<?php
declare(strict_types=1);

namespace App\Modules\Cron;

use RuntimeException;
use Throwable;

final class CronJobProcessor
{
    /** @var array<string, callable> */
    private array $handlers = [];

    public function __construct(private readonly CronJobRepository $jobs)
    {
    }

    public function registerHandler(string $jobType, callable $handler): void
    {
        $normalized = trim($jobType);
        if ($normalized === '') {
            return;
        }

        $this->handlers[$normalized] = $handler;
    }

    /**
     * @return array{created:int,skipped:int}
     */
    public function createScheduledJobs(): array
    {
        $created = 0;
        $skipped = 0;
        $schedules = $this->jobs->getDueSchedules();

        foreach ($schedules as $schedule) {
            $scheduleId = (int) ($schedule['id'] ?? 0);
            $jobType = trim((string) ($schedule['job_type'] ?? ''));
            $intervalSeconds = max(60, (int) ($schedule['interval_seconds'] ?? 0));

            if ($scheduleId <= 0 || $jobType === '') {
                continue;
            }

            $hasPending = $this->jobs->hasPendingJob($jobType);
            if ($hasPending) {
                $skipped++;
            } else {
                $payload = is_array($schedule['payload'] ?? null) ? (array) $schedule['payload'] : null;
                $this->jobs->enqueue(
                    $jobType,
                    $payload,
                    (int) ($schedule['priority'] ?? CronJobType::priorityFor($jobType)),
                    (int) ($schedule['max_attempts'] ?? CronJobType::maxAttemptsFor($jobType))
                );
                $created++;
            }

            $this->jobs->touchSchedule($scheduleId, $intervalSeconds);
        }

        return [
            'created' => $created,
            'skipped' => $skipped,
        ];
    }

    /**
     * @return array{processed:int,completed:int,retried:int,failed:int}
     */
    public function processQueue(int $limit = 20): array
    {
        $processed = 0;
        $completed = 0;
        $retried = 0;
        $failed = 0;

        $jobs = $this->jobs->fetchNext($limit);
        foreach ($jobs as $job) {
            $processed++;

            $jobId = (int) ($job['id'] ?? 0);
            $jobType = trim((string) ($job['job_type'] ?? ''));
            if ($jobId <= 0 || $jobType === '') {
                continue;
            }

            $handler = $this->handlers[$jobType] ?? null;
            if (!is_callable($handler)) {
                $defaultBackoff = $this->defaultBackoffSeconds((int) ($job['attempts'] ?? 0));
                $isFinal = $this->jobs->markFailed(
                    $jobId,
                    'Brak zarejestrowanego handlera dla typu joba: ' . $jobType,
                    $defaultBackoff
                );
                if ($isFinal) {
                    $failed++;
                } else {
                    $retried++;
                }
                continue;
            }

            try {
                $payload = is_array($job['payload'] ?? null) ? (array) $job['payload'] : [];
                $result = $handler($payload, $job);

                $ok = true;
                $message = '';
                $retryAfter = 0;
                $resultPayload = [];

                if (is_bool($result)) {
                    $ok = $result;
                } elseif (is_array($result)) {
                    $ok = ($result['ok'] ?? true) === true;
                    $message = trim((string) ($result['message'] ?? ''));
                    $retryAfter = max(0, (int) ($result['retry_after'] ?? 0));
                    $resultPayload = $result;
                }

                if ($ok) {
                    $this->jobs->markCompleted($jobId, $resultPayload === [] ? null : $resultPayload);
                    $completed++;
                    continue;
                }

                if ($message === '') {
                    $message = 'Handler zakonczyl job niepowodzeniem.';
                }
                $backoffSeconds = $retryAfter > 0 ? $retryAfter : $this->defaultBackoffSeconds((int) ($job['attempts'] ?? 0));
                $isFinal = $this->jobs->markFailed($jobId, $message, $backoffSeconds);
                if ($isFinal) {
                    $failed++;
                } else {
                    $retried++;
                }
            } catch (Throwable $exception) {
                $backoffSeconds = $this->defaultBackoffSeconds((int) ($job['attempts'] ?? 0));
                $isFinal = $this->jobs->markFailed($jobId, $exception->getMessage(), $backoffSeconds);
                if ($isFinal) {
                    $failed++;
                } else {
                    $retried++;
                }
            }
        }

        return [
            'processed' => $processed,
            'completed' => $completed,
            'retried' => $retried,
            'failed' => $failed,
        ];
    }

    /**
     * @return array{
     *   recovered:int,
     *   scheduled_created:int,
     *   scheduled_skipped:int,
     *   processed:int,
     *   completed:int,
     *   retried:int,
     *   failed:int,
     *   cleaned:int
     * }
     */
    public function run(int $limit = 20): array
    {
        if ($limit <= 0) {
            throw new RuntimeException('Limit przetwarzania cron musi byc wiekszy od 0.');
        }

        $recovered = $this->jobs->recoverStuck(15);
        $scheduled = $this->createScheduledJobs();
        $processed = $this->processQueue($limit);
        $cleaned = $this->jobs->cleanup(30);

        return [
            'recovered' => $recovered,
            'scheduled_created' => (int) ($scheduled['created'] ?? 0),
            'scheduled_skipped' => (int) ($scheduled['skipped'] ?? 0),
            'processed' => (int) ($processed['processed'] ?? 0),
            'completed' => (int) ($processed['completed'] ?? 0),
            'retried' => (int) ($processed['retried'] ?? 0),
            'failed' => (int) ($processed['failed'] ?? 0),
            'cleaned' => $cleaned,
        ];
    }

    private function defaultBackoffSeconds(int $attemptsAlreadyDone): int
    {
        $currentAttempt = max(1, $attemptsAlreadyDone + 1);
        $seconds = (int) (60 * (2 ** ($currentAttempt - 1)));

        return min(3600, max(60, $seconds));
    }
}