<?php

namespace Drupal\entity_reference_revisions\Plugin\Field\FieldWidget;

use Drupal\Core\Entity\Entity;
use Drupal\Core\Field\Plugin\Field\FieldWidget\EntityReferenceAutocompleteWidget;
use Drupal\Core\Form\FormStateInterface;

/**
 * Plugin implementation of the 'entity_reference_autocomplete' widget.
 *
 * @FieldWidget(
 *   id = "entity_reference_revisions_autocomplete",
 *   label = @Translation("Autocomplete"),
 *   description = @Translation("An autocomplete text field."),
 *   field_types = {
 *     "entity_reference_revisions"
 *   }
 * )
 */
class EntityReferenceRevisionsAutocompleteWidget extends EntityReferenceAutocompleteWidget {

  /**
   * {@inheritdoc}
   */
  public function massageFormValues(array $values, array $form, FormStateInterface $form_state) {
    $entity_type = $this->fieldDefinition->getFieldStorageDefinition()->getSetting('target_type');
    foreach ($values as $key => $value) {
      if($value['target_id']) {
        $entity = \Drupal::entityTypeManager()->getStorage($entity_type)->load($value['target_id']);
        // Add the current revision ID.
        $values[$key]['target_revision_id'] = $entity->getRevisionId();
      }
      // The entity_autocomplete form element returns an array when an entity
      // was "autocreated", so we need to move it up a level.
      if (is_array($value['target_id'])) {
        unset($values[$key]['target_id']);
        $values[$key] += $value['target_id'];
      }
    }
    return $values;
  }

}