the initial traffic source script

<script>
  /**
   * Original script is created by Lunametrics 
   * https://www.lunametrics.com/labs/recipes/utmz-cookie-replicator-for-gtm/
   * Modified by Analytics Mania https://www.analyticsmania.com/
   *
   * Data is stored in the __initialTrafficSource cookie in the following format; brackets
   * indicate optional data and are aexcluded from the stored string:
   *
   * utmcsr=SOURCE|utmcmd=MEDIUM[|utmccn=CAMPAIGN][|utmcct=CONTENT]
   * [|utmctr=TERM/KEYWORD]
   *
   * e.g.:
   * utmcsr=example.com|utmcmd=affl-link|utmccn=foo|utmcct=bar|utmctr=biz
   */
  (function(document) {
   
    var referrer = document.referrer;
    var gaReferral = {
      'utmcsr': '(direct)',
      'utmcmd': '(none)',
      'utmccn': '(not set)'
    };
		var thisHostname = document.location.hostname;
    var thisDomain = getDomain_(thisHostname);
    var referringDomain = getDomain_(document.referrer);
		var sessionCookie = getCookie_('__utmzzses');
    var cookieExpiration = new Date(+new Date() + 1000 * 60 * 60 * 24 * 30 * 24);
		var qs = document.location.search.replace('?', '');
		var hash = document.location.hash.replace('#', '');
    var gaParams = parseGoogleParams(qs + '#' + hash);
    var referringInfo = parseGaReferrer(referrer);
    var storedVals = getCookie_('__utmz') || getCookie_('__utmzz');
    var newCookieVals = [];
    var keyMap = {
      'utm_source': 'utmcsr',
      'utm_medium': 'utmcmd',
      'utm_campaign': 'utmccn',
      'utm_content': 'utmcct',
      'utm_term': 'utmctr',
      'gclid': 'utmgclid',
      'dclid': 'utmdclid'
    };

    var keyFilter = ['utmcsr', 'utmcmd', 'utmccn', 'utmcct', 'utmctr'];
    var keyName,
      values,
      _val,
      _key,
      raw,
      key,
      len,
      i;

    if (sessionCookie && referringDomain === thisDomain) {

      gaParams = null;
      referringInfo = null;

    }

    if (gaParams && (gaParams.utm_source || gaParams.gclid || gaParams.dclid)) {

      for (key in gaParams) {

        if (typeof gaParams[key] !== 'undefined') {

          keyName = keyMap[key];
          gaReferral[keyName] = gaParams[key];

        }

      }

      if (gaParams.gclid || gaParams.dclid) {

        gaReferral.utmcsr = 'google';
        gaReferral.utmcmd = gaReferral.utmgclid ? 'cpc' : 'cpm';

      }

    } else if (referringInfo) {

      gaReferral.utmcsr = referringInfo.source;
      gaReferral.utmcmd = referringInfo.medium;
      if (referringInfo.term) gaReferral.utmctr = referringInfo.term;

    } else if (storedVals) {

      values = {};
      raw = storedVals.split('|');
      len = raw.length;

      for (i = 0; i < len; i++) {

        _val = raw[i].split('=');
        _key = _val[0].split('.').pop();
        values[_key] = _val[1];

      }

      gaReferral = values;

    }

    for (key in gaReferral) {

      if (typeof gaReferral[key] !== 'undefined' && keyFilter.indexOf(key) >-1) {

        newCookieVals.push(key + '=' + gaReferral[key]);

      }

    }

    if (!getCookie_('initialTrafficSource')) {
      writeCookie_('initialTrafficSource', newCookieVals.join('|'), cookieExpiration, '/', thisDomain);
    }

    writeCookie_('__utmzzses', 1, null, '/', thisDomain);

    function parseGoogleParams(str) {

      var campaignParams = ['source', 'medium', 'campaign', 'term', 'content'];
      var regex = new RegExp('(utm_(' + campaignParams.join('|') + ')|(d|g)clid)=.*?([^&#]*|$)', 'gi');
      var gaParams = str.match(regex);
      var paramsObj,
        vals,
        len,
        i;

      if (gaParams) {

        paramsObj = {};
        len = gaParams.length;

        for (i = 0; i < len; i++) {

          vals = gaParams[i].split('=');

          if (vals) {

            paramsObj[vals[0]] = vals[1];

          }

        }

      }

      return paramsObj;

    }

    function parseGaReferrer(referrer) {

      if (!referrer) return;

      var searchEngines = {
        'daum.net': {
          'p': 'q',
          'n': 'daum'
        },
        'eniro.se': {
          'p': 'search_word',
          'n': 'eniro '
        },
        'naver.com': {
          'p': 'query',
          'n': 'naver '
        },
        'yahoo.com': {
          'p': 'p',
          'n': 'yahoo'
        },
        'msn.com': {
          'p': 'q',
          'n': 'msn'
        },
        'bing.com': {
          'p': 'q',
          'n': 'live'
        },
        'aol.com': {
          'p': 'q',
          'n': 'aol'
        },
        'lycos.com': {
          'p': 'q',
          'n': 'lycos'
        },
        'ask.com': {
          'p': 'q',
          'n': 'ask'
        },
        'altavista.com': {
          'p': 'q',
          'n': 'altavista'
        },
        'search.netscape.com': {
          'p': 'query',
          'n': 'netscape'
        },
        'cnn.com': {
          'p': 'query',
          'n': 'cnn'
        },
        'about.com': {
          'p': 'terms',
          'n': 'about'
        },
        'mamma.com': {
          'p': 'query',
          'n': 'mama'
        },
        'alltheweb.com': {
          'p': 'q',
          'n': 'alltheweb'
        },
        'voila.fr': {
          'p': 'rdata',
          'n': 'voila'
        },
        'search.virgilio.it': {
          'p': 'qs',
          'n': 'virgilio'
        },
        'baidu.com': {
          'p': 'wd',
          'n': 'baidu'
        },
        'alice.com': {
          'p': 'qs',
          'n': 'alice'
        },
        'yandex.com': {
          'p': 'text',
          'n': 'yandex'
        },
        'najdi.org.mk': {
          'p': 'q',
          'n': 'najdi'
        },
        'seznam.cz': {
          'p': 'q',
          'n': 'seznam'
        },
        'search.com': {
          'p': 'q',
          'n': 'search'
        },
        'wp.pl': {
          'p': 'szukaj ',
          'n': 'wirtulana polska'
        },
        'online.onetcenter.org': {
          'p': 'qt',
          'n': 'o*net'
        },
        'szukacz.pl': {
          'p': 'q',
          'n': 'szukacz'
        },
        'yam.com': {
          'p': 'k',
          'n': 'yam'
        },
        'pchome.com': {
          'p': 'q',
          'n': 'pchome'
        },
        'kvasir.no': {
          'p': 'q',
          'n': 'kvasir'
        },
        'sesam.no': {
          'p': 'q',
          'n': 'sesam'
        },
        'ozu.es': {
          'p': 'q',
          'n': 'ozu '
        },
        'terra.com': {
          'p': 'query',
          'n': 'terra'
        },
        'mynet.com': {
          'p': 'q',
          'n': 'mynet'
        },
        'ekolay.net': {
          'p': 'q',
          'n': 'ekolay'
        },
        'rambler.ru': {
          'p': 'words',
          'n': 'rambler'
        },
        'google': {
          'p': 'q',
          'n': 'google'
        }
      };
      var a = document.createElement('a');
      var values = {};
      var searchEngine,
        termRegex,
        term;

      a.href = referrer;

      // Shim for the billion google search engines
      if (a.hostname.indexOf('google') > -1) {

        referringDomain = 'google';

      }

      if (searchEngines[referringDomain]) {

        searchEngine = searchEngines[referringDomain];
        termRegex = new RegExp(searchEngine.p + '=.*?([^&#]*|$)', 'gi');
        term = a.search.match(termRegex);

        values.source = searchEngine.n;
        values.medium = 'organic';

        values.term = (term ? term[0].split('=')[1] : '') || '(not provided)';

      } else if (referringDomain !== thisDomain) {

        values.source = a.hostname;
        values.medium = 'referral';

      }

      return values;

    }

    function writeCookie_(name, value, expiration, path, domain) {

      var str = name + '=' + value + ';';
      if (expiration) str += 'Expires=' + expiration.toGMTString() + ';';
      if (path) str += 'Path=' + path + ';';
      if (domain) str += 'Domain=' + domain + ';';

      document.cookie = str;

    }

		function getCookie_(name) {

			var cookies = '; ' + document.cookie
			var cvals = cookies.split('; ' + name + '=');

			if (cvals.length > 1) return cvals.pop().split(';')[0];

		}

    function getDomain_(url) {

      if (!url) return;

      var a = document.createElement('a');
      a.href = url;

      try {

        return a.hostname.match(/[^.]*\.[^.]{2,3}(?:\.[^.]{2,3})?$/)[0];

      } catch(squelch) {}

    }

  })(document);
</script>