media_attribution/entity_embed_attribution.module

<?php

/**
 * @file
 * Contains entity_embed_attribution.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Url;
use Drupal\Core\Render\Markup;
use Drupal\Core\Entity\Entity\EntityFormDisplay;
use Drupal\Core\Entity\Entity\EntityViewDisplay;


/**
 * Implements hook_help().
 */
function entity_embed_attribution_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the entity_embed_attribution module.
    case 'help.page.entity_embed_attribution':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Attach an attribution and license info to embedded media') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_modules_installed().
 *
 * Add attribution form to media embed forms and view displays.
 */
function entity_embed_attribution_modules_installed($modules) {
  foreach (['media_browser', 'default'] as $form_variant) {
    $form_entity = EntityFormDisplay::load("media.image.$form_variant");
    $form_entity->setComponent('field_image_attribution',
      [
        'region' => 'content',
        'settings' => [
          'title' => 'Paragraph',
          'title_plural' => 'Paragraphs',
          'edit_mode' => 'open',
          'closed_mode' => 'summary',
          'autocollapse' => 'none',
          'closed_mode_threshold' => 0,
          'add_mode' => 'dropdown',
          'form_display_mode' => 'default',
          'default_paragraph_type' => '',
          'features' => [
            'duplicate' => 'duplicate',
            'collapse_edit_all' => 'collapse_edit_all',
          ]
        ],
        'type' => 'paragraphs',
      ])
      ->save();
  }

  foreach (['embedded', 'default'] as $entity_view_variant) {
    $view_entity = EntityViewDisplay::load("media.image.$entity_view_variant");
    $view_entity->setComponent('field_image_attribution', [
        'type' => 'entity_reference_revisions_entity_view',
        'label' => 'hidden',
        'settings' => ['view_mode' => 'default', 'link' => ''],
      ])->save();
  }
}

/**
 * Implementation of hook_preprocess_entity_embed_container().
 *
 * @param $variables
 */
function entity_embed_attribution_preprocess_entity_embed_container(&$variables) {

  if ($attributions = $variables['element']['#entity']->get('field_image_attribution')->referencedEntities()) {
    $attribution = $attributions[0];
    $author = $attribution->get('field_attribution_author')->getValue()[0];

    $source = $attribution->get('field_attribution_source')->getValue()[0];
    $license = $attribution->get('field_license')->entity;
    $license_link = $license->get('field_license_link')->getValue()[0];

    $attribution_text = [
      'source' => [
        '#type' => 'link',
        '#title' => $source['title'],
        '#prefix' => "<br>&ldquo;<cite>",
        '#suffix' => "</cite>&rdquo;",
        '#url' => Url::fromUri($source['uri']),
      ],
    ];
  }
  if (!empty($author)) {
    $attribution_text['author'] = [
      '#type' => 'link',
      '#title' => $author['title'],
      '#prefix' => ' ' . t('by') . ' ',
      '#url' => Url::fromUri($author['uri']),
    ];
  }
  if (!empty($license_link)) {
    $attribution_text['license'] = [
      '#type' => 'link',
      '#title' => $license_link['title'],
      '#prefix' => ' ' . t('is licensec under') . ' ',
      '#url' => Url::fromUri($license_link['uri']),
      '#suffix' => '.',

    ];
  }
//  $attribution_string = \Drupal::render($attribution_text);

  $variables['children'] = ['first' =>  ['#type' => 'markup', '#markup' => render($variables['children'])],
    $attribution_text
  ];




}