(function () {
  var cfg = window.EB_CONCIERGE || {};
  var botId = cfg.botId;
  var apiBase = (cfg.apiBase || '').replace(/\/$/, '');
  if (!botId || !apiBase) {
    // eslint-disable-next-line no-console
    console.error('[EventBuzz Concierge] Missing window.EB_CONCIERGE.botId or apiBase');
    return;
  }

  var storageKey = 'ebc_session_' + botId;
  var sessionId = null;
  try { sessionId = localStorage.getItem(storageKey); } catch {}

  function el(tag, attrs, children) {
    var n = document.createElement(tag);
    if (attrs) for (var k in attrs) n.setAttribute(k, attrs[k]);
    if (children) children.forEach(function (c) { n.appendChild(typeof c === 'string' ? document.createTextNode(c) : c); });
    return n;
  }

  function addCssOnce() {
    if (document.getElementById('ebc-css')) return;
    var link = el('link', { id: 'ebc-css', rel: 'stylesheet', href: apiBase.replace(/\/api$/, '') + '/embed/concierge-widget.css' });
    document.head.appendChild(link);
  }

  addCssOnce();

  var launcher = el('button', { class: 'ebc-launcher', type: 'button', 'aria-label': 'Chat with event concierge' }, ['Chat']);
  var panel = el('div', { class: 'ebc-panel', role: 'dialog', 'aria-label': 'Event concierge chat' });
  var header = el('div', { class: 'ebc-header' });
  var title = el('div', { class: 'ebc-title' }, ['Event Concierge']);
  var closeBtn = el('button', { class: 'ebc-close', type: 'button', 'aria-label': 'Close' }, ['×']);
  header.appendChild(title);
  header.appendChild(closeBtn);

  var messages = el('div', { class: 'ebc-messages' });
  var error = el('div', { class: 'ebc-error' }, ['']);
  var inputBar = el('div', { class: 'ebc-inputbar' });
  var input = el('input', { class: 'ebc-input', placeholder: 'Ask a question…', maxlength: '800' });
  var sendBtn = el('button', { class: 'ebc-send', type: 'button' }, ['Send']);
  inputBar.appendChild(input);
  inputBar.appendChild(sendBtn);

  panel.appendChild(header);
  panel.appendChild(messages);
  panel.appendChild(error);
  panel.appendChild(inputBar);
  document.body.appendChild(launcher);
  document.body.appendChild(panel);

  function setError(msg) {
    if (!msg) {
      error.style.display = 'none';
      error.textContent = '';
      return;
    }
    error.style.display = 'block';
    error.textContent = msg;
  }

  function addMessage(role, text) {
    var bubble = el('div', { class: 'ebc-msg' + (role === 'user' ? ' ebc-user' : '') });
    bubble.textContent = text;
    messages.appendChild(bubble);
    messages.scrollTop = messages.scrollHeight;
  }

  function openPanel() {
    panel.classList.add('ebc-open');
    input.focus();
  }
  function closePanel() {
    panel.classList.remove('ebc-open');
  }

  launcher.addEventListener('click', function () {
    if (panel.classList.contains('ebc-open')) closePanel();
    else openPanel();
  });
  closeBtn.addEventListener('click', closePanel);

  function http(path, body) {
    return fetch(apiBase + path, {
      method: body ? 'POST' : 'GET',
      headers: { 'Content-Type': 'application/json' },
      body: body ? JSON.stringify(body) : undefined,
      credentials: 'omit'
    }).then(function (r) {
      return r.json().then(function (j) { return { status: r.status, json: j }; });
    });
  }

  // Load config
  http('/public/concierge/' + encodeURIComponent(botId) + '/config').then(function (res) {
    if (res.json && res.json.success && res.json.data) {
      title.textContent = res.json.data.eventName ? ('Concierge · ' + res.json.data.eventName) : 'Event Concierge';
      var greet = res.json.data.greeting;
      if (greet) addMessage('assistant', greet.replace(/\{eventName\}/g, res.json.data.eventName || 'the event'));
      if (res.json.data.maxMessageLength) input.setAttribute('maxlength', String(res.json.data.maxMessageLength));
    }
  });

  function send() {
    var text = String(input.value || '').trim();
    if (!text) return;
    setError(null);
    input.value = '';
    addMessage('user', text);
    sendBtn.disabled = true;

    http('/public/concierge/' + encodeURIComponent(botId) + '/chat', {
      sessionId: sessionId || undefined,
      message: text
    }).then(function (res) {
      sendBtn.disabled = false;
      if (!res.json || !res.json.success) {
        setError((res.json && res.json.error && res.json.error.message) ? res.json.error.message : 'Request failed');
        return;
      }
      if (res.json.data && res.json.data.sessionId) {
        sessionId = res.json.data.sessionId;
        try { localStorage.setItem(storageKey, sessionId); } catch {}
      }
      addMessage('assistant', (res.json.data && res.json.data.reply) ? res.json.data.reply : '…');
    }).catch(function (e) {
      sendBtn.disabled = false;
      setError(e && e.message ? e.message : 'Network error');
    });
  }

  sendBtn.addEventListener('click', send);
  input.addEventListener('keydown', function (e) {
    if (e.key === 'Enter') send();
  });
})();