unused_media_filter-1.0.x-dev/src/Plugin/views/filter/UnusedMediaFilter.php

<?php

namespace Drupal\unused_media_filter\Plugin\views\filter;

use Drupal\Core\Entity\ContentEntityTypeInterface;
use Drupal\Core\Entity\Sql\SqlContentEntityStorage;
use Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItemInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\views\Attribute\ViewsFilter;
use Drupal\views\Plugin\views\filter\FilterPluginBase;
use Drupal\views\Views;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Unused media filter.
 *
 * The filter scans all content entities that have media reference fields.
 *
 * @ingroup views_filter_handlers
 */
#[ViewsFilter("unused_media")]
class UnusedMediaFilter extends FilterPluginBase {

  /**
   * Where the $query object will reside.
   *
   * @var \Drupal\views\Plugin\views\query\Sql
   */
  public $query = NULL;

  /**
   * Whether to enable filtering.
   *
   * @var bool
   */
  protected $enableFiltering = FALSE;

  /**
   * The entity type manager.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;

  /**
   * The entity field manager.
   *
   * @var \Drupal\Core\Entity\EntityFieldManagerInterface
   */
  protected $entityFieldManager;

  /**
   * The field type plugin manager.
   *
   * @var \Drupal\Core\Field\FieldTypePluginManagerInterface
   */
  protected $fieldTypePluginManager;

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition){
    $instance = parent::create($container, $configuration, $plugin_id, $plugin_definition);
    $instance->entityTypeManager = $container->get('entity_type.manager');
    $instance->entityFieldManager = $container->get('entity_field.manager');
    $instance->fieldTypePluginManager = $container->get('plugin.manager.field.field_type');
    return $instance;
  }

  /**
   * {@inheritdoc}
   */
  public function buildExposedForm(&$form, FormStateInterface $form_state) {
    parent::buildExposedForm($form, $form_state);
    $identifier = $this->options['expose']['identifier'];
    $form[$identifier] = [
      '#type' => 'checkbox',
      '#title' => $this->options['expose']['label'],
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function acceptExposedInput($input) {
    $this->enableFiltering = !empty($input['unused_media']);
    return parent::acceptExposedInput($input);
  }

  /**
   * {@inheritdoc}
   */
  public function query() {
    if (!$this->enableFiltering) {
      return;
    }

    // Prevent results using this filter from being cached as otherwise we need
    // to implement a complex logic to invalidate cache whenever an entity is
    // added as a reference somewhere.
    $this->view->live_preview = TRUE;

    $delta = 0;
    foreach ($this->getTables() as $table => $field) {
      $definition['table'] = $table;
      $definition['field'] = $field;
      $definition['left_table'] = 'media_field_data';
      $definition['left_field'] = 'mid';
      $definition['type'] = 'LEFT';
      $definition['adjusted'] = TRUE;
      $join = Views::pluginManager('join')->createInstance('standard', $definition);

      // There is no $base as we are joining to a query.
      $this->query->addRelationship("t{$delta}", $join, 'media');
      $this->query->addWhere('AND', "t{$delta}.{$field}", NULL, 'IS NULL');

      $delta++;
    }
  }

  /**
   * Get all tables that have file reference fields.
   *
   * @return array
   *  An array of tables and their target_id column.
   */
  protected function getTables() {
    $entity_types = $this->entityTypeManager->getDefinitions();
    $file_reference_tables = [];
    foreach ($entity_types as $entity_type_id => $entity_type) {
      // Check if it is content entity type.
      if ($entity_type instanceof ContentEntityTypeInterface) {
        $storage = $this->entityTypeManager->getStorage($entity_type_id);
        if (!$storage instanceof SqlContentEntityStorage) {
          continue;
        }
        $table_mapping = $storage->getTableMapping();
        $field_storage_definitions = $this->entityFieldManager->getFieldStorageDefinitions($entity_type_id);
        foreach ($field_storage_definitions as $field_name => $field_storage) {
          $field_type = $this->fieldTypePluginManager->getDefinition($field_storage->getType());
          if (is_a($field_type['class'], EntityReferenceItemInterface::class, TRUE)) {
            if ($field_storage->getSetting('target_type') === 'media') {
              $target_id_column = $table_mapping->getColumnNames($field_name)['target_id'];
              $tables = $table_mapping->getAllFieldTableNames($field_name);
              $file_reference_tables = array_merge($file_reference_tables, array_combine($tables, array_fill(0, count($tables), $target_id_column)));
            }
          }
        }
      }
    }
    return $file_reference_tables;
  }

}