/*!
 * \file pcps_acquisition_fpga.cc
 * \brief This class implements a Parallel Code Phase Search Acquisition for the FPGA
 * \authors <ul>
 *          <li> Marc Majoral, 2019. mmajoral(at)cttc.es
 *          <li> Javier Arribas, 2019. jarribas(at)cttc.es
 *          </ul>
 *
 * -------------------------------------------------------------------------
 *
 * Copyright (C) 2010-2019  (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 "pcps_acquisition_fpga.h"
#include "gnss_synchro.h"
#include <glog/logging.h>
#include <cmath>     // for ceil
#include <iostream>  // for operator<<
#include <utility>   // for move


#define AQ_DOWNSAMPLING_DELAY 40  // delay due to the downsampling filter in the acquisition

pcps_acquisition_fpga_sptr pcps_make_acquisition_fpga(pcpsconf_fpga_t conf_)
{
    return pcps_acquisition_fpga_sptr(new pcps_acquisition_fpga(std::move(conf_)));
}


pcps_acquisition_fpga::pcps_acquisition_fpga(pcpsconf_fpga_t conf_)
{
    acq_parameters = std::move(conf_);
    d_sample_counter = 0ULL;  // Sample Counter
    d_active = false;
    d_state = 0;
    d_fft_size = acq_parameters.samples_per_code;
    d_mag = 0;
    d_input_power = 0.0;
    d_num_doppler_bins = 0U;
    d_threshold = 0.0;
    d_doppler_step = 0U;
    d_doppler_index = 0U;
    d_test_statistics = 0.0;
    d_channel = 0U;
    d_gnss_synchro = nullptr;

    d_downsampling_factor = acq_parameters.downsampling_factor;
    d_select_queue_Fpga = acq_parameters.select_queue_Fpga;

    d_total_block_exp = acq_parameters.total_block_exp;

    d_make_2_steps = acq_parameters.make_2_steps;
    d_num_doppler_bins_step2 = acq_parameters.num_doppler_bins_step2;
    d_doppler_step2 = acq_parameters.doppler_step2;
    d_doppler_center_step_two = 0.0;

    d_doppler_max = acq_parameters.doppler_max;

    d_max_num_acqs = acq_parameters.max_num_acqs;

    acquisition_fpga = std::make_shared<Fpga_Acquisition>(acq_parameters.device_name, acq_parameters.code_length, acq_parameters.doppler_max, d_fft_size,
        acq_parameters.fs_in, acq_parameters.sampled_ms, acq_parameters.select_queue_Fpga, acq_parameters.all_fft_codes, acq_parameters.excludelimit);
}


void pcps_acquisition_fpga::set_local_code()
{
    acquisition_fpga->set_local_code(d_gnss_synchro->PRN);
}


void pcps_acquisition_fpga::init()
{
    d_gnss_synchro->Flag_valid_acquisition = false;
    d_gnss_synchro->Flag_valid_symbol_output = false;
    d_gnss_synchro->Flag_valid_pseudorange = false;
    d_gnss_synchro->Flag_valid_word = false;
    d_gnss_synchro->Acq_delay_samples = 0.0;
    d_gnss_synchro->Acq_doppler_hz = 0.0;
    d_gnss_synchro->Acq_samplestamp_samples = 0;
    d_mag = 0.0;
    d_input_power = 0.0;

    d_num_doppler_bins = static_cast<uint32_t>(std::ceil(static_cast<double>(static_cast<int32_t>(d_doppler_max) - static_cast<int32_t>(-d_doppler_max)) / static_cast<double>(d_doppler_step))) + 1;
}


void pcps_acquisition_fpga::set_state(int32_t state)
{
    d_state = state;
    if (d_state == 1)
        {
            d_gnss_synchro->Acq_delay_samples = 0.0;
            d_gnss_synchro->Acq_doppler_hz = 0.0;
            d_gnss_synchro->Acq_samplestamp_samples = 0;
            d_mag = 0.0;
            d_input_power = 0.0;
            d_test_statistics = 0.0;
            d_active = true;
        }
    else if (d_state == 0)
        {
        }
    else
        {
            LOG(ERROR) << "State can only be set to 0 or 1";
        }
}


void pcps_acquisition_fpga::send_positive_acquisition()
{
    // Declare positive acquisition using a message port
    // 0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
    DLOG(INFO) << "positive acquisition"
               << ", satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN
               << ", sample_stamp " << d_sample_counter
               << ", test statistics value " << d_test_statistics
               << ", test statistics threshold " << d_threshold
               << ", code phase " << d_gnss_synchro->Acq_delay_samples
               << ", doppler " << d_gnss_synchro->Acq_doppler_hz
               << ", magnitude " << d_mag
               << ", input signal power " << d_input_power;

    //the channel FSM is set, so, notify it directly the positive acquisition to minimize delays
    d_channel_fsm.lock()->Event_valid_acquisition();
}


void pcps_acquisition_fpga::send_negative_acquisition()
{
    // Declare negative acquisition using a message port
    DLOG(INFO) << "negative acquisition"
               << ", satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN
               << ", sample_stamp " << d_sample_counter
               << ", test statistics value " << d_test_statistics
               << ", test statistics threshold " << d_threshold
               << ", code phase " << d_gnss_synchro->Acq_delay_samples
               << ", doppler " << d_gnss_synchro->Acq_doppler_hz
               << ", magnitude " << d_mag
               << ", input signal power " << d_input_power;

    if (acq_parameters.repeat_satellite == true)
        {
            d_channel_fsm.lock()->Event_failed_acquisition_repeat();
        }
    else
        {
            d_channel_fsm.lock()->Event_failed_acquisition_no_repeat();
        }
}


void pcps_acquisition_fpga::acquisition_core(uint32_t num_doppler_bins, uint32_t doppler_step, int32_t doppler_min)
{
    uint32_t indext = 0U;
    float firstpeak = 0.0;
    float secondpeak = 0.0;
    uint32_t total_block_exp;
    uint64_t initial_sample;
    int32_t doppler;
    acquisition_fpga->set_doppler_sweep(num_doppler_bins, doppler_step, doppler_min);
    acquisition_fpga->run_acquisition();
    acquisition_fpga->read_acquisition_results(&indext,
        &firstpeak,
        &secondpeak,
        &initial_sample,
        &d_input_power,
        &d_doppler_index,
        &total_block_exp);

    doppler = static_cast<int32_t>(doppler_min) + doppler_step * (d_doppler_index - 1);

    if (total_block_exp > d_total_block_exp)
        {
            // if the attenuation factor of the FPGA FFT-IFFT is smaller than the reference attenuation factor then we need to update the reference attenuation factor
            std::cout << "changing blk exp..... d_total_block_exp = " << d_total_block_exp << " total_block_exp = " << total_block_exp << " chan = " << d_channel << std::endl;
            d_total_block_exp = total_block_exp;
            d_test_statistics = 0;
        }
    else
        {
            if (secondpeak > 0)
                {
                    d_test_statistics = firstpeak / secondpeak;
                }
            else
                {
                    d_test_statistics = 0.0;
                }
        }

    // debug
    //    if (d_test_statistics > d_threshold)
    //        {
    //            printf("firstpeak = %f, secondpeak = %f, test_statistics = %f reported block exp = %d PRN = %d inext = %d, initial_sample = %ld doppler = %d\n", firstpeak, secondpeak, d_test_statistics, (int)total_block_exp, (int)d_gnss_synchro->PRN, (int)indext, (long int)initial_sample, (int)doppler);
    //            printf("doppler_min = %d doppler_step = %d num_doppler_bins = %d\n", (int)doppler_min, (int)doppler_step, (int)num_doppler_bins);
    //        }

    d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
    d_sample_counter = initial_sample;

    if (d_select_queue_Fpga == 0)
        {
            if (d_downsampling_factor > 1)
                {
                    d_gnss_synchro->Acq_delay_samples = static_cast<double>(d_downsampling_factor * (indext));
                    d_gnss_synchro->Acq_samplestamp_samples = d_downsampling_factor * static_cast<uint64_t>(d_sample_counter) - static_cast<uint64_t>(44);  //33; //41; //+ 81*0.5; // delay due to the downsampling filter in the acquisition
                }
            else
                {
                    d_gnss_synchro->Acq_delay_samples = static_cast<double>(indext);
                    d_gnss_synchro->Acq_samplestamp_samples = d_sample_counter;  // delay due to the downsampling filter in the acquisition
                }
        }
    else
        {
            d_gnss_synchro->Acq_delay_samples = static_cast<double>(indext);
            d_gnss_synchro->Acq_samplestamp_samples = d_sample_counter;  // delay due to the downsampling filter in the acquisition
        }
}


void pcps_acquisition_fpga::set_active(bool active)
{
    d_active = active;

    d_input_power = 0.0;

    d_mag = 0.0;

    DLOG(INFO) << "Channel: " << d_channel
               << " , doing acquisition of satellite: " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN
               << " ,sample stamp: " << d_sample_counter << ", threshold: "
               << d_threshold << ", doppler_max: " << d_doppler_max
               << ", doppler_step: " << d_doppler_step
               // no CFAR algorithm in the FPGA
               << ", use_CFAR_algorithm_flag: false";

    acquisition_fpga->open_device();
    acquisition_fpga->configure_acquisition();
    acquisition_fpga->write_local_code();
    acquisition_fpga->set_block_exp(d_total_block_exp);

    acquisition_core(d_num_doppler_bins, d_doppler_step, -d_doppler_max);
    if (!d_make_2_steps)
        {
            acquisition_fpga->close_device();
            if (d_test_statistics > d_threshold)
                {
                    d_active = false;
                    send_positive_acquisition();
                    d_state = 0;  // Positive acquisition
                }
            else
                {
                    d_state = 0;
                    d_active = false;
                    send_negative_acquisition();
                }
        }
    else
        {
            if (d_test_statistics > d_threshold)
                {
                    d_doppler_center_step_two = static_cast<float>(d_gnss_synchro->Acq_doppler_hz);

                    uint32_t num_second_acq = 1;

                    while (num_second_acq < d_max_num_acqs)
                        {
                            acquisition_core(d_num_doppler_bins_step2, d_doppler_step2, d_doppler_center_step_two - static_cast<float>(floor(d_num_doppler_bins_step2 / 2.0)) * d_doppler_step2);
                            if (d_test_statistics > d_threshold)
                                {
                                    d_active = false;
                                    send_positive_acquisition();
                                    d_state = 0;  // Positive acquisition
                                    break;
                                }
                            num_second_acq = num_second_acq + 1;
                        }
                    acquisition_fpga->close_device();
                    if (d_test_statistics <= d_threshold)
                        {
                            d_state = 0;
                            d_active = false;
                            send_negative_acquisition();
                        }
                }
            else
                {
                    acquisition_fpga->close_device();
                    d_state = 0;
                    d_active = false;
                    send_negative_acquisition();
                }
        }
}


void pcps_acquisition_fpga::reset_acquisition(void)
{
    // this function triggers a HW reset of the FPGA PL.
    acquisition_fpga->open_device();
    acquisition_fpga->reset_acquisition();
    acquisition_fpga->close_device();
}