// ── Helpers ──

function buildMetaString(d) {
  let meta = `Model: ${d.model || '?'} | In: ${d.inputTokens || 0} | Out: ${d.outputTokens || 0}`;
  if (d.cacheCreationTokens > 0) meta += ` | Cache-Write: ${d.cacheCreationTokens}`;
  if (d.cacheReadTokens > 0) meta += ` | Cache-Read: ${d.cacheReadTokens}`;
  if ((d.iterations || 0) > 1) meta += ` | Iterations: ${d.iterations}`;
  if (d.durationMs) meta += ` | ${(d.durationMs / 1000).toFixed(1)}s`;
  if (d.stopReason && d.stopReason !== 'end_turn' && d.stopReason !== 'tool_use') meta += ` | Stop: ${d.stopReason}`;
  return meta;
}

// ── Chat State ──

const messages = [];
let isStreaming = false;
let pendingFiles = []; // [{ name, type, base64 }]
let pendingRefs = [];  // [{ path, from, to }] - Workspace-Dateireferenzen

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

  messages.length = 0;
  chatEl().innerHTML = '';
  lastKnownMessageId = 0;
  loadedArchiveCount = 0;

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

// ── Send Message ──

async function sendMessage() {
  const input = $('#input');
  const btn = $('#send');
  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;

  // Refs in den Text einbauen
  let msgText = text;
  if (pendingRefs.length > 0) {
    const refTags = pendingRefs.map(r => {
      if (r.from && r.to) return `[Datei: ${r.path}:${r.from}-${r.to}]`;
      return `[Datei: ${r.path}]`;
    });
    msgText = refTags.join('\n') + (text ? '\n' + text : '');
    clearPendingRefs();
  }

  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
      });
      labels.push((blockType === 'image' ? '📷 ' : '📄 ') + f.name);
    }
    if (msgText) content.push({ type: 'text', text: msgText });
    bubbleText = labels.join('\n') + (msgText ? '\n' + msgText : '');
    clearPendingFiles();
  } else {
    content = msgText;
    bubbleText = msgText;
  }

  messages.push({ role: 'user', content });
  addUserBubble(bubbleText, true);

  input.value = '';
  input.dispatchEvent(new Event('input'))
  btn.disabled = true;
  isStreaming = true;
  setMetaHtml('<span>⏳ Streaming...</span>');

  let fullText = '';
  let currentToolBox = null;

  try {
    const resp = await apiChat(messages, getCurrentSessionId());
    const reader = resp.body.getReader();
    const decoder = new TextDecoder();
    let buffer = '';
    let eventType = null;

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

          switch (eventType) {
            case 'text_start':
              endStreamBubble();
              startStreamBubble();
              break;

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

            case 'text_end':
              endStreamBubble();
              break;

            case 'tool_start':
              endStreamBubble();
              currentToolBox = addToolBoxLoading(data.name);
              break;

            case 'tool_end':
              finishToolBox(currentToolBox, data);
              currentToolBox = null;
              break;

            case 'error':
              endStreamBubble();
              addErrorBubble(data.error, true);
              // Fehlgeschlagene Message aus dem Array entfernen
              // damit das kaputte Bild nicht endlos mitgeschickt wird
              if (messages.length > 0 && messages[messages.length - 1].role === 'user') {
                messages.pop();
              }
              break;

            case 'done':
              endStreamBubble();
              if (data.stopReason === 'max_tokens') {
                addWarningBubble('⚠️ Antwort wurde abgeschnitten (max_tokens erreicht). Bitte frage nach dem Rest.', true);
              }
              if (data.model) {
                setMeta(buildMetaString(data));
              } else if (data.chainId) {
                // Leeres done (z.B. nach error/max_iterations) – Chain-Daten nachladen
                apiGetChain(data.chainId).then(chain => {
                  if (chain) setMeta(buildMetaString(chain));
                }).catch(() => {});
              }
              break;
          }
          eventType = null;
        }
      }
    }

  } catch (e) {
    endStreamBubble();
    // Prüfen ob Backend noch streamt (z.B. bei Netzwerkfehler)
    try {
      const status = await apiIsStreaming(getCurrentSessionId());
      if (status.streaming) {
        // Backend streamt noch weiter – Recovery-Poll starten
        setMetaHtml('<span>⏳ Streaming... (Verbindung wiederhergestellt)</span>');
        startStreamingPoll(getCurrentSessionId(), btn, status.chainId);
        return;
      }
    } catch (_) {}
    addErrorBubble('Netzwerk-Fehler: ' + e.message);
  } finally {
    if (!isStreaming || !_streamingPollInterval) {
      btn.disabled = false;
      isStreaming = false;
    }
    endStreamBubble();

    // Erst neue aus DB laden, dann gestreamte Elemente ersetzen
    await pollHistory();
    removeStreamedElements();
  }
}

// ── File Handling ──

function handleFileSelect(file) {
  if (!file) return;

  const maxSize = 20 * 1024 * 1024; // 20MB
  if (file.size > maxSize) {
    alert('Datei zu groß (max. 20MB)');
    return;
  }

  const allowed = ['image/jpeg', 'image/png', 'image/gif', 'image/webp', 'application/pdf'];
  if (!allowed.includes(file.type)) {
    alert('Nicht unterstützter Dateityp. Erlaubt: JPEG, PNG, GIF, WebP, PDF');
    return;
  }

  const reader = new FileReader();
  reader.onload = () => {
    const base64 = reader.result.split(',')[1];
    pendingFiles.push({ name: file.name, type: file.type, base64 });
    renderFilePreview();
  };
  reader.readAsDataURL(file);
}

function handleMultipleFiles(files) {
  for (const file of files) handleFileSelect(file);
}

function renderFilePreview() {
  const preview = $('#filePreview');
  if (!preview || pendingFiles.length === 0) {
    if (preview) { preview.innerHTML = ''; preview.hidden = true; }
    return;
  }

  preview.innerHTML = pendingFiles.map((f, i) => {
    const isImage = f.type.startsWith('image/');
    return `<div class="file-preview-inner">
      ${isImage ? '<img src="data:' + f.type + ';base64,' + f.base64 + '" class="file-thumb">' : '<span class="file-icon">📄</span>'}
      <span class="file-name">${esc(f.name)}</span>
      <button class="file-remove" onclick="removePendingFile(${i})">✕</button>
    </div>`;
  }).join('');
  preview.hidden = false;
}

function removePendingFile(index) {
  pendingFiles.splice(index, 1);
  renderFilePreview();
}

// ── Workspace Refs ──

function addPendingRef(ref) {
  // ref = "path" oder "path:from-to"
  const match = ref.match(/^(.+?):(\d+)-(\d+)$/);
  if (match) {
    pendingRefs.push({ path: match[1], from: parseInt(match[2]), to: parseInt(match[3]) });
  } else {
    pendingRefs.push({ path: ref, from: null, to: null });
  }
  renderRefPreview();
}

function removePendingRef(index) {
  pendingRefs.splice(index, 1);
  renderRefPreview();
}

function clearPendingRefs() {
  pendingRefs.length = 0;
  renderRefPreview();
}

function renderRefPreview() {
  const container = $('#refPreview');
  if (!container) return;

  if (pendingRefs.length === 0) {
    container.innerHTML = '';
    container.hidden = true;
    return;
  }

  container.innerHTML = pendingRefs.map((r, i) => {
    const label = r.from && r.to ? `${r.path}:${r.from}-${r.to}` : r.path;
    return `<div class="ref-preview-item">
      <span class="ref-icon">📂</span>
      <span class="ref-label">${esc(label)}</span>
      <button class="file-remove" onclick="removePendingRef(${i})">✕</button>
    </div>`;
  }).join('');
  container.hidden = false;
}

function clearPendingFiles() {
  pendingFiles.length = 0;
  const preview = $('#filePreview');
  if (preview) { preview.innerHTML = ''; preview.hidden = true; }
  const fileInput = $('#fileInput');
  if (fileInput) fileInput.value = '';
}