<?php

declare(strict_types=1);

namespace Shlinkio\Shlink\Core\Visit;

use Doctrine\ORM;
use Psr\EventDispatcher\EventDispatcherInterface;
use Shlinkio\Shlink\Core\Config\Options\TrackingOptions;
use Shlinkio\Shlink\Core\EventDispatcher\Event\UrlVisited;
use Shlinkio\Shlink\Core\ShortUrl\Entity\ShortUrl;
use Shlinkio\Shlink\Core\Visit\Entity\Visit;
use Shlinkio\Shlink\Core\Visit\Model\Visitor;

readonly class VisitsTracker implements VisitsTrackerInterface
{
    public function __construct(
        private ORM\EntityManagerInterface $em,
        private EventDispatcherInterface $eventDispatcher,
        private TrackingOptions $options,
    ) {
    }

    public function track(ShortUrl $shortUrl, Visitor $visitor): Visit|null
    {
        return $this->trackVisit(
            fn (Visitor $v) => Visit::forValidShortUrl($shortUrl, $v, $this->options->anonymizeRemoteAddr),
            $visitor,
        );
    }

    public function trackInvalidShortUrlVisit(Visitor $visitor): Visit|null
    {
        return $this->trackOrphanVisit(
            fn (Visitor $v) => Visit::forInvalidShortUrl($v, $this->options->anonymizeRemoteAddr),
            $visitor,
        );
    }

    public function trackBaseUrlVisit(Visitor $visitor): Visit|null
    {
        return $this->trackOrphanVisit(
            fn (Visitor $v) => Visit::forBasePath($v, $this->options->anonymizeRemoteAddr),
            $visitor,
        );
    }

    public function trackRegularNotFoundVisit(Visitor $visitor): Visit|null
    {
        return $this->trackOrphanVisit(
            fn (Visitor $v) => Visit::forRegularNotFound($v, $this->options->anonymizeRemoteAddr),
            $visitor,
        );
    }

    private function trackOrphanVisit(callable $createVisit, Visitor $visitor): Visit|null
    {
        if (! $this->options->trackOrphanVisits) {
            return null;
        }

        return $this->trackVisit($createVisit, $visitor);
    }

    /**
     * @param callable(Visitor $visitor): Visit $createVisit
     */
    private function trackVisit(callable $createVisit, Visitor $visitor): Visit|null
    {
        if ($this->options->disableTracking) {
            return null;
        }

        $visit = $createVisit($visitor->normalizeForTrackingOptions($this->options));

        // Wrap persisting the visit in a transaction, so that the ShortUrlVisitsCountTracker performs changes inside
        // that very same transaction atomically
        $this->em->wrapInTransaction(fn () => $this->em->persist($visit));
        $this->eventDispatcher->dispatch(new UrlVisited($visit->getId(), $visitor->remoteAddress));

        return $visit;
    }
}