disabled={!state.canStartVeto || !!busy}
              onClick={() => act('veto/start', null, 'Veto gestartet')}>
              Veto starten
            </button>
            {!state.canStartVeto && <p className="small muted">Der Knopf wird aktiv, sobald beide Teams bereit sind.</p>}
          </>
        ) : (
          <p className="small muted">
            {missing.length === 0
              ? 'Der Organisator kann das Veto jetzt starten.'
              : 'Sobald beide Teams bereit sind, startet der Organisator das Veto.'}
          </p>
        )}
        {isOrg && !state.viewer.playerId && <SelfJoin state={state} matchId={ctx.matchId} onJoined={ctx.onJoined} />}
        <MapPoolPreview maps={state.maps} />
      </div>
    );
  }
  if (state.status === 'veto') return <VetoBoard {...ctx} />;
  return (
    <>
      <SeriesList {...ctx} />
      <VetoBoard {...ctx} compact />
    </>
  );
}

/** Sagt konkret, was einem Team noch fehlt, damit es als bereit gilt. */
function readinessGap(team, requireFull) {
  const r = team.readiness;
  const gaps = [];
  if (!r.enough) {
    const need = requireFull ? team.teamSize - r.count : 1;
    gaps.push(requireFull
      ? `noch ${need} von ${team.teamSize} Spielern fehlen (Team muss vollständig sein)`
      : 'mindestens ein Spieler fehlt');
  }
  if (r.count > 0 && !r.allReady) gaps.push('noch nicht alle haben „bereit“ geklickt');
  if (r.count > 0 && !r.hasCaptain) gaps.push('kein Captain');
  return gaps.join(', ');
}

function MapPoolPreview({ maps }) {
  return (
    <div className="pool-preview" aria-label="Map-Pool">
      {maps.map((m) => (
        <span key={m.id} className="pool-chip" style={{ '--map': m.color ?? '#556' }}>
          <MapImage map={m} />
          <span className="pool-chip-name">{m.name}</span>
        </span>
      ))}
    </div>
  );
}

function PublicNotice() {
  return (
    <div className="alert">
      Du siehst diese Lobby ohne Zugang. Spieler treten über den Einladungslink ihres Teams bei,
      Zuschauer über den Zuschauerlink. Beides bekommst du vom Organisator.
    </div>
  );
}