/*!
 * \file beamformer.cc
 *
 * \brief Unpacks byte samples to NSR 2 bits samples
 * \author Javier Arribas 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 "beamformer.h"
#include <gnuradio/io_signature.h>
#include <sstream>


#define GNSS_SDR_BEAMFORMER_CHANNELS 8

beamformer_sptr make_beamformer()
{
    return beamformer_sptr(new beamformer());
}


beamformer::beamformer()
    : gr::sync_block("beamformer",
          gr::io_signature::make(GNSS_SDR_BEAMFORMER_CHANNELS, GNSS_SDR_BEAMFORMER_CHANNELS, sizeof(gr_complex)),
          gr::io_signature::make(1, 1, sizeof(gr_complex)))
{
    //initialize weight vector

    if (posix_memalign((void **)&weight_vector, 16, GNSS_SDR_BEAMFORMER_CHANNELS * sizeof(gr_complex)) == 0)
        {
        };

    for (int i = 0; i < GNSS_SDR_BEAMFORMER_CHANNELS; i++)
        {
            weight_vector[i] = gr_complex(1, 0);
        }
}


beamformer::~beamformer()
{
    free(weight_vector);
}


int beamformer::work(int noutput_items, gr_vector_const_void_star &input_items,
    gr_vector_void_star &output_items)
{
    gr_complex *out = reinterpret_cast<gr_complex *>(output_items[0]);
    // channel output buffers
    //  gr_complex *ch1 = (gr_complex *) input_items[0];
    //  gr_complex *ch2 = (gr_complex *) input_items[1];
    //  gr_complex *ch3 = (gr_complex *) input_items[2];
    //  gr_complex *ch4 = (gr_complex *) input_items[3];
    //  gr_complex *ch5 = (gr_complex *) input_items[4];
    //  gr_complex *ch6 = (gr_complex *) input_items[5];
    //  gr_complex *ch7 = (gr_complex *) input_items[6];
    //  gr_complex *ch8 = (gr_complex *) input_items[7];

    // NON-VOLK beamforming operation
    //TODO: Implement VOLK SIMD-accelerated beamformer!
    gr_complex sum;
    for (int n = 0; n < noutput_items; n++)
        {
            sum = gr_complex(0, 0);
            for (int i = 0; i < GNSS_SDR_BEAMFORMER_CHANNELS; i++)
                {
                    sum = sum + (reinterpret_cast<const gr_complex *>(input_items[i]))[n] * weight_vector[i];
                }
            out[n] = sum;
        }

    return noutput_items;
}
