<?php

/**
 * Event worker - turns queued domain events into local workflow executions.
 *
 * @package AfroIT_Messaging_WorkflowAutomations
 */

namespace AfroIT\Messaging\WorkflowAutomations\Async;


use AfroIT\Messaging\WorkflowAutomations\Events\Cart\CartAbandonedEvent;
use AfroIT\Messaging\WorkflowAutomations\Events\Event;
use AfroIT\Messaging\WorkflowAutomations\Events\Order\OrderCreatedEvent;
use AfroIT\Messaging\WorkflowAutomations\Events\Order\OrderStatusChangedEvent;
use AfroIT\Messaging\WorkflowAutomations\Events\Order\PaymentCompletedEvent;
use AfroIT\Messaging\WorkflowAutomations\Events\Generic\WorkflowTriggerEvent;
use AfroIT\Messaging\WorkflowAutomations\ExecutionEngine\ExecutionEngine;
use AfroIT\Messaging\WorkflowAutomations\Logging\Log;
use AfroIT\Messaging\WorkflowAutomations\Workflows\WorkflowTriggers;

if (! defined('ABSPATH')) {
    exit;
}

/**
 * Class EventWorker
 *
 * Fetches pending events from the queue, reconstructs Event objects,
 * and starts matching workflows in the local execution engine.
 */
final class EventWorker
{

    /**
     * @var EventQueueRepository
     */
    private EventQueueRepository $repository;

    /**
     * @var ExecutionEngine
     */
    private ExecutionEngine $execution_engine;

    /**
     * Constructor.
     *
     * @param EventQueueRepository|null $repository       Event queue repository.
     * @param ExecutionEngine|null      $execution_engine Local execution engine.
     */
    public function __construct(
        ?EventQueueRepository $repository = null,
        ?ExecutionEngine $execution_engine = null
    ) {
        $this->repository       = $repository ?? new EventQueueRepository();
        $this->execution_engine = $execution_engine ?? new ExecutionEngine();
    }

    /**
     * Process pending events from the queue.
     *
     * @param int $limit Max events to process per run.
     * @return int Number of events processed.
     */
    public function process(int $limit = 20): int
    {
        $jobs  = $this->repository->fetchPending($limit);
        $count = 0;

        foreach ($jobs as $job) {
            $this->repository->markProcessing((int) $job->id);

            try {
                $event = $this->reconstructEvent((string) $job->event_name, (string) $job->payload_json, (string) $job->created_at);

                if (null === $event) {
                    Log::warning('EventWorker: could not reconstruct event from job', array(
                        'event_name' => $job->event_name,
                        'job_id'     => $job->id,
                    ));
                    $this->repository->markFailed((int) $job->id);
                    continue;
                }

                $local = $this->execution_engine->start_from_event($event);
                if (empty($local['matched'])) {
                    Log::info('EventWorker: no matching workflows for event', array(
                        'event_name' => $job->event_name,
                        'job_id'     => $job->id,
                    ));
                }

                $this->repository->markProcessed((int) $job->id);
                $count++;
            } catch (\Throwable $e) {
                Log::error('EventWorker: processing failed (general error)', array(
                    'job_id'   => $job->id,
                    'message'  => $e->getMessage(),
                ));
                $this->repository->markFailed((int) $job->id);
            }
        }

        return $count;
    }

    /**
     * Reconstruct Event object from stored data.
     *
     * @param string $event_name   Event name.
     * @param string $payload_json JSON payload.
     * @param string $queued_created_at Fallback queue creation timestamp.
     * @return Event|null
     */
    private function reconstructEvent(string $event_name, string $payload_json, string $queued_created_at): ?Event
    {
        $payload = json_decode($payload_json, true);
        if (! is_array($payload)) {
            return null;
        }

        if (! isset($payload['event_class'])) {
            return null;
        }

        $class = $payload['event_class'];
        $occurred_at = isset($payload['occurred_at']) && '' !== (string) $payload['occurred_at']
            ? (string) $payload['occurred_at']
            : $queued_created_at;

        if (in_array($class, [OrderCreatedEvent::class, PaymentCompletedEvent::class])) {
            $order_id = $payload['order_id'] ?? 0;
            return $order_id > 0 ? new $class((int) $order_id, $occurred_at) : null;
        }

        if (OrderStatusChangedEvent::class === $class) {
            $order_id   = $payload['order_id'] ?? 0;
            $old_status = $payload['old_status'] ?? '';
            $new_status = $payload['new_status'] ?? '';
            return $order_id > 0 ? new OrderStatusChangedEvent((int) $order_id, $old_status, $new_status, $occurred_at) : null;
        }

        if (CartAbandonedEvent::class === $class) {
            $abandoned_cart_id = $payload['abandoned_cart_id'] ?? 0;
            $cart_data         = $payload['cart_data'] ?? array();
            return $abandoned_cart_id > 0 ? new CartAbandonedEvent((int) $abandoned_cart_id, $cart_data, $occurred_at) : null;
        }

        $triggers = WorkflowTriggers::getTriggers();
        if (isset($triggers[$event_name])) {
            return new WorkflowTriggerEvent($event_name, $payload, $occurred_at);
        }

        return null;
    }

}