/**
* Digital Voice Modem - Host Software
* GPLv2 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* @package DVM / Host Software
*
*/
//
// Based on code from the MMDVMHost project. (https://github.com/g4klx/MMDVMHost)
// Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
//
/*
*   Copyright (C) 2015,2016 by Jonathan Naylor G4KLX
*   Copyright (C) 2019-2021 by Bryan Biedenkapp N2PLL
*
*   This program is free software; you can redistribute it and/or modify
*   it under the terms of the GNU General Public License as published by
*   the Free Software Foundation; either version 2 of the License, or
*   (at your option) any later version.
*
*   This program is distributed in the hope that it will be useful,
*   but WITHOUT ANY WARRANTY; without even the implied warranty of
*   MERCHANTABILITY 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "Defines.h"
#include "dmr/lc/CSBK.h"
#include "edac/BPTC19696.h"
#include "edac/CRC.h"
#include "Log.h"
#include "Utils.h"

using namespace dmr::lc;
using namespace dmr;

#include <cstdio>
#include <cassert>

// ---------------------------------------------------------------------------
//  Public Class Members
// ---------------------------------------------------------------------------
/// <summary>
/// Initializes a new instance of the CSBK class.
/// </summary>
CSBK::CSBK() :
    m_verbose(false),
    m_CSBKO(CSBKO_NONE),
    m_FID(0x00U),
    m_lastBlock(true),
    m_bsId(0U),
    m_GI(false),
    m_Cdef(false),
    m_srcId(0U),
    m_dstId(0U),
    m_dataContent(false),
    m_CBF(0U),
    m_data(NULL),
    m_siteData(),
    m_siteNetActive(false)
{
    m_data = new uint8_t[12U];

    reset();
}

/// <summary>
/// Finalizes a instance of the CSBK class.
/// </summary>
CSBK::~CSBK()
{
    delete[] m_data;
}

/// <summary>
/// Decodes a DMR CSBK.
/// </summary>
/// <param name="bytes"></param>
/// <returns>True, if DMR CSBK was decoded, otherwise false.</returns>
bool CSBK::decode(const uint8_t* bytes)
{
    assert(bytes != NULL);

    // decode BPTC (196,96) FEC
    edac::BPTC19696 bptc;
    bptc.decode(bytes, m_data);

    // validate the CRC-CCITT 16
    m_data[10U] ^= CSBK_CRC_MASK[0U];
    m_data[11U] ^= CSBK_CRC_MASK[1U];

    bool valid = edac::CRC::checkCCITT162(m_data, DMR_LC_HEADER_LENGTH_BYTES);
    if (!valid)
        return false;

    // restore the checksum
    m_data[10U] ^= CSBK_CRC_MASK[0U];
    m_data[11U] ^= CSBK_CRC_MASK[1U];

    if (m_verbose) {
        Utils::dump(2U, "Decoded CSBK", m_data, DMR_LC_HEADER_LENGTH_BYTES);
    }

    m_CSBKO = m_data[0U] & 0x3FU;                                                   // CSBKO
    m_lastBlock = (m_data[0U] & 0x80U) == 0x80U;                                    // Last Block Marker
    m_FID = m_data[1U];                                                             // Feature ID

    switch (m_CSBKO) {
    case CSBKO_BSDWNACT:
        m_GI = false;
        m_bsId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                   // Base Station ID
        m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Source ID
        m_dataContent = false;
        m_CBF = 0U;
        break;

    case CSBKO_UU_V_REQ:
        m_GI = false;
        m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                  // Destination ID
        m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Source ID
        m_dataContent = false;
        m_CBF = 0U;
        break;

    case CSBKO_UU_ANS_RSP:
        m_GI = false;
        m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                  // Destination ID
        m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Source ID
        m_dataContent = false;
        m_CBF = 0U;
        break;

    case CSBKO_PRECCSBK:
        m_GI = (m_data[2U] & 0x40U) == 0x40U;
        m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                  // Destination ID
        m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Source ID
        m_dataContent = (m_data[2U] & 0x80U) == 0x80U;
        m_CBF = m_data[3U];
        break;

    case CSBKO_RAND: // CSBKO_CALL_ALRT when FID == FID_DMRA
        switch (m_FID)
        {
        case FID_DMRA:
            m_GI = (m_data[2U] & 0x40U) == 0x40U;                                   // Group or Individual
            m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];              // Destination ID
            m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];              // Source ID
            m_dataContent = (m_data[2U] & 0x80U) == 0x80U;                          //
            m_CBF = m_data[3U];                                                     // 
            break;

        /* Tier III */
        case FID_ETSI:
        default:
            m_serviceOptions = m_data[2U];                                          // Service Options
            m_targetAddress = (m_data[3U] >> 6 & 0x03U);                            // Target Address
            m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];              // Destination ID
            m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];              // Source ID
            break;
        }

    case CSBKO_ACK_RSP:
        m_GI = (m_data[2U] & 0x40U) == 0x40U;
        m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                  // Destination ID
        m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Source ID
        m_response = m_data[3U];                                                    // Response
        m_dataContent = false;
        break;

    case CSBKO_EXT_FNCT:
        m_GI = false;
        m_dstId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                  // Destination ID
        m_srcId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Source ID
        m_dataContent = (m_data[2U] & 0x80U) == 0x80U;                              //
        m_CBF = m_data[3U];                                                         //
        break;

    case CSBKO_NACK_RSP:
        m_GI = false;
        m_srcId = m_data[4U] << 16 | m_data[5U] << 8 | m_data[6U];                  // Source ID
        m_dstId = m_data[7U] << 16 | m_data[8U] << 8 | m_data[9U];                  // Destination ID
        m_response = m_data[3U];                                                    // Response
        m_dataContent = false;
        break;

    default:
        m_GI = false;
        m_srcId = 0U;
        m_dstId = 0U;
        m_dataContent = false;
        m_CBF = 0U;
        LogError(LOG_DMR, "unknown CSBK type, csbko = $%02X", m_CSBKO);
        return true;
    }

    return true;
}

/// <summary>
/// Encodes a DMR CSBK.
/// </summary>
/// <param name="bytes"></param>
void CSBK::encode(uint8_t* bytes)
{
    assert(bytes != NULL);

    m_data[0U] = m_CSBKO;                                                           // CSBKO
    m_data[0U] |= (m_lastBlock) ? 0x80U : 0x00U;                                    // Last Block Marker
    if (!m_Cdef) {
        m_data[1U] = m_FID;                                                         // Feature ID
    }

    switch (m_CSBKO) {
    case CSBKO_ACK_RSP:
        m_data[2U] = (uint8_t)(m_serviceType & 0x3FU);                              // Service Type
        m_data[2U] |= 0x80U;                                                        // Additional Information Field (always 1)
        if (m_GI) {
            m_data[2U] |= 0x40U;                                                    // Source Type
        }
        m_data[3U] = m_response;                                                    // Reason Code

        m_data[4U] = (m_srcId >> 16) & 0xFFU;                                       // Source ID
        m_data[5U] = (m_srcId >> 8) & 0xFFU;
        m_data[6U] = (m_srcId >> 0) & 0xFFU;

        m_data[7U] = (m_dstId >> 16) & 0xFFU;                                       // Destination ID
        m_data[8U] = (m_dstId >> 8) & 0xFFU;
        m_data[9U] = (m_dstId >> 0) & 0xFFU;
        break;

    case CSBKO_EXT_FNCT:
        if (m_GI) {
            m_data[2U] |= 0x40U;                                                    // Group or Individual
        }

        if (m_dataContent) {
            m_data[2U] |= 0x80U;                                                    //
        }

        m_data[3U] = m_CBF;                                                         //

        m_data[4U] = (m_srcId >> 16) & 0xFFU;                                       // Source ID
        m_data[5U] = (m_srcId >> 8) & 0xFFU;
        m_data[6U] = (m_srcId >> 0) & 0xFFU;

        m_data[7U] = (m_dstId >> 16) & 0xFFU;                                       // Destination ID
        m_data[8U] = (m_dstId >> 8) & 0xFFU;
        m_data[9U] = (m_dstId >> 0) & 0xFFU;
        break;

    case CSBKO_NACK_RSP:
        m_data[2U] = (uint8_t)(m_serviceType & 0x3FU);                              // Service Type
        m_data[2U] |= 0x80U;                                                        // Additional Information Field (always 1)
        if (m_GI) {
            m_data[2U] |= 0x40U;                                                    // Source Type
        }
        m_data[3U] = m_response;                                                    // Reason Code

        m_data[4U] = (m_srcId >> 16) & 0xFFU;                                       // Source ID
        m_data[5U] = (m_srcId >> 8) & 0xFFU;
        m_data[6U] = (m_srcId >> 0) & 0xFFU;

        m_data[7U] = (m_dstId >> 16) & 0xFFU;                                       // Destination ID
        m_data[8U] = (m_dstId >> 8) & 0xFFU;
        m_data[9U] = (m_dstId >> 0) & 0xFFU;
        break;

    default:
        if (m_GI) {
            m_data[2U] |= 0x40U;                                                    // Group or Individual
        }

        if (m_dataContent) {
            m_data[2U] |= 0x80U;                                                    //
        }

        m_data[3U] = m_CBF;                                                         //

        m_data[4U] = (m_dstId >> 16) & 0xFFU;                                       // Destination ID
        m_data[5U] = (m_dstId >> 8) & 0xFFU;
        m_data[6U] = (m_dstId >> 0) & 0xFFU;

        m_data[7U] = (m_srcId >> 16) & 0xFFU;                                       // Source ID
        m_data[8U] = (m_srcId >> 8) & 0xFFU;
        m_data[9U] = (m_srcId >> 0) & 0xFFU;
        break;

    /* Tier III */
    case CSBKO_ALOHA:
    {
        ulong64_t csbkValue = 0U;
        csbkValue = (csbkValue << 2) + 0U;                                          // Reserved
        csbkValue = (csbkValue << 1) + ((m_siteTSSync) ? 1U : 0U);                  // Site Time Slot Synchronization
        csbkValue = (csbkValue << 3) + DMR_ALOHA_VER_151;                           // DMR Spec. Version (1.5.1)
        csbkValue = (csbkValue << 1) + ((m_siteOffsetTiming) ? 1U : 0U);            // Site Timing: Aligned or Offset
        csbkValue = (csbkValue << 1) + ((m_siteNetActive) ? 1U : 0U);               // Site Networked
        csbkValue = (csbkValue << 5) + (m_alohaMask & 0x1FU);                       // MS Mask
        csbkValue = (csbkValue << 2) + 0U;                                          // Service Function
        csbkValue = (csbkValue << 4) + 0U;                                          // 
        csbkValue = (csbkValue << 1) + ((m_siteData.requireReg()) ? 1U : 0U);       // Require Registration
        csbkValue = (csbkValue << 4) + (m_backoffNo & 0x0FU);                       // Backoff Number
        csbkValue = (csbkValue << 16) + m_siteData.systemIdentity();                // Site Identity
        csbkValue = (csbkValue << 24) + m_srcId;                                    // Source ID

        // split value into bytes
        m_data[2U] = (uint8_t)((csbkValue >> 56) & 0xFFU);
        m_data[3U] = (uint8_t)((csbkValue >> 48) & 0xFFU);
        m_data[4U] = (uint8_t)((csbkValue >> 40) & 0xFFU);
        m_data[5U] = (uint8_t)((csbkValue >> 32) & 0xFFU);
        m_data[6U] = (uint8_t)((csbkValue >> 24) & 0xFFU);
        m_data[7U] = (uint8_t)((csbkValue >> 16) & 0xFFU);
        m_data[8U] = (uint8_t)((csbkValue >> 8) & 0xFFU);
        m_data[9U] = (uint8_t)((csbkValue >> 0) & 0xFFU);
        break;
    }
    break;
    case CSBKO_BROADCAST:
    {
        ulong64_t csbkValue = 0U;
        if (!m_Cdef) {
            csbkValue = m_anncType;                                                 // Announcement Type
        }

        switch (m_anncType)
        {
        case BCAST_ANNC_ANN_WD_TSCC:
            if (!m_Cdef) {
                // Broadcast Parms 1
                csbkValue = (csbkValue << 4) + 0U;                                  // Reserved
                csbkValue = (csbkValue << 4) + (m_colorCode & 0x0FU);               // Color Code 1
                csbkValue = (csbkValue << 4) + (m_colorCode & 0x0FU);               // Color Code 2
                csbkValue = (csbkValue << 1) + ((m_annWdCh1) ? 1U : 0U);            // Announce/Withdraw Channel 1
                csbkValue = (csbkValue << 1) + ((m_annWdCh2) ? 1U : 0U);            // Announce/Withdraw Channel 2

                csbkValue = (csbkValue << 1) + ((m_siteData.requireReg()) ? 1U : 0U); // Require Registration
                csbkValue = (csbkValue << 4) + (m_backoffNo & 0x0FU);               // Backoff Number
                csbkValue = (csbkValue << 16) + m_siteData.systemIdentity();        // Site Identity

                // Broadcast Parms 2
                csbkValue = (csbkValue << 12) + (m_logicalCh1 & 0xFFFU);            // Logical Channel 1
                csbkValue = (csbkValue << 12) + (m_logicalCh2 & 0xFFFU);            // Logical Channel 2
            }
            else {
                uint32_t calcSpace = (uint32_t)(m_siteIdenEntry.chSpaceKhz() / 0.125);
                float calcTxOffset = m_siteIdenEntry.txOffsetMhz() * 1000000;
                const uint32_t multiple = 100000;

                // calculate Rx frequency
                uint32_t rxFrequency = (uint32_t)((m_siteIdenEntry.baseFrequency() + ((calcSpace * 125) * m_logicalCh1)) + calcTxOffset);

                // generate frequency in mhz
                uint32_t rxFreqMhz = rxFrequency + multiple / 2;
                rxFreqMhz -= rxFreqMhz % multiple;
                rxFreqMhz /= multiple * 10;

                // generate khz offset
                uint32_t rxFreqKhz = rxFrequency - (rxFreqMhz * 1000000);

                // calculate Tx Frequency
                uint32_t txFrequency = (uint32_t)((m_siteIdenEntry.baseFrequency() + ((calcSpace * 125) * m_logicalCh1)));

                // generate frequency in mhz
                uint32_t txFreqMhz = txFrequency + multiple / 2;
                txFreqMhz -= txFreqMhz % multiple;
                txFreqMhz /= multiple * 10;

                // generate khz offset
                uint32_t txFreqKhz = txFrequency - (txFreqMhz * 1000000);

                csbkValue = (csbkValue << 8) + 0U;                                  // Reserved
                csbkValue = (csbkValue << 4) + 0U;                                  // Cdef Type (always 0 for ANN_WD_TSCC)
                csbkValue = (csbkValue << 2) + 0U;                                  // Reserved
                csbkValue = (csbkValue << 12) + (m_logicalCh1 & 0xFFFU);            // Logical Channel
                csbkValue = (csbkValue << 10) + txFreqMhz;                          // Transmit Freq Mhz
                csbkValue = (csbkValue << 13) + txFreqKhz;                          // Transmit Freq Offset Khz
                csbkValue = (csbkValue << 10) + rxFreqMhz;                          // Receive Freq Mhz
                csbkValue = (csbkValue << 13) + rxFreqKhz;                          // Receive Freq Khz
            }
            break;
        case BCAST_ANNC_SITE_PARMS:
            // Broadcast Parms 1
            csbkValue = (csbkValue << 14) + m_siteData.systemIdentity(true);        // Site Identity (Broadcast Parms 1)

            csbkValue = (csbkValue << 1) + ((m_siteData.requireReg()) ? 1U : 0U);   // Require Registration
            csbkValue = (csbkValue << 4) + (m_backoffNo & 0x0FU);                   // Backoff Number
            csbkValue = (csbkValue << 16) + m_siteData.systemIdentity();            // Site Identity

            // Broadcast Parms 2
            csbkValue = (csbkValue << 1) + 0U;                                      // Roaming TG Subscription/Attach
            csbkValue = (csbkValue << 1) + ((m_hibernating) ? 1U : 0U);             // TSCC Hibernating
            csbkValue = (csbkValue << 22) + 0U;                                     // Broadcast Parms 2 (Reserved)
            break;
        }

        // split value into bytes
        m_data[2U] = (uint8_t)((csbkValue >> 56) & 0xFFU);
        m_data[3U] = (uint8_t)((csbkValue >> 48) & 0xFFU);
        m_data[4U] = (uint8_t)((csbkValue >> 40) & 0xFFU);
        m_data[5U] = (uint8_t)((csbkValue >> 32) & 0xFFU);
        m_data[6U] = (uint8_t)((csbkValue >> 24) & 0xFFU);
        m_data[7U] = (uint8_t)((csbkValue >> 16) & 0xFFU);
        m_data[8U] = (uint8_t)((csbkValue >> 8) & 0xFFU);
        m_data[9U] = (uint8_t)((csbkValue >> 0) & 0xFFU);
    }
    break;
    }

    m_data[10U] ^= CSBK_CRC_MASK[0U];
    m_data[11U] ^= CSBK_CRC_MASK[1U];

    edac::CRC::addCCITT162(m_data, 12U);

    m_data[10U] ^= CSBK_CRC_MASK[0U];
    m_data[11U] ^= CSBK_CRC_MASK[1U];

    if (m_verbose) {
        Utils::dump(2U, "Encoded CSBK", m_data, DMR_LC_HEADER_LENGTH_BYTES);
    }

    // encode BPTC (196,96) FEC
    edac::BPTC19696 bptc;
    bptc.encode(m_data, bytes);
}

/// <summary>
/// Helper to reset data values to defaults.
/// </summary>
void CSBK::reset()
{
    m_colorCode = 0U;

    m_backoffNo = 1U;
    m_serviceType = 0U;
    m_serviceOptions = 0U;
    m_targetAddress = TGT_ADRS_TGID;

    m_response = 0U;

    /* Broadcast */
    m_anncType = BCAST_ANNC_SITE_PARMS;
    m_hibernating = false;

    m_annWdCh1 = false;
    m_logicalCh1 = DMR_CHNULL;
    m_annWdCh2 = false;
    m_logicalCh2 = DMR_CHNULL;

    /* Aloha */
    m_siteTSSync = false;
    m_siteOffsetTiming = false;
}

/** Local Site data */
/// <summary>
/// Sets local configured site data.
/// </summary>
/// <param name="siteData">Site data.</param>
void CSBK::setSiteData(SiteData siteData)
{
    m_siteData = siteData;
}

/// <summary>
/// Sets the identity lookup table entry.
/// </summary>
/// <param name="entry">Identity table entry.</param>
void CSBK::setIdenTable(lookups::IdenTable entry)
{
    m_siteIdenEntry = entry;
}

/// <summary>
/// Sets a flag indicating whether or not networking is active.
/// </summary>
/// <param name="netActive">Network active flag.</param>
void CSBK::setNetActive(bool netActive)
{
    m_siteNetActive = netActive;
}