/*
 * Copyright (C) 2003-2007 Funambol, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY, TITLE, NONINFRINGEMENT or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307  USA
 */

#if defined(WIN32) && !defined(_WIN32_WCE)
#define _WIN32_WINNT 0x0600
#endif

#include <windows.h>
#include <wincrypt.h>


#include "base/util/utils.h"
#include "spds/DESEncoder.h"


DESEncoder::DESEncoder() : DataTransformer(DT_DES) {
}

DESEncoder::~DESEncoder() {
}

char* DESEncoder::transform(char* data, TransformationInfo& info) {
    BOOL res = FALSE;

    HCRYPTPROV prov = 0;
    HCRYPTKEY key = 0;

    HCRYPTHASH hash=0;

    char* ret = NULL;

    DWORD sizeIn = info.size; // I reassign it to a DWORD
                              // just in case a long is not
                              // of the same size of a DWORD
    DWORD sizeOut = 0;

    DWORD dwParam = 0;

    char* password = stringdup(info.password);

    // -----------------------------------------------------

    res = CryptAcquireContext(
        &prov,
        NULL,
        MS_ENHANCED_PROV,
        PROV_RSA_FULL,
        CRYPT_VERIFYCONTEXT
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // Create hash object
    res = CryptCreateHash(
        prov,       // CSP handle
        CALG_MD5,   // hash algorith ID
        0,          // Key not used
        0,          // flags not used
        &hash       // handle to the hash object
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // hash password
    res = CryptHashData(
        hash,                     // hash handle
        (unsigned char*) password,// pointer to the data buffer
        strlen(password),         // data length
        0                         // flags not used
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // Create key from hash
    res = CryptDeriveKey(
        prov,       // CSP handle
        CALG_DES,   // algorithm id
        hash,       // hash object
        0,          // flags are not used
        &key        // key handle
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // set encryption mode to ECB
    dwParam=CRYPT_MODE_ECB;
    res = CryptSetKeyParam(
        key,                      // key handle
        KP_MODE,                   // set key mode flag
        (unsigned char*) &dwParam, // new mode value
        0                          // flags not used
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // set padding mode to PKCS5
    dwParam=PKCS5_PADDING;
    res = CryptSetKeyParam(
        key,                      // key handle
        KP_PADDING,                   // set key mode flag
        (unsigned char*) &dwParam, // new mode value
        0                          // flags not used
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // create big buffer
    sizeOut = sizeIn;

    // Get the size of the encrypted block
    res = CryptEncrypt(
        key,            // Key obtained earlier
        0,              // No hashing of data
        TRUE,           // Final or only buffer of data
        0,              // Must be zero
        NULL,           // No data this time
        &sizeOut,       // Length of the source data
        0               // Size of block
    );

    if ((res == FALSE) && (GetLastError() != ERROR_MORE_DATA)) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    // allocate and intialize the buffer
    ret = new char[sizeOut];
    memcpy(ret, data, sizeIn);

    // Now encrypt the data
    res = CryptEncrypt(
        key,                 // Key obtained earlier
        0,                   // No hashing of data
        TRUE,                // Final or only buffer of data
        0,                   // Must be zero
        (unsigned char*)ret, // Data buffer
        &sizeIn,             // Size of data
        sizeOut              // Size of block
    );

    if (res == FALSE) {
        lastErrorCode = ERR_DT_FAILURE;
        sprintf(lastErrorMsg, ERRMSG_DT_FAILURE, GetLastError());
        goto exit;
    }

    info.size = sizeIn;
    info.newReturnedData = TRUE;

 exit:

   // Destroy the session key.
   if (key)
     CryptDestroyKey (key);

   // Destroy the hash object.
   if (hash)
     CryptDestroyHash (hash);

   // Release the provider handle.
   if (prov)
     CryptReleaseContext (prov, 0);

   if (password) {
       delete [] password;
   }

   return ret;

}