class ConfigureBlockFormBase

abstract class ConfigureBlockFormBase extends FormBase implements BaseFormIdInterface {
    use AjaxFormHelperTrait;
    use ContextAwarePluginAssignmentTrait;
    use LayoutBuilderContextTrait;
    use LayoutRebuildTrait;
    
    /**
     * The plugin being configured.
     *
     * @var \Drupal\Core\Block\BlockPluginInterface
     */
    protected $block;
    
    /**
     * The layout tempstore repository.
     *
     * @var \Drupal\layout_builder\LayoutTempstoreRepositoryInterface
     */
    protected $layoutTempstoreRepository;
    
    /**
     * The block manager.
     *
     * @var \Drupal\Core\Block\BlockManagerInterface
     */
    protected $blockManager;
    
    /**
     * The UUID generator.
     *
     * @var \Drupal\Component\Uuid\UuidInterface
     */
    protected $uuidGenerator;
    
    /**
     * The plugin form manager.
     *
     * @var \Drupal\Core\Plugin\PluginFormFactoryInterface
     */
    protected $pluginFormFactory;
    
    /**
     * The field delta.
     *
     * @var int
     */
    protected $delta;
    
    /**
     * The current region.
     *
     * @var string
     */
    protected $region;
    
    /**
     * The UUID of the component.
     *
     * @var string
     */
    protected $uuid;
    
    /**
     * The section storage.
     *
     * @var \Drupal\layout_builder\SectionStorageInterface
     */
    protected $sectionStorage;
    
    /**
     * Constructs a new block form.
     *
     * @param \Drupal\layout_builder\LayoutTempstoreRepositoryInterface $layout_tempstore_repository
     *   The layout tempstore repository.
     * @param \Drupal\Core\Plugin\Context\ContextRepositoryInterface $context_repository
     *   The context repository.
     * @param \Drupal\Core\Block\BlockManagerInterface $block_manager
     *   The block manager.
     * @param \Drupal\Component\Uuid\UuidInterface $uuid
     *   The UUID generator.
     * @param \Drupal\Core\Plugin\PluginFormFactoryInterface $plugin_form_manager
     *   The plugin form manager.
     */
    public function __construct(LayoutTempstoreRepositoryInterface $layout_tempstore_repository, ContextRepositoryInterface $context_repository, BlockManagerInterface $block_manager, UuidInterface $uuid, PluginFormFactoryInterface $plugin_form_manager) {
        $this->layoutTempstoreRepository = $layout_tempstore_repository;
        $this->contextRepository = $context_repository;
        $this->blockManager = $block_manager;
        $this->uuidGenerator = $uuid;
        $this->pluginFormFactory = $plugin_form_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('layout_builder.tempstore_repository'), $container->get('context.repository'), $container->get('plugin.manager.block'), $container->get('uuid'), $container->get('plugin_form.factory'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getBaseFormId() {
        return 'layout_builder_configure_block';
    }
    
    /**
     * Builds the form for the block.
     *
     * @param array $form
     *   An associative array containing the structure of the form.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     * @param \Drupal\layout_builder\SectionStorageInterface $section_storage
     *   The section storage being configured.
     * @param int $delta
     *   The delta of the section.
     * @param \Drupal\layout_builder\SectionComponent $component
     *   The section component containing the block.
     *
     * @return array
     *   The form array.
     */
    public function doBuildForm(array $form, FormStateInterface $form_state, SectionStorageInterface $section_storage = NULL, $delta = NULL, SectionComponent $component = NULL) {
        $this->sectionStorage = $section_storage;
        $this->delta = $delta;
        $this->uuid = $component->getUuid();
        $this->block = $component->getPlugin();
        $form_state->setTemporaryValue('gathered_contexts', $this->getPopulatedContexts($section_storage));
        // @todo Remove once https://www.drupal.org/node/2268787 is resolved.
        $form_state->set('block_theme', $this->config('system.theme')
            ->get('default'));
        $form['#tree'] = TRUE;
        $form['settings'] = [];
        $subform_state = SubformState::createForSubform($form['settings'], $form, $form_state);
        $form['settings'] = $this->getPluginForm($this->block)
            ->buildConfigurationForm($form['settings'], $subform_state);
        $form['actions']['submit'] = [
            '#type' => 'submit',
            '#value' => $this->submitLabel(),
            '#button_type' => 'primary',
        ];
        if ($this->isAjax()) {
            $form['actions']['submit']['#ajax']['callback'] = '::ajaxSubmit';
            // @todo static::ajaxSubmit() requires data-drupal-selector to be the same
            //   between the various Ajax requests. A bug in
            //   \Drupal\Core\Form\FormBuilder prevents that from happening unless
            //   $form['#id'] is also the same. Normally, #id is set to a unique HTML
            //   ID via Html::getUniqueId(), but here we bypass that in order to work
            //   around the data-drupal-selector bug. This is okay so long as we
            //   assume that this form only ever occurs once on a page. Remove this
            //   workaround in https://www.drupal.org/node/2897377.
            $form['#id'] = Html::getId($form_state->getBuildInfo()['form_id']);
        }
        // Mark this as an administrative page for JavaScript ("Back to site" link).
        $form['#attached']['drupalSettings']['path']['currentPathIsAdmin'] = TRUE;
        return $form;
    }
    
    /**
     * Returns the label for the submit button.
     *
     * @return string
     *   Submit label.
     */
    protected abstract function submitLabel();
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        $subform_state = SubformState::createForSubform($form['settings'], $form, $form_state);
        $this->getPluginForm($this->block)
            ->validateConfigurationForm($form['settings'], $subform_state);
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        // Call the plugin submit handler.
        $subform_state = SubformState::createForSubform($form['settings'], $form, $form_state);
        $this->getPluginForm($this->block)
            ->submitConfigurationForm($form, $subform_state);
        // If this block is context-aware, set the context mapping.
        if ($this->block instanceof ContextAwarePluginInterface) {
            $this->block
                ->setContextMapping($subform_state->getValue('context_mapping', []));
        }
        $configuration = $this->block
            ->getConfiguration();
        $section = $this->sectionStorage
            ->getSection($this->delta);
        $section->getComponent($this->uuid)
            ->setConfiguration($configuration);
        $this->layoutTempstoreRepository
            ->set($this->sectionStorage);
        $form_state->setRedirectUrl($this->sectionStorage
            ->getLayoutBuilderUrl());
    }
    
    /**
     * {@inheritdoc}
     */
    protected function successfulAjaxSubmit(array $form, FormStateInterface $form_state) {
        return $this->rebuildAndClose($this->sectionStorage);
    }
    
    /**
     * Retrieves the plugin form for a given block.
     *
     * @param \Drupal\Core\Block\BlockPluginInterface $block
     *   The block plugin.
     *
     * @return \Drupal\Core\Plugin\PluginFormInterface
     *   The plugin form for the block.
     */
    protected function getPluginForm(BlockPluginInterface $block) {
        if ($block instanceof PluginWithFormsInterface) {
            return $this->pluginFormFactory
                ->createInstance($block, 'configure');
        }
        return $block;
    }
    
    /**
     * Retrieves the section storage object.
     *
     * @return \Drupal\layout_builder\SectionStorageInterface
     *   The section storage for the current form.
     */
    public function getSectionStorage() {
        return $this->sectionStorage;
    }
    
    /**
     * Retrieves the current layout section being edited by the form.
     *
     * @return \Drupal\layout_builder\Section
     *   The current layout section.
     */
    public function getCurrentSection() {
        return $this->sectionStorage
            ->getSection($this->delta);
    }
    
    /**
     * Retrieves the current component being edited by the form.
     *
     * @return \Drupal\layout_builder\SectionComponent
     *   The current section component.
     */
    public function getCurrentComponent() {
        return $this->getCurrentSection()
            ->getComponent($this->uuid);
    }

}