/*!
 *
 * Copyright (c) 2023-2023 Diality Inc. - All Rights Reserved.
 * \copyright
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * \file    encryption.cpp
 * \author  (last)      Behrouz NematiPour
 * \date    (last)      18-Jul-2023
 * \author  (original)  Behrouz NematiPour
 * \date    (original)  18-Jul-2023
 *
 */
#include "encryption.h"

// Linux

// Qt
#include <QDebug>
#include <QPasswordDigestor>

// Project
//#include "DeviceController.h"

QString encryption::__salt__ = "";

// Additional

int encryption::cryptOpen(const QString vDevice, const QString vFolder)
{
    qDebug() << vDevice << vFolder;
    return 0;
}

int encryption::cryptFormat(const QString vDevice)
{
    qDebug() << vDevice;
    return 0;
}

int encryption::cryptClose(const QString vFolder)
{
    qDebug() << vFolder;
    return 0;
}

int encryption::mkfsExt4(const QString vDevice)
{
    qDebug() << vDevice;
    return 0;
}

void encryption::varSalt(const QString &vSalt) {
    __salt__ = vSalt;
}

QString encryption::fixSalt() {
    const char c [ ] = { 56, 51, 104, 114, 48, 117, 50, 78, 51, 109, 94, 43, 105, 80, 48, 117, 114, 0 };
    return  QString(c);
}

/*!
 * \brief   encryption::hashedString
 * \details encrypts the string vString with an algorithm
 * \param   vString - the string to be encrypted.
 * \param   vSalt   - the encryption salt.
 * \return  encrypted string
 */
QString encryption::hashedString(const QString &vString, bool &ok, bool vAddMoreSalt) {
    int     iter    = 10000; // https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html#pbkdf2
    int     len     = 16;

    ok = vAddMoreSalt ? ! __salt__.isEmpty() : true;
    auto shuffle        = [](const QString &vString) -> QByteArray {
        auto reverse    = [](const QString &vString) -> QString    {
            if ( vString.trimmed().isEmpty() ) return QString();

            QString mReverse;
            int end = vString.size() - 1;
            int mid = end / 2;

            for(int i = mid; i >=   0; i-- ) {
                mReverse += vString.at(i);
            }

            for(int i = end; i >  mid; i-- ) {
                mReverse += vString.at(i);
            }
            return mReverse;
        };

        if ( vString.trimmed().isEmpty() ) return QByteArray();
        //DEBUG: qDebug()<<"string" << vString;
        QString    reversed = reverse(vString);
        //DEBUG: qDebug()<<"reversed" << reversed;
        QByteArray hexed    = reversed.toUtf8().toHex();
        //DEBUG: qDebug()<<"hexed"    << hexed;
        return     hexed;
    };

    QCryptographicHash::Algorithm algorithm = QCryptographicHash::Sha512;
    QString salt = fixSalt() + (vAddMoreSalt ? __salt__ : "");
    //DEBUG:    qDebug() << "salt:" << salt;
    QByteArray hashed = QPasswordDigestor::deriveKeyPbkdf2(algorithm, vString.toUtf8(), shuffle( salt ), iter, len).toHex();
    //DEBUG: qDebug() << "hashed:" << vString << hashed;
    return hashed;
}

/*!
 * \brief   encryption::isDefaultServicePassword
 * \details Checks if the current service password is the default password
 * \note    It is being used to force the user/manufacturer to set the service password.
 * \param   vPassword - the service pasword entered by user.
 * \return  true if the service password is the default.
 */
bool encryption::isDefaultServicePassword(const QString &vPassword, bool &ok)
{
    //DEBUG qDebug() << __FUNCTION__ << vPassword;
    return vPassword == defaultServicePassword(ok);
}

/*!
 * \brief   encryption::defaultPassword
 * \details The default password which will be used as an indication that the service password has not been set yet.
 * \return  the default password will be saved as hashed string.
 */
QString encryption::defaultServicePassword(bool &ok)
{
    QString _A1 = "tal";
    QString _S1 = QString("%1").arg(_A1     ).prepend("A"   );
    QString _S2 = QString("%1").arg(_A1     ).prepend("Ma"  );
    QString _S3 = QString("%1").arg(10*2+2  ).append ("leh" );
    QString hashed = hashedString(( QStringList() << _S1 << _S2 << _S3 ).join('.'), ok, false);
    //DEBUG qDebug() << __FUNCTION__ << hashed;
    return  hashed;
}

/*!
 * \brief   encryption::configurationsPassword
 * \details The password which will be used for encrypt partition.
 * \return  the password will be saved as hashed string.
 */
QString encryption::configurationsPassword(bool &ok, bool vReset)
{
    if ( vReset ) { // "Diality.2023"
        const char d [ ] = { 68, 105, 97, 108, 105, 116, 121, 46, 50, 48, 50, 51, 0 };
        return QString(d);
    }
    const char c [ ] = {
                       50, 75, 102,  98, 106,  67, 46,
                           68,  89, 115, 116, 109, 46,
                           71,  50,  75, 106,  90, 46,
                          105,  78, 105, 120,  73, 46,
                           78, 105,  51,  50,  89, 46,
                           84,  89, 112,  57, 117, 46,
                           77,  50,  52, 119, 103, 46,
                           50,  89,  98,  98, 106, 46,
                           78, 105,  48,  73,  78, 46,
                          109,  70,  50,  52, 119, 46,
                          103,  50,  76,  76,  90, 46,
                          104, 116, 117,  77,  73, 46,
                           78, 105, 111,  50,  89, 46,
                           84,  89, 112,  57, 117, 46,
                           77,  50,  52, 119,
                           0 };
    QString hashed = hashedString(QString(c), ok, true);
    //DEBUG qDebug() << __FUNCTION__ << hashed << ok;
    return  hashed;
}