<?php

namespace NoccyLabs\Mercureact\Broker;

use NoccyLabs\Mercureact\Broker\Subscriber\SubscriberInterface;
use Psr\Log\LoggerInterface;
use SplObjectStorage;

class TopicManager
{
    /** @var array<string,Topic> */
    private array $topics = [];

    private ?string $lastEventId = null;

    private SplObjectStorage $subscribers;

    public function __construct(private LoggerInterface $logger)
    {
        $this->subscribers = new SplObjectStorage();
    }

    public function getTopic(string $topic): Topic
    {
        if (!isset($this->topics[$topic])) {
            $this->logger->debug("Created topic: {$topic}");
            $this->topics[$topic] = new Topic($topic);
        }
        return $this->topics[$topic];
    }

    public function publish(Message $message): void
    {
        $this->lastEventId = $message->id;
        foreach ($message->topic as $topic) {
            $this->logger->debug("Publish: {$message->id} → ".json_encode($message->topic,JSON_UNESCAPED_SLASHES));
            $this->getTopic($topic)->publish($message);
        }
    }

    public function subscribe(SubscriberInterface $subscriber, array $topics): void
    {
        $this->logger->debug("Subscribed: ".$subscriber->getId()." + ".json_encode($topics,JSON_UNESCAPED_SLASHES));
        $this->subscribers->attach($subscriber);
        foreach ($topics as $topic) {
            $this->getTopic($topic)->addSubscriber($subscriber);
        }
    }

    public function unsubscribe(SubscriberInterface $subscriber, ?array $topics=null): void
    {
        $this->logger->debug("Unsubscribed: ".$subscriber->getId()." - ".json_encode($topics,JSON_UNESCAPED_SLASHES));
        if (!$topics) {
            $this->subscribers->detach($subscriber);
            foreach ($this->topics as $topic) {
                $topic->removeSubscriber($subscriber);
            }
            return;
        }
        foreach ($topics as $topic) {
            $this->getTopic($topic)->removeSubscriber($subscriber);
        }
    }

    public function getSubscriptions(): array
    {
        $all = [];

        foreach ($this->topics as $topic) {
            $subs = $topic->getSubscribers();
            foreach ($subs as $sub) {
                $all[] = [
                    'id' => './well-known/mercure/subsciptions/'.urlencode($topic->getTopic())."/".urlencode($sub->getId()),
                    'type' => "Subscription",
                    'topic' => $topic->getTopic(),
                    'subscriber' => $sub->getId(),
                    'active' => true,
                    'payload' => $sub->getPayload(),
                ];
            }
        }

        return $all;
    }

    public function getLastEventId(): ?string
    {
        return ($this->lastEventId !== null)?("urn:uuid:".$this->lastEventId):null;
    }

    public function getTopicCount(): int
    {
        return count($this->topics);
    }

    public function getSubscriberCount(): int
    {
        return count($this->subscribers);
    }

    public function garbageCollect(): void
    {
        $this->topics = array_filter(
            $this->topics,
            function (Topic $topic) {
                $topic->garbageCollect();
                return ($topic->getHistorySize() > 0 || $topic->getSubscriberCount() > 0) || ($topic->getAge() < 60);
            }
        );
    }

}