Php-Template/src/Events/Dispatcher.php

<?php

declare(strict_types=1);

namespace Siteworxpro\App\Events;

use Illuminate\Contracts\Events\Dispatcher as DispatcherContract;
use Illuminate\Contracts\Support\Arrayable;
use Illuminate\Support\Collection;
use Siteworxpro\App\Attributes\Events\ListensFor;

use function React\Async\await;
use function React\Async\coroutine;

/**
 * Class Dispatcher
 *
 * A custom event dispatcher that automatically registers event listeners
 * based on the ListensFor attribute.
 *
 * @package Siteworxpro\App\Events
 */
class Dispatcher implements DispatcherContract, Arrayable
{
    /**
     * @var array $listeners Registered event listeners
     */
    private array $listeners = [];

    /**
     * @var Collection $pushed Pushed events collection
     */
    private Collection $pushed;

    private array $subscribers = [];

    /**
     * @var string LISTENERS_NAMESPACE The namespace where listeners are located
     */
    private const string LISTENERS_NAMESPACE = 'Siteworxpro\\App\\Events\\Listeners\\';

    public function __construct()
    {
        $this->pushed = new Collection();
        $this->registerListeners();
    }

    /**
     * Register event listeners based on the ListensFor attribute.
     *
     * @return void
     */
    private function registerListeners(): void
    {
        // traverse the Listeners directory and register all listeners
        $listenersPath = __DIR__ . '/Listeners';
        $iterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($listenersPath));

        foreach ($iterator as $file) {
            if ($file->isFile() && $file->getExtension() === 'php') {
                $relativePath = str_replace($listenersPath . '/', '', $file->getPathname());
                $className = self::LISTENERS_NAMESPACE . str_replace(['/', '.php'], ['\\', ''], $relativePath);
                if (class_exists($className)) {
                    $reflectionClass = new \ReflectionClass($className);
                    $attributes = $reflectionClass->getAttributes(ListensFor::class);
                    foreach ($attributes as $attribute) {
                        $instance = $attribute->newInstance();
                        $eventClass = $instance->eventClass;
                        $this->listen($eventClass, new $className());
                    }
                }
            }
        }
    }

    /**
     * Register a listener for the given events.
     *
     * @param $events
     * @param $listener
     * @return void
     */
    public function listen($events, $listener = null): void
    {
        $this->listeners[$events][] = $listener;
    }

    /**
     * Check if there are listeners for the given event.
     *
     * @param $eventName
     * @return bool
     */
    public function hasListeners($eventName): bool
    {
        return isset($this->listeners[$eventName]) && !empty($this->listeners[$eventName]);
    }

    /**
     * Subscribe a subscriber to the dispatcher.
     *
     * @param Arrayable $subscriber
     * @return void
     */
    public function subscribe($subscriber): void
    {
        $this->subscribers[] = $subscriber;
    }

    /**
     * Dispatch an event and halt on the first non-null response.
     *
     * @param $event
     * @param array $payload
     * @return array|null
     * @throws \Throwable
     */
    public function until($event, $payload = []): array|null
    {
        return $this->dispatch($event, $payload, true);
    }

    /**
     * Dispatch an event to its listeners.
     *
     * @param $event
     * @param array $payload
     * @param bool $halt
     * @return array|null
     * @throws \Throwable
     */
    public function dispatch($event, $payload = [], $halt = false): array|null
    {
        if (is_object($event)) {
            $eventClass = get_class($event);
        } else {
            $eventClass = $event;
        }

        // Handle subscribers as a coroutine
        $promise = coroutine(function () use ($event, $payload, $halt, $eventClass, &$responses) {
            foreach ($this->subscribers as $subscriber) {
                if (method_exists($subscriber, 'handle')) {
                    $response = $subscriber->handle($event, $payload);
                    $responses[$eventClass] = $response;

                    if ($halt && $response !== null) {
                        return $responses;
                    }
                }
            }

            return null;
        });

        $listeners = $this->listeners[$eventClass] ?? null;

        // If no listeners, just await the subscriber promise
        if ($listeners === null) {
            return await($promise);
        }

        $responses = [];
        foreach ($listeners as $listener) {
            $response = $listener($event, $payload);
            $responses[$eventClass] = $response;

            if ($halt && $response !== null) {
                return $response;
            }
        }

        // Await the subscriber promise and merge responses
        $promiseResponses = await($promise);

        if (is_array($promiseResponses)) {
            $responses = array_merge($responses, $promiseResponses);
        }

        return $responses;
    }

    /**
     * Push an event to be dispatched later.
     *
     * @param $event
     * @param array $payload
     * @return void
     */
    public function push($event, $payload = []): void
    {
        $this->pushed->put($event, $payload);
    }

    /**
     * Flush a pushed event, dispatching it if it exists.
     *
     * @param $event
     * @return void
     * @throws \Throwable
     */
    public function flush($event): void
    {
        if ($this->pushed->has($event)) {
            $payload = $this->pushed->get($event);
            $this->dispatch($event, $payload);
            $this->pushed->forget([$event]);
        }
    }

    /**
     * Forget a pushed event without dispatching it.
     *
     * @param $event
     * @return void
     */
    public function forget($event): void
    {
        $this->pushed->forget([$event]);
    }

    /**
     * Forget all pushed events.
     *
     * @return void
     */
    public function forgetPushed(): void
    {
        $this->pushed = new Collection();
    }

    public function toArray(): array
    {
        return $this->listeners;
    }
}