Set subscriber cookie on signup

[MAILPOET-3924]

lib/Statistics/Track/SubscriberHandler.php

@@ -0,0 +1,46 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Statistics\Track;
+
+use MailPoet\Entities\SubscriberEntity;
+use MailPoet\Settings\TrackingConfig;
+use MailPoet\Subscribers\SubscribersRepository;
+
+class SubscriberHandler {
+  /** @var SubscriberCookie */
+  private $subscriberCookie;
+
+  /** @var SubscribersRepository */
+  private $subscribersRepository;
+
+  /** @var TrackingConfig */
+  private $trackingConfig;
+
+  public function __construct(
+    SubscriberCookie $subscriberCookie,
+    SubscribersRepository $subscribersRepository,
+    TrackingConfig $trackingConfig
+  ) {
+    $this->subscriberCookie = $subscriberCookie;
+    $this->subscribersRepository = $subscribersRepository;
+    $this->trackingConfig = $trackingConfig;
+  }
+
+  public function identifyByEmail(string $email): void {
+    if (!$this->trackingConfig->isCookieTrackingEnabled()) {
+      return;
+    }
+
+    $subscriber = $this->subscribersRepository->findOneBy(['email' => $email]);
+    if ($subscriber) {
+      $this->setCookieBySubscriber($subscriber);
+    }
+  }
+
+  private function setCookieBySubscriber(SubscriberEntity $subscriber): void {
+    $subscriberId = $subscriber->getId();
+    if ($subscriberId) {
+      $this->subscriberCookie->setSubscriberId($subscriberId);
+    }
+  }
+}