(function () {
  'use strict';

  var API_DEFAULT = 'https://chatbox.npgia-himlam.workers.dev/';
  var ID_PREFIX = 'avchat';
  var MODELS = { nivip: 'nivip', zerta: 'zerta' };
  var MODEL_LABELS = { nivip: 'Nivip', zerta: 'Zerta' };

  function baseUrl() {
    try {
      var v = localStorage.getItem('anivietdb-chat-api');
      if (v) return v;
    } catch (e) {}
    return API_DEFAULT;
  }

  function injectCss() {
    if (document.getElementById(ID_PREFIX + '-style')) return;
    var st = document.createElement('style');
    st.id = ID_PREFIX + '-style';
    st.textContent = [
      '.' + ID_PREFIX + '-fab {',
      '  position: fixed; right: 16px; bottom: 16px; width: 56px; height: 56px;',
      '  border-radius: 50%; border: none; cursor: pointer; font-size: 24px; z-index: 9998;',
      '  background: linear-gradient(135deg, #e84393, #a29bfe); color: #fff;',
      '  box-shadow: 0 8px 24px rgba(232,67,147,.5); display: flex; align-items: center; justify-content: center;',
      '  transition: transform .2s;',
      '}',
      '.' + ID_PREFIX + '-fab:hover { transform: scale(1.08); }',
      '.' + ID_PREFIX + '-box {',
      '  position: fixed; right: 16px; bottom: 16px; width: 340px; max-width: calc(100vw - 32px);',
      '  background: #14141f; color: #fff; border-radius: 12px; overflow: hidden;',
      '  box-shadow: 0 8px 30px rgba(0,0,0,.5); z-index: 9999;',
      '  font-family: Roboto, Arial, sans-serif; display: none;',
      '}',
      '.' + ID_PREFIX + '-head { background: #1d1d2e; padding: 12px 16px; border-bottom: 1px solid #333; display: flex; justify-content: space-between; align-items: center; }',
      '.' + ID_PREFIX + '-head h3 { margin: 0; font-size: 15px; color: #fff; }',
      '.' + ID_PREFIX + '-model { background: #14141f; color: #fff; border: 1px solid #444; border-radius: 6px; font-size: 12.5px; padding: 4px 6px; outline: none; cursor: pointer; }',
      '.' + ID_PREFIX + '-close { background: none; border: none; color: #aaa; font-size: 15px; cursor: pointer; padding: 0 4px; }',
      '.' + ID_PREFIX + '-close:hover { color: #fff; }',
      '.' + ID_PREFIX + '-msgs { padding: 14px; max-height: 340px; overflow-y: auto; font-size: 14px; line-height: 1.5; background: #fff; color: #222; }',
      '.' + ID_PREFIX + '-msgs .' + ID_PREFIX + '-user { text-align: right; margin: 6px 0; }',
      '.' + ID_PREFIX + '-msgs .' + ID_PREFIX + '-user::before { content: "Bạn: "; color: #007aff; font-weight: 700; }',
      '.' + ID_PREFIX + '-msgs .' + ID_PREFIX + '-ai { margin: 6px 0; white-space: pre-wrap; word-break: break-word; }',
      '.' + ID_PREFIX + '-msgs .' + ID_PREFIX + '-ai::before { content: "AI: "; color: #e84393; font-weight: 700; }',
      '.' + ID_PREFIX + '-msgs .' + ID_PREFIX + '-err { margin: 6px 0; color: #c0392b; white-space: pre-wrap; word-break: break-word; }',
      '.' + ID_PREFIX + '-input { display: flex; border-top: 1px solid #333; background: #1d1d2e; }',
      '.' + ID_PREFIX + '-input input { flex: 1; padding: 10px 12px; border: none; outline: none; background: #1d1d2e; color: #fff; font-size: 14px; }',
      '.' + ID_PREFIX + '-input button { background: #e84393; color: #fff; border: none; padding: 0 16px; cursor: pointer; font-size: 14px; }',
      '.' + ID_PREFIX + '-input button:disabled { opacity: .5; cursor: wait; }',
      '.' + ID_PREFIX + '-input button:hover:not(:disabled) { background: #d63384; }'
    ].join('\n');
    document.head.appendChild(st);
  }

  function el(tag, className, html) {
    var n = document.createElement(tag);
    if (className) n.className = className;
    if (html !== undefined) n.innerHTML = html;
    return n;
  }

  function escapeHtml(s) {
    return String(s).replace(/[&<>"']/g, function (c) {
      return { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c];
    });
  }

  function build() {
    injectCss();

    var fab = el('button', ID_PREFIX + '-fab', '&#128172;');
    fab.title = 'Chat với trợ lý gợi ý anime/manga';

    var box = el('div', ID_PREFIX + '-box');
    box.innerHTML =
      '<div class="' + ID_PREFIX + '-head">' +
      '<h3>Chatbox ANIVIETDB</h3>' +
      '<select class="' + ID_PREFIX + '-model" id="' + ID_PREFIX + '-model" aria-label="Chọn mô hình">' +
      Object.keys(MODELS).map(function (k) {
        return '<option value="' + k + '">' + MODEL_LABELS[k] + '</option>';
      }).join('') +
      '</select>' +
      '<button class="' + ID_PREFIX + '-close" id="' + ID_PREFIX + '-close" aria-label="Đóng">&#10005;</button>' +
      '</div>';
    var msgs = el('div', ID_PREFIX + '-msgs');
    msgs.innerHTML = '<div class="' + ID_PREFIX + '-ai">Chào bạn! Mình là trợ lý gợi ý anime, manga và light novel của ANIVIETDB. Bạn muốn xem gì hôm nay?</div>';
    box.appendChild(msgs);
    var inputRow = el('div', ID_PREFIX + '-input');
    var inp = el('input');
    inp.type = 'text';
    inp.placeholder = 'Nhập tin nhắn...';
    inp.autocomplete = 'off';
    var sendBtn = el('button', null, 'Gửi');
    inputRow.appendChild(inp);
    inputRow.appendChild(sendBtn);
    box.appendChild(inputRow);
    document.body.appendChild(box);
    document.body.appendChild(fab);

    var closeBtn = box.querySelector('#' + ID_PREFIX + '-close');
    var modelSel = box.querySelector('#' + ID_PREFIX + '-model');

    function currentModel() {
      var saved = null;
      try { saved = localStorage.getItem('anivietdb-chat-model'); } catch (e) {}
      return MODELS[saved] ? saved : 'nivip';
    }

    modelSel.value = currentModel();
    modelSel.addEventListener('change', function () {
      try { localStorage.setItem('anivietdb-chat-model', modelSel.value); } catch (e) {}
    });

    function toggle(show) {
      box.style.display = show ? 'block' : 'none';
      fab.style.display = show ? 'none' : 'block';
      if (show) inp.focus();
    }

    function send() {
      var msg = inp.value.trim();
      if (!msg) return;
      inp.value = '';
      msgs.innerHTML += '<div class="' + ID_PREFIX + '-user">' + escapeHtml(msg) + '</div>';
      msgs.scrollTop = msgs.scrollHeight;
      var p = el('div', ID_PREFIX + '-ai', '...');
      msgs.appendChild(p);
      msgs.scrollTop = msgs.scrollHeight;
      sendBtn.disabled = true;
      inp.disabled = true;
      fetch(baseUrl().replace(/\/+$/, '') + '/chat', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ message: msg, model: modelSel.value })
      }).then(function (r) {
        return r.json().catch(function () { return {}; }).then(function (d) {
          if (!r.ok) {
            var e = new Error((d && d.error) || ('HTTP ' + r.status));
            e.status = r.status;
            throw e;
          }
          return d;
        });
      }).then(function (d) {
        p.className = ID_PREFIX + '-ai';
        p.textContent = d.reply || '...';
        msgs.scrollTop = msgs.scrollHeight;
      }).catch(function (e) {
        p.className = ID_PREFIX + '-err';
        p.textContent = 'Lỗi: ' + (e.message || 'không rõ');
        msgs.scrollTop = msgs.scrollHeight;
      }).finally(function () {
        sendBtn.disabled = false;
        inp.disabled = false;
        inp.focus();
      });
    }

    fab.addEventListener('click', function () { toggle(true); });
    closeBtn.addEventListener('click', function () { toggle(false); });
    sendBtn.addEventListener('click', send);
    inp.addEventListener('keydown', function (e) { if (e.key === 'Enter') send(); });
  }

  function init() {
    if (document.getElementById(ID_PREFIX + '-fab')) return;
    build();
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init);
  } else {
    init();
  }
})();