// ── Helpers ──

function buildMetaBadges(d) {
  const badges = [];
  if (d.planMode) badges.push('📋 Plan-Modus');
  badges.push(prettyModelName(d.model));
  badges.push('Tokens: ' + (d.inputTokens || 0) + ' / ' + (d.outputTokens || 0));
  if (d.cacheCreationTokens > 0 || d.cacheReadTokens > 0) {
    badges.push('Cache: ' + (d.cacheReadTokens || 0) + ' / ' + (d.cacheCreationTokens || 0));
  }
  if ((d.iterations || 0) > 1) badges.push('Iterationen: ' + d.iterations);
  if (d.durationMs) badges.push((d.durationMs / 1000).toFixed(1) + 's');
  if (d.stopReason && d.stopReason !== 'end_turn' && d.stopReason !== 'tool_use') badges.push('Stop: ' + d.stopReason);
  return badges;
}

function addChainMetaBubble(d, streamed) {
  if (!d || !d.model) return;
  // Chain noch nicht finalisiert (läuft noch) → nicht anzeigen
  if (!d.inputTokens && !d.outputTokens && !d.durationMs) return;
  if (!isChainMetaVisible(d)) return;
  const div = _createChainMetaDiv(d, streamed ? 'streamed' : null);
  chatEl().appendChild(div);
  scrollDown();
}

// ── Stream Event Handler (shared between sendMessage + handleChoiceClick) ──

function handleStreamEvent(eventType, data) {
  switch (eventType) {
    case 'text_start':
      if (!_streamDiv) startStreamBubble();
      break;

    case 'text_delta':
      appendToStream(data.text);
      break;

    case 'text_end':
      pauseStreamBubble();
      break;

    case 'tool_start':
      endStreamBubble();
      if (isToolVisible(data.name)) {
        _currentToolBox = addToolBoxLoading(data.name);
      } else {
        _currentToolBox = null;
      }
      break;

    case 'tool_end':
      if (_currentToolBox) {
        finishToolBox(_currentToolBox, data);
      }
      _currentToolBox = null;
      break;

    case 'web_search_start':
      pauseStreamBubble();
      _currentToolBox = addToolBoxLoading('web_search');
      break;

    case 'web_search_end':
      if (_currentToolBox) {
        finishToolBox(_currentToolBox, { name: 'web_search', result: 'Suche abgeschlossen', isError: false, sources: data.sources });
      }
      _currentToolBox = null;
      break;

    case 'user_choice':
      endStreamBubble();
      addChoiceBubble(data.toolCallId, data.question, data.choices);
      break;

    // Preparer / Review / Finalizer events (shared pattern)
    case 'preparer_start': case 'review_start': case 'finalizer_start':
      endStreamBubble();
      addReviewBubble('start', data, eventType.split('_')[0] === 'review' ? undefined : eventType.split('_')[0]);
      break;

    case 'preparer_text': case 'review_text': case 'finalizer_text':
      appendToReviewText(data.text);
      break;

    case 'preparer_tool_use': case 'review_tool_use': case 'finalizer_tool_use':
      addReviewToolUse(data);
      break;

    case 'preparer_tool_end': case 'review_tool_end': case 'finalizer_tool_end':
      finishReviewToolBox(data);
      break;

    case 'preparer_done':
      finalizeReviewBubble(data.forwarded ? 'forwarded' : 'query', data, 'preparer');
      break;

    case 'review_feedback':
      finalizeReviewBubble('feedback', data);
      break;

    case 'review_approved':
      finalizeReviewBubble('approved', data);
      break;

    case 'finalizer_done':
      finalizeReviewBubble('done', data, 'finalizer');
      break;

    case 'error':
      endStreamBubble();
      addErrorBubble(data.error, true);
      break;

    case 'done':
      endStreamBubble();
      if (data.stopReason === 'max_tokens') {
        addWarningBubble('Antwort wurde abgeschnitten (max_tokens erreicht). Bitte frage nach dem Rest.', true);
      }
      _lastDoneChainData = null;
      if (data.model) {
        _lastDoneChainData = data;
      } else if (data.chainId) {
        apiGetChain(data.chainId).then(chain => {
          if (chain) _lastDoneChainData = chain;
        }).catch(() => {});
      }
      setMeta('Bereit');
      break;
  }
}

// ── Plan Mode ──

let _planModeActive = false;

function togglePlanMode() {
  _planModeActive = !_planModeActive;
  var btn = $('#planModeBtn');
  if (btn) {
    btn.classList.toggle('plan-mode-active', _planModeActive);
    btn.title = _planModeActive ? 'Plan-Modus deaktivieren' : 'Plan-Modus aktivieren';
  }
  var input = $('#input');
  if (input) {
    input.placeholder = _planModeActive ? 'Plannen...' : 'Nachricht...';
  }
}

// ── Chat State ──

let isStreaming = false;
let _lastDoneChainData = null; // Chain-Daten vom letzten done-Event
let _currentToolBox = null;   // Aktuell laufende Tool-Box (für Stream-Events)
let _chatAbandoned = false; // true wenn User weg-navigiert während Stream läuft
let _abortController = null; // AbortController für laufenden Stream

async function clearChat() {
  const archive = await apiArchive(getCurrentSessionId());
  if (!archive) return;

  chatEl().innerHTML = '';
  lastKnownMessageId = 0;
  loadedArchiveCount = 0;
  _oldestLoadedSortKey = 0;
  _hasMoreOlderMessages = false;
  clearReply();

  setMeta(`Archiviert: ${archive.chainCount} Chains, ${archive.messageCount} Messages`);
  showArchiveLoadButton();
}

function stopStreaming() {
  if (_abortController) {
    _abortController.abort();
  }
  // Backend explizit stoppen (kills laufende Tools/API-Calls)
  var sid = getCurrentSessionId();
  if (sid) apiStopChat(sid).catch(function() {});
}

// ── SSE Stream Runner (shared between sendMessage + handleChoiceClick) ──

async function _runStream(fetchPromise) {
  const sendBtn = $('#send');
  const stopBtn = $('#stop');
  const sid = getCurrentSessionId();

  sendBtn.disabled = true;
  sendBtn.hidden = true;
  stopBtn.hidden = false;
  isStreaming = true;
  _abortController = new AbortController();
  _currentToolBox = null;
  _chatAbandoned = false;
  setMetaHtml('<span><i class="fa fa-hourglass-half"></i> Streaming...</span>');

  try {
    const resp = await fetchPromise(_abortController.signal);
    const reader = resp.body.getReader();
    const decoder = new TextDecoder();
    let buffer = '';
    let eventType = null;

    while (true) {
      const { done, value } = await reader.read();
      if (done || _chatAbandoned) break;

      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split('\n');
      buffer = lines.pop() || '';

      for (const line of lines) {
        if (line.startsWith('event: ')) {
          eventType = line.substring(7).trim();
        } else if (line.startsWith('data: ') && eventType) {
          let data;
          try { data = JSON.parse(line.substring(6)); } catch { continue; }
          handleStreamEvent(eventType, data);
          eventType = null;
        }
      }
    }
  } catch (e) {
    if (_chatAbandoned) return;
    endStreamBubble();
    if (e.name === 'AbortError') {
      setMeta('Abgebrochen');
      await new Promise(r => setTimeout(r, 500));
    } else {
      try {
        const status = await apiIsStreaming(sid);
        if (status.streaming) {
          setMetaHtml('<span><i class="fa fa-hourglass-half"></i> Streaming... (Verbindung wiederhergestellt)</span>');
          startStreamingPoll(sid, sendBtn, status.chainId);
          return;
        }
      } catch (_) {}
      addErrorBubble('Netzwerk-Fehler: ' + e.message);
    }
  } finally {
    if (_chatAbandoned) return;
    if (!isStreaming || !_streamingPollInterval) {
      sendBtn.disabled = false;
      sendBtn.hidden = false;
      stopBtn.hidden = true;
      isStreaming = false;
      _abortController = null;
    }
    endStreamBubble();
    removeStreamedElements();
    await pollHistory();
    if (_lastDoneChainData) {
      addChainMetaBubble(_lastDoneChainData, false);
      _lastDoneChainData = null;
    }
  }
}

// ── Send Message ──

async function sendMessage() {
  const input = $('#input');
  const text = input.value.trim();
  if (!text && pendingFiles.length === 0 && pendingRefs.length === 0) return;

  // Content bauen: string oder array mit file-blocks
  let content;
  let bubbleText = text;

  // Reply-Zitat einbauen
  let msgText = text;
  if (pendingReply) {
    const roleLabel = pendingReply.role === 'user' ? 'User' : 'Assistant';
    const timeLabel = formatTimestamp(pendingReply.timestamp) || 'Jetzt';
    const quoteText = pendingReply.text.split('\n').map(l => '> ' + l).join('\n');
    const quoteHeader = `> [Zitat: ${timeLabel}, ${roleLabel}]:`;
    msgText = quoteHeader + '\n' + quoteText + '\n\n' + (text || '');
    clearReply();
  }

  // Refs in den Text einbauen
  if (pendingRefs.length > 0) {
    const refLines = pendingRefs.map(r => {
      if (r.from && r.to && r.from !== r.to) return `[Datei: ${r.path}:${r.from}-${r.to}]`;
      if (r.from) return `[Datei: ${r.path}:${r.from}]`;
      return `[Datei: ${r.path}]`;
    });
    msgText = refLines.join(' ') + '\n' + msgText;
    if (pendingRefs.some(r => r.from)) {
      if (pendingRefs.length > 1)
        msgText += `\n<hint>Lies referenzierte Dateien mit \`cat -n\`.</hint>`;
      else
        msgText += `\n<hint>Lies die referenzierte Datei mit \`cat -n\`.</hint>`;
    }
    clearPendingRefs();
  }

  let inlineImages = []; // Bilder für Inline-Anzeige
  if (pendingFiles.length > 0) {
    content = [];
    const labels = [];
    for (const f of pendingFiles) {
      const blockType = f.type.startsWith('image/') ? 'image' : 'document';
      content.push({
        type: blockType,
        source: { type: 'base64', media_type: f.type, data: f.base64 },
        _file_name: f.name
      });
      if (blockType === 'image') {
        inlineImages.push({ name: f.name, dataUrl: 'data:' + f.type + ';base64,' + f.base64 });
      }
      labels.push('[' + (blockType === 'image' ? 'Bild' : 'Datei') + ': ' + f.name + ']');
    }
    if (msgText) content.push({ type: 'text', text: msgText });
    bubbleText = labels.join('\n') + (msgText ? '\n' + msgText : '');
    clearPendingFiles();
  } else {
    content = msgText;
    bubbleText = msgText;
  }

  addUserBubble(bubbleText, true, '', null, false, null, inlineImages);

  input.value = '';
  input.dispatchEvent(new Event('input'));

  await _runStream((signal) => apiChat(content, getCurrentSessionId(), signal, _planModeActive));
}

// ── Choice Click Handler ──

async function handleChoiceClick(toolCallId, choice, bubbleDiv) {
  // Buttons deaktivieren und gewählte Option markieren
  const buttons = bubbleDiv.querySelectorAll('.choice-btn');
  buttons.forEach(btn => {
    btn.disabled = true;
    if (btn.textContent === choice) {
      btn.classList.add('choice-selected');
    } else {
      btn.classList.add('choice-unselected');
    }
  });
  bubbleDiv.classList.add('choice-answered');

  await _runStream((signal) => apiChatChoice(getCurrentSessionId(), toolCallId, choice, signal));
}