<?php

/**
 * @file
 * Drupal Module: Google Analytics.
 *
 * Adds the required Javascript to all your Drupal pages to allow tracking by
 * the Google Analytics statistics package.
 *
 * @author: Alexander Hass <https://drupal.org/user/85918>
 */

use Drupal\Component\Serialization\Json;
use Drupal\Component\Utility\Crypt;
use Drupal\Core\Cache\Cache;
use Drupal\Core\File\FileSystemInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Site\Settings;
use Drupal\Core\Url;
use Drupal\node\NodeInterface;
use GuzzleHttp\Exception\RequestException;
use Drupal\google_analytics\Component\Render\GoogleAnalyticsJavaScriptSnippet;

/**
 * Advertise the supported google analytics api details.
 */
function google_analytics_api() {
  return [
    'api' => 'analytics.js',
  ];
}

/**
 * Implements hook_help().
 */
function google_analytics_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.google_analytics':
      $output = '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Google Analytics adds a web statistics tracking system to your website. This system incorporates numerous statistical features. For an extensive listing of these features see the <a href=":project">Google Analytics</a> project site. Beyond that, additional information can be found at the <a href=":documentation">Drupal - Google Analytics documentation</a>.', [':documentation' => 'https://www.drupal.org/node/37694', ':project' => 'https://www.drupal.org/project/google_analytics']) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dt>' . t('Configuring Google Analytics') . '</dt>';
      $output .= '<dd>' . t('All settings for this module can be found on the <a href=":ga_settings">Google Analytics settings</a> page. When entering the Google Analytics account number here, it will automatically add the required JavaScript to every page generated. The <em>General Settings</em> section on this page provides additional instruction about setting up tracking thru the Google account.', [':ga_settings' => Url::fromRoute('google_analytics.admin_settings_form')->toString()]) . '</dd>';
      $output .= '<dt>' . t('Additional features') . '</dt>';
      $output .= '<dd>' . t('The Google Analytics module offers a bit more than basic tracking. <em>Page Tracking</em> for instance allows you to provide a list of pages to track, or a list of pages not to track. Role and Link tracking features are also available. For a comprehensive discussion on the setup and use of its many feature see the <a href=":documentation">Drupal - Google Analytics documentation</a>.', [':documentation' => 'https://www.drupal.org/node/37694']) . '</dd>';
      return $output;

    case 'google_analytics.admin_settings_form':
      return t('<a href=":ga_url">Google Analytics</a> is a free (registration required) website traffic and marketing effectiveness service.', [':ga_url' => 'https://marketingplatform.google.com/about/analytics/']);
  }
}

/**
 * Implements hook_page_attachments().
 *
 * Insert JavaScript to the appropriate scope/region of the page.
 */
function google_analytics_page_attachments(array &$page) {
  $account = \Drupal::currentUser();
  $config = \Drupal::config('google_analytics.settings');
  $id = $config->get('account');
  $request = \Drupal::request();
  $base_path = base_path();

  // Add module cache tags.
  $page['#cache']['tags'] = Cache::mergeTags(isset($page['#cache']['tags']) ? $page['#cache']['tags'] : [], $config->getCacheTags());

  // Get page http status code for visibility filtering.
  $status = NULL;
  if ($exception = $request->attributes->get('exception')) {
    $status = $exception->getStatusCode();
  }
  $trackable_status_codes = [
    // "Forbidden" status code.
    '403',
    // "Not Found" status code.
    '404',
  ];

  // 1. Check if the GA account number has a valid value.
  // 2. Track page views based on visibility value.
  // 3. Check if we should track the currently active user's role.
  // 4. Ignore pages visibility filter for 404 or 403 status codes.
  if (preg_match('/^UA-\d+-\d+$/', $id) && (_google_analytics_visibility_pages() || in_array($status, $trackable_status_codes)) && _google_analytics_visibility_user($account)) {
    // Init variables.
    $debug = $config->get('debug');
    $url_custom = '';

    // Add link tracking.
    $link_settings = [];
    if ($track_outbound = $config->get('track.outbound')) {
      $link_settings['trackOutbound'] = $track_outbound;
    }
    if ($track_mailto = $config->get('track.mailto')) {
      $link_settings['trackMailto'] = $track_mailto;
    }
    if (($track_download = $config->get('track.files')) && ($trackfiles_extensions = $config->get('track.files_extensions'))) {
      $link_settings['trackDownload'] = $track_download;
      $link_settings['trackDownloadExtensions'] = $trackfiles_extensions;
    }
    if ((\Drupal::moduleHandler()->moduleExists('colorbox')) && $track_colorbox = $config->get('track.colorbox')) {
      $link_settings['trackColorbox'] = $track_colorbox;
    }
    if ($track_domain_mode = $config->get('domain_mode')) {
      $link_settings['trackDomainMode'] = $track_domain_mode;
    }
    if ($track_cross_domains = $config->get('cross_domains')) {
      $link_settings['trackCrossDomains'] = preg_split('/(\r\n?|\n)/', $track_cross_domains);
    }
    if ($track_url_fragments = $config->get('track.urlfragments')) {
      $link_settings['trackUrlFragments'] = $track_url_fragments;
      $url_custom = 'location.pathname + location.search + location.hash';
    }

    if (!empty($link_settings)) {
      $page['#attached']['drupalSettings']['google_analytics'] = $link_settings;

      // Add debugging code.
      if ($debug) {
        $page['#attached']['library'][] = 'google_analytics/google_analytics.debug';
        // phpcs:disable
        // Add the JS test in development to the page.
        // $page['#attached']['library'][] = 'google_analytics/google_analytics.test';
        // phpcs:enable
      }
      else {
        $page['#attached']['library'][] = 'google_analytics/google_analytics';
      }
    }

    // Add messages tracking.
    $message_events = '';
    if ($message_types = $config->get('track.messages')) {
      $message_types = array_values(array_filter($message_types));
      $status_heading = [
        'status' => t('Status message'),
        'warning' => t('Warning message'),
        'error' => t('Error message'),
      ];

      foreach (\Drupal::messenger()->all(NULL, FALSE) as $type => $messages) {
        // Track only the selected message types.
        if (in_array($type, $message_types)) {
          foreach ($messages as $message) {
            // @todo: Track as exceptions?
            $message_events .= 'ga("send", "event", ' . Json::encode(t('Messages')) . ', ' . Json::encode($status_heading[$type]) . ', ' . Json::encode(strip_tags((string) $message)) . ');';
          }
        }
      }
    }

    // Site search tracking support.
    if (\Drupal::moduleHandler()->moduleExists('search') && $config->get('track.site_search') && (strpos(\Drupal::routeMatch()->getRouteName(), 'search.view') === 0) && $keys = ($request->query->has('keys') ? trim($request->get('keys')) : '')) {
      // hook_item_list__search_results() is not executed if search result is
      // empty. Make sure the counter is set to 0 if there are no results.
      $entity_id = \Drupal::routeMatch()->getParameter('entity')->id();
      $url_custom = '(window.google_analytics_search_results) ? ' . Json::encode(Url::fromRoute('search.view_' . $entity_id, [], ['query' => ['search' => $keys]])->toString()) . ' : ' . Json::encode(Url::fromRoute('search.view_' . $entity_id, ['query' => ['search' => 'no-results:' . $keys, 'cat' => 'no-results']])->toString());
    }

    // If this node is a translation of another node, pass the original
    // node instead.
    if (\Drupal::moduleHandler()->moduleExists('content_translation') && $config->get('translation_set')) {
      // Check if we have a node object, it has translation enabled, and its
      // language code does not match its source language code.
      if ($request->attributes->has('node')) {
        $node = $request->attributes->get('node');
        if ($node instanceof NodeInterface && \Drupal::service('entity.repository')->getTranslationFromContext($node) !== $node->getUntranslated()) {
          $url_custom = Json::encode(Url::fromRoute('entity.node.canonical', ['node' => $node->id()], ['language' => $node->getUntranslated()->language()])->toString());
        }
      }
    }

    // Track access denied (403) and file not found (404) pages.
    if ($status == '403') {
      // See https://www.google.com/support/analytics/bin/answer.py?answer=86927
      $url_custom = '"' . $base_path . '403.html?page=" + document.location.pathname + document.location.search + "&from=" + document.referrer';
    }
    elseif ($status == '404') {
      $url_custom = '"' . $base_path . '404.html?page=" + document.location.pathname + document.location.search + "&from=" + document.referrer';
    }

    // #2693595: User has entered an invalid login and clicked on forgot
    // password link. This link contains the username or email address and may
    // get send to Google if we do not override it. Override only if 'name'
    // query param exists. Last custom url condition, this need to win.
    //
    // URLs to protect are:
    // - user/password?name=username
    // - user/password?name=foo@example.com
    if (\Drupal::routeMatch()->getRouteName() == 'user.pass' && $request->query->has('name')) {
      $url_custom = '"' . $base_path . 'user/password"';
    }

    // Add custom dimensions and metrics.
    $custom_var = '';
    foreach (['dimension', 'metric'] as $google_analytics_custom_type) {
      $google_analytics_custom_vars = $config->get('custom.' . $google_analytics_custom_type);
      // Are there dimensions or metrics configured?
      if (!empty($google_analytics_custom_vars)) {
        // Add all the configured variables to the content.
        foreach ($google_analytics_custom_vars as $google_analytics_custom_var) {
          // Replace tokens in values.
          $types = [];
          if ($request->attributes->has('node')) {
            $node = $request->attributes->get('node');
            if ($node instanceof NodeInterface) {
              $types += ['node' => $node];
            }
          }
          $google_analytics_custom_var['value'] = \Drupal::token()->replace($google_analytics_custom_var['value'], $types, ['clear' => TRUE]);

          // Suppress empty values.
          if (!mb_strlen(trim($google_analytics_custom_var['value']))) {
            continue;
          }

          // Per documentation the max length of a dimension is 150 bytes.
          // A metric has no length limitation. It's not documented if this
          // limit means 150 bytes after url encoding or before.
          // See https://developers.google.com/analytics/devguides/collection/analyticsjs/field-reference#customs
          if ($google_analytics_custom_type == 'dimension' && mb_strlen($google_analytics_custom_var['value']) > 150) {
            $google_analytics_custom_var['value'] = substr($google_analytics_custom_var['value'], 0, 150);
          }

          // Cast metric values for json_encode to data type numeric.
          if ($google_analytics_custom_type == 'metric') {
            settype($google_analytics_custom_var['value'], 'float');
          };

          // Add variables to tracker.
          $custom_var .= 'ga("set", ' . Json::encode($google_analytics_custom_type . $google_analytics_custom_var['index']) . ', ' . Json::encode($google_analytics_custom_var['value']) . ');';
        }
      }
    }

    // Build tracker code.
    $script = '(function(i,s,o,g,r,a,m){';
    $script .= 'i["GoogleAnalyticsObject"]=r;i[r]=i[r]||function(){';
    $script .= '(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),';
    $script .= 'm=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)';
    $script .= '})(window,document,"script",';

    // Which version of the tracking library should be used?
    $library_tracker_url = 'https://www.google-analytics.com/' . ($debug ? 'analytics_debug.js' : 'analytics.js');

    // Should a local cached copy of analytics.js be used?
    if ($config->get('cache') && $url = _google_analytics_cache($library_tracker_url)) {
      // A dummy query-string is added to filenames, to gain control over
      // browser-caching. The string changes on every update or full cache
      // flush, forcing browsers to load a new copy of the files, as the
      // URL changed.
      $query_string = '?' . (\Drupal::state()->get('system.css_js_query_string') ?: '0');

      $script .= '"' . $url . $query_string . '"';
    }
    else {
      $script .= '"' . $library_tracker_url . '"';
    }
    $script .= ',"ga");';

    // Add any custom code snippets if specified.
    $codesnippet_create = $config->get('codesnippet.create');
    $codesnippet_before = $config->get('codesnippet.before');
    $codesnippet_after = $config->get('codesnippet.after');

    // Build the create only fields list.
    $create_only_fields = ['cookieDomain' => 'auto'];
    $create_only_fields = array_merge($create_only_fields, $codesnippet_create);

    // Domain tracking type.
    global $cookie_domain;
    $domain_mode = $config->get('domain_mode');
    $googleanalytics_adsense_script = '';

    // Per RFC 2109, cookie domains must contain at least one dot other than the
    // first. For hosts such as 'localhost' or IP Addresses we don't set a
    // cookie domain.
    if ($domain_mode == 1 && count(explode('.', $cookie_domain)) > 2 && !is_numeric(str_replace('.', '', $cookie_domain))) {
      $create_only_fields = array_merge($create_only_fields, ['cookieDomain' => $cookie_domain]);
      $googleanalytics_adsense_script .= 'window.google_analytics_domain_name = ' . Json::encode($cookie_domain) . ';';
    }
    elseif ($domain_mode == 2) {
      // Cross Domain tracking. 'autoLinker' need to be enabled in 'create'.
      $create_only_fields = array_merge($create_only_fields, ['allowLinker' => TRUE]);
      $googleanalytics_adsense_script .= 'window.google_analytics_domain_name = "none";';
    }

    // Track logged in users across all devices.
    if ($config->get('track.userid') && $account->isAuthenticated()) {
      $create_only_fields['userId'] = google_analytics_user_id_hash($account->id());
    }

    // Create a tracker.
    $script .= 'ga("create", ' . Json::encode($id) . ', ' . Json::encode($create_only_fields) . ');';

    // Prepare Adsense tracking.
    $googleanalytics_adsense_script .= 'window.google_analytics_uacct = ' . Json::encode($id) . ';';

    // Add enhanced link attribution after 'create', but before 'pageview' send.
    // @see https://support.google.com/analytics/answer/2558867
    if ($config->get('track.linkid')) {
      $script .= 'ga("require", "linkid", "linkid.js");';
    }

    // Add display features after 'create', but before 'pageview' send.
    // @see https://support.google.com/analytics/answer/2444872
    if ($config->get('track.displayfeatures')) {
      $script .= 'ga("require", "displayfeatures");';
    }

    // Domain tracking type.
    if ($domain_mode == 2) {
      // Cross Domain tracking
      // https://developers.google.com/analytics/devguides/collection/upgrade/reference/gajs-analyticsjs#cross-domain
      $script .= 'ga("require", "linker");';
      $script .= 'ga("linker:autoLink", ' . Json::encode($link_settings['trackCrossDomains']) . ');';
    }

    if ($config->get('privacy.anonymizeip')) {
      $script .= 'ga("set", "anonymizeIp", true);';
    }

    if (!empty($custom_var)) {
      $script .= $custom_var;
    }
    if (!empty($codesnippet_before)) {
      $script .= $codesnippet_before;
    }
    if (!empty($url_custom)) {
      $script .= 'ga("set", "page", ' . $url_custom . ');';
    }
    $script .= 'ga("send", "pageview");';

    if (!empty($message_events)) {
      $script .= $message_events;
    }
    if (!empty($codesnippet_after)) {
      $script .= $codesnippet_after;
    }

    if ($config->get('track.adsense')) {
      // Custom tracking. Prepend before all other JavaScript.
      // @TODO: https://support.google.com/adsense/answer/98142
      // sounds like it could be appended to $script.
      $script = $googleanalytics_adsense_script . $script;
    }

    $page['#attached']['html_head'][] = [
      [
        '#tag' => 'script',
        '#value' => new GoogleAnalyticsJavaScriptSnippet($script),
      ],
      'google_analytics_tracking_script',
    ];
  }
}

/**
 * Generate user id hash to implement USER_ID.
 *
 * The USER_ID value should be a unique, persistent, and non-personally
 * identifiable string identifier that represents a user or signed-in
 * account across devices.
 *
 * @param int $uid
 *   User id.
 *
 * @return string
 *   User id hash.
 */
function google_analytics_user_id_hash($uid) {
  return Crypt::hmacBase64($uid, \Drupal::service('private_key')->get() . Settings::getHashSalt());
}

/**
 * Implements hook_entity_extra_field_info().
 */
function google_analytics_entity_extra_field_info() {
  $extra['user']['user']['form']['google_analytics'] = [
    'label' => t('Google Analytics settings'),
    'description' => t('Google Analytics module form element.'),
    'weight' => 3,
  ];

  return $extra;
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function google_analytics_form_user_form_alter(&$form, FormStateInterface $form_state) {
  $config = \Drupal::config('google_analytics.settings');
  $account = $form_state->getFormObject()->getEntity();

  if ($account->hasPermission('opt-in or out of google analytics tracking') && ($visibility_user_account_mode = $config->get('visibility.user_account_mode')) != 0 && _google_analytics_visibility_roles($account)) {
    $account_data_google_analytics = \Drupal::service('user.data')->get('google_analytics', $account->id());

    $form['google_analytics'] = [
      '#type' => 'details',
      '#title' => t('Google Analytics settings'),
      '#weight' => 3,
      '#open' => TRUE,
    ];

    switch ($visibility_user_account_mode) {
      case 1:
        $description = t('Users are tracked by default, but you are able to opt out.');
        break;

      case 2:
        $description = t('Users are <em>not</em> tracked by default, but you are able to opt in.');
        break;
    }

    $form['google_analytics']['user_account_users'] = [
      '#type' => 'checkbox',
      '#title' => t('Enable user tracking'),
      '#description' => $description,
      '#default_value' => isset($account_data_google_analytics['user_account_users']) ? $account_data_google_analytics['user_account_users'] : ($visibility_user_account_mode == 1),
    ];

    // hook_user_update() is missing in D8, add custom submit handler.
    $form['actions']['submit']['#submit'][] = 'google_analytics_user_profile_form_submit';
  }
}

/**
 * Submit callback for user profile form to save the Google Analytics setting.
 */
function google_analytics_user_profile_form_submit($form, FormStateInterface $form_state) {
  $account = $form_state->getFormObject()->getEntity();
  if ($account->id() && $form_state->hasValue('user_account_users')) {
    \Drupal::service('user.data')->set('google_analytics', $account->id(), 'user_account_users', (int) $form_state->getValue('user_account_users'));
  }
}

/**
 * Implements hook_cron().
 */
function google_analytics_cron() {
  $config = \Drupal::config('google_analytics.settings');
  $request_time = \Drupal::time()->getRequestTime();

  // Regenerate the tracking code file every day.
  if ($request_time - \Drupal::state()->get('google_analytics.last_cache') >= 86400 && $config->get('cache')) {
    _google_analytics_cache('https://www.google-analytics.com/analytics.js', TRUE);
    \Drupal::state()->set('google_analytics.last_cache', $request_time);
  }
}

/**
 * Implements hook_preprocess_item_list__search_results().
 *
 * Collects and adds the number of search results to the head.
 */
function google_analytics_preprocess_item_list__search_results(&$variables) {
  $config = \Drupal::config('google_analytics.settings');

  // Only run on search results list.
  if ($config->get('track.site_search')) {
    // Get the pager manager to give us the number of items returned.
    /** @var \Drupal\Core\Pager\PagerManagerInterface $pager_manager */
    $pager_manager = \Drupal::service('pager.manager');
    $items = 0;
    if ($pager_manager->getPager()) {
      $items = $pager_manager->getPager()->getTotalItems();
    }
    $variables['#attached']['html_head'][] = [
      [
        '#tag' => 'script',
        '#value' => 'window.google_analytics_search_results = ' . $items . ';',
        '#weight' => JS_LIBRARY - 1,
      ],
      'google_analytics_search_script',
    ];
  }
}

/**
 * Download/Synchronize/Cache tracking code file locally.
 *
 * @param string $location
 *   The full URL to the external javascript file.
 * @param bool $synchronize
 *   Synchronize to local cache if remote file has changed.
 *
 * @return mixed
 *   The path to the local javascript file on success, boolean FALSE on failure.
 */
function _google_analytics_cache($location, $synchronize = FALSE) {
  $path = 'public://google_analytics';
  $file_destination = $path . '/' . basename($location);
  $filesystem = \Drupal::service('file_system');

  if (!file_exists($file_destination) || $synchronize) {
    // Download the latest tracking code.
    try {
      $data = (string) \Drupal::httpClient()
        ->get($location)
        ->getBody();

      if (file_exists($file_destination)) {
        // Synchronize tracking code and and replace local file if outdated.
        $data_hash_local = Crypt::hashBase64(file_get_contents($file_destination));
        $data_hash_remote = Crypt::hashBase64($data);
        // Check that the files directory is writable.
        if ($data_hash_local != $data_hash_remote &&  $filesystem->prepareDirectory($path)) {
          // Save updated tracking code file to disk.
          $filesystem->saveData($data, $file_destination, FileSystemInterface::EXISTS_REPLACE);
          // Based on Drupal Core class AssetDumper.
          if (extension_loaded('zlib') && \Drupal::config('system.performance')->get('js.gzip')) {
            $filesystem->saveData(gzencode($data, 9, FORCE_GZIP), $file_destination . '.gz', FileSystemInterface::EXISTS_REPLACE);
          }
          \Drupal::logger('google_analytics')->info('Locally cached tracking code file has been updated.');

          // Change query-strings on css/js files to enforce reload for all
          // users.
          _drupal_flush_css_js();
        }
      }
      else {
        // Check that the files directory is writable.
        if ($filesystem->prepareDirectory($path, FileSystemInterface::CREATE_DIRECTORY)) {
          // There is no need to flush JS here as core refreshes JS caches
          // automatically, if new files are added.
          $filesystem->saveData($data, $file_destination, FileSystemInterface::EXISTS_REPLACE);
          // Based on Drupal Core class AssetDumper.
          if (extension_loaded('zlib') && \Drupal::config('system.performance')->get('js.gzip')) {
            $filesystem->saveData(gzencode($data, 9, FORCE_GZIP), $file_destination . '.gz', FileSystemInterface::EXISTS_REPLACE);
          }
          \Drupal::logger('google_analytics')->info('Locally cached tracking code file has been saved.');

          // Return the local JS file path.
          return file_url_transform_relative(file_create_url($file_destination));
        }
      }
    }
    catch (RequestException $exception) {
      watchdog_exception('google_analytics', $exception);
    }
  }
  else {
    // Return the local JS file path.
    return file_url_transform_relative(file_create_url($file_destination));
  }
}

/**
 * Delete cached files and directory.
 */
function google_analytics_clear_js_cache() {
  $path = 'public://google_analytics';
  if (is_dir($path)) {
    \Drupal::service('file_system')->deleteRecursive($path);

    // Change query-strings on css/js files to enforce reload for all users.
    _drupal_flush_css_js();

    \Drupal::logger('google_analytics')->info('Local cache has been purged.');
  }
}

/**
 * Tracking visibility check for an user object.
 *
 * @param object $account
 *   A user object containing an array of roles to check.
 *
 * @return bool
 *   TRUE if the current user is being tracked by Google Analytics,
 *   otherwise FALSE.
 */
function _google_analytics_visibility_user($account) {
  $config = \Drupal::config('google_analytics.settings');
  $enabled = FALSE;

  // Is current user a member of a role that should be tracked?
  if (_google_analytics_visibility_roles($account)) {

    // Use the user's block visibility setting, if necessary.
    if (($visibility_user_account_mode = $config->get('visibility.user_account_mode')) != 0) {
      $user_data_google_analytics = \Drupal::service('user.data')->get('google_analytics', $account->id());
      if ($account->id() && isset($user_data_google_analytics['user_account_users'])) {
        $enabled = $user_data_google_analytics['user_account_users'];
      }
      else {
        $enabled = ($visibility_user_account_mode == 1);
      }
    }
    else {
      $enabled = TRUE;
    }

  }

  return $enabled;
}

/**
 * Tracking visibility check for user roles.
 *
 * Based on visibility setting this function returns TRUE if JS code should
 * be added for the current role and otherwise FALSE.
 *
 * @param object $account
 *   A user object containing an array of roles to check.
 *
 * @return bool
 *   TRUE if JS code should be added for the current role and otherwise FALSE.
 */
function _google_analytics_visibility_roles($account) {
  $config = \Drupal::config('google_analytics.settings');
  $enabled = $visibility_user_role_mode = $config->get('visibility.user_role_mode');
  $visibility_user_role_roles = $config->get('visibility.user_role_roles');

  if (count($visibility_user_role_roles) > 0) {
    // One or more roles are selected.
    foreach (array_values($account->getRoles()) as $user_role) {
      // Is the current user a member of one of these roles?
      if (in_array($user_role, $visibility_user_role_roles)) {
        // Current user is a member of a role that should be tracked/excluded
        // from tracking.
        $enabled = !$visibility_user_role_mode;
        break;
      }
    }
  }
  else {
    // No role is selected for tracking, therefore all roles should be tracked.
    $enabled = TRUE;
  }

  return $enabled;
}

/**
 * Tracking visibility check for pages.
 *
 * Based on visibility setting this function returns TRUE if JS code should
 * be added to the current page and otherwise FALSE.
 */
function _google_analytics_visibility_pages() {
  static $page_match;

  // Cache visibility result if function is called more than once.
  if (!isset($page_match)) {
    $config = \Drupal::config('google_analytics.settings');
    $visibility_request_path_mode = $config->get('visibility.request_path_mode');
    $visibility_request_path_pages = $config->get('visibility.request_path_pages');

    // Match path if necessary.
    if (!empty($visibility_request_path_pages)) {
      // Convert path to lowercase. This allows comparison of the same path
      // with different case. Ex: /Page, /page, /PAGE.
      $pages = mb_strtolower($visibility_request_path_pages);
      if ($visibility_request_path_mode < 2) {
        // Compare the lowercase path alias (if any) and internal path.
        $path = \Drupal::service('path.current')->getPath();
        $path_alias = mb_strtolower(\Drupal::service('path_alias.manager')->getAliasByPath($path));
        $page_match = \Drupal::service('path.matcher')->matchPath($path_alias, $pages) || (($path != $path_alias) && \Drupal::service('path.matcher')->matchPath($path, $pages));
        // When $visibility_request_path_mode has a value of 0, the tracking
        // code is displayed on all pages except those listed in $pages. When
        // set to 1, it is displayed only on those pages listed in $pages.
        $page_match = !($visibility_request_path_mode xor $page_match);
      }
      elseif (\Drupal::moduleHandler()->moduleExists('php')) {
        $page_match = php_eval($visibility_request_path_pages);
      }
      else {
        $page_match = FALSE;
      }
    }
    else {
      $page_match = TRUE;
    }

  }
  return $page_match;
}
