<?php

namespace Domain\CronJob;

class CronJobProcessor
{
    /** @var CronJobRepository */
    private $cronRepo;

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

    /**
     * @param CronJobRepository $cronRepo
     */
    public function __construct(CronJobRepository $cronRepo)
    {
        $this->cronRepo = $cronRepo;
    }

    /**
     * Zarejestruj handler dla typu zadania
     *
     * @param string $jobType
     * @param callable $handler fn($payload): bool|array — true/array = success, false/exception = fail
     */
    public function registerHandler($jobType, callable $handler)
    {
        $this->handlers[$jobType] = $handler;
    }

    /**
     * Utwórz zadania z harmonogramów, których next_run_at <= NOW
     *
     * @return int Liczba utworzonych zadań
     */
    public function createScheduledJobs()
    {
        $schedules = $this->cronRepo->getDueSchedules();
        $created = 0;

        foreach ($schedules as $schedule) {
            $jobType = $schedule['job_type'];

            // Nie twórz duplikatów
            if ($this->cronRepo->hasPendingJob($jobType)) {
                // Mimo duplikatu, przesuń next_run_at żeby nie sprawdzać co sekundę
                $this->cronRepo->touchSchedule($schedule['id'], (int) $schedule['interval_seconds']);
                continue;
            }

            $payload = null;
            if (!empty($schedule['payload'])) {
                $payload = json_decode($schedule['payload'], true);
            }

            $this->cronRepo->enqueue(
                $jobType,
                $payload,
                (int) $schedule['priority'],
                (int) $schedule['max_attempts']
            );

            $this->cronRepo->touchSchedule($schedule['id'], (int) $schedule['interval_seconds']);
            $created++;
        }

        return $created;
    }

    /**
     * Przetwórz kolejkę zadań
     *
     * @param int $limit
     * @return array Statystyki: ['processed' => int, 'succeeded' => int, 'failed' => int, 'skipped' => int]
     */
    public function processQueue($limit = 10)
    {
        $stats = ['processed' => 0, 'succeeded' => 0, 'failed' => 0, 'skipped' => 0];

        $jobs = $this->cronRepo->fetchNext($limit);

        foreach ($jobs as $job) {
            $jobType = $job['job_type'];
            $jobId = (int) $job['id'];
            $stats['processed']++;

            if (!isset($this->handlers[$jobType])) {
                $this->cronRepo->markFailed($jobId, 'No handler registered for job type: ' . $jobType, (int) $job['attempts']);
                $stats['skipped']++;
                continue;
            }

            try {
                $result = call_user_func($this->handlers[$jobType], $job['payload']);

                if ($result === false) {
                    $this->cronRepo->markFailed($jobId, 'Handler returned false', (int) $job['attempts']);
                    $stats['failed']++;
                } else {
                    $resultData = is_array($result) ? $result : null;
                    $this->cronRepo->markCompleted($jobId, $resultData);
                    $stats['succeeded']++;
                }
            } catch (\Exception $e) {
                $this->cronRepo->markFailed($jobId, $e->getMessage(), (int) $job['attempts']);
                $stats['failed']++;
            } catch (\Throwable $e) {
                $this->cronRepo->markFailed($jobId, $e->getMessage(), (int) $job['attempts']);
                $stats['failed']++;
            }
        }

        return $stats;
    }

    /**
     * Główna metoda: utwórz scheduled jobs + przetwórz kolejkę
     *
     * @param int $limit
     * @return array ['scheduled' => int, 'processed' => int, 'succeeded' => int, 'failed' => int, 'skipped' => int]
     */
    public function run($limit = 20)
    {
        // Odzyskaj stuck jobs
        $this->cronRepo->recoverStuck(30);

        // Utwórz zadania z harmonogramów
        $scheduled = $this->createScheduledJobs();

        // Przetwórz kolejkę
        $stats = $this->processQueue($limit);
        $stats['scheduled'] = $scheduled;

        // Cleanup starych zadań (raz na uruchomienie)
        $this->cronRepo->cleanup(30);

        return $stats;
    }
}