<?php

namespace WPForms\Vendor;

/**
 * Validates a host according to the IPv4, IPv6 and DNS (future) specifications.
 */
class HTMLPurifier_AttrDef_URI_Host extends HTMLPurifier_AttrDef
{
    /**
     * IPv4 sub-validator.
     * @type HTMLPurifier_AttrDef_URI_IPv4
     */
    protected $ipv4;
    /**
     * IPv6 sub-validator.
     * @type HTMLPurifier_AttrDef_URI_IPv6
     */
    protected $ipv6;
    public function __construct()
    {
        $this->ipv4 = new HTMLPurifier_AttrDef_URI_IPv4();
        $this->ipv6 = new HTMLPurifier_AttrDef_URI_IPv6();
    }
    /**
     * @param string $string
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($string, $config, $context)
    {
        $length = \strlen($string);
        // empty hostname is OK; it's usually semantically equivalent:
        // the default host as defined by a URI scheme is used:
        //
        //      If the URI scheme defines a default for host, then that
        //      default applies when the host subcomponent is undefined
        //      or when the registered name is empty (zero length).
        if ($string === '') {
            return '';
        }
        if ($length > 1 && $string[0] === '[' && $string[$length - 1] === ']') {
            //IPv6
            $ip = \substr($string, 1, $length - 2);
            $valid = $this->ipv6->validate($ip, $config, $context);
            if ($valid === \false) {
                return \false;
            }
            return '[' . $valid . ']';
        }
        // need to do checks on unusual encodings too
        $ipv4 = $this->ipv4->validate($string, $config, $context);
        if ($ipv4 !== \false) {
            return $ipv4;
        }
        // A regular domain name.
        // This doesn't match I18N domain names, but we don't have proper IRI support,
        // so force users to insert Punycode.
        // Underscores defined as Unreserved Characters in RFC 3986 are
        // allowed in a URI. There are cases where we want to consider a
        // URI containing "_" such as "_dmarc.example.com".
        // Underscores are not allowed in the default. If you want to
        // allow it, set Core.AllowHostnameUnderscore to true.
        $underscore = $config->get('Core.AllowHostnameUnderscore') ? '_' : '';
        // Based off of RFC 1738, but amended so that
        // as per RFC 3696, the top label need only not be all numeric.
        // The productions describing this are:
        $a = '[a-z]';
        // alpha
        $an = "[a-z0-9{$underscore}]";
        // alphanum
        $and = "[a-z0-9-{$underscore}]";
        // alphanum | "-"
        // domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum
        $domainlabel = "{$an}(?:{$and}*{$an})?";
        // AMENDED as per RFC 3696
        // toplabel    = alphanum | alphanum *( alphanum | "-" ) alphanum
        //      side condition: not all numeric
        $toplabel = "{$an}(?:{$and}*{$an})?";
        // hostname    = *( domainlabel "." ) toplabel [ "." ]
        if (\preg_match("/^(?:{$domainlabel}\\.)*({$toplabel})\\.?\$/i", $string, $matches)) {
            if (!\ctype_digit($matches[1])) {
                return $string;
            }
        }
        // PHP 5.3 and later support this functionality natively
        if (\function_exists('idn_to_ascii')) {
            if (\defined('IDNA_NONTRANSITIONAL_TO_ASCII') && \defined('INTL_IDNA_VARIANT_UTS46')) {
                $string = \idn_to_ascii($string, \IDNA_NONTRANSITIONAL_TO_ASCII, \INTL_IDNA_VARIANT_UTS46);
            } else {
                $string = \idn_to_ascii($string);
            }
            // If we have Net_IDNA2 support, we can support IRIs by
            // punycoding them. (This is the most portable thing to do,
            // since otherwise we have to assume browsers support
        } elseif ($config->get('Core.EnableIDNA') && \class_exists('WPForms\\Vendor\\Net_IDNA2')) {
            $idna = new Net_IDNA2(array('encoding' => 'utf8', 'overlong' => \false, 'strict' => \true));
            // we need to encode each period separately
            $parts = \explode('.', $string);
            try {
                $new_parts = array();
                foreach ($parts as $part) {
                    $encodable = \false;
                    for ($i = 0, $c = \strlen($part); $i < $c; $i++) {
                        if (\ord($part[$i]) > 0x7a) {
                            $encodable = \true;
                            break;
                        }
                    }
                    if (!$encodable) {
                        $new_parts[] = $part;
                    } else {
                        $new_parts[] = $idna->encode($part);
                    }
                }
                $string = \implode('.', $new_parts);
            } catch (\Exception $e) {
                // XXX error reporting
            }
        }
        // Try again
        if (\preg_match("/^({$domainlabel}\\.)*{$toplabel}\\.?\$/i", $string)) {
            return $string;
        }
        return \false;
    }
}
// vim: et sw=4 sts=4