#include "Swiften/SASL/SCRAMSHA1ClientAuthenticator.h"

#include <cassert>

#include <map>

#include <boost/lexical_cast.hpp>

#include "Swiften/StringCodecs/SHA1.h"

#include "Swiften/StringCodecs/Base64.h"

#include "Swiften/StringCodecs/HMACSHA1.h"

#include "Swiften/StringCodecs/PBKDF2.h"

#include "Swiften/StringPrep/StringPrep.h"

namespace Swift {

SCRAMSHA1ClientAuthenticator::SCRAMSHA1ClientAuthenticator(const String& nonce) : ClientAuthenticator("SCRAM-SHA-1"), step(Initial), clientnonce(nonce) {

}

ByteArray SCRAMSHA1ClientAuthenticator::getResponse() const {

if (step == Initial) {

return getGS2Header() + getInitialBareClientMessage();

}

else {

ByteArray clientKey = HMACSHA1::getResult(saltedPassword, "Client Key");

ByteArray storedKey = SHA1::getBinaryHash(clientKey);

ByteArray clientSignature = HMACSHA1::getResult(storedKey, authMessage);

ByteArray clientProof = clientKey;

for (unsigned int i = 0; i < clientProof.getSize(); ++i) {

clientProof[i] ^= clientSignature[i];

}

ByteArray result = ByteArray("c=") + Base64::encode(getGS2Header()) + ",r=" + clientnonce + serverNonce + ",p=" + Base64::encode(clientProof);

return result;

}

}

bool SCRAMSHA1ClientAuthenticator::setChallenge(const ByteArray& challenge) {

if (step == Initial) {

initialServerMessage = challenge;

std::map<char, String> keys = parseMap(String(initialServerMessage.getData(), initialServerMessage.getSize()));

// Extract the salt

ByteArray salt = Base64::decode(keys['s']);

// Extract the server nonce

String clientServerNonce = keys['r'];

if (clientServerNonce.getUTF8Size() <= clientnonce.getUTF8Size()) {

return false;

}

String receivedClientNonce = clientServerNonce.getSubstring(0, clientnonce.getUTF8Size());

if (receivedClientNonce != clientnonce) {

return false;

}

serverNonce = clientServerNonce.getSubstring(clientnonce.getUTF8Size(), clientServerNonce.npos());

// Extract the number of iterations

int iterations = 0;

try {

iterations = boost::lexical_cast<int>(keys['i'].getUTF8String());

}

catch (const boost::bad_lexical_cast&) {

return false;

}

return false;

}

// Compute all the values needed for the server signature

saltedPassword = PBKDF2::encode(StringPrep::getPrepared(getPassword(), StringPrep::SASLPrep), salt, iterations);

authMessage = getInitialBareClientMessage() + "," + initialServerMessage + "," + "c=" + Base64::encode(getGS2Header()) + ",r=" + clientnonce + serverNonce;

ByteArray serverKey = HMACSHA1::getResult(saltedPassword, "Server Key");

serverSignature = HMACSHA1::getResult(serverKey, authMessage);

step = Proof;

return true;

}

else {

ByteArray result = ByteArray("v=") + ByteArray(Base64::encode(serverSignature));

return challenge == result;

}

}

std::map<char, String> SCRAMSHA1ClientAuthenticator::parseMap(const String& s) {

std::map<char, String> result;

if (s.getUTF8Size() > 0) {

char key;

String value;

size_t i = 0;

bool expectKey = true;

while (i < s.getUTF8Size()) {

if (expectKey) {

key = s[i];

expectKey = false;

i++;

}

else if (s[i] == ',') {

result[key] = value;

value = "";

expectKey = true;

}

else {

value += s[i];

}

i++;

}

result[key] = value;

}

return result;

}

ByteArray SCRAMSHA1ClientAuthenticator::getInitialBareClientMessage() const {

String authenticationID = StringPrep::getPrepared(getAuthenticationID(), StringPrep::SASLPrep);

}

ByteArray SCRAMSHA1ClientAuthenticator::getGS2Header() const {

}

}