materio-d8/web/modules/custom/vue_link_formatter/src/Plugin/Field/FieldFormatter/VueLinkFormatter.php

<?php

namespace Drupal\vue_link_formatter\Plugin\Field\FieldFormatter;

use Drupal\Component\Utility\Unicode;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\link\Plugin\Field\FieldFormatter\LinkFormatter;
use Drupal\Core\Form\FormStateInterface;

/**
 * Plugin implementation of the 'link_separate' formatter.
 *
 * @todo https://www.drupal.org/node/1829202 Merge into 'link' formatter once
 *   there is a #type like 'item' that can render a compound label and content
 *   outside of a form context.
 *
 * @FieldFormatter(
 *   id = "vue_link_formatter",
 *   label = @Translation("Vue Link"),
 *   field_types = {
 *     "link"
 *   }
 * )
 */
class VueLinkFormatter extends LinkFormatter {

  /**
   * {@inheritdoc}
   */
  public static function defaultSettings() {
    return [
      'trim_length' => 80,
      'link_text' => '',
      'event_modifiers' => NULL,
      'methode' => '',
    ] + parent::defaultSettings();
  }

  public function settingsForm(array $parentForm, FormStateInterface $form_state) {
    $parentForm = parent::settingsForm($parentForm, $form_state);
    $settings = $this->getSettings();

    $form['link_text'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Link text, leave empty for default'),
      '#default_value' => $settings['link_text'],
    ];

    $form['methode'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Vue methode for @click vue-attribute.'),
      '#default_value' => $settings['methode'],
      '#required' => TRUE,
    ];

    $form['event_modifiers'] = [
      '#type' => 'checkboxes',
      '#title' => $this->t('Event modifiers'),
      '#default_value' => $settings['event_modifiers'],
      // '#empty_option' => $this->t('None'),
      '#options' => [
        'prevent' => $this->t('.prevent'),
        'stop' => $this->t('.stop'),
        'capture' => $this->t('.capture'),
        'self' => $this->t('.self'),
        'once' => $this->t('.once'),
        'passive' => $this->t('.passive'),
      ],
    ];

    return $form + $parentForm;
  }

  public function settingsSummary() {
    $settings = $this->getSettings();
    $summary = [];
    if (!empty($settings['link_text'])) {
      $summary[] = $this->t('Link text: @text"', ['@text' => $settings['link_text']]);
    }
    if (!empty($settings['methode'])) {
      $summary[] = $this->t('Click Methode: @text', ['@text' => $settings['methode']]);
    }
    if (!empty($settings['event_modifiers'])) {
      $summary[] = $this->t('Event modifier: @text', ['@text' => implode('.', $settings['event_modifiers'])]);
    }

    // TODO: add key event

    return $summary;
  }

  /**
   * {@inheritdoc}
   */
  public function viewElements(FieldItemListInterface $items, $langcode) {
    $element = array();
    $entity = $items->getEntity();
    $settings = $this->getSettings();

    foreach ($items as $delta => $item) {
      // By default use the full URL as the link text.
      $url = $this->buildUrl($item);
      $link_title = $url->toString();

      // If the link text field value is available, use it for the text.
      if (empty($settings['url_only']) && !empty($item->title)) {
        // Unsanitized token replacement here because the entire link title
        // gets auto-escaped during link generation in
        // \Drupal\Core\Utility\LinkGenerator::generate().
        $link_title = \Drupal::token()->replace($item->title, [$entity->getEntityTypeId() => $entity], ['clear' => TRUE]);
      }

      if (!empty($settings['link_text'])) {
        $link_title = $this->t($settings['link_text']);
      }

      // The link_separate formatter has two titles; the link text (as in the
      // field values) and the URL itself. If there is no link text value,
      // $link_title defaults to the URL, so it needs to be unset.
      // The URL version may need to be trimmed as well.
      if (empty($item->title) && empty($settings['link_text'])) {
        $link_title = NULL;
      }
      $url_title = $url->toString();
      if (!empty($settings['trim_length'])) {
        $link_title = Unicode::truncate($link_title, $settings['trim_length'], FALSE, TRUE);
        $url_title = Unicode::truncate($url_title, $settings['trim_length'], FALSE, TRUE);
      }

      $element[$delta] = array(
        '#theme' => 'link_formatter_vue_link_formatter',
        '#title' => $link_title,
        '#url_title' => $url_title,
        '#url' => $url,
        '#methode' => $settings['methode'],
        '#event_modifiers' => $settings['event_modifiers'],
      );


      $attributes = [];
      if (!empty($item->_attributes)) {
        // Set our RDFa attributes on the <a> element that is being built.
        $url->setOption('attributes', $item->_attributes);

        // Unset field item attributes since they have been included in the
        // formatter output and should not be rendered in the field template.
        unset($item->_attributes);
      }
    }
    return $element;
  }

}