<?php

declare(strict_types=1);

namespace App\Services\Media;

/**
 * Every address a hostname resolves to, IPv4 and IPv6.
 *
 * Its own class so the tests can answer for hosts that do not exist, and so
 * `RemoteImage` can refuse a name that points anywhere private before a single
 * byte is requested.
 */
class HostResolver
{
    /**
     * @return array<int, string>
     */
    public function resolve(string $host): array
    {
        $v4 = gethostbynamel($host) ?: [];
        $v6 = array_column(@dns_get_record($host, DNS_AAAA) ?: [], 'ipv6');

        return array_values(array_unique([...$v4, ...$v6]));
    }
}