/* -*- c++ -*- */
/*
 * Copyright 2005,2006,2010-2012,2014 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio 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, or (at your option)
 * any later version.
 *
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

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

#include "clock_recovery_mm_cc_impl.h"
#include <gnuradio/io_signature.h>
#include <gnuradio/prefs.h>
#include <gnuradio/math.h>
#include <stdexcept>
#include <iostream>

namespace gr {
  namespace digital {

    static const int FUDGE = 16;

    clock_recovery_mm_cc::sptr
    clock_recovery_mm_cc::make(float omega, float gain_omega,
			       float mu, float gain_mu,
			       float omega_relative_limit)
    {
      return gnuradio::get_initial_sptr
	(new clock_recovery_mm_cc_impl(omega, gain_omega,
				       mu, gain_mu,
				       omega_relative_limit));
    }

    clock_recovery_mm_cc_impl::clock_recovery_mm_cc_impl(float omega, float gain_omega,
							 float mu, float gain_mu,
							 float omega_relative_limit)
      : block("clock_recovery_mm_cc",
              io_signature::make(1, 1, sizeof(gr_complex)),
              io_signature::make2(1, 2, sizeof(gr_complex), sizeof(float))),
	d_mu(mu), d_omega(omega), d_gain_omega(gain_omega),
	d_omega_relative_limit(omega_relative_limit),
	d_gain_mu(gain_mu), d_last_sample(0), d_interp(new filter::mmse_fir_interpolator_cc()),
	d_verbose(prefs::singleton()->get_bool("clock_recovery_mm_cc", "verbose", false)),
	d_p_2T(0), d_p_1T(0), d_p_0T(0), d_c_2T(0), d_c_1T(0), d_c_0T(0)
    {
      if(omega <= 0.0)
	throw std::out_of_range("clock rate must be > 0");
      if(gain_mu <  0  || gain_omega < 0)
	throw std::out_of_range("Gains must be non-negative");

      set_omega(omega);			// also sets min and max omega
      set_relative_rate(1.0 / omega);
      set_history(3);			// ensure 2 extra input samples are available
    }

    clock_recovery_mm_cc_impl::~clock_recovery_mm_cc_impl()
    {
      delete d_interp;
    }

    void
    clock_recovery_mm_cc_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] =
	  (int)ceil((noutput_items * d_omega) + d_interp->ntaps()) + FUDGE;
    }

    gr_complex
    clock_recovery_mm_cc_impl::slicer_0deg(gr_complex sample)
    {
      float real=0, imag=0;

      if(sample.real() > 0)
	real = 1;
      if(sample.imag() > 0)
	imag = 1;
      return gr_complex(real,imag);
    }

    gr_complex
    clock_recovery_mm_cc_impl::slicer_45deg(gr_complex sample)
    {
      float real= -1, imag = -1;
      if(sample.real() > 0)
	real=1;
      if(sample.imag() > 0)
	imag = 1;
      return gr_complex(real,imag);
    }

    void
    clock_recovery_mm_cc_impl::set_omega (float omega)
    {
      d_omega = omega;
      d_omega_mid = omega;
      d_omega_lim = d_omega_relative_limit * omega;
    }

    int
    clock_recovery_mm_cc_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 gr_complex *in = (const gr_complex *)input_items[0];
      gr_complex *out = (gr_complex *)output_items[0];
      float *foptr = (float *)output_items[1];

      bool write_foptr = output_items.size() >= 2;

      int ii = 0; // input index
      int oo = 0; // output index
      int ni = ninput_items[0] - d_interp->ntaps() - FUDGE;  // don't use more input than this

      assert(d_mu >= 0.0);
      assert(d_mu <= 1.0);

      float mm_val = 0;
      gr_complex u, x, y;

      // This loop writes the error to the second output, if it exists
      if(write_foptr) {
	while(oo < noutput_items && ii < ni) {
	  d_p_2T = d_p_1T;
	  d_p_1T = d_p_0T;
	  d_p_0T = d_interp->interpolate(&in[ii], d_mu);

	  d_c_2T = d_c_1T;
	  d_c_1T = d_c_0T;
	  d_c_0T = slicer_0deg(d_p_0T);

	  x = (d_c_0T - d_c_2T) * conj(d_p_1T);
	  y = (d_p_0T - d_p_2T) * conj(d_c_1T);
	  u = y - x;
	  mm_val = u.real();
	  out[oo++] = d_p_0T;

	  // limit mm_val
	  mm_val = gr::branchless_clip(mm_val,1.0);
	  d_omega = d_omega + d_gain_omega * mm_val;
	  d_omega = d_omega_mid + gr::branchless_clip(d_omega-d_omega_mid, d_omega_lim);

	  d_mu = d_mu + d_omega + d_gain_mu * mm_val;
	  ii += (int)floor(d_mu);
	  d_mu -= floor(d_mu);

	  // write the error signal to the second output
	  foptr[oo-1] = mm_val;

	  if(ii < 0) // clamp it.  This should only happen with bogus input
	    ii = 0;
	}
      }
      // This loop does not write to the second output (ugly, but faster)
      else {
	while(oo < noutput_items && ii < ni) {
	  d_p_2T = d_p_1T;
	  d_p_1T = d_p_0T;
	  d_p_0T = d_interp->interpolate(&in[ii], d_mu);

	  d_c_2T = d_c_1T;
	  d_c_1T = d_c_0T;
	  d_c_0T = slicer_0deg(d_p_0T);

	  x = (d_c_0T - d_c_2T) * conj(d_p_1T);
	  y = (d_p_0T - d_p_2T) * conj(d_c_1T);
	  u = y - x;
	  mm_val = u.real();
	  out[oo++] = d_p_0T;

	  // limit mm_val
	  mm_val = gr::branchless_clip(mm_val,1.0);

	  d_omega = d_omega + d_gain_omega * mm_val;
	  d_omega = d_omega_mid + gr::branchless_clip(d_omega-d_omega_mid, d_omega_lim);

	  d_mu = d_mu + d_omega + d_gain_mu * mm_val;
	  ii += (int)floor(d_mu);
	  d_mu -= floor(d_mu);

	  if(d_verbose) {
	    std::cout << d_omega << "\t" << d_mu << std::endl;
	  }

	  if(ii < 0) // clamp it.  This should only happen with bogus input
	    ii = 0;
	}
      }

      if(ii > 0) {
	if(ii > ninput_items[0]) {
	  std::cerr << "clock_recovery_mm_cc: ii > ninput_items[0] ("
		    << ii << " > " << ninput_items[0] << std::endl;
	  assert(0);
	}
	consume_each(ii);
      }

      return oo;
    }

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