Merge pull request #295 from itk-dev/feature/LOOP-1195-fix-one-right-answer-only

LOOP-1195: Added event subscriber

Author: rimi-itk

web/profiles/custom/os2loop/modules/os2loop_upvote/os2loop_upvote.services.yml

@@ -3,3 +3,11 @@ services:
     class: Drupal\os2loop_upvote\Helper\FlagHelper
     arguments:
       - '@flag.count'
+
+  os2loop_upvote.flag_subscriber:
+    class: Drupal\os2loop_upvote\EventSubscriber\UpvoteFlagSubscriber
+    tags:
+      - { name: event_subscriber }
+    arguments:
+      - '@entity_type.manager'
+      - '@flag'

web/profiles/custom/os2loop/modules/os2loop_upvote/src/EventSubscriber/UpvoteFlagSubscriber.php

@@ -0,0 +1,125 @@
+<?php
+
+namespace Drupal\os2loop_upvote\EventSubscriber;
+
+use Drupal\comment\Entity\Comment;
+use Drupal\flag\FlagServiceInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Drupal\flag\Event\FlagEvents;
+use Drupal\flag\Event\FlaggingEvent;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+
+/**
+ * Event subscriber for flagging content or terms with subscribe.
+ */
+class UpvoteFlagSubscriber implements EventSubscriberInterface {
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * The flag service.
+   *
+   * @var \Drupal\flag\FlagServiceInterface
+   */
+  protected $flagService;
+
+  /**
+   * Helper constructor.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entityTypeManager
+   *   Entity type manager.
+   * @param \Drupal\flag\FlagServiceInterface $flagService
+   *   The flag service.
+   *
+   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
+   *   Thrown if the entity type doesn't exist.
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   *   Thrown if the storage handler couldn't be loaded.
+   */
+  public function __construct(EntityTypeManagerInterface $entityTypeManager, FlagServiceInterface $flagService) {
+    $this->entityTypeManager = $entityTypeManager;
+    $this->flagService = $flagService;
+  }
+
+  /**
+   * Event callback when an entity is flagged.
+   *
+   * @param \Drupal\flag\Event\FlaggingEvent $event
+   *   A flagging event.
+   */
+  public function onFlag(FlaggingEvent $event) {
+    $flag_type_id = $event->getFlagging()->getFlagId();
+    if ('os2loop_upvote_correct_answer' === $flag_type_id) {
+      // The flagged entity.
+      $entity = $event->getFlagging()->getFlaggable();
+      if ('comment' === $entity->getEntityTypeId()) {
+        /** @var \Drupal\comment\CommentInterface $entity */
+        $node = $entity->getCommentedEntity();
+        $node_comments = $this->getNodeComments($node->id());
+        foreach ($node_comments as $comment) {
+          if ($comment->id() !== $entity->id()) {
+            // Unflag comment.
+            $this->unflagComment($flag_type_id, $comment);
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events = [];
+    $events[FlagEvents::ENTITY_FLAGGED][] = ['onFlag'];
+    return $events;
+  }
+
+  /**
+   * Get all comments related to a node.
+   *
+   * @param string $nid
+   *   The Id of a node.
+   *
+   * @return array
+   *   A list of comments.
+   */
+  private function getNodeComments(string $nid): array {
+    try {
+      $comment_ids = $this->entityTypeManager
+        ->getStorage('comment')
+        ->getQuery('AND')
+        ->condition('entity_id', $nid)
+        ->condition('entity_type', 'node')
+        ->execute();
+
+      return $this->entityTypeManager
+        ->getStorage('comment')
+        ->loadMultiple($comment_ids);
+    }
+
+    catch (\Exception $exception) {
+      return [];
+    }
+  }
+
+  /**
+   * Unflag a comment if a flag exists.
+   *
+   * @param string $flag_type_id
+   *   The flag type.
+   * @param \Drupal\comment\Entity\Comment $comment
+   *   The comment to unflag.
+   */
+  private function unflagComment(string $flag_type_id, Comment $comment) {
+    $flag = $this->flagService->getFlagById($flag_type_id);
+    if ($this->flagService->getFlagging($flag, $comment)) {
+      $this->flagService->unflag($flag, $comment);
+    }
+  }
+
+}