class EntityFormWizardBase

abstract class EntityFormWizardBase extends FormWizardBase implements EntityFormWizardInterface {
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * @param \Drupal\Core\TempStore\SharedTempStoreFactory $tempstore
     *   Tempstore Factory for keeping track of values in each step of the
     *   wizard.
     * @param \Drupal\Core\Form\FormBuilderInterface $builder
     *   The Form Builder.
     * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
     *   The class resolver.
     * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
     *   The event dispatcher.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param $tempstore_id
     *   The shared temp store factory collection name.
     * @param null $machine_name
     *   The SharedTempStore key for our current wizard values.
     * @param null $step
     *   The current active step of the wizard.
     */
    public function __construct(SharedTempStoreFactory $tempstore, FormBuilderInterface $builder, ClassResolverInterface $class_resolver, EventDispatcherInterface $event_dispatcher, RouteMatchInterface $route_match, RendererInterface $renderer, $tempstore_id, EntityTypeManagerInterface $entity_type_manager, $machine_name = NULL, $step = NULL) {
        parent::__construct($tempstore, $builder, $class_resolver, $event_dispatcher, $route_match, $renderer, $tempstore_id, $machine_name, $step);
        $this->entityTypeManager = $entity_type_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getParameters() {
        $parameters = [
            'tempstore' => \Drupal::service('tempstore.shared'),
            'builder' => \Drupal::service('form_builder'),
            'class_resolver' => \Drupal::service('class_resolver'),
            'event_dispatcher' => \Drupal::service('event_dispatcher'),
            'entity_type_manager' => \Drupal::service('entity_type.manager'),
            'renderer' => \Drupal::service('renderer'),
        ];
        // Keep the deprecated entity manager service as a parameter as well for
        // BC, so that subclasses still work.
        if (\Drupal::hasService('entity.manager')) {
            $parameters['entity_manager'] = \Drupal::service('entity.manager');
        }
        return $parameters;
    }
    
    /**
     * {@inheritdoc}
     */
    public function initValues() {
        $storage = $this->entityTypeManager
            ->getStorage($this->getEntityType());
        if ($this->getMachineName()) {
            $values = $this->getTempstore()
                ->get($this->getMachineName());
            if (!$values) {
                $entity = $storage->load($this->getMachineName());
                $values[$this->getEntityType()] = $entity;
                $values['id'] = $entity->id();
                $values['label'] = $entity->label();
            }
        }
        else {
            $entity = $storage->create([]);
            $values[$this->getEntityType()] = $entity;
        }
        $event = new WizardEvent($this, $values);
        $this->dispatcher
            ->dispatch($event, FormWizardInterface::LOAD_VALUES);
        return $event->getValues();
    }
    
    /**
     * {@inheritdoc}
     */
    public function finish(array &$form, FormStateInterface $form_state) {
        $cached_values = $form_state->getTemporaryValue('wizard');
        
        /** @var \Drupal\Core\Entity\EntityInterface $entity */
        $entity = $cached_values[$this->getEntityType()];
        $entity->set('id', $cached_values['id']);
        $entity->set('label', $cached_values['label']);
        $status = $entity->save();
        $arguments = [
            '@entity-type' => $entity->getEntityType()
                ->getSingularLabel(),
            '%label' => $entity->label(),
        ];
        if ($status === SAVED_UPDATED) {
            $this->messenger()
                ->addMessage($this->t('The @entity-type %label has been updated.', $arguments));
            $this->logger($entity->getEntityType()
                ->getProvider())
                ->notice('Updated @entity-type %label.', $arguments);
        }
        elseif ($status === SAVED_NEW) {
            $this->messenger()
                ->addMessage($this->t('The @entity-type %label has been added.', $arguments));
            $this->logger($entity->getEntityType()
                ->getProvider())
                ->notice('Added @entity-type %label.', $arguments);
        }
        $form_state->setRedirectUrl($entity->toUrl('collection'));
        parent::finish($form, $form_state);
    }
    
    /**
     * Helper function for generating label and id form elements.
     *
     * @param array $form
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *
     * @return array
     */
    protected function customizeForm(array $form, FormStateInterface $form_state) {
        $form = parent::customizeForm($form, $form_state);
        if ($this->machine_name) {
            $entity = $this->entityTypeManager
                ->getStorage($this->getEntityType())
                ->load($this->machine_name);
        }
        else {
            $entity = NULL;
        }
        $cached_values = $form_state->getTemporaryValue('wizard');
        // If the entity already exists, allow for non-linear step interaction.
        if ($entity) {
            // Setup the step rendering theme element.
            $prefix = [
                '#theme' => [
                    'ctools_wizard_trail_links',
                ],
                '#wizard' => $this,
                '#cached_values' => $cached_values,
            ];
            $form['#prefix'] = \Drupal::service('renderer')->render($prefix);
        }
        // Get the current form operation.
        $operation = $this->getOperation($cached_values);
        $operations = $this->getOperations($cached_values);
        $default_operation = reset($operations);
        if ($operation['form'] == $default_operation['form']) {
            // Get the plugin definition of this entity.
            $definition = $this->entityTypeManager
                ->getDefinition($this->getEntityType());
            // Create id and label form elements.
            $form['name'] = [
                '#type' => 'fieldset',
                '#attributes' => [
                    'class' => [
                        'fieldset-no-legend',
                    ],
                ],
                '#title' => $this->getWizardLabel(),
            ];
            $form['name']['label'] = [
                '#type' => 'textfield',
                '#title' => $this->getMachineLabel(),
                '#required' => TRUE,
                '#size' => 32,
                '#default_value' => !empty($cached_values['label']) ? $cached_values['label'] : '',
                '#maxlength' => 255,
                '#disabled' => !empty($cached_values['label']),
            ];
            $form['name']['id'] = [
                '#type' => 'machine_name',
                '#maxlength' => 128,
                '#machine_name' => [
                    'source' => [
                        'name',
                        'label',
                    ],
                    'exists' => $this->exists(),
                ],
                '#description' => $this->t('A unique machine-readable name for this @entity_type. It must only contain lowercase letters, numbers, and underscores.', [
                    '@entity_type' => $definition->getLabel(),
                ]),
                '#default_value' => !empty($cached_values['id']) ? $cached_values['id'] : '',
                '#disabled' => !empty($cached_values['id']),
            ];
        }
        return $form;
    }

}