EventSerializer.php

<?php

declare(strict_types=1);

namespace Wwwision\DCBExample;

use JsonException;
use RuntimeException;
use Webmozart\Assert\Assert;
use Wwwision\DCBEventStore\Types\Event;
use Wwwision\DCBEventStore\Types\EventEnvelope;
use Wwwision\DCBExample\Event\CourseEvent;
use Wwwision\DCBExample\Event\DomainEvent;
use Wwwision\DCBExample\Event\StudentEvent;

use function get_debug_type;
use function json_decode;
use function json_encode;
use function sprintf;
use function strrpos;
use function substr;

use const JSON_THROW_ON_ERROR;

/**
 * Simple converter that expects Domain Events to implement the {@see DomainEvent} interface
 */
final readonly class EventSerializer
{
    public function convertEvent(Event|EventEnvelope $event): DomainEvent
    {
        if ($event instanceof EventEnvelope) {
            $event = $event->event;
        }
        try {
            $payload = json_decode($event->data->value, true, 512, JSON_THROW_ON_ERROR);
        } catch (JsonException $e) {
            throw new RuntimeException(sprintf('Failed to decode JSON: %s', $e->getMessage()), 1684510536, $e);
        }
        Assert::isArray($payload);
        /** @var class-string<DomainEvent> $eventClassName */
        $eventClassName = '\\Wwwision\\DCBExample\\Event\\' . $event->type->value;
        $domainEvent = $eventClassName::fromArray($payload);
        Assert::isInstanceOf($domainEvent, DomainEvent::class);
        return $domainEvent;
    }

    public function convertDomainEvent(DomainEvent $domainEvent): Event
    {
        try {
            $eventData = json_encode($domainEvent, JSON_THROW_ON_ERROR);
        } catch (JsonException $e) {
            throw new RuntimeException(sprintf('Failed to JSON encode payload of domain event %s: %s', get_debug_type($domainEvent), $e->getMessage()), 1685965020, $e);
        }
        $tags = [];
        if ($domainEvent instanceof CourseEvent) {
            $tags[] = "course:{$domainEvent->courseId->value}";
        }
        if ($domainEvent instanceof StudentEvent) {
            $tags[] = "student:{$domainEvent->studentId->value}";
        }
        return Event::create(
            type: substr($domainEvent::class, strrpos($domainEvent::class, '\\') + 1),
            data: $eventData,
            tags: $tags,
        );
    }
}