/* -*- c++ -*- */
/*
 * Copyright 2009,2010,2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <cmath>
#include <cstdio>

#include "pfb_clock_sync_fff_impl.h"
#include <gnuradio/io_signature.h>
#include <gnuradio/math.h>

namespace gr {
namespace digital {

pfb_clock_sync_fff::sptr pfb_clock_sync_fff::make(double sps,
                                                  float gain,
                                                  const std::vector<float>& taps,
                                                  unsigned int filter_size,
                                                  float init_phase,
                                                  float max_rate_deviation,
                                                  int osps)
{
    return gnuradio::make_block_sptr<pfb_clock_sync_fff_impl>(
        sps, gain, taps, filter_size, init_phase, max_rate_deviation, osps);
}

static int ios[] = { sizeof(float), sizeof(float), sizeof(float), sizeof(float) };
static std::vector<int> iosig(ios, ios + sizeof(ios) / sizeof(int));
pfb_clock_sync_fff_impl::pfb_clock_sync_fff_impl(double sps,
                                                 float loop_bw,
                                                 const std::vector<float>& taps,
                                                 unsigned int filter_size,
                                                 float init_phase,
                                                 float max_rate_deviation,
                                                 int osps)
    : block("pfb_clock_sync_fff",
            io_signature::make(1, 1, sizeof(float)),
            io_signature::makev(1, 4, iosig)),
      d_updated(false),
      d_nfilters(filter_size),
      d_max_dev(max_rate_deviation),
      d_osps(osps),
      d_error(0)
{
    if (taps.empty())
        throw std::runtime_error("pfb_clock_sync_fff: please specify a filter.");

    // Let scheduler adjust our relative_rate.
    enable_update_rate(true);

    d_sps = floor(sps);

    // Set the damping factor for a critically damped system
    d_damping = 2 * d_nfilters;

    // Set the bandwidth, which will then call update_gains()
    set_loop_bandwidth(loop_bw);

    // Store the last filter between calls to work
    // The accumulator keeps track of overflow to increment the stride correctly.
    // set it here to the fractional difference based on the initial phaes
    d_k = init_phase;
    d_rate = (sps - floor(sps)) * (double)d_nfilters;
    d_rate_i = (int)floor(d_rate);
    d_rate_f = d_rate - (float)d_rate_i;
    d_filtnum = (int)floor(d_k);

    d_filters.reserve(d_nfilters);
    d_diff_filters.reserve(d_nfilters);

    // Create an FIR filter for each channel and zero out the taps
    std::vector<float> vtaps(1, 0);
    for (int i = 0; i < d_nfilters; i++) {
        d_filters.emplace_back(vtaps);
        d_diff_filters.emplace_back(vtaps);
    }

    // Now, actually set the filters' taps
    std::vector<float> dtaps;
    create_diff_taps(taps, dtaps);
    set_taps(taps, d_taps, d_filters);
    set_taps(dtaps, d_dtaps, d_diff_filters);

    set_relative_rate((uint64_t)d_osps, (uint64_t)d_sps);
}

pfb_clock_sync_fff_impl::~pfb_clock_sync_fff_impl() {}

bool pfb_clock_sync_fff_impl::check_topology(int ninputs, int noutputs)
{
    return noutputs == 1 || noutputs == 4;
}

void pfb_clock_sync_fff_impl::forecast(int noutput_items,
                                       gr_vector_int& ninput_items_required)
{
    unsigned ninputs = ninput_items_required.size();
    for (unsigned i = 0; i < ninputs; i++)
        ninput_items_required[i] = (noutput_items + history()) * (d_sps / d_osps);
}

void pfb_clock_sync_fff_impl::update_taps(const std::vector<float>& taps)
{
    d_updated_taps = taps;
    d_updated = true;
}

/*******************************************************************
 SET FUNCTIONS
*******************************************************************/

void pfb_clock_sync_fff_impl::set_loop_bandwidth(float bw)
{
    if (bw < 0) {
        throw std::out_of_range("pfb_clock_sync_fff: invalid bandwidth. Must be >= 0.");
    }

    d_loop_bw = bw;
    update_gains();
}

void pfb_clock_sync_fff_impl::set_damping_factor(float df)
{
    if (df < 0 || df > 1.0) {
        throw std::out_of_range(
            "pfb_clock_sync_fff: invalid damping factor. Must be in [0,1].");
    }

    d_damping = df;
    update_gains();
}

void pfb_clock_sync_fff_impl::set_alpha(float alpha)
{
    if (alpha < 0 || alpha > 1.0) {
        throw std::out_of_range("pfb_clock_sync_fff: invalid alpha. Must be in [0,1].");
    }
    d_alpha = alpha;
}

void pfb_clock_sync_fff_impl::set_beta(float beta)
{
    if (beta < 0 || beta > 1.0) {
        throw std::out_of_range("pfb_clock_sync_fff: invalid beta. Must be in [0,1].");
    }
    d_beta = beta;
}

/*******************************************************************
 GET FUNCTIONS
*******************************************************************/

float pfb_clock_sync_fff_impl::loop_bandwidth() const { return d_loop_bw; }

float pfb_clock_sync_fff_impl::damping_factor() const { return d_damping; }

float pfb_clock_sync_fff_impl::alpha() const { return d_alpha; }

float pfb_clock_sync_fff_impl::beta() const { return d_beta; }

float pfb_clock_sync_fff_impl::clock_rate() const { return d_rate_f; }

/*******************************************************************
 *******************************************************************/

void pfb_clock_sync_fff_impl::update_gains()
{
    const float denom = (1.0 + 2.0 * d_damping * d_loop_bw + d_loop_bw * d_loop_bw);
    d_alpha = (4 * d_damping * d_loop_bw) / denom;
    d_beta = (4 * d_loop_bw * d_loop_bw) / denom;
}

void pfb_clock_sync_fff_impl::set_taps(const std::vector<float>& newtaps,
                                       std::vector<std::vector<float>>& ourtaps,
                                       std::vector<kernel::fir_filter_fff>& ourfilter)
{
    int i, j;

    const unsigned int ntaps = newtaps.size();
    d_taps_per_filter = (unsigned int)ceil((double)ntaps / (double)d_nfilters);

    // Create d_numchan vectors to store each channel's taps
    ourtaps.resize(d_nfilters);

    // Make a vector of the taps plus fill it out with 0's to fill
    // each polyphase filter with exactly d_taps_per_filter
    std::vector<float> tmp_taps;
    tmp_taps = newtaps;
    while ((float)(tmp_taps.size()) < d_nfilters * d_taps_per_filter) {
        tmp_taps.push_back(0.0);
    }

    // Partition the filter
    for (i = 0; i < d_nfilters; i++) {
        // Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
        ourtaps[i] = std::vector<float>(d_taps_per_filter, 0);
        for (j = 0; j < d_taps_per_filter; j++) {
            ourtaps[i][j] = tmp_taps[i + j * d_nfilters];
        }

        // Build a filter for each channel and add it's taps to it
        ourfilter[i].set_taps(ourtaps[i]);
    }

    // Set the history to ensure enough input items for each filter
    set_history(d_taps_per_filter + d_sps + d_sps);

    // Make sure there is enough output space for d_osps outputs/input.
    set_output_multiple(d_osps);
}

void pfb_clock_sync_fff_impl::create_diff_taps(const std::vector<float>& newtaps,
                                               std::vector<float>& difftaps)
{
    std::vector<float> diff_filter(3);
    diff_filter[0] = -1;
    diff_filter[1] = 0;
    diff_filter[2] = 1;

    float pwr = 0;
    difftaps.clear();
    difftaps.push_back(0);
    for (unsigned int i = 0; i < newtaps.size() - 2; i++) {
        float tap = 0;
        for (unsigned int j = 0; j < diff_filter.size(); j++) {
            tap += diff_filter[j] * newtaps[i + j];
        }
        difftaps.push_back(tap);
        pwr += fabsf(tap);
    }
    difftaps.push_back(0);

    // Normalize the taps
    for (unsigned int i = 0; i < difftaps.size(); i++) {
        difftaps[i] *= d_nfilters / pwr;
        if (difftaps[i] != difftaps[i]) {
            throw std::runtime_error(
                "pfb_clock_sync_fff::create_diff_taps produced NaN.");
        }
    }
}

std::string pfb_clock_sync_fff_impl::taps_as_string() const
{
    int i, j;
    std::stringstream str;
    str.precision(4);
    str.setf(std::ios::scientific);

    str << "[ ";
    for (i = 0; i < d_nfilters; i++) {
        str << "[" << d_taps[i][0] << ", ";
        for (j = 1; j < d_taps_per_filter - 1; j++) {
            str << d_taps[i][j] << ", ";
        }
        str << d_taps[i][j] << "],";
    }
    str << " ]" << std::endl;

    return str.str();
}

std::string pfb_clock_sync_fff_impl::diff_taps_as_string() const
{
    int i, j;
    std::stringstream str;
    str.precision(4);
    str.setf(std::ios::scientific);

    str << "[ ";
    for (i = 0; i < d_nfilters; i++) {
        str << "[" << d_dtaps[i][0] << ", ";
        for (j = 1; j < d_taps_per_filter - 1; j++) {
            str << d_dtaps[i][j] << ", ";
        }
        str << d_dtaps[i][j] << "],";
    }
    str << " ]" << std::endl;

    return str.str();
}

std::vector<std::vector<float>> pfb_clock_sync_fff_impl::taps() const { return d_taps; }

std::vector<std::vector<float>> pfb_clock_sync_fff_impl::diff_taps() const
{
    return d_dtaps;
}

std::vector<float> pfb_clock_sync_fff_impl::channel_taps(int channel) const
{
    std::vector<float> taps;
    for (int i = 0; i < d_taps_per_filter; i++) {
        taps.push_back(d_taps[channel][i]);
    }
    return taps;
}

std::vector<float> pfb_clock_sync_fff_impl::diff_channel_taps(int channel) const
{
    std::vector<float> taps;
    for (int i = 0; i < d_taps_per_filter; i++) {
        taps.push_back(d_dtaps[channel][i]);
    }
    return taps;
}

int pfb_clock_sync_fff_impl::general_work(int noutput_items,
                                          gr_vector_int& ninput_items,
                                          gr_vector_const_void_star& input_items,
                                          gr_vector_void_star& output_items)
{
    const float* in = (const float*)input_items[0];
    float* out = (float*)output_items[0];

    if (d_updated) {
        std::vector<float> dtaps;
        create_diff_taps(d_updated_taps, dtaps);
        set_taps(d_updated_taps, d_taps, d_filters);
        set_taps(dtaps, d_dtaps, d_diff_filters);
        d_updated = false;
        return 0; // history requirements may have changed.
    }

    float *err = NULL, *outrate = NULL, *outk = NULL;
    if (output_items.size() == 4) {
        err = (float*)output_items[1];
        outrate = (float*)output_items[2];
        outk = (float*)output_items[3];
    }

    int i = 0, count = 0;

    // produce output as long as we can and there are enough input samples
    while (i < noutput_items) {
        for (int out_idx = 0; out_idx < d_osps; out_idx++) {
            d_filtnum = (int)floor(d_k);

            // Keep the current filter number in [0, d_nfilters]
            // If we've run beyond the last filter, wrap around and go to next sample
            // If we've gone below 0, wrap around and go to previous sample
            while (d_filtnum >= d_nfilters) {
                d_k -= d_nfilters;
                d_filtnum -= d_nfilters;
                count += 1;
            }
            while (d_filtnum < 0) {
                d_k += d_nfilters;
                d_filtnum += d_nfilters;
                count -= 1;
            }

            out[i + out_idx] = d_filters[d_filtnum].filter(&in[count + out_idx]);
            d_k = d_k + d_rate_i + d_rate_f; // update phase

            if (output_items.size() == 4) {
                err[i] = d_error;
                outrate[i] = d_rate_f;
                outk[i] = d_k;
            }
        }

        // Update the phase and rate estimates for this symbol
        float diff = d_diff_filters[d_filtnum].filter(&in[count]);
        d_error = out[i] * diff;

        // Run the control loop to update the current phase (k) and
        // tracking rate estimates based on the error value
        // Interpolating here to update rates for ever sps.
        for (int s = 0; s < d_sps; s++) {
            d_rate_f = d_rate_f + d_beta * d_error;
            d_k = d_k + d_rate_f + d_alpha * d_error;
        }

        // Keep our rate within a good range
        d_rate_f = gr::branchless_clip(d_rate_f, d_max_dev);

        i += d_osps;
        count += (int)floor(d_sps);
    }

    consume_each(count);
    return i;
}

} /* namespace digital */
} /* namespace gr */
