materio-d8/web/modules/custom/materio_sapi/materio_sapi.module

<?php

/**
 * @file
 * Contains materio_sapi.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Solarium\QueryType\Select\Query\Query;
use Drupal\search_api\Query\QueryInterface;
use Drupal\Core\Template\Attribute;

/**
 * Implements hook_help().
 */
function materio_sapi_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the materio_sapi module.
    case 'help.page.materio_sapi':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Search Api Materio module') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_search_api_solr_query_alter();
 */
function materio_sapi_search_api_solr_query_alter(Query $solarium_query,  QueryInterface $query) {
  if ($termid = (int)$query->getOption('termid')) {
    // get solarium fileds name
    $index = $query->getIndex();
    $solrFields = $index->getServerInstance()
      ->getBackend()
      ->getSolrFieldNames($index);

    // tag_tid"itm_tag_tid"
    // thesaurus_tid"itm_thesaurus_tid"
    $tag_fname = $solrFields['tag_tid'];
    $thes_fname = $solrFields['thesaurus_tid'];
    // $solarium_query->addParam('bf', "recip(abs(ms(NOW,{$solrField})),3.16e-11,10,0.1)");
    // $bfparam = "if(or(gt(termfreq({$tag_fname},{$termid}),0),gt(termfreq({$thes_fname},{$termid}),0)),^21,0)";
    $bfparam = "if(or(exists(query({$tag_fname}:{$termid})),exists(query({$thes_fname}:{$termid}))),^21,0)";
    // boost=if(or(exists(query(itm_tag_tid:396)),exists(query(itm_thesaurus_tid:396))),^21,0 )
    $solarium_query->addParam('boost', $bfparam);
    // $solarium_query->addParam('debugQuery', 'on');
  }

}

/**
 * Prepares variables for fieldset element templates.
 *
 * Default template: fieldset.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - element: An associative array containing the properties of the element.
 *     Properties used: #attributes, #children, #description, #id, #title,
 *     #value.
 */
function materio_sapi_preprocess_fieldset(&$variables) {
  if (isset($variables['element']['#legend_attributes'])) {
    $variables['legend']['attributes'] = new Attribute($variables['element']['#legend_attributes']);
  }
}


// ? https://happyculture.coop/blog/drupal-8-declarer-un-champ-extrafield-calcule-computed-field
/**
 * Implements hook_entity_bundle_field_info().
 */
function materio_sapi_entity_bundle_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type, $bundle, array $base_field_definitions) {
  $fields = [];
  if ($entity_type->id() == 'node') {
    if ($bundle == 'materiau') {
      for ($i=0; $i < 5 ; $i++) { 
        $fields["thesaurus_$i"] = \Drupal\Core\Field\BaseFieldDefinition::create('entity_reference')
          ->setLabel(t("Thesaurus $i"))
          ->setComputed(TRUE)
          ->setSetting('target_type', 'taxonomy_term')
          ->setSetting('handler_settings',['target_bundles'=>['thesaurus'=>'thesaurus']] )
          ->setClass('\Drupal\materio_sapi\ThesaurusRefComputed')
          ->setDisplayConfigurable('view', FALSE);
      }
    }
  }
  return $fields;
}


// ? https://www.webomelette.com/creating-pseudo-fields-drupal-8
// /**
//  * Implements hook_entity_extra_field_info().
//  */
// function materio_sapi_entity_extra_field_info() {
//   $extra = array();

//   foreach (NodeType::loadMultiple() as $bundle) {
//     $extra['node'][$bundle->Id()]['display']['my_own_pseudo_field'] = array(
//       'label' => t('My own field'),
//       'description' => t('This is my own pseudo-field'),
//       'weight' => 100,
//       'visible' => false,
//     );
//   }

//   return $extra;
// }