edlp_d8/web/modules/custom/edlp_home/edlp_home.module

<?php
# @Author: Bachir Soussi Chiadmi <bach>
# @Date:   13-12-2017
# @Email:  bachir@figureslibres.io
# @Filename: edlp_home.module
# @Last modified by:   bach
# @Last modified time: 20-12-2017
# @License: GPL-V3


/**
 * Implements hook_theme().
 */
function edlp_home_theme($existing, $type, $theme, $path) {
  // @see https://www.drupal.org/docs/8/theming/twig/create-custom-twig-templates-from-custom-module

  return array(
    'edlp_home' => array(
      // 'render element' => '',
      'file' => 'includes/edlp_home.inc',
      'variables' => array(
        // 'presentation_node' => NULL,
        // 'last_fil_node' => NULL,
        // 'last_production_node' => NULL,
        'promoted_statics' => array(),
        'promoted_prods' => array(),
        'lastdocs_items' => NULL,
        'agenda_items' => NULL,
        // 'entrees_items' => NULL,
        'collection_link' => NULL,
        'production_link' => NULL,
        'agenda_link' => NULL,
      ),
    ),
  );
}

/**
 * Implements hook_theme_suggestions_HOOK().
 */
function edlp_home_theme_suggestions_edlp_home_alter(array &$suggestions, array $variables) {
  $is_mobile_domain = false;

  // get domains from domain module
  $domain_storage = \Drupal::entityTypeManager()->getStorage('domain');
  $mobile_domain_id = 'm_encyclopediedelaparole_org';
  // $mobile_domain = $domain_storage->load('m_encyclopediedelaparole_org');
  global $base_root;
  // get the current hostname (domain)
  $current_hostname = preg_replace('/http:\/\/|https:\/\//i', '', $base_root);
  // get the current domain
  $current_domain = $domain_storage->loadByHostname($current_hostname);

  if($current_domain){
    // we are in a main domain
    // $is_mobile_domain = ($current_domain->id() == $mobile_domain_id);
    $current_domain_id = $current_domain->id();
  }else{
    // we are not in a main domain, so we look for an alias
    $domain_alias_storage = \Drupal::entityTypeManager()->getStorage('domain_alias');
    $alias = $domain_alias_storage->loadByHostname($current_hostname);
    // dpm($alias, '$alias');
    $current_domain_id = $alias->getDomainId();
  }

  $is_mobile_domain = $current_domain_id == $mobile_domain_id;

  if($is_mobile_domain){
    array_unshift($suggestions, 'edlp_home__mobile');
  }
}