/*
  Copyright (C) 2003-2017 Paul Brossier <piem@aubio.org>

  This file is part of aubio.

  aubio 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.

  aubio 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 aubio.  If not, see <http://www.gnu.org/licenses/>.

*/

/* This algorithm was developed by A. de Cheveigné and H. Kawahara and
 * published in:
 *
 * de Cheveigné, A., Kawahara, H. (2002) "YIN, a fundamental frequency
 * estimator for speech and music", J. Acoust. Soc. Am. 111, 1917-1930.
 *
 * see http://recherche.ircam.fr/equipes/pcm/pub/people/cheveign.html
 */

#include "aubio_priv.h"
#include "fvec.h"
#include "mathutils.h"
#include "cvec.h"
#include "spectral/fft.h"
#include "pitch/pitchyinfast.h"

struct _aubio_pitchyinfast_t
{
  fvec_t *yin;
  smpl_t tol;
  smpl_t confidence;
  fvec_t *tmpdata;
  fvec_t *sqdiff;
  fvec_t *kernel;
  fvec_t *samples_fft;
  fvec_t *kernel_fft;
  aubio_fft_t *fft;
};

aubio_pitchyinfast_t *
new_aubio_pitchyinfast (uint_t bufsize)
{
  aubio_pitchyinfast_t *o = AUBIO_NEW (aubio_pitchyinfast_t);
  o->yin = new_fvec (bufsize / 2);
  o->tmpdata = new_fvec (bufsize);
  o->sqdiff = new_fvec (bufsize / 2);
  o->kernel = new_fvec (bufsize);
  o->samples_fft = new_fvec (bufsize);
  o->kernel_fft = new_fvec (bufsize);
  o->fft = new_aubio_fft (bufsize);
  o->tol = 0.15;
  return o;
}

void
del_aubio_pitchyinfast (aubio_pitchyinfast_t * o)
{
  del_fvec (o->yin);
  del_fvec (o->tmpdata);
  del_fvec (o->sqdiff);
  del_fvec (o->kernel);
  del_fvec (o->samples_fft);
  del_fvec (o->kernel_fft);
  del_aubio_fft (o->fft);
  AUBIO_FREE (o);
}

/* all the above in one */
void
aubio_pitchyinfast_do (aubio_pitchyinfast_t * o, const fvec_t * input, fvec_t * out)
{
  const smpl_t tol = o->tol;
  fvec_t* yin = o->yin;
  const uint_t length = yin->length;
  uint_t B = o->tmpdata->length;
  uint_t W = o->yin->length; // B / 2
  fvec_t tmp_slice, kernel_ptr;
  smpl_t *yin_data = yin->data;
  uint_t tau;
  sint_t period;
  smpl_t tmp2 = 0.;

  // compute r_t(0) + r_t+tau(0)
  {
    fvec_t *squares = o->tmpdata;
    fvec_weighted_copy(input, input, squares);
#if 0
    for (tau = 0; tau < W; tau++) {
      tmp_slice.data = squares->data + tau;
      tmp_slice.length = W;
      o->sqdiff->data[tau] = fvec_sum(&tmp_slice);
    }
#else
    tmp_slice.data = squares->data;
    tmp_slice.length = W;
    o->sqdiff->data[0] = fvec_sum(&tmp_slice);
    for (tau = 1; tau < W; tau++) {
      o->sqdiff->data[tau] = o->sqdiff->data[tau-1];
      o->sqdiff->data[tau] -= squares->data[tau-1];
      o->sqdiff->data[tau] += squares->data[W+tau-1];
    }
#endif
    fvec_add(o->sqdiff, o->sqdiff->data[0]);
  }
  // compute r_t(tau) = -2.*ifft(fft(samples)*fft(samples[W-1::-1]))
  {
    fvec_t *compmul = o->tmpdata;
    fvec_t *rt_of_tau = o->samples_fft;
    aubio_fft_do_complex(o->fft, input, o->samples_fft);
    // build kernel, take a copy of first half of samples
    tmp_slice.data = input->data;
    tmp_slice.length = W;
    kernel_ptr.data = o->kernel->data + 1;
    kernel_ptr.length = W;
    fvec_copy(&tmp_slice, &kernel_ptr);
    // reverse them
    fvec_rev(&kernel_ptr);
    // compute fft(kernel)
    aubio_fft_do_complex(o->fft, o->kernel, o->kernel_fft);
    // compute complex product
    compmul->data[0]  = o->kernel_fft->data[0] * o->samples_fft->data[0];
    for (tau = 1; tau < W; tau++) {
      compmul->data[tau]    = o->kernel_fft->data[tau] * o->samples_fft->data[tau];
      compmul->data[tau]   -= o->kernel_fft->data[B-tau] * o->samples_fft->data[B-tau];
    }
    compmul->data[W]    = o->kernel_fft->data[W] * o->samples_fft->data[W];
    for (tau = 1; tau < W; tau++) {
      compmul->data[B-tau]  = o->kernel_fft->data[B-tau] * o->samples_fft->data[tau];
      compmul->data[B-tau] += o->kernel_fft->data[tau] * o->samples_fft->data[B-tau];
    }
    // compute inverse fft
    aubio_fft_rdo_complex(o->fft, compmul, rt_of_tau);
    // compute square difference r_t(tau) = sqdiff - 2 * r_t_tau[W-1:-1]
    for (tau = 0; tau < W; tau++) {
      yin_data[tau] = o->sqdiff->data[tau] - 2. * rt_of_tau->data[tau+W];
    }
  }

  // now build yin and look for first minimum
  fvec_set_all(out, 0.);
  yin_data[0] = 1.;
  for (tau = 1; tau < length; tau++) {
    tmp2 += yin_data[tau];
    if (tmp2 != 0) {
      yin->data[tau] *= tau / tmp2;
    } else {
      yin->data[tau] = 1.;
    }
    period = tau - 3;
    if (tau > 4 && (yin_data[period] < tol) &&
        (yin_data[period] < yin_data[period + 1])) {
      out->data[0] = fvec_quadratic_peak_pos (yin, period);
      goto beach;
    }
  }
  out->data[0] = fvec_quadratic_peak_pos (yin, fvec_min_elem (yin) );
beach:
  return;
}

smpl_t
aubio_pitchyinfast_get_confidence (aubio_pitchyinfast_t * o) {
  o->confidence = 1. - fvec_min (o->yin);
  return o->confidence;
}

uint_t
aubio_pitchyinfast_set_tolerance (aubio_pitchyinfast_t * o, smpl_t tol)
{
  o->tol = tol;
  return 0;
}

smpl_t
aubio_pitchyinfast_get_tolerance (aubio_pitchyinfast_t * o)
{
  return o->tol;
}