<?php
use Drupal\node\Entity\Node;

// use Drupal\Core\Entity\EntityTypeInterface;
// use Drupal\Core\Field\BaseFieldDefinition;
// use Drupal\Core\Field\FieldStorageDefinitionInterface;

// https://www.drupal.org/project/drupal/issues/2916266#comment-12301574

function popsu_uniqdate_entity_presave(Drupal\Core\Entity\EntityInterface $entity) {
  if ($entity->getEntityTypeId() === 'node' && $entity->bundle() === 'evenement') {
    if ($entity->hasField('field_date') && !$entity->get('field_date')->isEmpty()) {
      // $first_term = $entity->get('field_tags')->first()->target_id;
      $dates = $entity->get('field_date')->getValue();
      asort($dates);
      $last_date = array_pop($dates);
      $entity->set('field_last_date_only', $last_date);
    }
    else {
      $entity->set('field_last_date_only', NULL);
    }
  }
}

// /**
//  * Implement hook_entity_bundle_field_info().
//  *
//  * @param EntityTypeInterface $entity_type
//  * @param $bundle
//  * @param array $base_field_definitions
//  * @return array
//  */
// function popsu_uniqdate_entity_bundle_field_info(EntityTypeInterface $entity_type, $bundle, array $base_field_definitions) {
//   if ($entity_type->id() == 'node' && $bundle == 'evenement') {
//     $fields['computed_date_unique'] = BaseFieldDefinition::create('datetime')
//       ->setName('computed_date_unique')
//       ->setLabel(t('Computed Date Unique'))
//       ->setDescription(t('Computed Date Unique.'))
//       // // The Entity Type this field belongs to.
//       ->setTargetEntityTypeId($entity_type->id())
//       // // The Entity Type bundle this field belongs to.
//       ->setTargetBundle($bundle)
//       // ->setSetting('target_type', 'node')
//       ->setCardinality(1)
//       ->setComputed(TRUE)
//       ->setRevisionable(FALSE)
//       ->setTranslatable(FALSE)
//       ->setDisplayConfigurable('view', TRUE)
//       ->setDisplayOptions('view', [
//           'label' => 'hidden',
//           'weight' => -5,
//         ])
//       ->setClass(\Drupal\popsu_uniqdate\Plugin\Field\FieldType\ComputedUniqDate::class);

//       return $fields;
//   }
// }


// /**
//  * Implements hook_views_data_alter().
//  */
// function popsu_uniqdate_views_data_alter(array &$data) {
//   if (isset($data['node'])) {
//     // Add the Computed Date Unique field to Views.
//     $data['node']['computed_date_unique'] = [
//       'title' => t('Computed Date Unique'),
//       'field' => [
//         'id' => 'views_computed_date_unique',
//       ],
//     ];
//   }
// }