should probably include the heckin form

src/Form/ConfirmDeleteMediaAndFile.php

@@ -0,0 +1,182 @@
+<?php
+
+namespace Drupal\islandora\Form;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Entity\Form\DeleteMultipleForm;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\TempStore\PrivateTempStoreFactory;
+use Drupal\Core\Url;
+use Drupal\islandora\MediaSource\MediaSourceService;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Confirmation form for the 'Delete media and file(s)' action.
+ */
+class ConfirmDeleteMediaAndFile extends DeleteMultipleForm {
+
+  /**
+   * Media source service.
+   *
+   * @var \Drupal\islandora\MediaSource\MediaSourceService
+   */
+  protected $mediaSourceService;
+
+  /**
+   * Logger.
+   *
+   * @var Psr\Log\LoggerInterface
+   */
+  protected $logger;
+
+  /**
+   * List of media targeted.
+   *
+   * @var array
+   */
+  protected $selection = [];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(AccountInterface $current_user, EntityTypeManagerInterface $entity_type_manager, PrivateTempStoreFactory $temp_store_factory, MessengerInterface $messenger, MediaSourceService $media_source_service, LoggerInterface $logger) {
+    $this->currentUser = $current_user;
+    $this->entityTypeManager = $entity_type_manager;
+    $this->tempStore = $temp_store_factory->get('media_and_file_delete_confirm');
+    $this->messenger = $messenger;
+    $this->mediaSourceService = $media_source_service;
+    $this->logger = $logger;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('current_user'),
+      $container->get('entity_type.manager'),
+      $container->get('tempstore.private'),
+      $container->get('messenger'),
+      $container->get('islandora.media_source_service'),
+      $container->get('logger.channel.islandora'));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'media_and_file_delete_confirm_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getQuestion() {
+    return $this->formatPlural(count($this->selection),
+      'Are you sure you want to delete this media and associated files?',
+      'Are you sure you want to delete these media and associated files?');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCancelUrl() {
+    return new Url('entity.media.collection');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state, $entity_type_id = NULL) {
+    return parent::buildForm($form, $form_state, 'media');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    // Similar to parent::submitForm(), but let's blend in the related files and
+    // optimize based on the fact that we know we're working with media.
+    $total_count = 0;
+    $delete_media = [];
+    $delete_media_translations = [];
+    $delete_files = [];
+    $inaccessible_entities = [];
+    $media_storage = $this->entityTypeManager->getStorage('media');
+    $file_storage = $this->entityTypeManager->getStorage('file');
+    $media = $media_storage->loadMultiple(array_keys($this->selection));
+    foreach ($this->selection as $id => $selected_langcodes) {
+      $entity = $media[$id];
+      if (!$entity->access('delete', $this->currentUser)) {
+        $inaccessible_entities[] = $entity;
+        continue;
+      }
+      // Check for files.
+      $source_field = $this->mediaSourceService->getSourceFieldName($entity->bundle());
+      foreach ($entity->get($source_field)->referencedEntities() as $file) {
+        if (!$file->access('delete', $this->currentUser)) {
+          $inaccessible_entities[] = $file;
+          continue;
+        }
+        $delete_files[$file->id()] = $file;
+        $total_count++;
+      }
+      foreach ($selected_langcodes as $langcode) {
+        // We're only working with media, which are translatable.
+        $entity = $entity->getTranslation($langcode);
+        if ($entity->isDefaultTranslation()) {
+          $delete_media[$id] = $entity;
+          unset($delete_media_translations[$id]);
+          $total_count += count($entity->getTranslationLanguages());
+        }
+        elseif (!isset($delete_media[$id])) {
+          $delete_media_translations[$id][] = $entity;
+        }
+      }
+    }
+    if ($delete_media) {
+      $media_storage->delete($delete_media);
+      foreach ($delete_media as $entity) {
+        $this->logger->notice('The media %label has been deleted.', [
+          '%label' => $entity->label(),
+        ]);
+      }
+    }
+    if ($delete_files) {
+      $file_storage->delete($delete_files);
+      foreach ($delete_files as $entity) {
+        $this->logger->notice('The file %label has been deleted.', [
+          '%label' => $entity->label(),
+        ]);
+      }
+    }
+    if ($delete_media_translations) {
+      foreach ($delete_media_translations as $id => $translations) {
+        $entity = $media[$id];
+        foreach ($translations as $translation) {
+          $entity->removeTranslation($translation->language()->getId());
+        }
+        $entity->save();
+        foreach ($translations as $translation) {
+          $this->logger->notice('The media %label @language translation has been deleted', [
+            '%label' => $entity->label(),
+            '@language' => $translation->language()->getName(),
+          ]);
+        }
+        $total_count += count($translations);
+      }
+    }
+    if ($total_count) {
+      $this->messenger->addStatus($this->getDeletedMessage($total_count));
+    }
+    if ($inaccessible_entities) {
+      $this->messenger->addWarning($this->getInaccessibleMessage(count($inaccessible_entities)));
+    }
+    $this->tempStore->delete($this->currentUser->id());
+    $form_state->setRedirectUrl($this->getCancelUrl());
+  }
+
+}