class MediaPermissions

class MediaPermissions implements ContainerInjectionInterface {
    use StringTranslationTrait;
    
    /**
     * The entity type manager service.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * MediaPermissions constructor.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager service.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager) {
        $this->entityTypeManager = $entity_type_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_type.manager'));
    }
    
    /**
     * Returns an array of media type permissions.
     *
     * @return array
     *   The media type permissions.
     *
     * @see \Drupal\user\PermissionHandlerInterface::getPermissions()
     */
    public function mediaTypePermissions() {
        $perms = [];
        // Generate media permissions for all media types.
        $media_types = $this->entityTypeManager
            ->getStorage('media_type')
            ->loadMultiple();
        foreach ($media_types as $type) {
            $perms += $this->buildPermissions($type);
        }
        return $perms;
    }
    
    /**
     * Returns a list of media permissions for a given media type.
     *
     * @param \Drupal\media\MediaTypeInterface $type
     *   The media type.
     *
     * @return array
     *   An associative array of permission names and descriptions.
     */
    protected function buildPermissions(MediaTypeInterface $type) {
        $type_id = $type->id();
        $type_params = [
            '%type_name' => $type->label(),
        ];
        return [
            "create {$type_id} media" => [
                'title' => $this->t('%type_name: Create new media', $type_params),
            ],
            "edit own {$type_id} media" => [
                'title' => $this->t('%type_name: Edit own media', $type_params),
            ],
            "edit any {$type_id} media" => [
                'title' => $this->t('%type_name: Edit any media', $type_params),
            ],
            "delete own {$type_id} media" => [
                'title' => $this->t('%type_name: Delete own media', $type_params),
            ],
            "delete any {$type_id} media" => [
                'title' => $this->t('%type_name: Delete any media', $type_params),
            ],
        ];
    }

}