Issue #2581027: Save widget information on facet entity

config/schema/facetapi.facet.schema.yml

@@ -23,3 +23,9 @@ facetapi.facet.*:
     widget:
       type: string
       label: 'Field identifier'
+    widget_configs:
+      type: sequence
+      label: 'Widget plugin configurations'
+      sequence:
+        type: string
+        label: 'Widget plugin configurations'

src/Entity/Facet.php

@@ -41,6 +41,7 @@ use Drupal\facetapi\Result\ResultInterface;
  *     "search_api_index",
  *     "field_identifier",
  *     "widget",
+ *     "widget_configs",
  *   },
  *   links = {
  *     "canonical" = "/admin/config/search/search-api/index/{search_api_index}/facets",
@@ -80,6 +81,13 @@ class Facet extends ConfigEntityBase implements FacetInterface {
    */
   protected $widget;
 
+  /**
+   * Configuration for the widget. This is a key-value stored array.
+   *
+   * @var string
+   */
+  protected $widget_configs;
+
   /**
    * An array of options configuring this index.
    *

src/Form/FacetForm.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\facetapi\Form;
 
+use Drupal\Core\Config\Config;
 use Drupal\Core\Entity\EntityForm;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Form\FormStateInterface;
@@ -236,12 +237,13 @@ class FacetForm extends EntityForm {
       $widget_instance = $this->getWidgetPluginManager()->createInstance($widget);
       // @todo Create, use and save SubFormState already here, not only in
       //   validate(). Also, use proper subset of $form for first parameter?
-      if ($config_form = $widget_instance->buildConfigurationForm([], $form_state)) {
-        $form['widget_config']['#type'] = 'details';
-        $form['widget_config']['#title'] = $this->t('Configure the %widget widget', ['%widget' => $this->getWidgetPluginManager()->getDefinition($widget)['label']]);
-        $form['widget_config']['#open'] = $facet->isNew();
+      $config = $this->config('facetapi.facet.' . $facet->id());
+      if ($config_form = $widget_instance->buildConfigurationForm([], $form_state, ($config instanceof Config) ? $config : null )) {
+        $form['widget_configs']['#type'] = 'details';
+        $form['widget_configs']['#title'] = $this->t('Configure the %widget widget', ['%widget' => $this->getWidgetPluginManager()->getDefinition($widget)['label']]);
+        $form['widget_configs']['#open'] = $facet->isNew();
 
-        $form['widget_config'] += $config_form;
+        $form['widget_configs'] += $config_form;
       }
     }
   }

src/Plugin/facetapi/Widget/CheckboxWidget.php

@@ -9,7 +9,7 @@ use Drupal\facetapi\Widget\WidgetInterface;
 /**
  * @FacetApiWidget(
  *   id = "checkbox",
- *   label = @Translation("Checkbox widget"),
+ *   label = @Translation("List of checkboxes"),
  *   description = @Translation("A widget that shows checkboxes"),
  * )
  *
@@ -36,7 +36,26 @@ class CheckboxWidget implements WidgetInterface {
   /**
    * {@inheritdoc}
    */
-  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
+  public function buildConfigurationForm(array $form, FormStateInterface $form_state, $config) {
+    $checkbox_options = [
+      'before' => $this->t('Before'),
+      'after' => $this->t('After'),
+    ];
+
+    $form['checkbox_placement'] = [
+      '#type' => 'radios',
+      '#title' => $this->t('Checkbox placement'),
+      '#description' => $this->t('Choose where the checkboxes should be placed'),
+      '#options' => $checkbox_options,
+      '#required' => TRUE,
+    ];
+    if (!is_null($config)) {
+      $widget_configs = $config->get('widget_configs');
+      if (isset($widget_configs['checkbox_placement'])) {
+        $form['checkbox_placement']['#default_value'] = $widget_configs['checkbox_placement'];
+      }
+    }
+
     return $form;
   }