class ConfigureSectionForm

class ConfigureSectionForm extends FormBase {
    use AjaxFormHelperTrait;
    use LayoutBuilderContextTrait;
    use LayoutBuilderHighlightTrait;
    use LayoutRebuildTrait;
    
    /**
     * The layout tempstore repository.
     *
     * @var \Drupal\layout_builder\LayoutTempstoreRepositoryInterface
     */
    protected $layoutTempstoreRepository;
    
    /**
     * The plugin being configured.
     *
     * @var \Drupal\Core\Layout\LayoutInterface|\Drupal\Core\Plugin\PluginFormInterface
     */
    protected $layout;
    
    /**
     * The section being configured.
     *
     * @var \Drupal\layout_builder\Section
     */
    protected $section;
    
    /**
     * The plugin form manager.
     *
     * @var \Drupal\Core\Plugin\PluginFormFactoryInterface
     */
    protected $pluginFormFactory;
    
    /**
     * The section storage.
     *
     * @var \Drupal\layout_builder\SectionStorageInterface
     */
    protected $sectionStorage;
    
    /**
     * The field delta.
     *
     * @var int
     */
    protected $delta;
    
    /**
     * The plugin ID.
     *
     * @var string
     */
    protected $pluginId;
    
    /**
     * Indicates whether the section is being added or updated.
     *
     * @var bool
     */
    protected $isUpdate;
    
    /**
     * Constructs a new ConfigureSectionForm.
     *
     * @param \Drupal\layout_builder\LayoutTempstoreRepositoryInterface $layout_tempstore_repository
     *   The layout tempstore repository.
     * @param \Drupal\Core\Plugin\PluginFormFactoryInterface $plugin_form_manager
     *   The plugin form manager.
     */
    public function __construct(LayoutTempstoreRepositoryInterface $layout_tempstore_repository, PluginFormFactoryInterface $plugin_form_manager) {
        $this->layoutTempstoreRepository = $layout_tempstore_repository;
        $this->pluginFormFactory = $plugin_form_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('layout_builder.tempstore_repository'), $container->get('plugin_form.factory'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'layout_builder_configure_section';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state, SectionStorageInterface $section_storage = NULL, $delta = NULL, $plugin_id = NULL) {
        $this->sectionStorage = $section_storage;
        $this->delta = $delta;
        $this->isUpdate = is_null($plugin_id);
        $this->pluginId = $plugin_id;
        $section = $this->getCurrentSection();
        if ($this->isUpdate) {
            if ($label = $section->getLayoutSettings()['label']) {
                $form['#title'] = $this->t('Configure @section', [
                    '@section' => $label,
                ]);
            }
        }
        // Passing available contexts to the layout plugin here could result in an
        // exception since the layout may not have a context mapping for a required
        // context slot on creation.
        $this->layout = $section->getLayout();
        $form_state->setTemporaryValue('gathered_contexts', $this->getPopulatedContexts($this->sectionStorage));
        $form['#tree'] = TRUE;
        $form['layout_settings'] = [];
        $subform_state = SubformState::createForSubform($form['layout_settings'], $form, $form_state);
        $form['layout_settings'] = $this->getPluginForm($this->layout)
            ->buildConfigurationForm($form['layout_settings'], $subform_state);
        $form['actions']['submit'] = [
            '#type' => 'submit',
            '#value' => $this->isUpdate ? $this->t('Update') : $this->t('Add section'),
            '#button_type' => 'primary',
        ];
        if ($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']);
        }
        $target_highlight_id = $this->isUpdate ? $this->sectionUpdateHighlightId($delta) : $this->sectionAddHighlightId($delta);
        $form['#attributes']['data-layout-builder-target-highlight-id'] = $target_highlight_id;
        // Mark this as an administrative page for JavaScript ("Back to site" link).
        $form['#attached']['drupalSettings']['path']['currentPathIsAdmin'] = TRUE;
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        $subform_state = SubformState::createForSubform($form['layout_settings'], $form, $form_state);
        $this->getPluginForm($this->layout)
            ->validateConfigurationForm($form['layout_settings'], $subform_state);
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        // Call the plugin submit handler.
        $subform_state = SubformState::createForSubform($form['layout_settings'], $form, $form_state);
        $this->getPluginForm($this->layout)
            ->submitConfigurationForm($form['layout_settings'], $subform_state);
        // If this layout is context-aware, set the context mapping.
        if ($this->layout instanceof ContextAwarePluginInterface) {
            $this->layout
                ->setContextMapping($subform_state->getValue('context_mapping', []));
        }
        $configuration = $this->layout
            ->getConfiguration();
        $section = $this->getCurrentSection();
        $section->setLayoutSettings($configuration);
        if (!$this->isUpdate) {
            $this->sectionStorage
                ->insertSection($this->delta, $section);
        }
        $this->layoutTempstoreRepository
            ->set($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 layout.
     *
     * @param \Drupal\Core\Layout\LayoutInterface $layout
     *   The layout plugin.
     *
     * @return \Drupal\Core\Plugin\PluginFormInterface
     *   The plugin form for the layout.
     *
     * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
     */
    protected function getPluginForm(LayoutInterface $layout) {
        if ($layout instanceof PluginWithFormsInterface) {
            return $this->pluginFormFactory
                ->createInstance($layout, 'configure');
        }
        if ($layout instanceof PluginFormInterface) {
            return $layout;
        }
        throw new \InvalidArgumentException(sprintf('The "%s" layout does not provide a configuration form', $layout->getPluginId()));
    }
    
    /**
     * Retrieves the section storage property.
     *
     * @return \Drupal\layout_builder\SectionStorageInterface
     *   The section storage for the current form.
     */
    public function getSectionStorage() {
        return $this->sectionStorage;
    }
    
    /**
     * Retrieves the layout being modified by the form.
     *
     * @return \Drupal\Core\Layout\LayoutInterface|\Drupal\Core\Plugin\PluginFormInterface
     *   The layout for the current form.
     */
    public function getCurrentLayout() : LayoutInterface {
        return $this->layout;
    }
    
    /**
     * Retrieves the section being modified by the form.
     *
     * @return \Drupal\layout_builder\Section
     *   The section for the current form.
     */
    public function getCurrentSection() : Section {
        if (!isset($this->section)) {
            if ($this->isUpdate) {
                $this->section = $this->sectionStorage
                    ->getSection($this->delta);
            }
            else {
                $this->section = new Section($this->pluginId);
            }
        }
        return $this->section;
    }

}