Event based notifications library idea

01_routing.php

<?php

$container = new SomePSR11Container();
// $container->regiseter();

$notifications = new N1215\Notification\Registrar($container);
$notifications
    ->source(N1215\Events\UserRegistered::class)
    ->to(N1215\Notification\UserTargetSelector::class)
    ->inSingleFormOf(
       N1215\Notification\UserRegisteredMailTemplate::class,
       N1215\Notification\UserRegisteredSmsTemplate::class
    )
    ->retry(3);

$notifications
    ->source(N1215\Events\UserRegistered::class)
    ->to(N1215\Notification\SystemTargetSelector::class)  
    ->inMultipleFormsOf(
        N1215\Notification\UserRegisteredMailTemplateForSystem::class,
        N1215\Notification\UserRegisteredSlackTemplateForSystem::class
    )
    ->retry(2);

$notifications
    ->source(N1215\Events\UserRegistered::class)
    ->to(N1215\Notification\LogTargetSelector::class)  
    ->inMultipleFormsOf(
        N1215\Notification\UserRegisteredLogTemplate::class,
    )
    ->retry(2);


$notifictionCenter = $notifications->build(); 

// implements PSR-14's Listener Provider Interface
$userRegistered = new UserRegistered(new User('[email protected]');
$listeners = $notifictionCenter->getListenersForEvent($userRegistered);

// or implements PSR-14's EventDispatcher Interface
$notificationCenter->dispatch($userRegistered);

                                     

02_user.php

<?php

namespace N1215\Models;

class User implements NotificationTargetInterface
{
    private string $email;

    public function __construct(string $email)
    {
        $this->email = $email;
    }

    public function getNotificationSinks(): NotificationSinkInterface[]
    {
        return [new MailSink($this->email)];
    }
}

03_user_registerd.php

<?php

namespace N1215\Events;

class UserRegistered
{
    private User $user;

    private DateTime $registeredAt;

    public function __cosntruct(User $user, DateTime $registeredAt)
    {
        $this->user = $user;
        $this->registeredAt = $registeredAt;
    }

    public function getUser(): User
    {
        return $user;
    }
    
    public function getRegisteredAt(): DateTime
    {
        return $this->registeredAt;
    }
}

04_mail_channel.php

<?php

namespace N1215\Notification;

class MailChannel implements ChannelIntetface
{
    /**
     * @param MessageInterface $message
     * @param SinkInterface $sink
     * 
     */
    public function send(MessageInterface $message, SinkInterface $sink)
    {
       // send mail
    }
}

05_target_selector.php

<?php

namespace N1215\Notification;

class UserTargetSelector
{
    public function supportsEvent($event): bool 
    {
        return $event instanceof UserRegistered;
    }

    public function select($event): NotificationTargetInterface
    {
        return $event->getUser();
    }
}

06_message_template.php

<?php

namespace N1215\Notification;

class UserRegisteredTemplate implements MessageTemplate {
    public function supportsEvent($event): bool
    {
        return $event instanceof UserRegistered;
    }

    public function getChannel(): string
    {
        return MailChannel::class;
    }

    public function render($event, SinkInterface $sink): MailMessage
    {
        return new MailMessage();
    }
}