[POC - DON'T MERGE] SDT-151: POC for contextual filters.

src/EventSubscriber/QuerySubscriber.php

@@ -4,6 +4,7 @@
 
 namespace Drupal\oe_list_pages\EventSubscriber;
 
+use Drupal\Core\Field\EntityReferenceFieldItemListInterface;
 use Drupal\facets\FacetInterface;
 use Drupal\facets\FacetManager\DefaultFacetManager;
 use Drupal\facets\QueryType\QueryTypePluginManager;
@@ -179,6 +180,27 @@ protected function processFacetActiveValues(array $facets, array $preset_filter_
     return $facets_by_filter;
   }
 
+  /**
+   * Get original field name from facet config.
+   *
+   * @param \Drupal\facets\Entity\FacetInterface $facet
+   *   The facet.
+   *
+   * @return string|null
+   *   The field name if found.
+   */
+  protected function getFieldName(FacetInterface $facet) : ?string {
+    $field = $facet->getFacetSource()->getIndex()->getField($facet->getFieldIdentifier());
+    $field_name = $field->getOriginalFieldIdentifier();
+    $property_path = $field->getPropertyPath();
+    $parts = explode(':', $property_path);
+    if (count($parts) > 1) {
+      $field_name = $parts[0];
+    }
+
+    return $field_name;
+  }
+
   /**
    * Applies the preset filter values onto the facet.
    *
@@ -191,7 +213,27 @@ protected function processFacetActiveValues(array $facets, array $preset_filter_
    *   The preset values.
    */
   protected function applyPresetFilterValues(FacetInterface $facet, ListPresetFilter $preset_filter): void {
-    $facet->setActiveItems($preset_filter->getValues());
+
+    if ($preset_filter->getType() == 'contextual') {
+      /** @var \Drupal\node\NodeInterface $current_node */
+      $current_node = \Drupal::routeMatch()->getParameter('node');
+      $field_name = $this->getFieldName($facet);
+      $field = $current_node->get($field_name);
+      $field_definition = $field->getFieldDefinition();
+      $values = [];
+      /* @todo create a plugin type MultiSelectFilterFieldPlugin */
+      if (in_array(EntityReferenceFieldItemListInterface::class, class_implements($field_definition->getClass()))) {
+        $field_value = $current_node->get($field_name)->getValue();
+        $values = array_map(function ($value) {
+          return $value['target_id'];
+        }, $field_value);
+      }
+    }
+    else {
+      $values = $preset_filter->getValues();
+    }
+
+    $facet->setActiveItems($values);
     if ($preset_filter->getOperator() === ListPresetFilter::NOT_OPERATOR) {
       $facet->setQueryOperator(ListPresetFilter::AND_OPERATOR);
       $facet->setExclude(TRUE);

src/ListPresetFilter.php

@@ -36,6 +36,13 @@ class ListPresetFilter {
    */
   protected $values = [];
 
+  /**
+   * The type.
+   *
+   * @var string
+   */
+  protected $type;
+
   /**
    * ListPresetFilter constructor.
    *
@@ -45,11 +52,14 @@ class ListPresetFilter {
    *   The operator.
    * @param string $operator
    *   The operator.
+   * @param string $type
+   *   The type.
    */
-  public function __construct(string $facet_id, array $values, string $operator = self::OR_OPERATOR) {
+  public function __construct(string $facet_id, array $values, string $operator = self::OR_OPERATOR, string $type = 'static') {
     $this->facetId = $facet_id;
     $this->operator = $operator;
     $this->values = $values;
+    $this->type = $type;
   }
 
   /**
@@ -126,4 +136,24 @@ public static function getOperators(): array {
     ];
   }
 
+  /**
+   * Gets the type.
+   *
+   * @return string
+   *   The type.
+   */
+  public function getType(): string {
+    return $this->type;
+  }
+
+  /**
+   * Sets the type.
+   *
+   * @param string $type
+   *   The type.
+   */
+  public function setType(string $type): void {
+    $this->type = $type;
+  }
+
 }

src/ListPresetFiltersBuilder.php

@@ -410,7 +410,7 @@ public function setDefaultValueSubmit(array &$form, FormStateInterface $form_sta
     $widget = $facet->getWidgetInstance();
 
     $preset_filter = $widget->prepareDefaultFilterValue($facet, $current_filters[$filter_id], $subform_state);
-    $current_filters[$filter_id] = new ListPresetFilter($facet_id, $preset_filter['values'], $preset_filter['operator']);
+    $current_filters[$filter_id] = new ListPresetFilter($facet_id, $preset_filter['values'], $preset_filter['operator'], $preset_filter['type']);
 
     // Set the current filters on the form state so they can be used elsewhere.
     static::setListSourceCurrentFilterValues($form_state, $list_source, $current_filters);

src/Plugin/facets/widget/ListPagesWidgetBase.php

@@ -34,6 +34,7 @@ public function prepareValueForUrl(FacetInterface $facet, array &$form, FormStat
    */
   public function prepareDefaultFilterValue(FacetInterface $facet, array $form, FormStateInterface $form_state): array {
     return [
+      'type' => 'static',
       'operator' => ListPresetFilter::OR_OPERATOR,
       'values' => $this->prepareValueForUrl($facet, $form, $form_state),
     ];

src/Plugin/facets/widget/MultiselectWidget.php

@@ -100,6 +100,19 @@ public function buildDefaultValueForm(array $form, FormStateInterface $form_stat
       '#title' => $this->t('Operator'),
     ];
 
+    $filter_type_options = [
+      'static' => $this->t('Static'),
+      'contextual' => $this->t('Contextual'),
+    ];
+
+    $form['oe_list_pages_filter_type'] = [
+      '#type' => 'radios',
+      '#weight' => -10,
+      '#options' => $filter_type_options,
+      '#default_value' => !empty($preset_filter) && !empty($preset_filter->getType()) ? $preset_filter->getType() : 'static',
+      '#title' => $this->t('Filter type'),
+    ];
+
     $form[$facet->id()] = [
       '#type' => 'multivalue',
       '#title' => $facet->getName(),
@@ -208,13 +221,20 @@ public function buildDefaultValueForm(array $form, FormStateInterface $form_stat
 
   /**
    * {@inheritdoc}
+   *
+   * @SuppressWarnings(PHPMD.CyclomaticComplexity)
    */
   public function getDefaultValuesLabel(FacetInterface $facet, ListSourceInterface $list_source, ListPresetFilter $filter): string {
     $field_definition = $this->getFieldDefinition($facet, $list_source);
     $field_type = !empty($field_definition) ? $field_definition->getType() : NULL;
 
     $filter_value = $filter->getValues();
     $filter_operators = ListPresetFilter::getOperators();
+    $filter_type = $filter->getType();
+    if ($filter_type === 'contextual') {
+      return $filter_operators[$filter->getOperator()] . ': ' . $this->t('Contextual value');
+    }
+
     if (in_array(EntityReferenceFieldItemListInterface::class, class_implements($field_definition->getClass()))) {
       $entity_storage = $this->entityTypeManager->getStorage($field_definition->getSetting('target_type'));
       $values = [];
@@ -330,6 +350,7 @@ public function prepareDefaultFilterValue(FacetInterface $facet, array $form, Fo
 
     $operator = $form_state->getValue('oe_list_pages_filter_operator');
     return [
+      'type' => $form_state->getValue('oe_list_pages_filter_type'),
       'operator' => $operator,
       'values' => $values,
     ];