// ── Chat State ──

const messages = [];
let isStreaming = false;

function clearChat() {
  messages.length = 0;
  chatEl().innerHTML = '';
  setMeta('');
}

// ── Send Message ──

async function sendMessage() {
  const input = $('#input');
  const btn = $('#send');
  const model = $('#model').value;
  const systemPrompt = $('#systemPrompt').value.trim();
  const text = input.value.trim();
  if (!text) return;

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

  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(model, messages, systemPrompt);
    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);
              break;

            case 'done':
              endStreamBubble();
              let meta = `Model: ${data.model || 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;
        }
      }
    }

    if (fullText) {
      messages.push({ role: 'assistant', content: fullText });
    }

  } catch (e) {
    endStreamBubble();
    addErrorBubble('Netzwerk-Fehler: ' + e.message);
  } finally {
    btn.disabled = false;
    isStreaming = false;
    endStreamBubble();
  }
}