class D6NodeDeriver

class D6NodeDeriver extends DeriverBase implements ContainerDeriverInterface {
    use MigrationDeriverTrait;
    use StringTranslationTrait;
    
    /**
     * The base plugin ID this derivative is for.
     *
     * @var string
     */
    protected $basePluginId;
    
    /**
     * Whether or not to include translations.
     *
     * @var bool
     */
    protected $includeTranslations;
    
    /**
     * The migration field discovery service.
     *
     * @var \Drupal\migrate_drupal\FieldDiscoveryInterface
     */
    protected $fieldDiscovery;
    
    /**
     * D6NodeDeriver constructor.
     *
     * @param string $base_plugin_id
     *   The base plugin ID for the plugin ID.
     * @param bool $translations
     *   Whether or not to include translations.
     * @param \Drupal\migrate_drupal\FieldDiscoveryInterface $field_discovery
     *   The migration field discovery service.
     */
    public function __construct($base_plugin_id, $translations, FieldDiscoveryInterface $field_discovery) {
        $this->basePluginId = $base_plugin_id;
        $this->includeTranslations = $translations;
        $this->fieldDiscovery = $field_discovery;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, $base_plugin_id) {
        // Translations don't make sense unless we have content_translation.
        return new static($base_plugin_id, $container->get('module_handler')
            ->moduleExists('content_translation'), $container->get('migrate_drupal.field_discovery'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDerivativeDefinitions($base_plugin_definition) {
        if ($base_plugin_definition['id'] == 'd6_node_translation' && !$this->includeTranslations) {
            // Refuse to generate anything.
            return $this->derivatives;
        }
        $node_types = static::getSourcePlugin('d6_node_type');
        try {
            $node_types->checkRequirements();
        } catch (RequirementsException $e) {
            // If the d6_node_type requirements failed, that means we do not have a
            // Drupal source database configured - there is nothing to generate.
            return $this->derivatives;
        }
        try {
            foreach ($node_types as $row) {
                $node_type = $row->getSourceProperty('type');
                $values = $base_plugin_definition;
                $values['label'] = $this->t("@label (@type)", [
                    '@label' => $values['label'],
                    '@type' => $node_type,
                ]);
                $values['source']['node_type'] = $node_type;
                $values['destination']['default_bundle'] = $node_type;
                // If this migration is based on the d6_node_revision migration or
                // is for translations of nodes, it should explicitly depend on the
                // corresponding d6_node variant.
                if (in_array($base_plugin_definition['id'], [
                    'd6_node_revision',
                    'd6_node_translation',
                ])) {
                    $values['migration_dependencies']['required'][] = 'd6_node:' . $node_type;
                }
                
                /** @var \Drupal\migrate\Plugin\Migration $migration */
                $migration = \Drupal::service('plugin.manager.migration')->createStubMigration($values);
                $this->fieldDiscovery
                    ->addBundleFieldProcesses($migration, 'node', $node_type);
                $this->derivatives[$node_type] = $migration->getPluginDefinition();
            }
        } catch (DatabaseExceptionWrapper $e) {
            // Once we begin iterating the source plugin it is possible that the
            // source tables will not exist. This can happen when the
            // MigrationPluginManager gathers up the migration definitions but we do
            // not actually have a Drupal 6 source database.
        }
        return $this->derivatives;
    }

}