<?php

declare(ticks=1);

namespace Siteworxpro\App\Async;

use Siteworxpro\App\Annotations\Async\HandlesMessage;
use Siteworxpro\App\Async\Queues\Queue;
use Siteworxpro\App\Services\Facades\Logger;

class Consumer
{
    private static bool $shutDown = false;

    private const array QUEUES = [
        'default' => Queues\DefaultQueue::class,
    ];

    private array $queues = [];

    private array $handlers = [];

    private const string HANDLER_NAMESPACE = 'Siteworxpro\\App\\Async\\Handlers\\';

    public function __construct(array $queues = [])
    {
        if ($queues === []) {
            $queues = self::QUEUES;
        } else {
            $mappedQueues = [];
            foreach ($queues as $queueName) {
                if (isset(self::QUEUES[$queueName])) {
                    $mappedQueues[] = self::QUEUES[$queueName];
                } else {
                    throw new \InvalidArgumentException("Queue '$queueName' is not defined.");
                }
            }
            $queues = $mappedQueues;
        }


        foreach ($queues as $queueClass) {
            $this->queues[] = new $queueClass();
        }

        $this->registerHandlers();
    }

    private function registerHandlers(): void
    {
        $recursiveIterator = new \RecursiveIteratorIterator(
            new \RecursiveDirectoryIterator(__DIR__ . '/Handlers/')
        );

        foreach ($recursiveIterator as $file) {
            if ($file->isFile() && $file->getExtension() === 'php') {
                $relativePath = str_replace(__DIR__ . '/Handlers/', '', $file->getPathname());
                $className = self::HANDLER_NAMESPACE . str_replace('/', '\\', substr($relativePath, 0, -4));


                if (class_exists($className)) {
                    $reflection = new \ReflectionClass($className);
                    $attributes = $reflection->getAttributes(HandlesMessage::class);
                    foreach ($attributes as $attribute) {
                        $instance = $attribute->newInstance();
                        $messageClass = $instance->getMessageClass();
                        $this->handlers[$messageClass][] = $className;
                    }
                }
            }
        }
    }

    /**
     * @param $signal
     */
    public static function handleSignal($signal): void
    {
        switch ($signal) {
            // Graceful
            case SIGINT:
            case SIGTERM:
            case SIGHUP:
                self::$shutDown = true;

                break;

            // Not Graceful
            case SIGKILL:
                exit(9);
        }
    }

    private function shouldShutDown(): bool
    {
        return self::$shutDown;
    }

    public function start(): void
    {
        if (!\function_exists('pcntl_signal')) {
            throw new \RuntimeException('The pcntl extension is required to handle signals.');
        }

        Logger::info('Starting queue consumer...');

        \pcntl_signal(SIGINT, [self::class, 'handleSignal']);
        \pcntl_signal(SIGTERM, [self::class, 'handleSignal']);
        \pcntl_signal(SIGHUP, [self::class, 'handleSignal']);

        while (true) {
            if ($this->shouldShutDown()) {
                Logger::info('Shutting down queue consumer...');
                break;
            }

            /** @var Queue $queue */
            foreach ($this->queues as $queue) {
                Logger::info('Listening to queue: ' . $queue->queueName());
                $message = $queue->pop();
                if ($message) {
                    Logger::info('Processing message of type: ' . get_class($message));

                    $handlers = $this->getHandlerForMessage($message);

                    foreach ($handlers as $handler) {
                        $handler($message);
                    }
                }
            }

            sleep(1);
        }
    }

    private function getHandlerForMessage($message): array
    {
        $callables = [];

        $messageClass = get_class($message);
        if (isset($this->handlers[$messageClass])) {
            $handlerClasses = $this->handlers[$messageClass];

            foreach ($handlerClasses as $handlerClass) {
                if (class_exists($handlerClass)) {
                    $handlerInstance = new $handlerClass();

                    $callables[] = $handlerInstance;
                }
            }

            return $callables;
        }

        throw new \RuntimeException("No handler found for message class: $messageClass");
    }
}