<?php declare(strict_types=1);
defined('MW_PATH') or exit('No direct script access allowed');

/**
 * IpHelper
 *
 * @package MailWizz EMA
 * @author MailWizz Development Team <support@mailwizz.com>
 * @link https://www.mailwizz.com/
 * @copyright MailWizz EMA (https://www.mailwizz.com)
 * @license https://www.mailwizz.com/license/
 * @since 1.3.8.1
 */

class IpHelper
{
    /**
     * Checks if an IPv4 or IPv6 address is contained in the list of given IPs or subnets.
     *
     * @author Fabien Potencier <fabien@symfony.com>
     * @param string       $requestIp IP to check
     * @param string|array $ips       List of IPs or subnets (can be a string if only a single one)
     *
     * @return bool Whether the IP is valid
     */
    public static function isIpInRange(string $requestIp, $ips): bool
    {
        if (!is_array($ips)) {
            $ips = [$ips];
        }

        $method = substr_count($requestIp, ':') > 1 ? 'checkIp6' : 'checkIp4';

        foreach ($ips as $ip) {
            if (self::$method($requestIp, $ip)) {
                return true;
            }
        }

        return false;
    }

    /**
     * Compares two IPv4 addresses.
     * In case a subnet is given, it checks if it contains the request IP.
     *
     * @author Fabien Potencier <fabien@symfony.com>
     * @param string $requestIp IPv4 address to check
     * @param string $ip        IPv4 address or subnet in CIDR notation
     *
     * @return bool Whether the request IP matches the IP, or whether the request IP is within the CIDR subnet
     */
    public static function checkIp4(string $requestIp, string $ip): bool
    {
        if (!filter_var($requestIp, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {
            return false;
        }

        if (false !== strpos($ip, '/')) {
            [$address, $netmask] = explode('/', $ip, 2);

            if ($netmask === '0') {
                return (bool)filter_var($address, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4);
            }

            if ($netmask < 0 || $netmask > 32) {
                return false;
            }
        } else {
            $address = $ip;
            $netmask = 32;
        }

        return 0 === substr_compare(sprintf('%032b', ip2long($requestIp)), sprintf('%032b', ip2long($address)), 0, (int)$netmask);
    }

    /**
     * Compares two IPv6 addresses.
     * In case a subnet is given, it checks if it contains the request IP.
     *
     * @author David Soria Parra <dsp at php dot net>
     *
     * @see https://github.com/dsp/v6tools
     *
     * @param string $requestIp IPv6 address to check
     * @param string $ip        IPv6 address or subnet in CIDR notation
     *
     * @return bool Whether the IP is valid
     *
     * @throws RuntimeException When IPV6 support is not enabled
     */
    public static function checkIp6(string $requestIp, string $ip): bool
    {
        if (!((extension_loaded('sockets') && defined('AF_INET6')) || @inet_pton('::1'))) {
            throw new RuntimeException('Unable to check Ipv6. Check that PHP was not compiled with option "disable-ipv6".');
        }

        if (false !== strpos($ip, '/')) {
            [$address, $netmask] = explode('/', $ip, 2);

            if ($netmask < 1 || $netmask > 128) {
                return false;
            }
        } else {
            $address = $ip;
            $netmask = 128;
        }

        $bytesAddr = unpack('n*', (string)inet_pton($address));
        $bytesTest = unpack('n*', (string)inet_pton($requestIp));

        if (!$bytesAddr || !$bytesTest) {
            return false;
        }

        for ($i = 1, $ceil = ceil((int)$netmask / 16); $i <= $ceil; ++$i) {
            $left = (int)$netmask - 16 * ($i - 1);
            $left = ($left <= 16) ? $left : 16;
            $mask = ~(0xffff >> $left) & 0xffff;
            if (($bytesAddr[$i] & $mask) != ($bytesTest[$i] & $mask)) {
                return false;
            }
        }

        return true;
    }
}
