Limit number of confirmation emails sent to one email

MAILPOET-1734

lib/Config/Migrator.php

@@ -199,6 +199,7 @@ class Migrator {
       'deleted_at TIMESTAMP NULL,',
       'unconfirmed_data longtext,',
       'source ENUM("form", "imported", "administrator", "api", "wordpress_user", "unknown") DEFAULT "unknown",',
+      'count_confirmations int(11) unsigned NOT NULL DEFAULT 0,',
       'PRIMARY KEY  (id),',
       'UNIQUE KEY email (email),',
       'KEY wp_user_id (wp_user_id),',

lib/Models/SubscriberSegment.php

@@ -14,6 +14,10 @@ class SubscriberSegment extends Model {
   static function unsubscribeFromSegments($subscriber, $segment_ids = array()) {
     if($subscriber === false) return false;
 
+    // Reset confirmation emails count, so user can resubscribe
+    $subscriber->count_confirmations = 0;
+    $subscriber->save();
+
     $wp_segment = Segment::getWPSegment();
     $wc_segment = Segment::getWooCommerceSegment();
 

lib/Subscribers/ConfirmationEmailMailer.php

@@ -10,6 +10,8 @@ use MailPoet\Util\Helpers;
 
 class ConfirmationEmailMailer {
 
+  const MAX_CONFIRMATION_EMAILS = 3;
+
   /** @var Mailer */
   private $mailer;
 
@@ -29,6 +31,12 @@ class ConfirmationEmailMailer {
       return false;
     }
 
+    $subscriber->count_confirmations++;
+    $subscriber->save();
+    if(!is_user_logged_in() && $subscriber->count_confirmations > self::MAX_CONFIRMATION_EMAILS) {
+      return false;
+    }
+
     $segments = $subscriber->segments()->findMany();
     $segment_names = array_map(function($segment) {
       return $segment->name;

tests/integration/Models/SubscriberSegmentTest.php

@@ -117,6 +117,7 @@ class SubscriberSegmentTest extends \MailPoetTest {
     expect($subscriber->subscriptions[2]['segment_id'])->equals($segment_3->id);
 
     // verify that subscriber is not subscribed only to the non-WP segment (#2)
+    $subscriber = $this->subscriber;
     SubscriberSegment::unsubscribeFromSegments($subscriber, array($segment_1->id, $segment_2->id, $segment_3->id));
     $subscriber = Subscriber::findOne($subscriber->id)->withSubscriptions();