class ContentTranslationFormHooks

class ContentTranslationFormHooks {
  use StringTranslationTrait;
  public function __construct(protected readonly EntityTypeManagerInterface $entityTypeManager, protected readonly AccountInterface $currentUser, protected readonly ContentTranslationManagerInterface $contentTranslationManager, protected readonly RedirectDestinationInterface $redirectDestination, protected readonly FieldSyncWidget $fieldSyncWidget) {
  }
  
  /**
   * Implements hook_form_alter().
   */
  public function formAlter(array &$form, FormStateInterface $form_state) : void {
    $form_object = $form_state->getFormObject();
    if (!$form_object instanceof ContentEntityFormInterface) {
      return;
    }
    $entity = $form_object->getEntity();
    $op = $form_object->getOperation();
    // Let the content translation handler alter the content entity form. This
    // can be the 'add' or 'edit' form. It also tries a 'default' form in case
    // neither of the aforementioned forms are defined.
    if ($entity instanceof ContentEntityInterface && $entity->isTranslatable() && count($entity->getTranslationLanguages()) > 1 && in_array($op, [
      'edit',
      'add',
      'default',
    ], TRUE)) {
      $controller = $this->entityTypeManager
        ->getHandler($entity->getEntityTypeId(), 'translation');
      $controller->entityFormAlter($form, $form_state, $entity);
      // @todo Move the following lines to the code generating the property form
      //   elements once we have an official #multilingual FAPI key.
      $translations = $entity->getTranslationLanguages();
      $form_langcode = $form_object->getFormLangcode($form_state);
      // Handle fields shared between translations when there is at least one
      // translation available or a new one is being created.
      if (!$entity->isNew() && (!isset($translations[$form_langcode]) || count($translations) > 1)) {
        foreach ($entity->getFieldDefinitions() as $field_name => $definition) {
          // Allow the widget to define if it should be treated as multilingual
          // by respecting an already set #multilingual key.
          if (isset($form[$field_name]) && !isset($form[$field_name]['#multilingual'])) {
            $form[$field_name]['#multilingual'] = $definition->isTranslatable();
          }
        }
      }
      // The footer region, if defined, may contain multilingual widgets so we
      // need to always display it.
      if (isset($form['footer'])) {
        $form['footer']['#multilingual'] = TRUE;
      }
    }
  }
  
  /**
   * Implements hook_form_FORM_ID_alter() for 'field_config_edit_form'.
   */
  public function formFieldConfigEditFormAlter(array &$form, FormStateInterface $form_state) : void {
    $field = $form_state->getFormObject()
      ->getEntity();
    $bundle_is_translatable = $this->contentTranslationManager
      ->isEnabled($field->getTargetEntityTypeId(), $field->getTargetBundle());
    $form['translatable'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Users may translate this field'),
      '#default_value' => $field->isTranslatable(),
      '#weight' => -1,
      '#disabled' => !$bundle_is_translatable,
      '#access' => $field->getFieldStorageDefinition()
        ->isTranslatable(),
    ];
    // Provide helpful pointers for administrators.
    if ($this->currentUser
      ->hasPermission('administer content translation') && !$bundle_is_translatable) {
      $toggle_url = Url::fromRoute('language.content_settings_page', [], [
        'query' => $this->redirectDestination
          ->getAsArray(),
      ])
        ->toString();
      $form['translatable']['#description'] = $this->t('To configure translation for this field, <a href=":language-settings-url">enable language support</a> for this type.', [
        ':language-settings-url' => $toggle_url,
      ]);
    }
    if ($field->isTranslatable()) {
      $element = $this->fieldSyncWidget
        ->widget($field);
      if ($element) {
        $form['third_party_settings']['content_translation']['translation_sync'] = $element;
        $form['third_party_settings']['content_translation']['translation_sync']['#weight'] = -10;
      }
    }
  }

}