// ── Settings: Logs ────────────────────────────────────────────────────────

let _logsLiveTimer = null;
let _logsActiveLevel = '';

function escLog(s) { return String(s).replace(/[&<>]/g, c => ({'&':'&amp;','<':'&lt;','>':'&gt;'}[c])); }

window.loadSettingsLogs = async function() {
  const viewer = $('s-log-viewer');
  if (!viewer) return;
  try {
    const data = await fetch('/api/logs?limit=300').then(r => r.json());
    const items = (data.items || []).filter(item =>
      !_logsActiveLevel || item.level === _logsActiveLevel
    );
    const count = $('s-log-count');
    if (count) count.textContent = items.length + ' entries';
    if (!items.length) {
      viewer.innerHTML = '<div class="s-log-empty">No log entries</div>';
      return;
    }
    viewer.innerHTML = items.map(item => {
      const ts = item.ts ? item.ts.replace('T', ' ').replace(/\.\d+Z$/, ' UTC') : '';
      return `<div class="s-log-row">
        <span class="s-log-ts">${escLog(ts)}</span>
        <span class="s-log-level ${escLog(item.level)}">${escLog(item.level)}</span>
        <span class="s-log-msg">${escLog(item.msg)}</span>
      </div>`;
    }).join('');
  } catch(e) {
    viewer.innerHTML = `<div class="s-log-empty">Failed to load logs: ${escLog(e.message)}</div>`;
  }
};

$('s-logs-refresh-btn')?.addEventListener('click', () => loadSettingsLogs());

$('s-logs-clear-btn')?.addEventListener('click', async () => {
  await fetch('/api/logs', { method: 'DELETE' });
  const viewer = $('s-log-viewer');
  if (viewer) viewer.innerHTML = '<div class="s-log-empty">Logs cleared</div>';
  const count = $('s-log-count');
  if (count) count.textContent = '';
});

$('s-logs-live-toggle')?.addEventListener('change', function() {
  clearInterval(_logsLiveTimer);
  if (this.checked) {
    loadSettingsLogs();
    _logsLiveTimer = setInterval(loadSettingsLogs, 3000);
  }
});

document.querySelectorAll('.s-log-filter').forEach(btn => {
  btn.addEventListener('click', function() {
    document.querySelectorAll('.s-log-filter').forEach(b => b.classList.remove('is-active'));
    this.classList.add('is-active');
    _logsActiveLevel = this.dataset.logLevel;
    loadSettingsLogs();
  });
});

// ── Settings: About ───────────────────────────────────────────────────────

// Fetch and display the server version in the About page
(async function loadAppVersion() {
  try {
    const d = await fetch('/api/version').then(r => r.json());
    const el = $('s-about-version');
    if (el && d.version) el.textContent = 'v' + d.version;
  } catch (_) {}
})();

// Lazy-load changelog when the details element is opened
$('about-changelog-details')?.addEventListener('toggle', async function () {
  if (!this.open) return;
  const content = $('about-changelog-content');
  const status = $('about-changelog-status');
  if (!content || content.textContent.trim()) return;
  if (status) status.textContent = 'Loading…';
  try {
    const text = await fetch('/api/changelog').then(r => r.ok ? r.text() : Promise.reject(r.status));
    content.textContent = text;
    if (status) status.textContent = '';
  } catch(e) {
    content.textContent = 'Could not load changelog: ' + e;
    if (status) status.textContent = 'error';
  }
});

function renderSettingsAbout() {
  const el = $('s-about-backends');
  if (!el) return;
  const available = new Set((_ttsBackends || []).filter(b => b.available).map(b => b.id));
  const all = (_ttsBackends || []);
  if (!all.length) { el.innerHTML = ''; return; }
  el.innerHTML = all.map(b => {
    const online = available.has(b.id);
    return `<span class="s-about-backend ${online ? 'online' : 'offline'}">
      <span class="mdi mdi-speaker-outline"></span>${escHtml(b.label)}
      <span class="mdi ${online ? 'mdi-check-circle-outline' : 'mdi-close-circle-outline'}"></span>
    </span>`;
  }).join('');
}

// ── Voices import ──────────────────────────────────────────────────────────

$('s-import-voices-file')?.addEventListener('change', async function () {
  const file = this.files?.[0];
  if (!file) return;
  const st = $('s-import-status');
  if (st) st.textContent = 'Uploading…';
  try {
    const fd = new FormData();
    fd.append('file', file);
    const r = await fetch('/api/voices/import', { method:'POST', body: fd });
    if (!r.ok) { const e = await r.json().catch(()=>({})); throw new Error(e.detail || r.statusText); }
    const d = await r.json();
    if (st) st.textContent = `Imported ${d.imported} files.`;
    toast(`Imported ${d.imported} voice files`, 'success');
    this.value = '';
  } catch(e) {
    if (st) st.textContent = 'Import failed.';
    toast('Import failed: ' + e.message, 'error');
  }
});

// ── Conversation Playground ────────────────────────────────────────────────

(function initConversationPlayground() {
  const chatWindow    = $('conv-chat-window');
  const micBtn        = $('conv-mic-btn');
  const micIcon       = $('conv-mic-icon');
  const micStatus     = $('conv-mic-status');
  const micTimer      = $('conv-mic-timer');
  const textInput     = $('conv-text-input');
  const sendBtn       = $('conv-send-btn');
  const clearBtn      = $('conv-clear-btn');
  const sttSel        = $('conv-stt-select');
  const llmUrlInp     = $('conv-llm-url');
  const llmFetchBtn   = $('conv-llm-fetch-btn');
  const llmModelSel   = $('conv-llm-model-select');
  const ttsBkSel      = $('conv-tts-backend-select');
  const ttsFetchBtn   = $('conv-tts-fetch-btn');
  const ttsVoiceSel   = $('conv-tts-voice-select');
  const systemPrompt  = $('conv-system-prompt');
  const turnHistory   = $('conv-turn-history');
  if (!chatWindow || !micBtn) return;

  // Warn if microphone API is unavailable (HTTP on non-localhost = insecure context)
  if (!navigator.mediaDevices?.getUserMedia) {
    if (micStatus) {
      micStatus.textContent = 'Mic unavailable — insecure context';
      micStatus.style.color = 'var(--red, #e05)';
    }
    if (micBtn) {
      micBtn.disabled = true;
      micBtn.title = 'Browser blocks microphone on HTTP. Use http://localhost:7890 or HTTPS.\n' +
                     'Chrome fix: chrome://flags/#unsafely-treat-insecure-origin-as-secure';
      micBtn.style.opacity = '0.4';
    }
    const flagsUrl = 'chrome://flags/#unsafely-treat-insecure-origin-as-secure';
    const warn = document.createElement('div');
    warn.style.cssText = 'background:var(--red,#c00);color:#fff;padding:12px 16px;border-radius:8px;margin:0 0 12px;font-size:13px;line-height:1.7;flex-shrink:0';
    warn.innerHTML =
      '<strong>⚠ Microphone blocked by browser</strong><br>' +
      'Browsers only allow microphone access on <b>secure contexts</b> (HTTPS or localhost).<br>' +
      'Quick fix: open the app at <b>http://localhost:7890</b> instead of the IP address.<br>' +
      'Remote access fix: add the URL in Chrome flags:<br>' +
      '<div style="display:flex;align-items:center;gap:8px;margin-top:6px">' +
        `<code style="flex:1;background:rgba(0,0,0,.35);color:#fff;border-radius:4px;padding:4px 8px;font-size:12px;word-break:break-all;font-family:monospace">${flagsUrl}</code>` +
        `<button onclick="navigator.clipboard?.writeText('${flagsUrl}').then(()=>{this.textContent='Copied!';setTimeout(()=>this.textContent='Copy',1500)})" ` +
          'style="flex-shrink:0;background:rgba(255,255,255,.2);border:1px solid rgba(255,255,255,.45);color:#fff;border-radius:4px;padding:4px 10px;font-size:12px;cursor:pointer;font-weight:600">Copy</button>' +
      '</div>';
    // Insert inside the chat window so it scrolls with the conversation and
    // never pushes the input bar off-screen.
    if (chatWindow) chatWindow.prepend(warn);
  }

  // Restore conv LLM URL from server settings
  if (llmUrlInp && _appSettings && _appSettings.conv_llm_url) llmUrlInp.value = _appSettings.conv_llm_url;
  if (llmUrlInp) llmUrlInp.addEventListener('input', () => {
    _patchSettings({ conv_llm_url: llmUrlInp.value });
    if (_appSettings) _appSettings.conv_llm_url = llmUrlInp.value;
  });

  let mediaRecorder = null;
  let recChunks = [];
  let recTimerInterval = null;
  let recStart = 0;
  let conversationHistory = [];
  let turnCount = 0;
  let isProcessing = false;
  let vadAudioCtx = null;
  let vadRafId = null;
  let liveInterimText = '';
  let speechRec = null;
  const VAD_THRESHOLD = 0.02;   // raised to ignore background noise
  const VAD_MIN_REC_MS = 800;   // wait 800ms before VAD starts checking (avoids click/noise at start)
  const VAD_SILENCE_MS = 1000;
  const INTERRUPT_THRESHOLD = 0.04;  // higher than VAD to avoid echo triggering interruption
  const INTERRUPT_HOLD_MS  = 350;    // speech must persist this long to interrupt
  // Whisper hallucinations on silence/noise — discard these from the live preview
  const HALLUCINATION_RE = /^(reich|danke\s*(schön)?|vielen\s*dank|thank\s*you|thanks|you|copyright|abonnieren|untertitel|zарегистрируйтесь)[.!?,\s]*$/i;
  const origPlaceholder = textInput?.placeholder || '';
  const vadToggle       = $('conv-vad-toggle');
  const handsFreeToggle = $('conv-handsfree-toggle');
  let previewTranscribing = false;
  let convCurrentAudio = null;
  let autoMicGeneration = 0;
  const audioQueue = [];
  let audioQueuePlaying = false;
  let audioQueueDrainCb = null;
  let interruptCtx = null;
  let interruptRafId = null;
  let interruptStream = null;
  let interruptSpeechStart = 0;
  let vadHadSpeech = false;         // true once RMS crossed threshold during this recording
  let vadLastVoiceMs = 0;           // last timestamp speech was detected (for preview gate)
  let cancelNextBlob = false;       // set by VAD when no speech was detected → skip STT
  let convCurrentSentenceBubble = null; // assistant bubble to update with current TTS sentence

  // ── Populate STT backends ────────────────────────────────────────────────
  async function loadConvSttBackends() {
    if (!sttSel) return;
    const prev = sttSel.value;
    try {
      const d = await fetch('/api/stt-backends').then(r => r.json());
      const all = d.backends || [];
      if (!all.length) {
        sttSel.innerHTML = '<option value="configured">Default (configured)</option>';
        return;
      }
      sttSel.innerHTML = all.map(b => {
        const icon = b.available ? '✓' : '✗';
        const label = `${icon} ${escHtml(b.label)}`;
        const disabled = !b.available;
        return `<option value="${escHtml(b.id)}"${disabled ? ' disabled' : ''}>${label}</option>`;
      }).join('');
      // Restore prev selection or pick first available
      const opt = sttSel.querySelector(`option[value="${CSS.escape(prev)}"]`);
      if (opt && !opt.disabled) { sttSel.value = prev; }
      else {
        const first = sttSel.querySelector('option:not([disabled])');
        if (first) sttSel.value = first.value;
      }
    } catch(_) {
      sttSel.innerHTML = '<option value="configured">Default (configured)</option>';
    }
  }

  // ── Populate TTS backends (reuse global _ttsBackends) ───────────────────
  function populateConvTtsBackends() {
    if (!ttsBkSel) return;
    const prev = ttsBkSel.value;
    const all = _ttsBackends || [];
    if (!all.length) {
      ttsBkSel.innerHTML = '<option value="">No TTS backend available</option>';
      return;
    }
    ttsBkSel.innerHTML = all.map(b => {
      const icon = b.available ? '✓' : '✗';
      return `<option value="${escHtml(b.id)}"${!b.available ? ' disabled' : ''}>${icon} ${escHtml(b.label)}</option>`;
    }).join('');
    const opt = ttsBkSel.querySelector(`option[value="${CSS.escape(prev)}"]`);
    if (opt && !opt.disabled) { ttsBkSel.value = prev; }
    else {
      const first = ttsBkSel.querySelector('option:not([disabled])');
      if (first) ttsBkSel.value = first.value;
    }
  }

  // ── Fetch LLM models ─────────────────────────────────────────────────────
  async function fetchLlmModels() {
    if (!llmModelSel) return;
    const url = llmUrlInp?.value.trim() || '';
    llmFetchBtn.disabled = true;
    try {
      const d = await fetch('/api/conversation/llm-models' + (url ? '?url=' + encodeURIComponent(url) : '')).then(r => r.json());
      const models = d.models || [];
      llmModelSel.innerHTML = models.length
        ? models.map(m => `<option value="${escHtml(m)}">${escHtml(m)}</option>`).join('')
        : '<option value="">No models found</option>';
    } catch(e) {
      llmModelSel.innerHTML = '<option value="">Fetch failed</option>';
    } finally {
      llmFetchBtn.disabled = false;
    }
  }

  // ── Fetch TTS voices ─────────────────────────────────────────────────────
  async function fetchConvTtsVoices() {
    if (!ttsVoiceSel || !ttsBkSel) return;
    const backend = ttsBkSel.value;
    if (!backend) return;
    ttsFetchBtn.disabled = true;
    try {
      const rawVoices = await fetch('/api/tts-voices?backend=' + encodeURIComponent(backend)).then(r => r.json());
      ttsVoiceSel.innerHTML = rawVoices.length
        ? rawVoices.map(v => { const id = backendVoiceId(v); return `<option value="${escHtml(id)}">${escHtml(id)}</option>`; }).join('')
        : '<option value="">No voices</option>';
    } catch(e) {
      ttsVoiceSel.innerHTML = '<option value="">Fetch failed</option>';
    } finally {
      ttsFetchBtn.disabled = false;
    }
  }

  // ── Chat bubble helpers ──────────────────────────────────────────────────
  function timeStr() {
    const now = new Date();
    return now.getHours().toString().padStart(2,'0') + ':' + now.getMinutes().toString().padStart(2,'0');
  }

  function removeWelcome() {
    const w = chatWindow.querySelector('.conv-chat-welcome');
    if (w) w.remove();
  }

  function addBubble(role, text) {
    removeWelcome();
    const wrap = document.createElement('div');
    wrap.className = `conv-bubble-wrap conv-bubble-wrap--${role}`;
    const bubble = document.createElement('div');
    bubble.className = `conv-bubble conv-bubble--${role}`;
    bubble.textContent = text || '';
    const meta = document.createElement('div');
    meta.className = 'conv-bubble-meta';
    meta.textContent = timeStr();
    wrap.appendChild(bubble);
    wrap.appendChild(meta);
    chatWindow.appendChild(wrap);
    chatWindow.scrollTop = chatWindow.scrollHeight;
    return bubble;
  }

  function addTypingBubble() {
    removeWelcome();
    const wrap = document.createElement('div');
    wrap.className = 'conv-bubble-wrap conv-bubble-wrap--assistant';
    wrap.id = 'conv-typing-wrap';
    const bubble = document.createElement('div');
    bubble.className = 'conv-bubble conv-bubble--assistant';
    bubble.innerHTML = '<span class="conv-typing"><span></span><span></span><span></span></span>';
    wrap.appendChild(bubble);
    chatWindow.appendChild(wrap);
    chatWindow.scrollTop = chatWindow.scrollHeight;
    return bubble;
  }

  function addErrorBubble(msg) {
    removeWelcome();
    const wrap = document.createElement('div');
    wrap.className = 'conv-bubble-wrap conv-bubble-wrap--assistant';
    const bubble = document.createElement('div');
    bubble.className = 'conv-bubble conv-bubble--error';
    bubble.innerHTML = `<span class="mdi mdi-alert-outline"></span> ${escHtml(msg)}`;
    wrap.appendChild(bubble);
    chatWindow.appendChild(wrap);
    chatWindow.scrollTop = chatWindow.scrollHeight;
  }

  // ── Stats panel ──────────────────────────────────────────────────────────
  function fmtMs(ms) { return ms == null ? '—' : ms >= 1000 ? (ms/1000).toFixed(2)+'s' : ms+'ms'; }

  function updateStatBar(id, val, maxVal) {
    const fill = $(id);
    if (fill) fill.style.width = maxVal > 0 ? Math.min(100, (val / maxVal) * 100) + '%' : '0%';
  }

  function updateStats(stats) {
    const { stt_ms, llm_ttft_ms, llm_total_ms, tts_ms, total_ms } = stats;
    const max = total_ms || 1;
    const set = (valId, fillId, ms) => {
      const el = $(valId); if (el) el.textContent = fmtMs(ms);
      updateStatBar(fillId, ms || 0, max);
    };
    set('cpv-stt',   'cpf-stt',   stt_ms);
    set('cpv-ttft',  'cpf-ttft',  llm_ttft_ms);
    set('cpv-llm',   'cpf-llm',   llm_total_ms);
    set('cpv-tts',   'cpf-tts',   tts_ms);
    set('cpv-total', 'cpf-total', total_ms);
  }

  function addHistoryItem(n, totalMs, ok) {
    const empty = turnHistory?.querySelector('.conv-history-empty');
    if (empty) empty.remove();
    const item = document.createElement('div');
    item.className = 'conv-hist-item';
    const cls = ok ? 'conv-hist-ok' : 'conv-hist-err';
    const icon = ok ? 'mdi-check-circle-outline' : 'mdi-alert-outline';
    item.innerHTML = `<span class="conv-hist-num">#${n}</span>
      <span class="${cls}"><span class="mdi ${icon}"></span></span>
      <span class="conv-hist-time ${cls}">${fmtMs(totalMs)}</span>`;
    turnHistory.insertBefore(item, turnHistory.firstChild);
  }

  // ── Recording ────────────────────────────────────────────────────────────
  function startRecTimer() {
    recStart = Date.now();
    recTimerInterval = setInterval(() => {
      const s = Math.floor((Date.now() - recStart) / 1000);
      if (micTimer) micTimer.textContent = s + 's';
    }, 500);
  }

  function stopRecTimer() {
    clearInterval(recTimerInterval);
    if (micTimer) micTimer.textContent = '';
  }

  // ── Audio queue — plays multi-chunk TTS responses sequentially ──────────────
  function clearAudio() {
    if (convCurrentAudio) { try { convCurrentAudio.pause(); } catch(_){} convCurrentAudio = null; }
    audioQueue.length = 0;
    audioQueuePlaying = false;
    audioQueueDrainCb = null;
    stopInterruptMonitor();
  }

  function stopInterruptMonitor() {
    cancelAnimationFrame(interruptRafId); interruptRafId = null;
    if (interruptCtx) { try { interruptCtx.close(); } catch(_){} interruptCtx = null; }
    if (interruptStream) { interruptStream.getTracks().forEach(t => t.stop()); interruptStream = null; }
    interruptSpeechStart = 0;
  }

  async function startInterruptMonitor() {
    if (interruptCtx || !navigator.mediaDevices?.getUserMedia) return;
    try {
      interruptStream = await navigator.mediaDevices.getUserMedia({ audio: true });
      interruptCtx = new (window.AudioContext || window.webkitAudioContext)();
      await interruptCtx.resume(); // may be suspended when created outside a user gesture
      const src = interruptCtx.createMediaStreamSource(interruptStream);
      const analyser = interruptCtx.createAnalyser();
      analyser.fftSize = 256;
      src.connect(analyser);
      const buf = new Float32Array(analyser.fftSize);

      function tick() {
        // Stop monitoring once nothing is playing and queue is empty
        if (!audioQueuePlaying && !audioQueue.length && !convCurrentAudio) {
          stopInterruptMonitor();
          return;
        }
        analyser.getFloatTimeDomainData(buf);
        let rms = 0;
        for (const s of buf) rms += s * s;
        rms = Math.sqrt(rms / buf.length);

        if (rms > INTERRUPT_THRESHOLD) {
          if (!interruptSpeechStart) interruptSpeechStart = Date.now();
          if (Date.now() - interruptSpeechStart >= INTERRUPT_HOLD_MS) {
            // User is talking — interrupt the AI.
            // Force-release isProcessing so startRecording's guard doesn't block us.
            stopInterruptMonitor();
            clearAudio();
            autoMicGeneration++;
            isProcessing = false;
            micBtn.classList.remove('processing');
            micIcon.className = 'mdi mdi-microphone';
            if (sendBtn) sendBtn.disabled = false;
            if (textInput) textInput.disabled = false;
            startRecording().catch(() => {});
            return;
          }
        } else {
          interruptSpeechStart = 0;
        }
        interruptRafId = requestAnimationFrame(tick);
      }
      interruptRafId = requestAnimationFrame(tick);
    } catch (_) { stopInterruptMonitor(); }
  }

  function playNextAudio() {
    if (!audioQueue.length) {
      audioQueuePlaying = false;
      convCurrentAudio = null;
      convCurrentSentenceBubble = null;
      if (audioQueueDrainCb) {
        const cb = audioQueueDrainCb;
        audioQueueDrainCb = null;
        setTimeout(cb, 150);
      } else if (micStatus && !isProcessing) {
        micStatus.textContent = 'Ready';
      }
      return;
    }
    audioQueuePlaying = true;
    const item = audioQueue.shift(); // {url, text}
    // Show the sentence text in the typing bubble if it still shows "..."
    if (convCurrentSentenceBubble && item.text) {
      if (convCurrentSentenceBubble.querySelector('.conv-typing')) {
        convCurrentSentenceBubble.innerHTML = '';
        convCurrentSentenceBubble.textContent = item.text;
      }
    }
    const el = new Audio(item.url);
    convCurrentAudio = el;
    el.addEventListener('ended', () => { URL.revokeObjectURL(item.url); playNextAudio(); });
    el.play().catch(() => { URL.revokeObjectURL(item.url); playNextAudio(); });
    if (micStatus) micStatus.textContent = 'Speaking…';
    startInterruptMonitor();
  }

  function enqueueAudio(b64, mime, text) {
    const binStr = atob(b64);
    const arr = new Uint8Array(binStr.length);
    for (let i = 0; i < binStr.length; i++) arr[i] = binStr.charCodeAt(i);
    const url = URL.createObjectURL(new Blob([arr], { type: mime || 'audio/wav' }));
    audioQueue.push({ url, text: text || '' });
    if (!audioQueuePlaying) playNextAudio();
  }

  // ── Chunked Whisper preview (fallback for browsers without SpeechRecognition) ──
  async function transcribeForPreview() {
    if (previewTranscribing || !recChunks.length) return;
    // When VAD is on, gate on detected speech to avoid transcribing silence.
    // When VAD is off the user controls recording manually — always transcribe.
    if (vadToggle?.checked && (!vadHadSpeech || Date.now() - vadLastVoiceMs > 5000)) return;
    previewTranscribing = true;
    try {
      const mime = (mediaRecorder && mediaRecorder.mimeType) || 'audio/webm';
      const ext = mime.includes('ogg') ? '.ogg' : '.webm';
      const blob = new Blob(recChunks, { type: mime });
      const fd = new FormData();
      fd.append('file', new File([blob], 'preview' + ext, { type: mime }));
      fd.append('backend', sttSel?.value || 'configured');
      const r = await fetch('/api/transcribe-bytes', { method: 'POST', body: fd });
      if (r.ok) {
        const d = await r.json();
        const txt = (d.text || '').trim();
        if (txt && txt.length > 3 && !HALLUCINATION_RE.test(txt)
            && mediaRecorder && mediaRecorder.state === 'recording') {
          liveInterimText = txt;
          if (textInput) textInput.value = txt;
        }
      }
    } catch (_) {}
    finally { previewTranscribing = false; }
  }

  // ── Auto-restart mic after agent finishes speaking ───────────────────────
  function scheduleAutoMic() {
    if (!handsFreeToggle?.checked) return;
    const gen = ++autoMicGeneration;
    function tryStart() {
      if (gen !== autoMicGeneration || isProcessing) return;
      startRecording().catch(() => {});
    }
    if (audioQueuePlaying || audioQueue.length > 0) {
      // Audio still queued — trigger after queue drains
      audioQueueDrainCb = tryStart;
    } else if (convCurrentAudio && !convCurrentAudio.ended) {
      convCurrentAudio.addEventListener('ended', () => setTimeout(tryStart, 150), { once: true });
    } else {
      setTimeout(tryStart, 300);
    }
  }

  async function startRecording() {
    if (isProcessing) return;
    stopInterruptMonitor(); // release mic stream before opening a recording stream
    if (!navigator.mediaDevices?.getUserMedia) {
      toast('Microphone unavailable — browser requires a secure context (HTTPS or localhost). ' +
            'Access the app via http://localhost:7890 or enable it in chrome://flags/#unsafely-treat-insecure-origin-as-secure', 'error', 8000);
      return;
    }
    let stream;
    try {
      stream = await navigator.mediaDevices.getUserMedia({ audio: true });
    } catch(e) {
      toast('Microphone access denied: ' + e.message, 'error');
      return;
    }

    liveInterimText = '';
    previewTranscribing = false;
    vadHadSpeech = false;
    vadLastVoiceMs = 0;
    cancelNextBlob = false;
    recChunks = [];
    mediaRecorder = new MediaRecorder(stream);
    mediaRecorder.ondataavailable = e => {
      if (e.data.size > 0) {
        recChunks.push(e.data);
        // Only run preview when speech was detected (prevents "reich" on silence chunks)
        if (mediaRecorder.state === 'recording' && vadHadSpeech) transcribeForPreview();
      }
    };
    mediaRecorder.onstop = () => {
      stream.getTracks().forEach(t => t.stop());
      if (cancelNextBlob) {
        // VAD fired but no speech was detected — reset without calling STT
        cancelNextBlob = false;
        if (textInput) { textInput.readOnly = false; textInput.classList.remove('listening'); textInput.placeholder = origPlaceholder; textInput.value = ''; }
        if (sendBtn) sendBtn.disabled = false;
        micBtn.classList.remove('processing');
        micIcon.className = 'mdi mdi-microphone';
        if (micStatus) micStatus.textContent = 'Ready';
        isProcessing = false;
        return;
      }
      const blob = new Blob(recChunks, { type: mediaRecorder.mimeType || 'audio/webm' });
      processBlob(blob);
    };
    // timeslice: 750ms when VAD is off (manual recording) for faster Whisper preview;
    // 1500ms with VAD on (chunks are gated anyway, smaller slices waste CPU).
    mediaRecorder.start(vadToggle?.checked ? 1500 : 750);
    micBtn.classList.add('recording');
    micIcon.className = 'mdi mdi-stop';
    if (micStatus) micStatus.textContent = 'Recording…';
    startRecTimer();

    // Set input to listening mode (read-only; Whisper preview text will appear here)
    if (textInput) {
      textInput.readOnly = true;
      textInput.value = '';
      textInput.placeholder = 'Listening…';
      textInput.classList.add('listening');
    }
    if (sendBtn) sendBtn.disabled = true;

    // Also try Web Speech API for faster interim results (works on HTTPS / localhost)
    const SpeechRec = window.SpeechRecognition || window.webkitSpeechRecognition;
    if (SpeechRec) {
      try {
        speechRec = new SpeechRec();
        speechRec.continuous = true;
        speechRec.interimResults = true;
        speechRec.onresult = e => {
          let final = '', interim = '';
          for (let i = 0; i < e.results.length; i++) {
            if (e.results[i].isFinal) final += e.results[i][0].transcript;
            else interim += e.results[i][0].transcript;
          }
          liveInterimText = final + interim;
          if (textInput) textInput.value = liveInterimText;
        };
        speechRec.onerror = () => { speechRec = null; };
        speechRec.start();
      } catch(_) { speechRec = null; }
    }

    // VAD: auto-stop on silence using AudioContext
    if (vadToggle?.checked) {
      try {
        vadAudioCtx = new AudioContext();
        const src = vadAudioCtx.createMediaStreamSource(stream);
        const analyser = vadAudioCtx.createAnalyser();
        analyser.fftSize = 1024;
        src.connect(analyser);
        const vadBuf = new Float32Array(analyser.fftSize);
        let vadLastVoice = Date.now();
        const levelWrap = $('conv-level-wrap');
        const levelFill = $('conv-level-fill');
        if (levelWrap) levelWrap.classList.add('active');

        function vadTick() {
          if (!mediaRecorder || mediaRecorder.state !== 'recording') return;
          analyser.getFloatTimeDomainData(vadBuf);
          let rms = 0;
          for (const s of vadBuf) rms += s * s;
          rms = Math.sqrt(rms / vadBuf.length);
          if (levelFill) levelFill.style.width = Math.min(100, rms * 5000) + '%';
          if (rms > VAD_THRESHOLD) {
            vadLastVoice = Date.now();
            vadLastVoiceMs = Date.now();
            vadHadSpeech = true;
          }
          const elapsed = Date.now() - recStart;
          const silence = Date.now() - vadLastVoice;
          if (elapsed > VAD_MIN_REC_MS) {
            const remaining = VAD_SILENCE_MS - silence;
            if (micStatus) {
              micStatus.textContent = remaining < VAD_SILENCE_MS * 0.7
                ? `Sending in ${(Math.max(0, remaining) / 1000).toFixed(1)}s…`
                : 'Recording…';
            }
            if (silence >= VAD_SILENCE_MS) {
              if (!vadHadSpeech) {
                // Silence the whole time — cancel without calling STT
                cancelNextBlob = true;
                if (micStatus) micStatus.textContent = 'Ready';
              }
              stopRecording();
              return;
            }
          }
          vadRafId = requestAnimationFrame(vadTick);
        }
        vadRafId = requestAnimationFrame(vadTick);
      } catch(_) { vadAudioCtx = null; }
    }
  }

  function stopRecording() {
    if (!mediaRecorder || mediaRecorder.state === 'inactive') return;

    // Clean up VAD
    cancelAnimationFrame(vadRafId);
    vadRafId = null;
    if (vadAudioCtx) { try { vadAudioCtx.close(); } catch(_){} vadAudioCtx = null; }
    const levelWrap = $('conv-level-wrap');
    const levelFill = $('conv-level-fill');
    if (levelWrap) levelWrap.classList.remove('active');
    if (levelFill) levelFill.style.width = '0%';

    // Clean up live speech recognition
    if (speechRec) { try { speechRec.stop(); } catch(_){} speechRec = null; }
    previewTranscribing = false;

    mediaRecorder.stop();
    stopRecTimer();
    micBtn.classList.remove('recording');
    micBtn.classList.add('processing');
    micIcon.className = 'mdi mdi-dots-horizontal';
    if (micStatus) micStatus.textContent = 'Processing…';
    isProcessing = true;
  }

  // ── Send turn via SSE ─────────────────────────────────────────────────────
  async function processBlob(blob) {
    autoMicGeneration++; // cancel any pending auto-mic from previous turn
    clearAudio();
    turnCount++;
    const turnN = turnCount;
    const t0 = Date.now();

    // Transition input from listening/readOnly state to processing/disabled state
    if (textInput) {
      textInput.readOnly = false;
      textInput.classList.remove('listening');
      textInput.placeholder = origPlaceholder;
      textInput.value = '';
      textInput.disabled = true;
    }
    if (sendBtn) sendBtn.disabled = true;

    // Show user bubble seeded with live interim transcript (if available)
    const userBubble = addBubble('user', liveInterimText || '…');
    const assistantBubble = addTypingBubble();
    convCurrentSentenceBubble = assistantBubble; // sentence text will appear here while audio plays
    let assistantText = '';
    let lastStats = null;

    const form = new FormData();
    form.append('audio', blob, 'audio.webm');
    form.append('stt_backend', sttSel?.value || 'configured');
    form.append('llm_url', llmUrlInp?.value.trim() || '');
    form.append('llm_model', llmModelSel?.value || '');
    form.append('tts_backend', ttsBkSel?.value || 'voice_clone');
    form.append('tts_voice', ttsVoiceSel?.value || '');
    form.append('system_prompt', systemPrompt?.value.trim() || 'You are a helpful voice assistant.');
    form.append('history', JSON.stringify(conversationHistory.slice(-20)));

    try {
      const resp = await fetch('/api/conversation/turn', { method: 'POST', body: form });
      if (!resp.ok) { let _d=''; try { const _j=await resp.json(); _d=JSON.stringify(_j.detail||_j); } catch(_){} throw new Error('Server error ' + resp.status + (_d ? ': ' + _d : '')); }
      const reader = resp.body.getReader();
      const dec = new TextDecoder();
      let buf = '';

      while (true) {
        const { done, value } = await reader.read();
        if (done) break;
        buf += dec.decode(value, { stream: true });
        const lines = buf.split('\n');
        buf = lines.pop();
        for (const line of lines) {
          if (!line.startsWith('data:')) continue;
          let evt;
          try { evt = JSON.parse(line.slice(5).trim()); } catch(_) { continue; }

          if (evt.type === 'transcript') {
            userBubble.textContent = evt.text || '(empty)';
            if (micStatus) micStatus.textContent = 'Generating reply…';
          } else if (evt.type === 'token') {
            if (assistantBubble.querySelector('.conv-typing')) assistantBubble.innerHTML = '';
            convCurrentSentenceBubble = null; // LLM tokens take over the bubble now
            assistantText += evt.delta;
            assistantBubble.textContent = assistantText;
            chatWindow.scrollTop = chatWindow.scrollHeight;
          } else if (evt.type === 'llm_done') {
            assistantText = evt.text || assistantText;
            assistantBubble.textContent = assistantText;
            convCurrentSentenceBubble = null;
            if (micStatus) micStatus.textContent = 'Synthesising speech…';
          } else if (evt.type === 'audio') {
            enqueueAudio(evt.b64, evt.mime || 'audio/wav', evt.text || '');
          } else if (evt.type === 'stats') {
            lastStats = evt;
            updateStats(evt);
          } else if (evt.type === 'done') {
            conversationHistory.push({ role: 'user', content: userBubble.textContent });
            conversationHistory.push({ role: 'assistant', content: assistantText });
            addHistoryItem(turnN, lastStats?.total_ms ?? (Date.now() - t0), true);
            scheduleAutoMic(); // triggers after audio queue drains
          } else if (evt.type === 'error') {
            clearAudio();
            const wrap = assistantBubble.closest('.conv-bubble-wrap');
            if (wrap) wrap.remove();
            const stage = evt.stage?.toUpperCase() || 'ERR';
            let msg = evt.message || 'Unknown error';
            const detailMatch = msg.match(/HTTP \d+:\s*(.+)/s);
            if (detailMatch) msg = detailMatch[1].trim();
            if (msg.length > 300) msg = msg.slice(0, 300) + '…';
            addErrorBubble(`[${stage}] ${msg}`);
            addHistoryItem(turnN, Date.now() - t0, false);
            if (micStatus) micStatus.textContent = 'Error — ready';
          }
        }
      }
    } catch(e) {
      clearAudio();
      const wrap = assistantBubble.closest('.conv-bubble-wrap');
      if (wrap) wrap.remove();
      addErrorBubble(e.message);
      addHistoryItem(turnN, Date.now() - t0, false);
      if (micStatus) micStatus.textContent = 'Error — ready';
    } finally {
      liveInterimText = '';
      previewTranscribing = false;
      isProcessing = false;
      micBtn.classList.remove('processing');
      micIcon.className = 'mdi mdi-microphone';
      if (sendBtn) sendBtn.disabled = false;
      if (textInput) { textInput.disabled = false; textInput.value = ''; }
      if (audioQueuePlaying || audioQueue.length || convCurrentAudio) startInterruptMonitor();
    }
  }

  // ── Text-input turn (skips STT, sends text directly) ────────────────────
  async function processText(text) {
    text = text.trim();
    if (!text || isProcessing) return;
    autoMicGeneration++; // cancel any pending auto-mic
    clearAudio();
    isProcessing = true;
    if (sendBtn) sendBtn.disabled = true;
    if (textInput) { textInput.disabled = true; textInput.value = ''; }
    micBtn.classList.add('processing');
    micIcon.className = 'mdi mdi-dots-horizontal';
    if (micStatus) micStatus.textContent = 'Processing…';

    turnCount++;
    const turnN = turnCount;
    const t0 = Date.now();

    const userBubble = addBubble('user', text);
    const assistantBubble = addTypingBubble();
    convCurrentSentenceBubble = assistantBubble;
    let assistantText = '';
    let lastStats = null;

    const form = new FormData();
    form.append('text', text);
    form.append('stt_backend', sttSel?.value || 'configured');
    form.append('llm_url', llmUrlInp?.value.trim() || '');
    form.append('llm_model', llmModelSel?.value || '');
    form.append('tts_backend', ttsBkSel?.value || 'voice_clone');
    form.append('tts_voice', ttsVoiceSel?.value || '');
    form.append('system_prompt', systemPrompt?.value.trim() || 'You are a helpful voice assistant.');
    form.append('history', JSON.stringify(conversationHistory.slice(-20)));

    try {
      const resp = await fetch('/api/conversation/turn', { method: 'POST', body: form });
      if (!resp.ok) { let _d=''; try { const _j=await resp.json(); _d=JSON.stringify(_j.detail||_j); } catch(_){} throw new Error('Server error ' + resp.status + (_d ? ': ' + _d : '')); }
      const reader = resp.body.getReader();
      const dec = new TextDecoder();
      let buf = '';

      while (true) {
        const { done, value } = await reader.read();
        if (done) break;
        buf += dec.decode(value, { stream: true });
        const lines = buf.split('\n');
        buf = lines.pop();
        for (const line of lines) {
          if (!line.startsWith('data:')) continue;
          let evt;
          try { evt = JSON.parse(line.slice(5).trim()); } catch(_) { continue; }

          if (evt.type === 'transcript') {
            if (micStatus) micStatus.textContent = 'Generating reply…';
          } else if (evt.type === 'token') {
            if (assistantBubble.querySelector('.conv-typing')) assistantBubble.innerHTML = '';
            convCurrentSentenceBubble = null;
            assistantText += evt.delta;
            assistantBubble.textContent = assistantText;
            chatWindow.scrollTop = chatWindow.scrollHeight;
          } else if (evt.type === 'llm_done') {
            assistantText = evt.text || assistantText;
            assistantBubble.textContent = assistantText;
            convCurrentSentenceBubble = null;
            if (micStatus) micStatus.textContent = 'Synthesising speech…';
          } else if (evt.type === 'audio') {
            enqueueAudio(evt.b64, evt.mime || 'audio/wav', evt.text || '');
          } else if (evt.type === 'stats') {
            lastStats = evt;
            updateStats(evt);
          } else if (evt.type === 'done') {
            conversationHistory.push({ role: 'user', content: text });
            conversationHistory.push({ role: 'assistant', content: assistantText });
            addHistoryItem(turnN, lastStats?.total_ms ?? (Date.now() - t0), true);
            scheduleAutoMic(); // triggers after audio queue drains
          } else if (evt.type === 'error') {
            clearAudio();
            const wrap = assistantBubble.closest('.conv-bubble-wrap');
            if (wrap) wrap.remove();
            addErrorBubble(`[${evt.stage?.toUpperCase() || 'ERR'}] ${evt.message || 'Unknown error'}`);
            addHistoryItem(turnN, Date.now() - t0, false);
            if (micStatus) micStatus.textContent = 'Error — ready';
          }
        }
      }
    } catch(e) {
      clearAudio();
      const wrap = assistantBubble.closest('.conv-bubble-wrap');
      if (wrap) wrap.remove();
      addErrorBubble(e.message);
      addHistoryItem(turnN, Date.now() - t0, false);
      if (micStatus) micStatus.textContent = 'Error — ready';
    } finally {
      isProcessing = false;
      micBtn.classList.remove('processing');
      micIcon.className = 'mdi mdi-microphone';
      if (sendBtn) sendBtn.disabled = false;
      if (textInput) textInput.disabled = false;
      if (audioQueuePlaying || audioQueue.length || convCurrentAudio) startInterruptMonitor();
    }
  }

  // ── Wire up events ───────────────────────────────────────────────────────
  micBtn.addEventListener('click', () => {
    if (isProcessing) return;
    autoMicGeneration++; // cancel any pending hands-free auto-restart
    if (mediaRecorder && mediaRecorder.state === 'recording') {
      stopRecording();
    } else {
      clearAudio(); // stop agent if still speaking
      startRecording();
    }
  });

  // Text input — Enter key or Send button
  sendBtn?.addEventListener('click', () => processText(textInput?.value || ''));
  textInput?.addEventListener('keydown', e => {
    if (e.key === 'Enter' && !e.shiftKey) { e.preventDefault(); processText(textInput.value); }
  });

  clearBtn?.addEventListener('click', () => {
    conversationHistory = [];
    turnCount = 0;
    chatWindow.innerHTML = '<div class="conv-chat-welcome"><span class="mdi mdi-forum-outline" style="font-size:32px;opacity:.25"></span><p>Type a message or press the microphone button below to start.</p></div>';
    if (turnHistory) turnHistory.innerHTML = '<div class="conv-history-empty">No turns yet.</div>';
    ['cpv-stt','cpv-ttft','cpv-llm','cpv-tts','cpv-total'].forEach(id => { const el = $(id); if(el) el.textContent='—'; });
    ['cpf-stt','cpf-ttft','cpf-llm','cpf-tts','cpf-total'].forEach(id => { const el = $(id); if(el) el.style.width='0%'; });
  });

  llmFetchBtn?.addEventListener('click', fetchLlmModels);
  ttsFetchBtn?.addEventListener('click', fetchConvTtsVoices);

  // Re-populate TTS when backend changes
  ttsBkSel?.addEventListener('change', () => { ttsVoiceSel.innerHTML = '<option value="">— fetch voices —</option>'; });

  // ── Init ─────────────────────────────────────────────────────────────────
  loadConvSttBackends();
  populateConvTtsBackends();

  // Keep TTS backend select in sync after global backend refresh
  window._ttsRefreshHooks = window._ttsRefreshHooks || [];
  window._ttsRefreshHooks.push(populateConvTtsBackends);
})();