const { useState, useEffect, useRef, useCallback } = React;

const api = {
    token: null,
    async get(url) {
        const r = await fetch(url, { headers: { 'X-Admin-Token': this.token } });
        if (!r.ok) throw new Error((await r.json().catch(() => ({}))).error || r.statusText);
        return r.json();
    },
    async post(url, data) {
        const r = await fetch(url, { method: 'POST', headers: { 'Content-Type': 'application/json', 'X-Admin-Token': this.token }, body: JSON.stringify(data) });
        if (!r.ok) throw new Error((await r.json().catch(() => ({}))).error || r.statusText);
        return r.json();
    },
};

function wsUrl() {
    return `${location.protocol === 'https:' ? 'wss:' : 'ws:'}//${location.host}`;
}

/* ================================================================== */
/*  Login                                                              */
/* ================================================================== */

function LoginPage({ onLogin }) {
    const [pw, setPw] = useState('');
    const [err, setErr] = useState('');
    const submit = async () => {
        try {
            const res = await api.post('/api/admin/login', { password: pw });
            api.token = res.token;
            onLogin(res.token);
        } catch (e) { setErr(e.message); }
    };
    return (
        <div className="min-h-screen flex items-center justify-center bg-gray-100">
            <div className="bg-white rounded-2xl shadow-lg p-8 w-full max-w-sm">
                <h1 className="text-2xl font-bold mb-6 text-center">🔐 Admin-Login</h1>
                <input type="password" className="w-full p-3 border rounded-lg mb-3 text-center" placeholder="Passwort" value={pw} onChange={(e) => setPw(e.target.value)} onKeyDown={(e) => e.key === 'Enter' && submit()} autoFocus />
                {err && <p className="text-red-500 text-sm mb-3 text-center">{err}</p>}
                <button onClick={submit} className="w-full py-3 bg-indigo-600 text-white rounded-lg font-bold hover:bg-indigo-700">Anmelden</button>
            </div>
        </div>
    );
}

/* ================================================================== */
/*  Config Page                                                        */
/* ================================================================== */

function ConfigPage({ config, setConfig, saveConfig }) {
    const [newSetName, setNewSetName] = useState('');
    const [newSetTableId, setNewSetTableId] = useState('');
    const [msg, setMsg] = useState('');

    const addSet = () => {
        if (!newSetName || !newSetTableId) return;
        const updated = {
            ...config,
            sets: [...(config.sets || []), { id: Date.now().toString(36), name: newSetName, tableId: parseInt(newSetTableId) }],
        };
        setConfig(updated);
        saveConfig(updated);
        setNewSetName('');
        setNewSetTableId('');
        setMsg('Fragenset hinzugefügt');
        setTimeout(() => setMsg(''), 2000);
    };

    const removeSet = (id) => {
        const updated = { ...config, sets: config.sets.filter((s) => s.id !== id) };
        setConfig(updated);
        saveConfig(updated);
    };

    const updateAnswersTable = (val) => {
        const updated = { ...config, answersTableId: val ? parseInt(val) : null };
        setConfig(updated);
        saveConfig(updated);
    };

    return (
        <div className="space-y-6">
            <div className="bg-white rounded-xl shadow p-6">
                <h2 className="text-xl font-bold mb-4">📋 Fragensets</h2>
                {(config.sets || []).map((s) => (
                    <div key={s.id} className="flex items-center justify-between py-2 border-b last:border-0">
                        <div><span className="font-semibold">{s.name}</span> <span className="text-gray-400 text-sm">(Table ID: {s.tableId})</span></div>
                        <button onClick={() => removeSet(s.id)} className="text-red-500 hover:text-red-700 text-sm">Entfernen</button>
                    </div>
                ))}
                <div className="mt-4 flex gap-2 flex-wrap">
                    <input className="flex-1 min-w-0 p-2 border rounded-lg" placeholder="Name" value={newSetName} onChange={(e) => setNewSetName(e.target.value)} />
                    <input className="w-32 p-2 border rounded-lg" placeholder="Table ID" type="number" value={newSetTableId} onChange={(e) => setNewSetTableId(e.target.value)} />
                    <button onClick={addSet} className="px-4 py-2 bg-indigo-600 text-white rounded-lg font-bold hover:bg-indigo-700">+</button>
                </div>
                {msg && <p className="text-green-600 text-sm mt-2">{msg}</p>}
            </div>
            <div className="bg-white rounded-xl shadow p-6">
                <h2 className="text-xl font-bold mb-4">💾 Antworten-Tabelle</h2>
                <div className="flex gap-2 items-center">
                    <span className="text-gray-600">Table ID:</span>
                    <input className="w-32 p-2 border rounded-lg" type="number" value={config.answersTableId || ''} onChange={(e) => updateAnswersTable(e.target.value)} placeholder="Table ID" />
                </div>
            </div>
        </div>
    );
}

/* ================================================================== */
/*  Stats Page                                                         */
/* ================================================================== */

function StatsPage() {
    const [data, setData] = useState(null);
    const [filter, setFilter] = useState('');

    useEffect(() => {
        api.get('/api/admin/stats').then(setData).catch(console.error);
    }, []);

    if (!data) return <p className="text-center py-8">Lade Statistiken...</p>;
    if (!data.answers.length) return <p className="text-center py-8 text-gray-500">Noch keine Ergebnisse vorhanden.</p>;

    // Group by session
    const sessions = {};
    data.answers.forEach((a) => {
        const sid = a['Session_ID'] || 'Unbekannt';
        if (!sessions[sid]) sessions[sid] = { modus: a['Modus'], fragenset: a['Fragenset'], date: a['Zeitstempel'], answers: [] };
        sessions[sid].answers.push(a);
    });

    // Group by user
    const users = {};
    data.answers.forEach((a) => {
        const u = a['Nutzername'] || 'Unbekannt';
        if (!users[u]) users[u] = { total: 0, correct: 0, points: 0 };
        users[u].total++;
        if (a['Richtig']) users[u].correct++;
        users[u].points += a['Punkte'] || 0;
    });

    return (
        <div className="space-y-6">
            <div className="bg-white rounded-xl shadow p-6">
                <h2 className="text-xl font-bold mb-4">📊 Übersicht</h2>
                <div className="grid grid-cols-3 gap-4 text-center">
                    <div className="bg-indigo-50 rounded-lg p-4">
                        <div className="text-2xl font-bold text-indigo-600">{Object.keys(sessions).length}</div>
                        <div className="text-sm text-gray-500">Sessions</div>
                    </div>
                    <div className="bg-emerald-50 rounded-lg p-4">
                        <div className="text-2xl font-bold text-emerald-600">{Object.keys(users).length}</div>
                        <div className="text-sm text-gray-500">Teilnehmer</div>
                    </div>
                    <div className="bg-amber-50 rounded-lg p-4">
                        <div className="text-2xl font-bold text-amber-600">{data.answers.length}</div>
                        <div className="text-sm text-gray-500">Antworten</div>
                    </div>
                </div>
            </div>

            <div className="bg-white rounded-xl shadow p-6">
                <h3 className="text-lg font-bold mb-3">👤 Pro Teilnehmer</h3>
                <input className="w-full p-2 border rounded-lg mb-3" placeholder="Filtern..." value={filter} onChange={(e) => setFilter(e.target.value)} />
                <div className="overflow-x-auto">
                    <table className="w-full text-sm">
                        <thead><tr className="border-b"><th className="text-left py-2">Name</th><th>Richtig</th><th>Gesamt</th><th>Quote</th><th>Punkte</th></tr></thead>
                        <tbody>
                            {Object.entries(users)
                                .filter(([u]) => !filter || u.toLowerCase().includes(filter.toLowerCase()))
                                .sort(([, a], [, b]) => b.points - a.points)
                                .map(([u, v]) => (
                                    <tr key={u} className="border-b last:border-0">
                                        <td className="py-2 font-medium">{u}</td>
                                        <td className="text-center text-green-600">{v.correct}</td>
                                        <td className="text-center">{v.total}</td>
                                        <td className="text-center">{Math.round((v.correct / v.total) * 100)}%</td>
                                        <td className="text-center font-bold">{v.points}</td>
                                    </tr>
                                ))}
                        </tbody>
                    </table>
                </div>
            </div>

            <div className="bg-white rounded-xl shadow p-6">
                <h3 className="text-lg font-bold mb-3">📁 Sessions</h3>
                {Object.entries(sessions).reverse().map(([sid, s]) => {
                    const total = s.answers.length;
                    const correct = s.answers.filter((a) => a['Richtig']).length;
                    const uniqueUsers = new Set(s.answers.map((a) => a['Nutzername'])).size;
                    return (
                        <div key={sid} className="border-b last:border-0 py-3">
                            <div className="flex justify-between">
                                <span><span className={`text-xs px-2 py-0.5 rounded-full text-white ${s.modus === 'Live' ? 'bg-indigo-600' : 'bg-emerald-600'}`}>{s.modus}</span> <strong>{s.fragenset}</strong></span>
                                <span className="text-sm text-gray-400">{s.date ? new Date(s.date).toLocaleString('de') : ''}</span>
                            </div>
                            <div className="text-sm text-gray-500 mt-1">{uniqueUsers} Teilnehmer — {correct}/{total} richtig gesamt</div>
                        </div>
                    );
                })}
            </div>
        </div>
    );
}

/* ================================================================== */
/*  Live Setup Page                                                    */
/* ================================================================== */

function LiveSetupPage({ config, token, onSessionCreated }) {
    const [setId, setSetId] = useState('');
    const [shuffle, setShuffle] = useState(true);
    const [scoring, setScoring] = useState('binary');
    const [timeLimit, setTimeLimit] = useState(30);
    const [error, setError] = useState('');
    const [loading, setLoading] = useState(false);

    const create = () => {
        if (!setId) return setError('Bitte ein Fragenset waehlen');
        setLoading(true);
        setError('');
        const ws = new WebSocket(wsUrl());
        ws.onopen = () => {
            ws.send(JSON.stringify({ type: 'admin-create', token, setId, options: { shuffle, scoring, timeLimit } }));
        };
        ws.onmessage = (e) => {
            const msg = JSON.parse(e.data);
            if (msg.type === 'session-created') {
                onSessionCreated(msg.code, ws);
            } else if (msg.type === 'error') {
                setError(msg.message);
                setLoading(false);
                ws.close();
            }
        };
        ws.onerror = () => { setError('WebSocket Fehler'); setLoading(false); };
    };

    return (
        <div className="bg-white rounded-xl shadow p-6 max-w-md mx-auto">
            <h2 className="text-xl font-bold mb-4">🎮 Live-Session erstellen</h2>
            <div className="space-y-4">
                <div>
                    <label className="block text-sm font-medium mb-1">Fragenset</label>
                    <select className="w-full p-3 border rounded-lg" value={setId} onChange={(e) => setSetId(e.target.value)}>
                        <option value="">— Bitte wählen —</option>
                        {(config.sets || []).map((s) => <option key={s.id} value={s.id}>{s.name}</option>)}
                    </select>
                </div>
                <label className="flex items-center gap-2 cursor-pointer">
                    <input type="checkbox" checked={shuffle} onChange={() => setShuffle(!shuffle)} className="w-5 h-5 accent-indigo-600" />
                    Fragen mischen
                </label>
                <div>
                    <label className="block text-sm font-medium mb-1">Punktevergabe</label>
                    <select className="w-full p-3 border rounded-lg" value={scoring} onChange={(e) => setScoring(e.target.value)}>
                        <option value="binary">Binär (1000 / 0)</option>
                        <option value="time">Zeitbasiert (schneller = mehr Punkte)</option>
                    </select>
                </div>
                {scoring === 'time' && (
                    <div>
                        <label className="block text-sm font-medium mb-1">Sekunden pro Frage</label>
                        <input type="number" className="w-full p-3 border rounded-lg" value={timeLimit} onChange={(e) => setTimeLimit(parseInt(e.target.value) || 30)} min={5} max={120} />
                    </div>
                )}
                {error && <p className="text-red-500 text-sm">{error}</p>}
                <button onClick={create} disabled={loading} className="w-full py-3 bg-indigo-600 text-white rounded-lg font-bold hover:bg-indigo-700 disabled:opacity-50">
                    {loading ? 'Erstelle...' : 'Session erstellen'}
                </button>
            </div>
        </div>
    );
}

/* ================================================================== */
/*  Live Control Page                                                  */
/* ================================================================== */

function LiveControlPage({ token, code, ws }) {
    const [session, setSession] = useState(null);
    const [phase, setPhase] = useState('waiting');
    const [answerCount, setAnswerCount] = useState(0);
    const [result, setResult] = useState(null);
    const [leaderboardData, setLeaderboardData] = useState([]);

    useEffect(() => {
        if (!ws) return;

        const handler = (e) => {
            const msg = JSON.parse(e.data);
            switch (msg.type) {
                case 'session-created':
                    setSession({ code: msg.code, setName: msg.setName, questionCount: msg.questionCount, options: msg.options });
                    break;
                case 'admin-joined':
                    setSession(msg.session);
                    if (msg.session.status === 'waiting') setPhase('waiting');
                    else if (msg.session.status === 'ended') setPhase('ended');
                    else setPhase('active');
                    setLeaderboardData(msg.session.leaderboard);
                    break;
                case 'player-joined':
                case 'player-left':
                    setSession((s) => s ? { ...s, players: msg.players, playerCount: msg.playerCount } : s);
                    break;
                case 'game-start':
                    setPhase('active');
                    break;
                case 'question':
                    setPhase('question');
                    setAnswerCount(0);
                    setResult(null);
                    break;
                case 'answer-count':
                    setAnswerCount(msg.count);
                    break;
                case 'question-result':
                    setResult(msg);
                    setLeaderboardData(msg.leaderboard);
                    setPhase('result');
                    break;
                case 'game-end':
                    setLeaderboardData(msg.leaderboard);
                    setPhase('ended');
                    break;
            }
        };

        ws.addEventListener('message', handler);
        return () => ws.removeEventListener('message', handler);
    }, [ws]);

    const start = () => ws.send(JSON.stringify({ type: 'admin-start', token, code }));
    const next = () => ws.send(JSON.stringify({ type: 'admin-next', token, code }));
    const end = () => ws.send(JSON.stringify({ type: 'admin-end', token, code }));
    const showResult = () => {
        // Force show result by telling server (same as next but for current question)
        // We can reuse admin-next if status is 'active' → actually we need showResult
        // For now, the master clicks "weiter" after everyone answered or time is up
    };

    const presentUrl = `${location.origin}/present#${code}`;

    return (
        <div className="space-y-4 max-w-lg mx-auto">
            <div className="bg-white rounded-xl shadow p-6 text-center">
                <h2 className="text-xl font-bold mb-2">Session-Code</h2>
                <div className="text-5xl font-mono font-extrabold tracking-widest text-indigo-600 mb-2">{code}</div>
                <p className="text-gray-400 text-sm">{session?.setName} — {session?.questionCount || '?'} Fragen</p>
                <a href={presentUrl} target="_blank" rel="noopener" className="inline-block mt-2 text-sm text-indigo-500 hover:underline">📺 Präsentations-Fenster öffnen</a>
            </div>

            <div className="bg-white rounded-xl shadow p-6">
                <h3 className="font-bold mb-2">Teilnehmer ({session?.players?.length || 0})</h3>
                <div className="flex flex-wrap gap-2">
                    {(session?.players || []).map((n) => <span key={n} className="px-3 py-1 bg-gray-100 rounded-full text-sm">{n}</span>)}
                </div>
            </div>

            {phase === 'waiting' && (
                <button onClick={start} disabled={!session?.players?.length} className="w-full py-4 bg-green-600 text-white rounded-xl text-xl font-bold hover:bg-green-700 disabled:opacity-50">
                    ▶ Quiz starten
                </button>
            )}

            {phase === 'question' && (
                <div className="bg-white rounded-xl shadow p-6 text-center">
                    <p className="text-lg mb-2">Antworten: <strong>{answerCount}</strong> / {session?.players?.length || 0}</p>
                    <button onClick={next} className="w-full py-3 bg-indigo-600 text-white rounded-xl font-bold hover:bg-indigo-700 mt-2">Ergebnis zeigen ➜</button>
                </div>
            )}

            {phase === 'result' && (
                <div className="bg-white rounded-xl shadow p-6">
                    <h3 className="font-bold text-center mb-3">Ergebnis</h3>
                    {result?.stats && (
                        <div className="grid grid-cols-2 gap-2 mb-4">
                            {Object.entries(result.stats).map(([k, v]) => (
                                <div key={k} className={`p-2 rounded-lg text-white text-center ${k === 'A' ? 'bg-red-500' : k === 'B' ? 'bg-blue-500' : k === 'C' ? 'bg-amber-500' : 'bg-green-500'}`}>
                                    {k}: <strong>{v}</strong>
                                </div>
                            ))}
                        </div>
                    )}
                    <p className="text-center text-sm text-gray-400 mb-2">Richtig: {result?.correctAnswer?.join(', ')}</p>
                    <button onClick={next} className="w-full py-3 bg-indigo-600 text-white rounded-xl font-bold hover:bg-indigo-700">Nächste Frage ➜</button>
                </div>
            )}

            {phase === 'ended' && (
                <div className="bg-white rounded-xl shadow p-6 text-center">
                    <h3 className="text-xl font-bold mb-4">🏁 Quiz beendet</h3>
                </div>
            )}

            {leaderboardData.length > 0 && (
                <div className="bg-white rounded-xl shadow p-6">
                    <h3 className="font-bold mb-2 text-center">🏆 Leaderboard</h3>
                    {leaderboardData.map((e) => (
                        <div key={e.name} className="flex justify-between py-2 px-3 bg-gray-50 rounded-lg mb-1">
                            <span>{e.rank}. {e.name}</span><span className="font-bold">{e.score}</span>
                        </div>
                    ))}
                </div>
            )}

            {phase !== 'ended' && phase !== 'waiting' && (
                <button onClick={end} className="w-full py-3 bg-red-500 text-white rounded-xl font-bold hover:bg-red-600">⏹ Session beenden</button>
            )}
        </div>
    );
}

/* ================================================================== */
/*  Admin App                                                          */
/* ================================================================== */

function AdminApp() {
    const [token, setToken] = useState(null);
    const [tab, setTab] = useState('config');
    const [config, setConfig] = useState({ sets: [], answersTableId: null });
    const [liveCode, setLiveCode] = useState(null);
    const [liveWs, setLiveWs] = useState(null);

    useEffect(() => {
        if (token) {
            api.token = token;
            api.get('/api/admin/config').then(setConfig).catch(console.error);
        }
    }, [token]);

    const saveConfig = async (c) => {
        try { await api.post('/api/admin/config', c); } catch (e) { console.error(e); }
    };

    const handleSessionCreated = (code, ws) => {
        setLiveCode(code);
        setLiveWs(ws);
        setTab('live-control');
    };

    if (!token) return <LoginPage onLogin={setToken} />;

    const tabs = [
        { id: 'config', label: '⚙️ Konfiguration' },
        { id: 'live', label: '🎮 Live-Session' },
        { id: 'stats', label: '📊 Statistiken' },
    ];
    if (liveCode) tabs.splice(2, 0, { id: 'live-control', label: '🎛️ Steuerung' });

    return (
        <div className="min-h-screen bg-gray-100">
            <div className="bg-white shadow">
                <div className="max-w-3xl mx-auto px-4 py-3 flex items-center justify-between">
                    <h1 className="text-xl font-bold">⚡ Quizalarm Admin</h1>
                    <a href="/" className="text-gray-400 hover:text-gray-600 text-sm">← Zur App</a>
                </div>
                <div className="max-w-3xl mx-auto px-4 flex gap-1 overflow-x-auto">
                    {tabs.map((t) => (
                        <button key={t.id} onClick={() => setTab(t.id)} className={`px-4 py-2 text-sm font-medium rounded-t-lg whitespace-nowrap ${tab === t.id ? 'bg-gray-100 text-indigo-600 border-b-2 border-indigo-600' : 'text-gray-500 hover:text-gray-700'}`}>{t.label}</button>
                    ))}
                </div>
            </div>
            <div className="max-w-3xl mx-auto p-4">
                {tab === 'config' && <ConfigPage config={config} setConfig={setConfig} saveConfig={saveConfig} />}
                {tab === 'live' && <LiveSetupPage config={config} token={token} onSessionCreated={handleSessionCreated} />}
                {tab === 'live-control' && <LiveControlPage token={token} code={liveCode} ws={liveWs} />}
                {tab === 'stats' && <StatsPage />}
            </div>
        </div>
    );
}

ReactDOM.createRoot(document.getElementById('root')).render(<AdminApp />);