app/bundles/CampaignBundle/Executioner/Helper/NotificationHelper.php

<?php

namespace Mautic\CampaignBundle\Executioner\Helper;

use Mautic\CampaignBundle\Entity\Event;
use Mautic\CoreBundle\Helper\CoreParametersHelper;
use Mautic\CoreBundle\Model\NotificationModel;
use Mautic\LeadBundle\Entity\Lead;
use Mautic\UserBundle\Entity\User;
use Mautic\UserBundle\Model\UserModel;
use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
use Symfony\Component\Routing\Router;
use Symfony\Contracts\Translation\TranslatorInterface;

class NotificationHelper
{
    public function __construct(
        private UserModel $userModel,
        private NotificationModel $notificationModel,
        private TranslatorInterface $translator,
        private Router $router,
        private CoreParametersHelper $coreParametersHelper
    ) {
    }

    public function notifyOfFailure(Lead $contact, Event $event): void
    {
        $user = $this->getUser($contact, $event);
        if (!$user || !$user->getId()) {
            return;
        }

        $this->notificationModel->addNotification(
            $event->getCampaign()->getName().' / '.$event->getName(),
            'error',
            false,
            $this->translator->trans(
                'mautic.campaign.event.failed',
                [
                    '%contact%' => '<a href="'.$this->router->generate(
                        'mautic_contact_action',
                        ['objectAction' => 'view', 'objectId' => $contact->getId()]
                    ).'" data-toggle="ajax">'.$contact->getPrimaryIdentifier().'</a>',
                ]
            ),
            null,
            null,
            $user
        );
    }

    public function notifyOfUnpublish(Event $event): void
    {
        /**
         * Pass a fake lead so we can just get the campaign creator.
         */
        $user = $this->getUser(new Lead(), $event);

        if (!$user || !$user->getId()) {
            return;
        }

        $campaign = $event->getCampaign();

        $this->notificationModel->addNotification(
            $campaign->getName().' / '.$event->getName(),
            'error',
            false,
            $this->translator->trans(
                'mautic.campaign.event.failed.campaign.unpublished',
                [
                    '%campaign%' => '<a href="'.$this->router->generate(
                        'mautic_campaign_action',
                        [
                            'objectAction' => 'view',
                            'objectId'     => $campaign->getId(),
                        ],
                        UrlGeneratorInterface::ABSOLUTE_URL
                    ).'" data-toggle="ajax">'.$campaign->getName().'</a>',
                    '%event%' => $event->getName(),
                ]
            ),
            null,
            null,
            $user
        );

        $subject = $this->translator->trans(
            'mautic.campaign.event.campaign_unpublished.title',
            [
                '%title%' => $campaign->getName(),
            ]
        );

        $content = $this->translator->trans(
            'mautic.campaign.event.failed.campaign.unpublished',
            [
                '%campaign%' => '<a href="'.$this->router->generate(
                    'mautic_campaign_action',
                    [
                        'objectAction' => 'view',
                        'objectId'     => $campaign->getId(),
                    ],
                    UrlGeneratorInterface::ABSOLUTE_URL
                ).'" data-toggle="ajax">'.$campaign->getName().'</a>',
                '%event%' => $event->getName(),
            ]
        );

        $sendToAuthor = $this->coreParametersHelper->get('campaign_send_notification_to_author', 1);
        if ($sendToAuthor) {
            $this->userModel->emailUser($user, $subject, $content);
        } else {
            $emailAddresses =  array_map('trim', explode(',', $this->coreParametersHelper->get('campaign_notification_email_addresses')));
            $this->userModel->sendMailToEmailAddresses($emailAddresses, $subject, $content);
        }
    }

    /**
     * @return User|null
     */
    private function getUser(Lead $contact, Event $event)
    {
        // Default is to notify the contact owner
        if ($owner = $contact->getOwner()) {
            return $owner;
        }

        // If the contact doesn't have an owner, notify the one that created the campaign
        if ($campaignCreator = $event->getCampaign()->getCreatedBy()) {
            if ($owner = $this->userModel->getEntity($campaignCreator)) {
                return $owner;
            }
        }

        // If all else fails, notifiy a system admins
        return $this->userModel->getSystemAdministrator();
    }
}