/*!
 * \file galileo_e1b_telemetry_decoder_cc.cc
 * \brief Implementation of a Galileo INAV message demodulator block
 * \author Mara Branzanti 2013. mara.branzanti(at)gmail.com
 * \author Javier Arribas 2013. jarribas(at)cttc.es
 *
 * -------------------------------------------------------------------------
 *
 * Copyright (C) 2010-2018  (see AUTHORS file for a list of contributors)
 *
 * GNSS-SDR is a software defined Global Navigation
 *          Satellite Systems receiver
 *
 * This file is part of GNSS-SDR.
 *
 * GNSS-SDR 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 3 of the License, or
 * (at your option) any later version.
 *
 * GNSS-SDR 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 GNSS-SDR. If not, see <https://www.gnu.org/licenses/>.
 *
 * -------------------------------------------------------------------------
 */


#include "galileo_e1b_telemetry_decoder_cc.h"
#include "control_message_factory.h"
#include "convolutional.h"
#include "gnss_synchro.h"
#include <boost/lexical_cast.hpp>
#include <gnuradio/io_signature.h>
#include <glog/logging.h>
#include <volk_gnsssdr/volk_gnsssdr.h>
#include <iostream>


#define CRC_ERROR_LIMIT 6

using google::LogMessage;


galileo_e1b_telemetry_decoder_cc_sptr
galileo_e1b_make_telemetry_decoder_cc(const Gnss_Satellite &satellite, bool dump)
{
    return galileo_e1b_telemetry_decoder_cc_sptr(new galileo_e1b_telemetry_decoder_cc(satellite, dump));
}


void galileo_e1b_telemetry_decoder_cc::viterbi_decoder(double *page_part_symbols, int *page_part_bits)
{
    Viterbi(page_part_bits, out0, state0, out1, state1,
        page_part_symbols, KK, nn, DataLength);
}


void galileo_e1b_telemetry_decoder_cc::deinterleaver(int rows, int cols, double *in, double *out)
{
    for (int r = 0; r < rows; r++)
        {
            for (int c = 0; c < cols; c++)
                {
                    out[c * rows + r] = in[r * cols + c];
                }
        }
}


galileo_e1b_telemetry_decoder_cc::galileo_e1b_telemetry_decoder_cc(
    const Gnss_Satellite &satellite,
    bool dump) : gr::block("galileo_e1b_telemetry_decoder_cc", gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)),
                     gr::io_signature::make(1, 1, sizeof(Gnss_Synchro)))
{
    // Ephemeris data port out
    this->message_port_register_out(pmt::mp("telemetry"));
    // initialize internal vars
    d_dump = dump;
    d_satellite = Gnss_Satellite(satellite.get_system(), satellite.get_PRN());
    LOG(INFO) << "Initializing GALILEO E1B TELEMETRY PROCESSING";
    d_samples_per_symbol = (Galileo_E1_CODE_CHIP_RATE_HZ / Galileo_E1_B_CODE_LENGTH_CHIPS) / Galileo_E1_B_SYMBOL_RATE_BPS;

    // set the preamble
    unsigned short int preambles_bits[GALILEO_INAV_PREAMBLE_LENGTH_BITS] = GALILEO_INAV_PREAMBLE;

    d_symbols_per_preamble = GALILEO_INAV_PREAMBLE_LENGTH_BITS * d_samples_per_symbol;

    memcpy(static_cast<unsigned short int *>(this->d_preambles_bits), static_cast<unsigned short int *>(preambles_bits), GALILEO_INAV_PREAMBLE_LENGTH_BITS * sizeof(unsigned short int));

    // preamble bits to sampled symbols
    d_preambles_symbols = static_cast<int *>(volk_gnsssdr_malloc(d_symbols_per_preamble * sizeof(int), volk_gnsssdr_get_alignment()));
    int n = 0;
    for (int i = 0; i < GALILEO_INAV_PREAMBLE_LENGTH_BITS; i++)
        {
            for (unsigned int j = 0; j < d_samples_per_symbol; j++)
                {
                    if (d_preambles_bits[i] == 1)
                        {
                            d_preambles_symbols[n] = 1;
                        }
                    else
                        {
                            d_preambles_symbols[n] = -1;
                        }
                    n++;
                }
        }
    d_sample_counter = 0;
    d_stat = 0;
    d_preamble_index = 0;

    d_flag_frame_sync = false;

    d_flag_parity = false;
    d_TOW_at_current_symbol = 0;
    delta_t = 0;
    d_CRC_error_counter = 0;
    flag_even_word_arrived = 0;
    d_flag_preamble = false;
    d_channel = 0;
    flag_TOW_set = false;

    // vars for Viterbi decoder
    int max_states = 1 << mm; /* 2^mm */
    g_encoder[0] = 121;       // Polynomial G1
    g_encoder[1] = 91;        // Polynomial G2
    out0 = static_cast<int *>(volk_gnsssdr_malloc(max_states * sizeof(int), volk_gnsssdr_get_alignment()));
    out1 = static_cast<int *>(volk_gnsssdr_malloc(max_states * sizeof(int), volk_gnsssdr_get_alignment()));
    state0 = static_cast<int *>(volk_gnsssdr_malloc(max_states * sizeof(int), volk_gnsssdr_get_alignment()));
    state1 = static_cast<int *>(volk_gnsssdr_malloc(max_states * sizeof(int), volk_gnsssdr_get_alignment()));
    /* create appropriate transition matrices */
    nsc_transit(out0, state0, 0, g_encoder, KK, nn);
    nsc_transit(out1, state1, 1, g_encoder, KK, nn);
}


galileo_e1b_telemetry_decoder_cc::~galileo_e1b_telemetry_decoder_cc()
{
    volk_gnsssdr_free(d_preambles_symbols);
    volk_gnsssdr_free(out0);
    volk_gnsssdr_free(out1);
    volk_gnsssdr_free(state0);
    volk_gnsssdr_free(state1);
    if (d_dump_file.is_open() == true)
        {
            try
                {
                    d_dump_file.close();
                }
            catch (const std::exception &ex)
                {
                    LOG(WARNING) << "Exception in destructor closing the dump file " << ex.what();
                }
        }
}


void galileo_e1b_telemetry_decoder_cc::decode_word(double *page_part_symbols, int frame_length)
{
    double page_part_symbols_deint[frame_length];
    // 1. De-interleave
    deinterleaver(GALILEO_INAV_INTERLEAVER_ROWS, GALILEO_INAV_INTERLEAVER_COLS, page_part_symbols, page_part_symbols_deint);

    // 2. Viterbi decoder
    // 2.1 Take into account the NOT gate in G2 polynomial (Galileo ICD Figure 13, FEC encoder)
    // 2.2 Take into account the possible inversion of the polarity due to PLL lock at 180�
    for (int i = 0; i < frame_length; i++)
        {
            if ((i + 1) % 2 == 0)
                {
                    page_part_symbols_deint[i] = -page_part_symbols_deint[i];
                }
        }

    int page_part_bits[frame_length / 2];
    viterbi_decoder(page_part_symbols_deint, page_part_bits);

    // 3. Call the Galileo page decoder
    std::string page_String;
    for (int i = 0; i < (frame_length / 2); i++)
        {
            if (page_part_bits[i] > 0)
                {
                    page_String.push_back('1');
                }
            else
                {
                    page_String.push_back('0');
                }
        }

    if (page_part_bits[0] == 1)
        {
            // DECODE COMPLETE WORD (even + odd) and TEST CRC
            d_nav.split_page(page_String, flag_even_word_arrived);
            if (d_nav.flag_CRC_test == true)
                {
                    LOG(INFO) << "Galileo E1 CRC correct in channel " << d_channel << " from satellite " << d_satellite;
                    //std::cout << "Galileo E1 CRC correct on channel " << d_channel << " from satellite " << d_satellite << std::endl;
                }
            else
                {
                    std::cout << "Galileo E1 CRC error in channel " << d_channel << " from satellite " << d_satellite << std::endl;
                    LOG(INFO) << "Galileo E1 CRC error in channel " << d_channel << " from satellite " << d_satellite;
                }
            flag_even_word_arrived = 0;
        }
    else
        {
            // STORE HALF WORD (even page)
            d_nav.split_page(page_String.c_str(), flag_even_word_arrived);
            flag_even_word_arrived = 1;
        }

    // 4. Push the new navigation data to the queues
    if (d_nav.have_new_ephemeris() == true)
        {
            // get object for this SV (mandatory)
            std::shared_ptr<Galileo_Ephemeris> tmp_obj = std::make_shared<Galileo_Ephemeris>(d_nav.get_ephemeris());
            std::cout << "New Galileo E1 I/NAV message received in channel " << d_channel << ": ephemeris from satellite " << d_satellite << std::endl;
            this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
        }
    if (d_nav.have_new_iono_and_GST() == true)
        {
            // get object for this SV (mandatory)
            std::shared_ptr<Galileo_Iono> tmp_obj = std::make_shared<Galileo_Iono>(d_nav.get_iono());
            std::cout << "New Galileo E1 I/NAV message received in channel " << d_channel << ": iono/GST model parameters from satellite " << d_satellite << std::endl;
            this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
        }
    if (d_nav.have_new_utc_model() == true)
        {
            // get object for this SV (mandatory)
            std::shared_ptr<Galileo_Utc_Model> tmp_obj = std::make_shared<Galileo_Utc_Model>(d_nav.get_utc_model());
            std::cout << "New Galileo E1 I/NAV message received in channel " << d_channel << ": UTC model parameters from satellite " << d_satellite << std::endl;
            this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
        }
    if (d_nav.have_new_almanac() == true)
        {
            std::shared_ptr<Galileo_Almanac> tmp_obj = std::make_shared<Galileo_Almanac>(d_nav.get_almanac());
            this->message_port_pub(pmt::mp("telemetry"), pmt::make_any(tmp_obj));
            //debug
            std::cout << "Galileo E1 I/NAV almanac received in channel " << d_channel << " from satellite " << d_satellite << std::endl;
            DLOG(INFO) << "GPS_to_Galileo time conversion:";
            DLOG(INFO) << "A0G=" << tmp_obj->A_0G_10;
            DLOG(INFO) << "A1G=" << tmp_obj->A_1G_10;
            DLOG(INFO) << "T0G=" << tmp_obj->t_0G_10;
            DLOG(INFO) << "WN_0G_10=" << tmp_obj->WN_0G_10;
            DLOG(INFO) << "Current parameters:";
            DLOG(INFO) << "d_TOW_at_current_symbol=" << d_TOW_at_current_symbol;
            DLOG(INFO) << "d_nav.WN_0=" << d_nav.WN_0;
            delta_t = tmp_obj->A_0G_10 + tmp_obj->A_1G_10 * (d_TOW_at_current_symbol - tmp_obj->t_0G_10 + 604800 * (fmod((d_nav.WN_0 - tmp_obj->WN_0G_10), 64)));
            DLOG(INFO) << "delta_t=" << delta_t << "[s]";
        }
}


void galileo_e1b_telemetry_decoder_cc::set_satellite(const Gnss_Satellite &satellite)
{
    d_satellite = Gnss_Satellite(satellite.get_system(), satellite.get_PRN());
    DLOG(INFO) << "Setting decoder Finite State Machine to satellite " << d_satellite;
    DLOG(INFO) << "Navigation Satellite set to " << d_satellite;
}


void galileo_e1b_telemetry_decoder_cc::set_channel(int channel)
{
    d_channel = channel;
    LOG(INFO) << "Navigation channel set to " << channel;
    // ############# ENABLE DATA FILE LOG #################
    if (d_dump == true)
        {
            if (d_dump_file.is_open() == false)
                {
                    try
                        {
                            d_dump_filename = "telemetry";
                            d_dump_filename.append(boost::lexical_cast<std::string>(d_channel));
                            d_dump_filename.append(".dat");
                            d_dump_file.exceptions(std::ifstream::failbit | std::ifstream::badbit);
                            d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
                            LOG(INFO) << "Telemetry decoder dump enabled on channel " << d_channel << " Log file: " << d_dump_filename.c_str();
                        }
                    catch (const std::ifstream::failure &e)
                        {
                            LOG(WARNING) << "channel " << d_channel << " Exception opening trk dump file " << e.what();
                        }
                }
        }
}


int galileo_e1b_telemetry_decoder_cc::general_work(int noutput_items __attribute__((unused)), gr_vector_int &ninput_items __attribute__((unused)),
    gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
{
    int corr_value = 0;
    int preamble_diff = 0;

    Gnss_Synchro **out = reinterpret_cast<Gnss_Synchro **>(&output_items[0]);            // Get the output buffer pointer
    const Gnss_Synchro **in = reinterpret_cast<const Gnss_Synchro **>(&input_items[0]);  // Get the input buffer pointer

    Gnss_Synchro current_symbol;  //structure to save the synchronization information and send the output object to the next block
    //1. Copy the current tracking output
    current_symbol = in[0][0];
    d_symbol_history.push_back(current_symbol);  //add new symbol to the symbol queue
    d_sample_counter++;                          //count for the processed samples
    consume_each(1);

    d_flag_preamble = false;
    unsigned int required_symbols = GALILEO_INAV_PAGE_SYMBOLS + d_symbols_per_preamble;

    if (d_symbol_history.size() > required_symbols)
        {
            // TODO Optimize me!
            //******* preamble correlation ********
            for (int i = 0; i < d_symbols_per_preamble; i++)
                {
                    if (d_symbol_history.at(i).Prompt_I < 0)  // symbols clipping
                        {
                            corr_value -= d_preambles_symbols[i];
                        }
                    else
                        {
                            corr_value += d_preambles_symbols[i];
                        }
                }
        }

    //******* frame sync ******************
    if (d_stat == 0)  //no preamble information
        {
            if (abs(corr_value) >= d_symbols_per_preamble)
                {
                    d_preamble_index = d_sample_counter;  //record the preamble sample stamp
                    LOG(INFO) << "Preamble detection for Galileo satellite " << this->d_satellite;
                    d_stat = 1;  // enter into frame pre-detection status
                }
        }
    else if (d_stat == 1)  // possible preamble lock
        {
            if (abs(corr_value) >= d_symbols_per_preamble)
                {
                    //check preamble separation
                    preamble_diff = d_sample_counter - d_preamble_index;
                    if (abs(preamble_diff - GALILEO_INAV_PREAMBLE_PERIOD_SYMBOLS) == 0)
                        {
                            //try to decode frame
                            LOG(INFO) << "Starting page decoder for Galileo satellite " << this->d_satellite;
                            d_preamble_index = d_sample_counter;  //record the preamble sample stamp
                            d_stat = 2;
                        }
                    else
                        {
                            if (preamble_diff > GALILEO_INAV_PREAMBLE_PERIOD_SYMBOLS)
                                {
                                    d_stat = 0;  // start again
                                }
                        }
                }
        }
    else if (d_stat == 2)
        {
            if (d_sample_counter == d_preamble_index + GALILEO_INAV_PREAMBLE_PERIOD_SYMBOLS)
                {
                    // NEW Galileo page part is received
                    // 0. fetch the symbols into an array
                    int frame_length = GALILEO_INAV_PAGE_PART_SYMBOLS - d_symbols_per_preamble;
                    double page_part_symbols[frame_length];

                    for (int i = 0; i < frame_length; i++)
                        {
                            if (corr_value > 0)
                                {
                                    page_part_symbols[i] = d_symbol_history.at(i + d_symbols_per_preamble).Prompt_I;  // because last symbol of the preamble is just received now!
                                }
                            else
                                {
                                    page_part_symbols[i] = -d_symbol_history.at(i + d_symbols_per_preamble).Prompt_I;  // because last symbol of the preamble is just received now!
                                }
                        }

                    //call the decoder
                    decode_word(page_part_symbols, frame_length);
                    if (d_nav.flag_CRC_test == true)
                        {
                            d_CRC_error_counter = 0;
                            d_flag_preamble = true;               //valid preamble indicator (initialized to false every work())
                            d_preamble_index = d_sample_counter;  //record the preamble sample stamp (t_P)
                            if (!d_flag_frame_sync)
                                {
                                    d_flag_frame_sync = true;
                                    DLOG(INFO) << " Frame sync SAT " << this->d_satellite << " with preamble start at "
                                               << d_symbol_history.at(0).Tracking_sample_counter << " [samples]";
                                }
                        }
                    else
                        {
                            d_CRC_error_counter++;
                            d_preamble_index = d_sample_counter;  //record the preamble sample stamp
                            if (d_CRC_error_counter > CRC_ERROR_LIMIT)
                                {
                                    LOG(INFO) << "Lost of frame sync SAT " << this->d_satellite;
                                    d_flag_frame_sync = false;
                                    d_stat = 0;
                                }
                        }
                }
        }

    // UPDATE GNSS SYNCHRO DATA
    //2. Add the telemetry decoder information
    if (this->d_flag_preamble == true and d_nav.flag_TOW_set == true)
        //update TOW at the preamble instant
        {
            if (d_nav.flag_TOW_5 == true)  //page 5 arrived and decoded, so we are in the odd page (since Tow refers to the even page, we have to add 1 sec)
                {
                    //TOW_5 refers to the even preamble, but when we decode it we are in the odd part, so 1 second later plus the decoding delay
                    d_TOW_at_current_symbol = d_nav.TOW_5 + static_cast<double>(GALILEO_INAV_PAGE_PART_SECONDS) + static_cast<double>(required_symbols - 1) * GALILEO_E1_CODE_PERIOD;  //-GALILEO_E1_CODE_PERIOD;//+ (double)GALILEO_INAV_PREAMBLE_LENGTH_BITS/(double)GALILEO_TELEMETRY_RATE_BITS_SECOND;
                    d_nav.flag_TOW_5 = false;
                }

            else if (d_nav.flag_TOW_6 == true)  //page 6 arrived and decoded, so we are in the odd page (since Tow refers to the even page, we have to add 1 sec)
                {
                    //TOW_6 refers to the even preamble, but when we decode it we are in the odd part, so 1 second later plus the decoding delay
                    d_TOW_at_current_symbol = d_nav.TOW_6 + static_cast<double>(GALILEO_INAV_PAGE_PART_SECONDS) + static_cast<double>(required_symbols - 1) * GALILEO_E1_CODE_PERIOD;  //-GALILEO_E1_CODE_PERIOD;//+ (double)GALILEO_INAV_PREAMBLE_LENGTH_BITS/(double)GALILEO_TELEMETRY_RATE_BITS_SECOND;
                    d_nav.flag_TOW_6 = false;
                }
            else
                {
                    //this page has no timing information
                    d_TOW_at_current_symbol += GALILEO_E1_CODE_PERIOD;  // + GALILEO_INAV_PAGE_PART_SYMBOLS*GALILEO_E1_CODE_PERIOD;
                }
        }
    else  //if there is not a new preamble, we define the TOW of the current symbol
        {
            d_TOW_at_current_symbol += GALILEO_E1_CODE_PERIOD;
        }

    //if (d_flag_frame_sync == true and d_nav.flag_TOW_set==true and d_nav.flag_CRC_test == true)

    if (d_nav.flag_GGTO_1 == true and d_nav.flag_GGTO_2 == true and d_nav.flag_GGTO_3 == true and d_nav.flag_GGTO_4 == true)  //all GGTO parameters arrived
        {
            delta_t = d_nav.A_0G_10 + d_nav.A_1G_10 * (d_TOW_at_current_symbol - d_nav.t_0G_10 + 604800.0 * (fmod((d_nav.WN_0 - d_nav.WN_0G_10), 64.0)));
        }

    if (d_flag_frame_sync == true and d_nav.flag_TOW_set == true)
        {
            current_symbol.Flag_valid_word = true;
        }
    else
        {
            current_symbol.Flag_valid_word = false;
        }

    current_symbol.TOW_at_current_symbol_s = floor(d_TOW_at_current_symbol * 1000.0) / 1000.0;
    current_symbol.TOW_at_current_symbol_s -= delta_t;  //Galileo to GPS TOW

    if (d_dump == true)
        {
            // MULTIPLEXED FILE RECORDING - Record results to file
            try
                {
                    double tmp_double;
                    unsigned long int tmp_ulong_int;
                    tmp_double = d_TOW_at_current_symbol;
                    d_dump_file.write(reinterpret_cast<char *>(&tmp_double), sizeof(double));
                    tmp_ulong_int = current_symbol.Tracking_sample_counter;
                    d_dump_file.write(reinterpret_cast<char *>(&tmp_ulong_int), sizeof(unsigned long int));
                    tmp_double = 0;
                    d_dump_file.write(reinterpret_cast<char *>(&tmp_double), sizeof(double));
                }
            catch (const std::ifstream::failure &e)
                {
                    LOG(WARNING) << "Exception writing observables dump file " << e.what();
                }
        }

    // remove used symbols from history
    if (d_symbol_history.size() > required_symbols)
        {
            d_symbol_history.pop_front();
        }
    //3. Make the output (copy the object contents to the GNURadio reserved memory)
    *out[0] = current_symbol;
    //std::cout<<"GPS L1 TLM output on CH="<<this->d_channel << " SAMPLE STAMP="<<d_sample_counter/d_decimation_output_factor<<std::endl;
    return 1;
}
