/*
 * Copyright (c) 2010-2016 Isode Limited.
 * All rights reserved.
 * See the COPYING file for more information.
 */

#include <Swiften/TLS/ServerIdentityVerifier.h>

#include <boost/algorithm/string.hpp>

#include <Swiften/IDN/IDNConverter.h>

namespace Swift {

ServerIdentityVerifier::ServerIdentityVerifier(const JID& jid, IDNConverter* idnConverter, bool checkServer) : domainValid(false), checkServer_(checkServer) {
    domain = jid.getDomain();
    boost::optional<std::string> domainResult = idnConverter->getIDNAEncoded(domain);
    if (!!domainResult) {
        encodedDomain = *domainResult;
        domainValid = true;
    }
}

bool ServerIdentityVerifier::certificateVerifies(Certificate::ref certificate) {
    bool hasSAN = false;

    if (certificate == nullptr) {
        return false;
    }
    // DNS names
    std::vector<std::string> dnsNames = certificate->getDNSNames();
    for (const auto& dnsName : dnsNames) {
        if (matchesDomain(dnsName)) {
            return true;
        }
    }
    hasSAN |= !dnsNames.empty();

    std::string prefix = (checkServer_) ? "_xmpp-server." : "_xmpp-client.";

    // SRV names
    std::vector<std::string> srvNames = certificate->getSRVNames();
    for (const auto& srvName : srvNames) {
        // Only match SRV names that begin with the service; this isn't required per
        // spec, but we're being purist about this.
        if (boost::starts_with(srvName, prefix) && matchesDomain(srvName.substr(prefix.size(), srvName.npos))) {
            return true;
        }
    }
    hasSAN |= !srvNames.empty();

    // XmppAddr
    std::vector<std::string> xmppAddresses = certificate->getXMPPAddresses();
    for (const auto& xmppAddress : xmppAddresses) {
        if (matchesAddress(xmppAddress)) {
            return true;
        }
    }
    hasSAN |= !xmppAddresses.empty();

    // CommonNames. Only check this if there was no SAN (according to spec).
    if (!hasSAN) {
        std::vector<std::string> commonNames = certificate->getCommonNames();
        for (const auto& commonName : commonNames) {
            if (matchesDomain(commonName)) {
                return true;
            }
        }
    }

    return false;
}

bool ServerIdentityVerifier::matchesDomain(const std::string& s) const {
    if (!domainValid) {
        return false;
    }
    if (boost::starts_with(s, "*.")) {
        std::string matchString(s.substr(2, s.npos));
        std::string matchDomain = encodedDomain;
        size_t dotIndex = matchDomain.find('.');
        if (dotIndex != matchDomain.npos) {
            matchDomain = matchDomain.substr(dotIndex + 1, matchDomain.npos);
        }
        return boost::iequals(matchString, matchDomain);
    }
    else {
        return boost::iequals(s, encodedDomain);
    }
}

bool ServerIdentityVerifier::matchesAddress(const std::string& s) const {
    return boost::iequals(s, domain);
}

}