// ── Image Attachments Auto-Loading ──

async function _autoLoadImageAttachments(messageId) {
  // Finde die User-Bubble mit dieser messageId
  const bubble = document.querySelector('.msg.user[data-message-id="' + messageId + '"]');
  if (!bubble) return;
  const placeholders = bubble.querySelectorAll('.inline-image-placeholder');
  if (placeholders.length === 0) return;

  try {
    const resp = await fetch('/api/attachments/' + messageId);
    const attachments = await resp.json();
    const imageAtts = attachments.filter(function(a) { return a.type === 'image'; });

    placeholders.forEach(function(ph) {
      const filename = ph.dataset.filename;
      // Bild anhand Dateiname zuordnen, oder der Reihe nach
      const att = imageAtts.find(function(a) { return a.fileName === filename; }) || imageAtts.shift();
      if (att) {
        const img = document.createElement('img');
        img.className = 'inline-user-image';
        img.src = 'data:' + att.mediaType + ';base64,' + att.data;
        img.alt = filename;
        img.title = filename;
        img.addEventListener('click', function() { showKreaImageModal(filename, img.src); });
        ph.replaceWith(img);
      }
    });
  } catch (e) {
    // Platzhalter bleiben stehen bei Fehler
  }
}

// ── History State ──

let lastKnownMessageId = 0;
let _oldestLoadedMessageId = 0;
let _hasMoreOlderMessages = false;
let historyPollInterval = null;


// ── History Loading ──

async function loadHistory() {
  try {
    const sid = getCurrentSessionId();

    const data = await apiHistory(sid, null, isDeletedVisible());
    const entries = data.entries || [];

    // Älteste geladene Message-ID merken für Nachladen
    _hasMoreOlderMessages = data.hasMore;
    _oldestLoadedMessageId = _findOldestMessageId(entries);

    if (data.hasMore) {
      showOlderMessagesButton(data.remainingCount);
    } else {
      // Keine älteren Nachrichten mehr → Archiv-Button anzeigen falls vorhanden
      const archives = await apiListArchives(sid);
      if (archives.length > 0) {
        showArchiveLoadButton();
      }
    }

    for (const entry of entries) {
      renderMessages(entry.messages, true);
      if (entry.chain) addChainMetaBubble(entry.chain, false);
    }

    scrollDown();
    setMeta('Bereit');
    startHistoryPolling();
  } catch (e) {
    console.error('History laden fehlgeschlagen:', e);
  }
}

async function loadOlderMessages() {
  if (!_hasMoreOlderMessages || !_oldestLoadedMessageId) return;

  const btn = chatEl().querySelector('.older-messages-btn');
  if (btn) {
    btn.disabled = true;
    btn.innerHTML = '<i class="fa fa-hourglass-half"></i> Wird geladen...';
  }

  try {
    const sid = getCurrentSessionId();
    const data = await apiHistory(sid, _oldestLoadedMessageId, isDeletedVisible());
    const entries = data.entries || [];

    _hasMoreOlderMessages = data.hasMore;
    const newOldest = _findOldestMessageId(entries);
    if (newOldest > 0) _oldestLoadedMessageId = newOldest;

    // Button entfernen
    removeOlderMessagesButton();

    // Scroll-Position merken
    const chat = chatEl();
    const oldScrollHeight = chat.scrollHeight;

    // Nachrichten oben einfügen (vor dem ersten .msg Element)
    const fragment = document.createDocumentFragment();
    const imageMessageIds = [];
    for (const entry of entries) {
      _renderMessagesIntoFragment(fragment, _mergeConsecutiveAssistantTexts(entry.messages), imageMessageIds);
      if (entry.chain && isChainMetaVisible(entry.chain)) {
        const badges = buildMetaBadges(entry.chain);
        const metaDiv = document.createElement('div');
        metaDiv.className = 'chain-meta';
        metaDiv.innerHTML = badges.map(b => '<span class="chain-meta-badge">' + esc(b) + '</span>').join('');
        fragment.appendChild(metaDiv);
      }
    }

    // Einfügen: vor dem ersten .msg oder .chain-meta Element
    const firstMsg = chat.querySelector('.msg, .chain-meta, .tool-box');
    if (firstMsg) {
      chat.insertBefore(fragment, firstMsg);
    } else {
      chat.appendChild(fragment);
    }

    // Bild-Attachments automatisch laden
    for (const mid of imageMessageIds) _autoLoadImageAttachments(mid);

    // Neuen Button oder Archiv-Button anzeigen
    if (data.hasMore) {
      showOlderMessagesButton(data.remainingCount);
    } else {
      const archives = await apiListArchives(sid);
      if (archives.length > 0) {
        showArchiveLoadButton();
      }
    }

    // Scroll-Position beibehalten
    const newScrollHeight = chat.scrollHeight;
    chat.scrollTop += (newScrollHeight - oldScrollHeight);

  } catch (e) {
    console.error('Ältere Nachrichten laden fehlgeschlagen:', e);
    if (_hasMoreOlderMessages) {
      showOlderMessagesButton(0);
    }
  }
}

// ── Helper Functions ──

function _findOldestMessageId(entries) {
  for (const entry of entries) {
    if (entry.messages && entry.messages.length > 0) {
      return entry.messages[0].id;
    }
  }
  return 0;
}

function _mergeConsecutiveAssistantTexts(msgs) {
  const result = [];
  for (const msg of msgs) {
    if (msg.type === 'text' && msg.role === 'assistant') {
      const prev = result.length > 0 ? result[result.length - 1] : null;
      if (prev && prev.type === 'text' && prev.role === 'assistant'
          && prev.iteration === msg.iteration
          && !_isReviewMessage(msg.content) && !_isReviewMessage(prev.content)) {
        prev.content = (prev.content || '') + ' ' + (msg.content || '');
        if (msg.id) prev.id = msg.id;
        if (msg.createdAt) prev.createdAt = msg.createdAt;
        if (msg.isMarked) prev.isMarked = true;
        continue;
      }
    }
    result.push(Object.assign({}, msg));
  }
  return result;
}

// ── Fragment Rendering (shared between loadOlderMessages + loadLatestArchive) ──

/**
 * Renders a merged message list into a DocumentFragment.
 * @param {DocumentFragment} fragment
 * @param {Array} msgs - Already merged messages
 * @param {Array} imageMessageIds - Collects message IDs with image attachments
 * @param {object} opts - { archived: bool }
 */
function _renderMessagesIntoFragment(fragment, msgs, imageMessageIds, opts) {
  const archived = opts && opts.archived;
  for (var _msgIdx = 0; _msgIdx < msgs.length; _msgIdx++) {
    const msg = msgs[_msgIdx];
    switch (msg.type) {
      case 'text': {
        const isReviewMsg = _isReviewMessage(msg.content);
        if (msg.role === 'user' && !isReviewMsg) {
          const div = _createMessageBubble({ role: 'user', timestamp: msg.createdAt, messageId: msg.id, isMarked: msg.isMarked, deletedOn: msg.deletedOn, archived });
          renderUserContent(div, msg.content);
          _addBubbleActions(div, { timestamp: msg.createdAt, messageId: msg.id, deletedOn: msg.deletedOn, isMarked: msg.isMarked });
          fragment.appendChild(div);
          if (msg.attachmentCount > 0) {
            if (/\[Bild: [^\]]+\]/.test(msg.content) && imageMessageIds) {
              imageMessageIds.push(msg.id);
            }
            div.appendChild(createAttachmentIndicator(msg.id, msg.attachmentCount, msg.attachmentNames));
          }
        } else if (isReviewMsg) {
          const div = _createMessageBubble({ role: msg.role, extraClass: 'review-bubble', timestamp: msg.createdAt, messageId: msg.id, isMarked: msg.isMarked, deletedOn: msg.deletedOn, archived });
          div.innerHTML = renderMarkdown(msg.content);
          parseFluentEmojis(div);
          _addBubbleActions(div, { timestamp: msg.createdAt, messageId: msg.id, deletedOn: msg.deletedOn, isMarked: msg.isMarked });
          fragment.appendChild(div);
        } else if (msg.role === 'assistant') {
          const div = _createMessageBubble({ role: 'assistant', timestamp: msg.createdAt, messageId: msg.id, isMarked: msg.isMarked, deletedOn: msg.deletedOn, archived });
          div.innerHTML = renderMarkdown(msg.content);
          parseFluentEmojis(div);
          _addBubbleActions(div, { timestamp: msg.createdAt, messageId: msg.id, deletedOn: msg.deletedOn, isMarked: msg.isMarked });
          fragment.appendChild(div);
        }
        break;
      }
      case 'tool_use':
        if (msg.toolName === 'ask_user_choice') {
          _renderChoiceBubbleInFragment(fragment, msgs, _msgIdx);
          continue;
        }
        if (!isToolVisible(msg.toolName)) continue;
        var toolDiv = document.createElement('div');
        toolDiv.className = 'tool-box' + (archived ? ' archived' : '');
        renderToolBoxContent(toolDiv, msg.toolName, msg.content, null, false);
        fragment.appendChild(toolDiv);
        break;
      case 'web_search_result': {
        if (!isToolVisible('web_search')) continue;
        var wsSources = [];
        try { wsSources = JSON.parse(msg.content || '[]'); } catch(e) {}
        if (wsSources.length === 0) continue;
        var wsDiv = document.createElement('div');
        wsDiv.className = 'tool-box' + (archived ? ' archived' : '');
        wsDiv.dataset.toolName = 'web_search';
        renderToolBoxContent(wsDiv, 'web_search', null, null, false, wsSources);
        fragment.appendChild(wsDiv);
        break;
      }
      case 'tool_result': {
        if (msg._choiceHandled) continue;
        const prevBoxes = fragment.querySelectorAll('.tool-box');
        const lastToolBox = prevBoxes[prevBoxes.length - 1];
        if (lastToolBox && !lastToolBox.querySelector('.tool-result')) {
          const rd = document.createElement('div');
          rd.className = 'tool-result' + (msg.isError ? ' tool-error' : '');
          rd.textContent = truncate(msg.content || '', 300);
          rd.hidden = true;
          lastToolBox.appendChild(rd);
        }
        continue;
      }
      case 'error': {
        var errDiv = document.createElement('div');
        errDiv.className = 'msg system-info' + (archived ? ' archived' : '');
        errDiv.style.color = 'var(--dangerous)';
        errDiv.textContent = (msg.content || '').trim();
        fragment.appendChild(errDiv);
        break;
      }
      default:
        continue;
    }
  }
}

function _isReviewMessage(content) {
  return content && (content.startsWith('[Review:') || content.startsWith('[Review-Feedback') || content.startsWith('[Finalizer:') || content.startsWith('[Preparer:'));
}

function _renderChoiceBubbleInFragment(fragment, msgs, msgIdx) {
  var msg = msgs[msgIdx];
  try {
    var choiceInput = typeof msg.content === 'string' ? JSON.parse(msg.content) : msg.content;
    var choiceQuestion = choiceInput.question || '';
    var choiceOptions = Array.isArray(choiceInput.choices) ? choiceInput.choices : [String(choiceInput.choices || '')];
    var selectedChoice = null;
    for (var ci = msgIdx + 1; ci < msgs.length; ci++) {
      if (msgs[ci].type === 'tool_result' && msgs[ci].toolCallId === msg.toolCallId) {
        selectedChoice = msgs[ci].content;
        msgs[ci]._choiceHandled = true;
        break;
      }
    }
    var choiceDiv = document.createElement('div');
    choiceDiv.className = 'msg choice-bubble' + (selectedChoice ? ' choice-answered' : '');
    choiceDiv.dataset.toolCallId = msg.toolCallId || '';
    if (msg.id) choiceDiv.dataset.messageId = msg.id;

    var qDiv = document.createElement('div');
    qDiv.className = 'choice-question';
    qDiv.innerHTML = renderMarkdown(choiceQuestion);
    parseFluentEmojis(qDiv);
    choiceDiv.appendChild(qDiv);

    var btnsDiv = document.createElement('div');
    btnsDiv.className = 'choice-buttons';
    for (var co of choiceOptions) {
      var cbtn = document.createElement('button');
      cbtn.className = 'choice-btn';
      cbtn.textContent = co;
      if (selectedChoice) {
        cbtn.disabled = true;
        cbtn.classList.add(co === selectedChoice ? 'choice-selected' : 'choice-unselected');
      } else {
        (function(toolCallId, choice, bubble) {
          cbtn.addEventListener('click', function() { handleChoiceClick(toolCallId, choice, bubble); });
        })(msg.toolCallId, co, choiceDiv);
      }
      btnsDiv.appendChild(cbtn);
    }
    choiceDiv.appendChild(btnsDiv);

    if (msg.createdAt) _addTimestamp(choiceDiv, msg.createdAt);
    fragment.appendChild(choiceDiv);
  } catch(e) {
    console.error('Choice-Bubble Rendering fehlgeschlagen:', e);
  }
}

// ── Render Messages (for pollHistory + loadHistory) ──

function renderMessages(msgs, addToConversation) {
  msgs = _mergeConsecutiveAssistantTexts(msgs);
  for (var _rmIdx = 0; _rmIdx < msgs.length; _rmIdx++) {
    const msg = msgs[_rmIdx];
    if (msg.id > lastKnownMessageId) lastKnownMessageId = msg.id;

    switch (msg.type) {
      case 'text':
        if (_isReviewMessage(msg.content)) {
          addReviewBubbleStatic(msg.content, msg.createdAt, msg.id, msg.isMarked, msg.deletedOn);
        } else if (msg.role === 'user') {
          addUserBubble(msg.content, false, msg.createdAt, msg.id, msg.isMarked, msg.deletedOn);
          if (msg.attachmentCount > 0) {
            _autoLoadImageAttachments(msg.id);
            addAttachmentIndicator(msg.id, msg.attachmentCount, msg.attachmentNames);
          }
        } else if (msg.role === 'assistant') {
          addAssistantBubble(msg.content, msg.createdAt, msg.id, msg.isMarked, msg.deletedOn);
        }
        break;

      case 'tool_use':
        if (msg.toolName === 'ask_user_choice') {
          try {
            var choiceInput2 = typeof msg.content === 'string' ? JSON.parse(msg.content) : msg.content;
            var choiceQ2 = choiceInput2.question || '';
            var choiceOpts2 = Array.isArray(choiceInput2.choices) ? choiceInput2.choices : [String(choiceInput2.choices || '')];
            // Voraus-Suche nach zugehörigem tool_result
            var selectedChoice2 = null;
            for (var ci2 = _rmIdx + 1; ci2 < msgs.length; ci2++) {
              if (msgs[ci2].type === 'tool_result' && msgs[ci2].toolCallId === msg.toolCallId) {
                selectedChoice2 = msgs[ci2].content;
                msgs[ci2]._choiceHandled = true;
                break;
              }
            }
            if (selectedChoice2) {
              addChoiceBubbleStatic(msg.toolCallId, choiceQ2, choiceOpts2, selectedChoice2, msg.createdAt, msg.id);
            } else {
              addChoiceBubble(msg.toolCallId, choiceQ2, choiceOpts2, false);
            }
          } catch(e) {
            console.error('Choice-Bubble Rendering fehlgeschlagen:', e);
          }
          break;
        }
        if (isToolVisible(msg.toolName)) {
          addToolBoxStatic(msg.toolName, msg.content, null, false);
        }
        break;

      case 'web_search_result': {
        if (isToolVisible('web_search')) {
          var wsSrc = [];
          try { wsSrc = JSON.parse(msg.content || '[]'); } catch(e) {}
          if (wsSrc.length > 0) addToolBoxStatic('web_search', null, null, false, wsSrc);
        }
        break;
      }

      case 'tool_result':
        if (msg._choiceHandled) break;
        // tool_result wird dem vorherigen tool_use-Box angehängt wenn möglich
        appendToolResult(msg.content, msg.isError);
        break;

      case 'error':
        addErrorBubble(msg.content);
        break;
    }
  }
}

// ── Polling ──

let _pollLock = false;

function startHistoryPolling(intervalMs = 3000) {
  if (historyPollInterval) return;
  historyPollInterval = setInterval(pollHistory, intervalMs);
}

function stopHistoryPolling() {
  if (historyPollInterval) {
    clearInterval(historyPollInterval);
    historyPollInterval = null;
  }
}

async function pollHistory(force = false) {
  if (isStreaming && !force) return;
  if (_pollLock) return;
  _pollLock = true;

  try {
    const newMessages = await apiHistoryPoll(getCurrentSessionId(), lastKnownMessageId, isDeletedVisible());
    if (newMessages.length > 0) {
      renderMessages(newMessages, true);
      scrollDown();
    }
  } catch (e) {
    console.error('History poll fehlgeschlagen:', e);
  } finally {
    _pollLock = false;
  }
}