/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * XSEC
 *
 * NSSCryptoProvider := Provider to support NSS
 *
 * Author(s): Milan Tomic
 *
 */

#include <xsec/framework/XSECError.hpp>
#include <xsec/enc/NSS/NSSCryptoProvider.hpp>
#include <xsec/enc/NSS/NSSCryptoX509.hpp>
#include <xsec/enc/NSS/NSSCryptoKeyDSA.hpp>
#include <xsec/enc/NSS/NSSCryptoKeyRSA.hpp>
#include <xsec/enc/NSS/NSSCryptoKeyHMAC.hpp>
#include <xsec/enc/NSS/NSSCryptoHash.hpp>
#include <xsec/enc/NSS/NSSCryptoHashHMAC.hpp>
#include <xsec/enc/NSS/NSSCryptoSymmetricKey.hpp>
#include <xsec/enc/XSCrypt/XSCryptCryptoBase64.hpp>
#include <xsec/enc/XSECCryptoException.hpp>

#if defined (XSEC_HAVE_NSS)

#include <xercesc/util/Janitor.hpp>

XSEC_USING_XERCES(ArrayJanitor);

int NSSCryptoProvider::m_initialised = 0;

// --------------------------------------------------------------------------------
//           Constructor
// --------------------------------------------------------------------------------

void NSSCryptoProvider::Init(const char * dbDir) {
    ++m_initialised;

    if (m_initialised > 1)
        return;

    SECStatus s;

    if (dbDir != NULL)
        s = NSS_Init(dbDir);
    else
        s = NSS_NoDB_Init(NULL);

    if (s != SECSuccess) {

        throw XSECCryptoException(XSECCryptoException::MemoryError,
            "NSSCryptoProvider:NSSCryptoProvider - Error initializing NSS");

    }
}

NSSCryptoProvider::NSSCryptoProvider(const char * dbDir) {
    Init(dbDir);
}


// --------------------------------------------------------------------------------
//           Empty constructor
// --------------------------------------------------------------------------------

NSSCryptoProvider::NSSCryptoProvider()
{
    Init(NULL);
}

// --------------------------------------------------------------------------------
//           Destructor
// --------------------------------------------------------------------------------

NSSCryptoProvider::~NSSCryptoProvider()
{
  if (m_initialised == 1) {

    PK11_LogoutAll();

      SECStatus s = NSS_Shutdown();

    // Note that NSS will fail to shut down if any memory leaks are detected (NSS
    // objects were not released). This is security measure to prevent abuse of your
    // private keys.
    if (s != SECSuccess) {

      //throw XSECCryptoException(XSECCryptoException::GeneralError,
          //    "NSSCryptoProvider:NSSCryptoProvider - Error shuting down NSS");

    }

  }
  m_initialised--;
}

// --------------------------------------------------------------------------------
//           Get NSS string
// --------------------------------------------------------------------------------

const XMLCh * NSSCryptoProvider::getProviderName() const {
    return DSIGConstants::s_unicodeStrPROVNSS;
}

unsigned int NSSCryptoProvider::getMaxHashSize() const {
    return 128;
}


// --------------------------------------------------------------------------------
//           Hash
// --------------------------------------------------------------------------------

XSECCryptoHash* NSSCryptoProvider::hash(XSECCryptoHash::HashType type) const {
    NSSCryptoHash* ret;

    XSECnew(ret, NSSCryptoHash(type));

    return ret;
}

// --------------------------------------------------------------------------------
//           Hash HMAC
// --------------------------------------------------------------------------------

XSECCryptoHash* NSSCryptoProvider::HMAC(XSECCryptoHash::HashType type)const {
    NSSCryptoHashHMAC* ret;

    XSECnew(ret, NSSCryptoHashHMAC(type));

    return ret;
}

// --------------------------------------------------------------------------------
//           Get HMAC key
// --------------------------------------------------------------------------------

XSECCryptoKeyHMAC* NSSCryptoProvider::keyHMAC(void) const {

    NSSCryptoKeyHMAC* ret;

    XSECnew(ret, NSSCryptoKeyHMAC());

    return ret;
}

// --------------------------------------------------------------------------------
//           Get DSA key
// --------------------------------------------------------------------------------

XSECCryptoKeyDSA* NSSCryptoProvider::keyDSA() const {

    NSSCryptoKeyDSA * ret;

    XSECnew(ret, NSSCryptoKeyDSA());

    return ret;
}

// --------------------------------------------------------------------------------
//           Get RSA key
// --------------------------------------------------------------------------------

XSECCryptoKeyRSA* NSSCryptoProvider::keyRSA() const {

    NSSCryptoKeyRSA * ret;

    XSECnew(ret, NSSCryptoKeyRSA());

    return ret;
}

XSECCryptoKeyEC* NSSCryptoProvider::keyEC() const {

    throw XSECCryptoException(XSECCryptoException::UnsupportedError,
        "NSSCryptoProvider::keyEC - EC support not available");
}

XSECCryptoKey* NSSCryptoProvider::keyDER(const char* buf, unsigned long len, bool base64) const {

    throw XSECCryptoException(XSECCryptoException::UnsupportedError,
        "NSSCryptoProvider::keyDER - DER decoding support not available");
}

// --------------------------------------------------------------------------------
//           Get symmetric key
// --------------------------------------------------------------------------------

XSECCryptoSymmetricKey* NSSCryptoProvider::keySymmetric(XSECCryptoSymmetricKey::SymmetricKeyType alg) const {

    // Only temporary

    NSSCryptoSymmetricKey * ret;

    XSECnew(ret, NSSCryptoSymmetricKey(alg));

    return ret;
}

// --------------------------------------------------------------------------------
//           Get X509 class
// --------------------------------------------------------------------------------

XSECCryptoX509* NSSCryptoProvider::X509() const {

    NSSCryptoX509 * ret;

    XSECnew(ret, NSSCryptoX509());

    return ret;
}

// --------------------------------------------------------------------------------
//           Get Base64
// --------------------------------------------------------------------------------

XSECCryptoBase64* NSSCryptoProvider::base64() const {

    // NSS does provide a Base64 decoder/encoder,
    // but rather use the internal implementation.

    XSCryptCryptoBase64 * ret;

    XSECnew(ret, XSCryptCryptoBase64());

    return ret;
}

// --------------------------------------------------------------------------------
//     Translate a Base64 number to a SECItem
// --------------------------------------------------------------------------------

SECItem* NSSCryptoProvider::b642SI(const char* b64, unsigned int b64Len) {

    SECItem * rv;

    unsigned char * os;
    XSECnew(os, unsigned char[b64Len]);
    ArrayJanitor<unsigned char> j_os(os);

    // Decode
    XSCryptCryptoBase64 b;

    b.decodeInit();
    unsigned int retLen = b.decode((unsigned char *) b64, b64Len, os, b64Len);
    retLen += b.decodeFinish(&os[retLen], b64Len - retLen);

    rv = SECITEM_AllocItem(NULL, NULL, retLen);
    rv->len = retLen;
    memcpy(rv->data, os, retLen);

    return rv;
}

// --------------------------------------------------------------------------------
//     Translate a SECItem to a Base64 I2OSP number 
// --------------------------------------------------------------------------------

unsigned char* NSSCryptoProvider::SI2b64(SECItem* n, unsigned int& retLen) {

    unsigned char * b64;
    // Naieve length calculation
    unsigned int bufLen = n->len * 2 + 4;

    XSECnew(b64, unsigned char[bufLen]);
    ArrayJanitor<unsigned char> j_b64(b64);

  // Encode
    XSCryptCryptoBase64 b;

    b.encodeInit();
    retLen = b.encode(n->data, (unsigned int) n->len, b64, bufLen);
    retLen += b.encodeFinish(&b64[retLen], bufLen - retLen);

    j_b64.release();
    return b64;
}

// --------------------------------------------------------------------------------
//           Check if hash algorithm is supported
// --------------------------------------------------------------------------------

bool NSSCryptoProvider::algorithmSupported(XSECCryptoHash::HashType alg) const {

    switch (alg) {

    case (XSECCryptoHash::HASH_SHA1) :
    case (XSECCryptoHash::HASH_MD5) :
    case (XSECCryptoHash::HASH_SHA256) :
    case (XSECCryptoHash::HASH_SHA384) :
    case (XSECCryptoHash::HASH_SHA512) :
        return true;

    default:
        return false;

    }

    return false;
}

// --------------------------------------------------------------------------------
//           Check if cypher algorithm is supported
// --------------------------------------------------------------------------------

bool NSSCryptoProvider::algorithmSupported(XSECCryptoSymmetricKey::SymmetricKeyType alg) const {

    switch (alg) {

    case (XSECCryptoSymmetricKey::KEY_AES_128) :
    case (XSECCryptoSymmetricKey::KEY_AES_192) :
    case (XSECCryptoSymmetricKey::KEY_AES_256) :

        //return m_haveAES;
    return true;

    case (XSECCryptoSymmetricKey::KEY_3DES_192) :

        return true;

    default:

        return false;

    }

    return false;
}


// --------------------------------------------------------------------------------
//           Generate random data
// --------------------------------------------------------------------------------

unsigned int NSSCryptoProvider::getRandom(unsigned char* buffer, unsigned int numOctets) const {

  SECStatus s = PK11_GenerateRandom(buffer, numOctets);

  if (s != SECSuccess) {
        throw XSECException(XSECException::InternalError,
            "NSSCryptoProvider() - Error generating Random data");
  }

    return numOctets;
}

#endif /* XSEC_HAVE_NSS */