michaelschiemer/src/Framework/Database/Events/DomainEventCollector.php

<?php

declare(strict_types=1);

namespace App\Framework\Database\Events;

/**
 * External collector for domain events using WeakMap
 * Keeps entities clean as simple value objects with automatic memory management
 */
final class DomainEventCollector
{
    /** @var \WeakMap<object, object[]> Events mapped to entities with automatic GC */
    private \WeakMap $eventsByEntity;

    public function __construct()
    {
        $this->eventsByEntity = new \WeakMap();
    }

    /**
     * Record a domain event for an entity
     */
    public function recordEvent(object $entity, object $event): void
    {
        if (! isset($this->eventsByEntity[$entity])) {
            $this->eventsByEntity[$entity] = [];
        }
        $this->eventsByEntity[$entity][] = $event;
    }

    /**
     * Get all recorded domain events for an entity
     *
     * @return object[]
     */
    public function getEventsForEntity(object $entity): array
    {
        return $this->eventsByEntity[$entity] ?? [];
    }

    /**
     * Clear all recorded domain events for an entity
     * (Optional - WeakMap handles cleanup automatically)
     */
    public function clearEventsForEntity(object $entity): void
    {
        unset($this->eventsByEntity[$entity]);
    }

    /**
     * Get all recorded domain events across all entities
     *
     * @return object[]
     */
    public function getAllEvents(): array
    {
        $allEvents = [];
        foreach ($this->eventsByEntity as $events) {
            $allEvents = array_merge($allEvents, $events);
        }

        return $allEvents;
    }

    /**
     * Check if there are any domain events for an entity
     */
    public function hasEventsForEntity(object $entity): bool
    {
        return isset($this->eventsByEntity[$entity]) && ! empty($this->eventsByEntity[$entity]);
    }

    /**
     * Get domain events of a specific type for an entity
     *
     * @template T
     * @param class-string<T> $eventClass
     * @return T[]
     */
    public function getEventsOfTypeForEntity(object $entity, string $eventClass): array
    {
        $events = $this->getEventsForEntity($entity);

        return array_filter(
            $events,
            fn (object $event) => $event instanceof $eventClass
        );
    }

    /**
     * Get count of events for an entity
     */
    public function getEventCountForEntity(object $entity): int
    {
        return count($this->getEventsForEntity($entity));
    }

    /**
     * Get total count of all events across all entities
     */
    public function getTotalEventCount(): int
    {
        $total = 0;
        foreach ($this->eventsByEntity as $events) {
            $total += count($events);
        }

        return $total;
    }

    /**
     * Get count of tracked entities
     */
    public function getTrackedEntityCount(): int
    {
        return count($this->eventsByEntity);
    }
}