EntityReferenceAutocompleteWithFieldSelect.php

<?php

namespace Drupal\tfnsw_corp_asa_standard\Plugin\Field\FieldWidget;

use Drupal\Component\Utility\NestedArray;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\Plugin\Field\FieldWidget\EntityReferenceAutocompleteWidget;
use Drupal\Core\Form\FormStateInterface;

/**
 * Widget that uses autocomplete.
 *
 * @FieldWidget(
 *   id = "entity_reference_field",
 *   label = @Translation("Autocomplete with field dropdown"),
 *   description = @Translation("An autocomplete text field with field dropdown."),
 *   field_types = {
 *     "entity_reference_field"
 *   }
 * )
 */
class EntityReferenceAutocompleteWithFieldSelect extends EntityReferenceAutocompleteWidget {

  const ALLOWED_FIELDS = [
    'field_date_released',
    'field_date_published',
  ];
  const PARAGRAPH_BUNDLE = 'asa_standard_dates';
  const PARAGRAPH_FIELD = 'field_dates';
  const AJAX_WRAPPER_ID = 'entity_reference_field';

  /**
   * {@inheritdoc}
   */
  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
    $wrapper_id = sprintf('%s-%s-%s', self::AJAX_WRAPPER_ID, $this->fieldDefinition->getName(), $delta);
    $element += parent::formElement($items, $delta, $element, $form, $form_state);
    $element += [
      '#theme_wrappers' => ['container'],
    ];
    $element['#attributes'] = ['class' => ['form--inline', 'clearfix']];
    $element['target_id']['#weight'] = 0;
    $element['target_id']['#ajax'] = [
      'callback' => [get_class($this), 'autocompleteAjax'],
      'wrapper' => $wrapper_id,
      'progress' => [
        'type' => 'throbber',
      ],
      'event' => 'autocompleteclose',
    ];

    $options = [];
    // Workaround for now to avoid errors with select options not existing.
    foreach (self::ALLOWED_FIELDS as $field) {
      $options[$field] = t('Please choose a reference first');
    }

    $entity_id = NULL;
    if ($items[$delta]->target_id) {
      $entity_id = $items[$delta]->target_id;
    }
    elseif ($form_state->getValue($this->fieldDefinition->getName())) {
      $entity_id = $form_state->getValue($this->fieldDefinition->getName())[$delta]['target_id'];
    }

    if ($entity_id) {
      $options = array_merge($options, self::getDateOptions($this->getFieldSetting('target_type'), $entity_id));
    }
    $element['field_name'] = [
      '#prefix' => '<div id="' . $wrapper_id . '">',
      '#suffix' => '</div>',
      '#type' => 'select',
      '#title' => t('Field name (value @delta)', ['@delta' => $delta + 1]),
      '#title_display' => 'invisible',
      '#options' => $options,
      '#weight' => 1,
      '#default_value' => isset($items[$delta]->field_name) ? $items[$delta]->field_name : '',
    ];

    return $element;
  }

  /**
   * Autocomplete ajax functionality to display the date values of the entity.
   *
   * @param array $form
   *   The complete form.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The form state.
   *
   * @return array
   *   The altered form array.
   */
  public function autocompleteAjax(array &$form, FormStateInterface $form_state) {
    $triggering_element = $form_state->getTriggeringElement();

    // Go one level up in the form, to the widgets container.
    $element = NestedArray::getValue($form, array_slice($triggering_element['#array_parents'], 0, -1));

    return $element['field_name'];
  }

  /**
   * Gets an array of date options, keyed by field name.
   *
   * @param string $entity_type
   *   The entity type.
   * @param int $entity_id
   *   The entity id.
   *
   * @return array
   *   An array of options.
   */
  private static function getDateOptions($entity_type, $entity_id) {
    $items = [];

    $entity = \Drupal::entityTypeManager()->getStorage($entity_type)->load($entity_id);
    if (!$entity) {
      return $items;
    }
    /** @var \Drupal\Core\Datetime\DateFormatterInterface $date_formatter */
    $date_formatter = \Drupal::service('date.formatter');
    $date_entities = $entity->{self::PARAGRAPH_FIELD}->referencedEntities();
    $date_entity = reset($date_entities);
    $field_name_labels = self::getFieldLabels();
    // Render the date values.
    foreach ($field_name_labels as $field_name => $label) {
      $date = $date_entity->{$field_name}->date;
      $options = [
        '@label' => $label,
        '@value' => $date ? $date_formatter->format($date->format('U'), 'short_date_only') : 'Not set',
      ];
      $items[$field_name] = t('Date @label: @value', $options);
    }
    return $items;
  }

  /**
   * Return an array keyed by field name with values for the labels in config.
   *
   * @return array
   *   The field names and labels.
   */
  private static function getFieldLabels() {
    /** @var \Drupal\Core\Entity\EntityFieldManagerInterface $field_manager */
    $field_manager = \Drupal::service('entity_field.manager');
    $fields = $field_manager->getFieldDefinitions('paragraph', self::PARAGRAPH_BUNDLE);
    $field_labels = [];
    foreach (self::ALLOWED_FIELDS as $field_name) {
      if (isset($fields[$field_name])) {
        $field_labels[$field_name] = $fields[$field_name]->getLabel();
      }
    }

    return $field_labels;
  }

}