// ── Chat State ──

const messages = [];
let isStreaming = false;
let pendingFile = null; // { name, type, base64 }

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 && !pendingFile) return;

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

  if (pendingFile) {
    content = [];
    const blockType = pendingFile.type.startsWith('image/') ? 'image' : 'document';
    content.push({
      type: blockType,
      source: { type: 'base64', media_type: pendingFile.type, data: pendingFile.base64 },
      _file_name: pendingFile.name
    });
    if (text) content.push({ type: 'text', text });
    bubbleText = (blockType === 'image' ? '📷 ' : '📄 ') + pendingFile.name + (text ? '\n' + text : '');
    clearPendingFile();
  } else {
    content = text;
  }

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

  input.value = '';
  input.style.height = 'auto';
  btn.disabled = true;
  isStreaming = true;
  setMetaHtml('<span style="color:#7c83ff">⏳ 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();
              let meta = `Model: ${data.model || '?'} | In: ${data.inputTokens || 0} | Out: ${data.outputTokens || 0}`;
              if (data.iterations > 1) meta += ` | Iterations: ${data.iterations}`;
              if (data.durationMs) meta += ` | ${(data.durationMs / 1000).toFixed(1)}s`;
              setMeta(meta);
              break;
          }
          eventType = null;
        }
      }
    }

  } catch (e) {
    endStreamBubble();
    addErrorBubble('Netzwerk-Fehler: ' + e.message);
  } finally {
    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];
    pendingFile = { name: file.name, type: file.type, base64 };
    showFilePreview();
  };
  reader.readAsDataURL(file);
}

function showFilePreview() {
  const preview = $('#filePreview');
  if (!preview || !pendingFile) return;

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

function clearPendingFile() {
  pendingFile = null;
  const preview = $('#filePreview');
  if (preview) {
    preview.innerHTML = '';
    preview.hidden = true;
  }
  const fileInput = $('#fileInput');
  if (fileInput) fileInput.value = '';
}