Add backend classes for fetching inconsistent data

[MAILPOET-1587]

mailpoet/lib/Util/DataInconsistency/DataInconsistencyRepository.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Util\DataInconsistency;
+
+use MailPoet\Cron\Workers\SendingQueue\SendingQueue;
+use MailPoet\Entities\ScheduledTaskEntity;
+use MailPoetVendor\Doctrine\ORM\EntityManager;
+
+class DataInconsistencyRepository {
+  private EntityManager $entityManager;
+
+  public function __construct(
+    EntityManager $entityManager
+  ) {
+    $this->entityManager = $entityManager;
+  }
+
+  public function getOrphanedSendingTasksCount(): int {
+    return (int)$this->entityManager->createQueryBuilder()
+      ->select('count(st.id)')
+      ->from(ScheduledTaskEntity::class, 'st')
+      ->leftJoin('st.sendingQueue', 'sq')
+      ->where('sq.id IS NULL')
+      ->andWhere('st.type = :type')
+      ->setParameter('type', SendingQueue::TASK_TYPE)
+      ->getQuery()
+      ->getSingleScalarResult();
+  }
+}