<?php

declare(strict_types=1);

final class NotificationRepository
{
    private string $systemPath;

    public function __construct()
    {
        $this->systemPath = storage_path('system/notifications.json');
    }

    public function systemConfig(): array
    {
        $config = decode_json_file($this->systemPath, []);
        $changed = false;

        if (!isset($config['cron_token']) || !is_string($config['cron_token']) || $config['cron_token'] === '') {
            $config['cron_token'] = bin2hex(random_bytes(24));
            $changed = true;
        }

        if (!isset($config['subject']) || !is_string($config['subject']) || $config['subject'] === '') {
            $host = parse_url(app_origin(), PHP_URL_HOST);
            $host = is_string($host) && $host !== '' ? $host : 'localhost';
            $config['subject'] = 'mailto:hello@' . $host;
            $changed = true;
        }

        if ($changed) {
            $this->writeJson($this->systemPath, $config);
        }

        return $config;
    }

    public function saveVapidKeys(string $publicKey, string $privateKey): void
    {
        $config = $this->systemConfig();
        $config['vapid_public_key'] = $publicKey;
        $config['vapid_private_key'] = $privateKey;
        $this->writeJson($this->systemPath, $config);
    }

    public function subscriptionsForUser(string $username): array
    {
        $payload = decode_json_file($this->subscriptionsPath($username), ['subscriptions' => []]);

        return array_values(array_filter($payload['subscriptions'] ?? [], 'is_array'));
    }

    public function saveSubscription(string $username, array $subscription): void
    {
        $endpoint = trim((string) ($subscription['endpoint'] ?? ''));
        if ($endpoint === '') {
            throw new RuntimeException('Die Subscription ist unvollständig.');
        }

        $subscriptions = $this->subscriptionsForUser($username);
        $saved = false;

        foreach ($subscriptions as &$entry) {
            if (($entry['endpoint'] ?? '') === $endpoint) {
                $entry = array_merge($entry, $subscription, [
                    'updated_at' => date(DATE_ATOM),
                ]);
                $saved = true;
                break;
            }
        }
        unset($entry);

        if (!$saved) {
            $subscription['created_at'] = date(DATE_ATOM);
            $subscription['updated_at'] = date(DATE_ATOM);
            $subscriptions[] = $subscription;
        }

        $this->writeJson($this->subscriptionsPath($username), ['subscriptions' => array_values($subscriptions)]);
    }

    public function removeSubscription(string $username, string $endpoint): void
    {
        $endpoint = trim($endpoint);
        if ($endpoint === '') {
            return;
        }

        $subscriptions = array_values(array_filter(
            $this->subscriptionsForUser($username),
            static fn (array $entry): bool => ($entry['endpoint'] ?? '') !== $endpoint
        ));

        $this->writeJson($this->subscriptionsPath($username), ['subscriptions' => $subscriptions]);
    }

    public function removeInvalidSubscriptions(string $username, array $endpoints): void
    {
        foreach ($endpoints as $endpoint) {
            if (is_string($endpoint) && $endpoint !== '') {
                $this->removeSubscription($username, $endpoint);
            }
        }
    }

    public function reminderState(string $username): array
    {
        return decode_json_file($this->reminderStatePath($username), []);
    }

    public function saveReminderState(string $username, array $state): void
    {
        $this->writeJson($this->reminderStatePath($username), $state);
    }

    public function subscriptionCount(string $username): int
    {
        return count($this->subscriptionsForUser($username));
    }

    private function subscriptionsPath(string $username): string
    {
        return storage_path('users/' . normalize_username($username) . '/push-subscriptions.json');
    }

    private function reminderStatePath(string $username): string
    {
        return storage_path('users/' . normalize_username($username) . '/notification-state.json');
    }

    private function writeJson(string $path, array $payload): void
    {
        $directory = dirname($path);
        if (!is_dir($directory)) {
            mkdir($directory, 0775, true);
        }

        $bytes = file_put_contents(
            $path,
            json_encode($payload, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES),
            LOCK_EX
        );

        if ($bytes === false) {
            throw new RuntimeException('Die Benachrichtigungsdaten konnten nicht gespeichert werden.');
        }
    }
}