async function send(){
  const text=$('msg').value.trim();
  if(!text&&!S.pendingFiles.length)return;
  // Slash command intercept -- local commands handled without agent round-trip
  if(text.startsWith('/')&&!S.pendingFiles.length&&executeCommand(text)){
    $('msg').value='';autoResize();hideCmdDropdown();return;
  }
  // Don't send while an inline message edit is active
  if(document.querySelector('.msg-edit-area'))return;
  // If busy, queue the message instead of dropping it
  if(S.busy){
    if(text){
      MSG_QUEUE.push(text);
      $('msg').value='';autoResize();
      updateQueueBadge();
      showToast(`Queued: "${text.slice(0,40)}${text.length>40?'\u2026':''}"`,2000);
    }
    return;
  }
  if(!S.session){await newSession();await renderSessionList();}

  const activeSid=S.session.session_id;

  setComposerStatus(S.pendingFiles&&S.pendingFiles.length?'Uploading…':'');
  let uploaded=[];
  try{uploaded=await uploadPendingFiles();}
  catch(e){if(!text){setComposerStatus(`Upload error: ${e.message}`);return;}}

  let msgText=text;
  if(uploaded.length&&!msgText)msgText=`I've uploaded ${uploaded.length} file(s): ${uploaded.join(', ')}`;
  else if(uploaded.length)msgText=`${text}\n\n[Attached files: ${uploaded.join(', ')}]`;
  if(!msgText){setComposerStatus('Nothing to send');return;}

  $('msg').value='';autoResize();
  const displayText=text||(uploaded.length?`Uploaded: ${uploaded.join(', ')}`:'(file upload)');
  const userMsg={role:'user',content:displayText,attachments:uploaded.length?uploaded:undefined,_ts:Date.now()/1000};
  S.toolCalls=[];  // clear tool calls from previous turn
  clearLiveToolCards();  // clear any leftover live cards from last turn
  S.messages.push(userMsg);renderMessages();appendThinking();setBusy(true);
  INFLIGHT[activeSid]={messages:[...S.messages],uploaded};
  startApprovalPolling(activeSid);
  S.activeStreamId = null;  // will be set after stream starts

  // Set provisional title from user message immediately so session appears
  // in the sidebar right away with a meaningful name (server may refine later)
  if(S.session&&(S.session.title==='Untitled'||!S.session.title)){
    const provisionalTitle=displayText.slice(0,64);
    S.session.title=provisionalTitle;
    syncTopbar();
    // Persist it and refresh the sidebar now -- don't wait for done
    api('/api/session/rename',{method:'POST',body:JSON.stringify({
      session_id:activeSid, title:provisionalTitle
    })}).catch(()=>{});  // fire-and-forget, server refines on done
    renderSessionList();  // session appears in sidebar immediately
  } else {
    renderSessionList();  // ensure it's visible even if already titled
  }

  // Start the agent via POST, get a stream_id back
  let streamId;
  try{
    const startData=await api('/api/chat/start',{method:'POST',body:JSON.stringify({
      session_id:activeSid,message:msgText,
      model:S.session.model||$('modelSelect').value,workspace:S.session.workspace,
      attachments:uploaded.length?uploaded:undefined
    })});
    streamId=startData.stream_id;
    S.activeStreamId = streamId;
    markInflight(activeSid, streamId);
    // Show Cancel button
    const cancelBtn=$('btnCancel');
    if(cancelBtn) cancelBtn.style.display='inline-flex';
  }catch(e){
    delete INFLIGHT[activeSid];
    stopApprovalPolling();
    // Only hide approval card if it belongs to the session that just finished
    if(!_approvalSessionId || _approvalSessionId===activeSid) hideApprovalCard(true);removeThinking();
    S.messages.push({role:'assistant',content:`**Error:** ${e.message}`});
    renderMessages();setBusy(false);setComposerStatus(`Error: ${e.message}`);
    return;
  }

  // Open SSE stream and render tokens live
  let assistantText='';
  let assistantRow=null;
  let assistantBody=null;
  // Thinking tag patterns for streaming display
  const _thinkPairs=[
    {open:'<think>',close:'</think>'},
    {open:'<|channel>thought\n',close:'<channel|>'}
  ];

  function ensureAssistantRow(){
    if(assistantRow)return;
    removeThinking();
    const tr=$('toolRunningRow');if(tr)tr.remove();
    $('emptyState').style.display='none';
    assistantRow=document.createElement('div');assistantRow.className='msg-row';
    assistantBody=document.createElement('div');assistantBody.className='msg-body';
    const role=document.createElement('div');role.className='msg-role assistant';
    const _bn=window._botName||'Hermes';
    const icon=document.createElement('div');icon.className='role-icon assistant';icon.textContent=_bn.charAt(0).toUpperCase();
    const lbl=document.createElement('span');lbl.style.fontSize='12px';lbl.textContent=_bn;
    role.appendChild(icon);role.appendChild(lbl);
    assistantRow.appendChild(role);assistantRow.appendChild(assistantBody);
    $('msgInner').appendChild(assistantRow);
  }

  // ── Shared SSE handler wiring (used for initial connection and reconnect) ──
  let _reconnectAttempted=false;

  // rAF-throttled rendering: buffer tokens, render at most once per frame
  let _renderPending=false;
  // Extract display text from assistantText, stripping completed thinking blocks
  // and hiding content still inside an open thinking block.
  function _streamDisplay(){
    const raw=assistantText;
    for(const {open,close} of _thinkPairs){
      if(raw.startsWith(open)){
        const ci=raw.indexOf(close,open.length);
        if(ci!==-1){
          // Thinking block complete — strip it, show the rest
          return raw.slice(ci+close.length).replace(/^\s+/,'');
        }
        // Still inside thinking block — show placeholder
        return '';
      }
      // Hide partial tag prefixes while streaming so users don't see
      // `<thi`, `<think`, etc. before the model finishes the token.
      if(open.startsWith(raw)) return '';
    }
    return raw;
  }
  function _scheduleRender(){
    if(_renderPending) return;
    _renderPending=true;
    requestAnimationFrame(()=>{
      _renderPending=false;
      if(assistantBody){
        const txt=_streamDisplay();
        const isThinking=!txt&&assistantText.length>0;
        assistantBody.innerHTML=txt?renderMd(txt):(isThinking?'<span style="color:var(--muted);font-size:13px">Thinking\u2026</span>':'');
      }
      scrollIfPinned();
    });
  }

  function _wireSSE(source){
    source.addEventListener('token',e=>{
      if(!S.session||S.session.session_id!==activeSid) return;
      const d=JSON.parse(e.data);
      assistantText+=d.text;
      ensureAssistantRow();
      _scheduleRender();
    });

    source.addEventListener('tool',e=>{
      const d=JSON.parse(e.data);
      if(!S.session||S.session.session_id!==activeSid) return;
      removeThinking();
      const oldRow=$('toolRunningRow');if(oldRow)oldRow.remove();
      const tc={name:d.name, preview:d.preview||'', args:d.args||{}, snippet:'', done:false};
      S.toolCalls.push(tc);
      appendLiveToolCard(tc);
      scrollIfPinned();
    });

    source.addEventListener('approval',e=>{
      const d=JSON.parse(e.data);
      d._session_id=activeSid;
      showApprovalCard(d);
      playNotificationSound();
      sendBrowserNotification('Approval required',d.description||'Tool approval needed');
    });

    source.addEventListener('done',e=>{
      source.close();
      const d=JSON.parse(e.data);
      delete INFLIGHT[activeSid];
      clearInflight();
      stopApprovalPolling();
      if(!_approvalSessionId || _approvalSessionId===activeSid) hideApprovalCard(true);
      if(S.session&&S.session.session_id===activeSid){
        S.activeStreamId=null;
        const _cb=$('btnCancel');if(_cb)_cb.style.display='none';
      }
      if(S.session&&S.session.session_id===activeSid){
        S.session=d.session;S.messages=d.session.messages||[];
        // Stamp _ts on the last assistant message if it has no timestamp
        const lastAsst=[...S.messages].reverse().find(m=>m.role==='assistant');
        if(lastAsst&&!lastAsst._ts&&!lastAsst.timestamp) lastAsst._ts=Date.now()/1000;
        if(d.usage){S.lastUsage=d.usage;_syncCtxIndicator(d.usage);}
        if(d.session.tool_calls&&d.session.tool_calls.length){
          S.toolCalls=d.session.tool_calls.map(tc=>({...tc,done:true}));
        } else {
          S.toolCalls=S.toolCalls.map(tc=>({...tc,done:true}));
        }
        if(uploaded.length){
          const lastUser=[...S.messages].reverse().find(m=>m.role==='user');
          if(lastUser)lastUser.attachments=uploaded;
        }
        clearLiveToolCards();
        S.busy=false;
        syncTopbar();renderMessages();loadDir('.');
      }
      renderSessionList();setBusy(false);setStatus('');
      setComposerStatus('');
      playNotificationSound();
      sendBrowserNotification('Response complete',assistantText?assistantText.slice(0,100):'Task finished');
    });

    source.addEventListener('compressed',e=>{
      // Context was auto-compressed during this turn -- show a system message
      if(!S.session||S.session.session_id!==activeSid) return;
      try{
        const d=JSON.parse(e.data);
        const sysMsg={role:'assistant',content:'*[Context was auto-compressed to continue the conversation]*'};
        S.messages.push(sysMsg);
        showToast(d.message||'Context compressed');
      }catch(err){}
    });

    source.addEventListener('apperror',e=>{
      // Application-level error sent explicitly by the server (rate limit, crash, etc.)
      // This is distinct from the SSE network 'error' event below.
      source.close();
      delete INFLIGHT[activeSid];clearInflight();stopApprovalPolling();
      if(!_approvalSessionId||_approvalSessionId===activeSid) hideApprovalCard(true);
      if(S.session&&S.session.session_id===activeSid){
        S.activeStreamId=null;const _cbe=$('btnCancel');if(_cbe)_cbe.style.display='none';
        clearLiveToolCards();if(!assistantText)removeThinking();
        try{
          const d=JSON.parse(e.data);
          const isRateLimit=d.type==='rate_limit';
          const isAuthMismatch=d.type==='auth_mismatch';
          const label=isRateLimit?'Rate limit reached':isAuthMismatch?(typeof t==='function'?t('provider_mismatch_label'):'Provider mismatch'):'Error';
          const hint=d.hint?`\n\n*${d.hint}*`:'';
          S.messages.push({role:'assistant',content:`**${label}:** ${d.message}${hint}`});
        }catch(_){
          S.messages.push({role:'assistant',content:'**Error:** An error occurred. Check server logs.'});
        }
        renderMessages();
      }else if(typeof trackBackgroundError==='function'){
        const _errTitle=(typeof _allSessions!=='undefined'&&_allSessions.find(s=>s.session_id===activeSid)||{}).title||null;
        try{const d=JSON.parse(e.data);trackBackgroundError(activeSid,_errTitle,d.message||'Error');}
        catch(_){trackBackgroundError(activeSid,_errTitle,'Error');}
      }
      if(!S.session||!INFLIGHT[S.session.session_id]){setBusy(false);setComposerStatus('');}
    });

    source.addEventListener('warning',e=>{
      // Non-fatal warning from server (e.g. fallback activated, retrying)
      if(!S.session||S.session.session_id!==activeSid) return;
      try{
        const d=JSON.parse(e.data);
        // Show as a small inline notice, not a full error
        setComposerStatus(`${d.message||'Warning'}`);
        // If it's a fallback notice, show it briefly then clear
        if(d.type==='fallback') setTimeout(()=>setComposerStatus(''),4000);
      }catch(_){}
    });

    source.addEventListener('error',e=>{
      source.close();
      // Attempt one reconnect if the stream is still active server-side
      if(!_reconnectAttempted && streamId){
        _reconnectAttempted=true;
        setComposerStatus('Reconnecting…');
        setTimeout(async()=>{
          try{
            const st=await api(`/api/chat/stream/status?stream_id=${encodeURIComponent(streamId)}`);
            if(st.active){
              setComposerStatus('Reconnected');
              _wireSSE(new EventSource(new URL(`/api/chat/stream?stream_id=${encodeURIComponent(streamId)}`,location.origin).href,{withCredentials:true}));
              return;
            }
          }catch(_){}
          _handleStreamError();
        },1500);
        return;
      }
      _handleStreamError();
    });

    source.addEventListener('cancel',e=>{
      source.close();
      delete INFLIGHT[activeSid];clearInflight();stopApprovalPolling();
      if(!_approvalSessionId||_approvalSessionId===activeSid) hideApprovalCard(true);
      if(S.session&&S.session.session_id===activeSid){
        S.activeStreamId=null;const _cbc=$('btnCancel');if(_cbc)_cbc.style.display='none';
      }
      if(S.session&&S.session.session_id===activeSid){
        clearLiveToolCards();if(!assistantText)removeThinking();
        S.messages.push({role:'assistant',content:'*Task cancelled.*'});renderMessages();
      }
      renderSessionList();
      if(!S.session||!INFLIGHT[S.session.session_id]){setBusy(false);setComposerStatus('');}
    });
  }

  function _handleStreamError(){
    delete INFLIGHT[activeSid];clearInflight();stopApprovalPolling();
    if(!_approvalSessionId||_approvalSessionId===activeSid) hideApprovalCard(true);
    if(S.session&&S.session.session_id===activeSid){
      S.activeStreamId=null;const _cbe=$('btnCancel');if(_cbe)_cbe.style.display='none';
      clearLiveToolCards();if(!assistantText)removeThinking();
      S.messages.push({role:'assistant',content:'**Error:** Connection lost'});renderMessages();
    }else{
      // User switched away — show background error banner
      if(typeof trackBackgroundError==='function'){
        // Look up session title from the session list cache so the banner names it correctly
        const _errTitle=(typeof _allSessions!=='undefined'&&_allSessions.find(s=>s.session_id===activeSid)||{}).title||null;
        trackBackgroundError(activeSid,_errTitle,'Connection lost');
      }
    }
    if(!S.session||!INFLIGHT[S.session.session_id]){setBusy(false);setComposerStatus('');}
  }

  _wireSSE(new EventSource(new URL(`/api/chat/stream?stream_id=${encodeURIComponent(streamId)}`,location.origin).href,{withCredentials:true}));

}

function transcript(){
  const lines=[`# Hermes session ${S.session?.session_id||''}`,``,
    `Workspace: ${S.session?.workspace||''}`,`Model: ${S.session?.model||''}`,``];
  for(const m of S.messages){
    if(!m||m.role==='tool')continue;
    let c=m.content||'';
    if(Array.isArray(c))c=c.filter(p=>p&&p.type==='text').map(p=>p.text||'').join('\n');
    const ct=String(c).trim();
    if(!ct&&!m.attachments?.length)continue;
    const attach=m.attachments?.length?`\n\n_Files: ${m.attachments.join(', ')}_`:'';
    lines.push(`## ${m.role}`,'',ct+attach,'');
  }
  return lines.join('\n');
}

function autoResize(){const el=$('msg');el.style.height='auto';el.style.height=Math.min(el.scrollHeight,200)+'px';updateSendBtn();}


// ── Approval polling ──
let _approvalPollTimer = null;
let _approvalHideTimer = null;
let _approvalVisibleSince = 0;
let _approvalSignature = '';
const APPROVAL_MIN_VISIBLE_MS = 30000;

// showApprovalCard moved above respondApproval

function _clearApprovalHideTimer() {
  if (_approvalHideTimer) {
    clearTimeout(_approvalHideTimer);
    _approvalHideTimer = null;
  }
}

function _resetApprovalCardState() {
  _clearApprovalHideTimer();
  _approvalVisibleSince = 0;
  _approvalSignature = '';
}

function hideApprovalCard(force=false) {
  const card = $("approvalCard");
  if (!card) return;
  if (!force && _approvalVisibleSince) {
    const remaining = APPROVAL_MIN_VISIBLE_MS - (Date.now() - _approvalVisibleSince);
    if (remaining > 0) {
      const scheduledSignature = _approvalSignature;
      _clearApprovalHideTimer();
      _approvalHideTimer = setTimeout(() => {
        _approvalHideTimer = null;
        if (_approvalSignature !== scheduledSignature) return;
        hideApprovalCard(true);
      }, remaining);
      return;
    }
  }
  _approvalSessionId = null;
  _resetApprovalCardState();
  card.classList.remove("visible");
  $("approvalCmd").textContent = "";
  $("approvalDesc").textContent = "";
}

// Track session_id of the active approval so respond goes to the right session
let _approvalSessionId = null;

function showApprovalCard(pending) {
  const keys = pending.pattern_keys || (pending.pattern_key ? [pending.pattern_key] : []);
  const desc = (pending.description || "") + (keys.length ? " [" + keys.join(", ") + "]" : "");
  const cmd = pending.command || "";
  const sig = JSON.stringify({desc, cmd, sid: pending._session_id || (S.session && S.session.session_id) || null});
  const card = $("approvalCard");
  const sameApproval = card.classList.contains("visible") && _approvalSignature === sig;
  $("approvalDesc").textContent = desc;
  $("approvalCmd").textContent = cmd;
  _approvalSessionId = pending._session_id || (S.session && S.session.session_id) || null;
  _approvalSignature = sig;
  if (!sameApproval) {
    _approvalVisibleSince = Date.now();
    _clearApprovalHideTimer();
  }
  // Re-enable buttons in case a previous approval disabled them
  ["approvalBtnOnce","approvalBtnSession","approvalBtnAlways","approvalBtnDeny"].forEach(id => {
    const b = $(id); if (b) { b.disabled = false; b.classList.remove("loading"); }
  });
  card.classList.add("visible");
  if (!sameApproval) card.scrollIntoView({block:"nearest", behavior:"smooth"});
  // Apply current locale to data-i18n elements inside the card
  if (typeof applyLocaleToDOM === "function") applyLocaleToDOM();
  // Focus Allow once button so Enter works immediately
  const onceBtn = $("approvalBtnOnce");
  if (onceBtn) setTimeout(() => onceBtn.focus(), 50);
}

async function respondApproval(choice) {
  const sid = _approvalSessionId || (S.session && S.session.session_id);
  if (!sid) return;
  // Disable all buttons immediately to prevent double-submit
  ["approvalBtnOnce","approvalBtnSession","approvalBtnAlways","approvalBtnDeny"].forEach(id => {
    const b = $(id);
    if (b) { b.disabled = true; if (b.id === "approvalBtn" + choice.charAt(0).toUpperCase() + choice.slice(1)) b.classList.add("loading"); }
  });
  _approvalSessionId = null;
  hideApprovalCard(true);
  try {
    await api("/api/approval/respond", {
      method: "POST",
      body: JSON.stringify({ session_id: sid, choice })
    });
  } catch(e) { setStatus(t("approval_responding") + " " + e.message); }
}

function startApprovalPolling(sid) {
  stopApprovalPolling();
  _approvalPollTimer = setInterval(async () => {
    if (!S.busy || !S.session || S.session.session_id !== sid) {
      stopApprovalPolling(); hideApprovalCard(true); return;
    }
    try {
      const data = await api("/api/approval/pending?session_id=" + encodeURIComponent(sid));
      if (data.pending) { data.pending._session_id=sid; showApprovalCard(data.pending); }
      else { hideApprovalCard(); }
    } catch(e) { /* ignore poll errors */ }
  }, 1500);
}

function stopApprovalPolling() {
  if (_approvalPollTimer) { clearInterval(_approvalPollTimer); _approvalPollTimer = null; }
}

// ── Notifications and Sound ──────────────────────────────────────────────────

function playNotificationSound(){
  if(!window._soundEnabled) return;
  try{
    const ctx=new (window.AudioContext||window.webkitAudioContext)();
    const osc=ctx.createOscillator();
    const gain=ctx.createGain();
    osc.connect(gain);gain.connect(ctx.destination);
    osc.type='sine';osc.frequency.setValueAtTime(660,ctx.currentTime);
    osc.frequency.setValueAtTime(880,ctx.currentTime+0.1);
    gain.gain.setValueAtTime(0.3,ctx.currentTime);
    gain.gain.exponentialRampToValueAtTime(0.01,ctx.currentTime+0.3);
    osc.start(ctx.currentTime);osc.stop(ctx.currentTime+0.3);
    osc.onended=()=>ctx.close();
  }catch(e){console.warn('Notification sound failed:',e);}
}

function sendBrowserNotification(title,body){
  if(!window._notificationsEnabled||!document.hidden) return;
  if(!('Notification' in window)) return;
  const botName=window._botName||'Hermes';
  if(Notification.permission==='granted'){
    new Notification(title||botName,{body:body});
  }else if(Notification.permission!=='denied'){
    Notification.requestPermission().then(p=>{
      if(p==='granted') new Notification(title||botName,{body:body});
    });
  }
}

// ── Panel navigation (Chat / Tasks / Skills / Memory) ──