// ── DOM Helpers ──

const $ = (sel) => document.querySelector(sel);
const chatEl = () => $('#chat');
const metaEl = () => $('#meta');

function scrollDown() {
  const chat = chatEl();
  chat.scrollTop = chat.scrollHeight;
}

function esc(s) {
  const d = document.createElement('div');
  d.textContent = s;
  return d.innerHTML;
}

function truncate(s, max) {
  return s && s.length > max ? s.substring(0, max) + '...' : (s || '');
}

// ── Message Bubbles ──

function addUserBubble(text, streamed = false) {
  const div = document.createElement('div');
  div.className = 'msg user';
  if (streamed) div.classList.add('streamed');
  div.textContent = text;
  chatEl().appendChild(div);
  scrollDown();
}

function addAssistantBubble(text) {
  const div = document.createElement('div');
  div.className = 'msg assistant';
  div.textContent = text;
  chatEl().appendChild(div);
  scrollDown();
  return div;
}

function addErrorBubble(text, streamed = false) {
  const div = document.createElement('div');
  div.className = 'msg system-info';
  if (streamed) div.classList.add('streamed');
  div.style.color = '#ff6b6b';
  div.textContent = text;
  chatEl().appendChild(div);
  scrollDown();
}

// ── Streaming Bubble ──

let _streamDiv = null;
let _streamText = '';

function startStreamBubble() {
  _streamDiv = document.createElement('div');
  _streamDiv.className = 'msg assistant streamed';
  _streamDiv.innerHTML = '<span class="cursor"></span>';
  _streamText = '';
  chatEl().appendChild(_streamDiv);
  scrollDown();
}

function appendToStream(text) {
  if (!_streamDiv) startStreamBubble();
  _streamText += text;
  _streamDiv.textContent = _streamText;
  const cursor = document.createElement('span');
  cursor.className = 'cursor';
  _streamDiv.appendChild(cursor);
  scrollDown();
}

function endStreamBubble() {
  if (_streamDiv) {
    const cursor = _streamDiv.querySelector('.cursor');
    if (cursor) cursor.remove();
    if (!_streamText.trim()) _streamDiv.remove();
  }
  _streamDiv = null;
  _streamText = '';
}

// ── Tool Boxes ──

function addToolBoxLoading(name) {
  const div = document.createElement('div');
  div.className = 'tool-box streamed';
  div.innerHTML = '<span class="tool-name">' + esc(name) + '</span> <span class="tool-spinner">⏳</span>';
  chatEl().appendChild(div);
  scrollDown();
  return div;
}

function finishToolBox(div, data) {
  if (!div) return;
  div.innerHTML = '<span class="tool-name">' + esc(data.name) + '</span>'
    + '<span class="tool-input">' + esc(truncate(data.input, 120)) + '</span>'
    + '<div class="tool-result ' + (data.isError ? 'tool-error' : '') + '">'
    + esc(truncate(data.result, 300)) + '</div>';
  scrollDown();
}

function addToolBoxStatic(name, input, result, isError) {
  const div = document.createElement('div');
  div.className = 'tool-box';
  div.innerHTML = '<span class="tool-name">' + esc(name) + '</span>'
    + '<span class="tool-input">' + esc(truncate(input, 120)) + '</span>';
  if (result) {
    div.innerHTML += '<div class="tool-result ' + (isError ? 'tool-error' : '') + '">'
      + esc(truncate(result, 300)) + '</div>';
  }
  chatEl().appendChild(div);
  scrollDown();
}

// ── Streamed Elements ──

function removeStreamedElements() {
  chatEl().querySelectorAll('.streamed').forEach(el => el.remove());
}

// ── Attachment Indicator ──

function addAttachmentIndicator(messageId, count, namesJson) {
  const chat = chatEl();
  const lastMsg = chat.lastElementChild;
  if (!lastMsg) return;

  let names = [];
  try { if (namesJson) names = JSON.parse(namesJson); } catch {}

  const indicator = document.createElement('div');
  indicator.className = 'attachment-indicator';

  const nameList = names.filter(n => n).join(', ');
  indicator.textContent = `📎 ${count} Datei${count > 1 ? 'en' : ''}` + (nameList ? `: ${nameList}` : '');
  indicator.style.cursor = 'pointer';
  indicator.title = 'Klicken zum Anzeigen';
  indicator.addEventListener('click', () => loadAndShowAttachments(messageId, indicator));
  lastMsg.appendChild(indicator);
}

async function loadAndShowAttachments(messageId, indicator) {
  if (indicator.dataset.loaded) return;
  indicator.dataset.loaded = '1';
  indicator.textContent = '📎 Laden...';

  try {
    const resp = await fetch(`/api/attachments/${messageId}`);
    const attachments = await resp.json();

    const container = document.createElement('div');
    container.className = 'attachment-container';

    for (const att of attachments) {
      if (att.type === 'image') {
        const img = document.createElement('img');
        img.src = `data:${att.mediaType};base64,${att.data}`;
        img.className = 'attachment-image';
        img.title = att.fileName || 'Bild';
        container.appendChild(img);
      } else {
        const link = document.createElement('a');
        link.href = `data:${att.mediaType};base64,${att.data}`;
        link.download = att.fileName || 'datei';
        link.className = 'attachment-file';
        link.textContent = `📄 ${att.fileName || 'Dokument'}`;
        container.appendChild(link);
      }
    }

    indicator.textContent = `📎 ${attachments.length} Datei${attachments.length > 1 ? 'en' : ''}`;
    indicator.parentElement.appendChild(container);
  } catch (e) {
    indicator.textContent = '📎 Fehler beim Laden';
    indicator.dataset.loaded = '';
  }
}

// ── Meta Bar ──

function setMeta(text) {
  metaEl().textContent = text;
}

function setMetaHtml(html) {
  metaEl().innerHTML = html;
}

// ── Archive Button ──

function showArchiveLoadButton() {
  const existing = chatEl().querySelector('.archive-load-btn');
  if (existing) existing.remove();

  const btn = document.createElement('button');
  btn.className = 'archive-load-btn';
  btn.textContent = '📦 Archivierte Nachrichten laden';
  btn.addEventListener('click', loadLatestArchive);

  // Immer ganz oben im Chat
  chatEl().prepend(btn);
}

function removeArchiveLoadButton() {
  const btn = chatEl().querySelector('.archive-load-btn');
  if (btn) btn.remove();
}