/*
   Copyright (C) 2003 Paul Brossier

   This program 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 2 of the License, or
   (at your option) any later version.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

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

/** pitch yinfft structure */
struct _aubio_pitchyinfft_t {
  fvec_t * win;       /**< temporal weighting window */
  fvec_t * winput;    /**< windowed spectrum */
  cvec_t * res;       /**< complex vector to compute square difference function */
  fvec_t * sqrmag;    /**< square difference function */
  fvec_t * weight;    /**< spectral weighting window (psychoacoustic model) */
  cvec_t * fftout;    /**< Fourier transform output */
  aubio_fft_t * fft;  /**< fft object to compute square difference function */
  fvec_t * yinfft;    /**< Yin function */
};

static const smpl_t freqs[] = {0., 20., 25., 31.5, 40., 50., 63., 80., 100.,
  125., 160., 200., 250., 315., 400., 500., 630., 800., 1000., 1250.,
  1600., 2000., 2500., 3150., 4000., 5000., 6300., 8000., 9000., 10000.,
  12500., 15000., 20000.,  25100};

static const smpl_t weight[] = {-75.8, -70.1, -60.8, -52.1, -44.2, -37.5,
  -31.3, -25.6, -20.9, -16.5, -12.6, -9.6, -7.0, -4.7, -3.0, -1.8, -0.8,
  -0.2, -0.0, 0.5, 1.6, 3.2, 5.4, 7.8, 8.1, 5.3, -2.4, -11.1, -12.8,
  -12.2, -7.4, -17.8, -17.8, -17.8};

aubio_pitchyinfft_t * new_aubio_pitchyinfft (uint_t bufsize)
{
  aubio_pitchyinfft_t * p = AUBIO_NEW(aubio_pitchyinfft_t);
  p->winput = new_fvec(bufsize,1);
  p->fft    = new_aubio_fft(bufsize, 1);
  p->fftout = new_cvec(bufsize,1);
  p->sqrmag = new_fvec(bufsize,1);
  p->res    = new_cvec(bufsize,1);
  p->yinfft = new_fvec(bufsize/2+1,1);
  p->win    = new_aubio_window(bufsize, aubio_win_hanningz);
  p->weight      = new_fvec(bufsize/2+1,1);
  {
    uint_t i = 0, j = 1;
    smpl_t freq = 0, a0 = 0, a1 = 0, f0 = 0, f1 = 0;
    for (i=0; i<p->weight->length; i++) {
      freq = (smpl_t)i/(smpl_t)bufsize*(smpl_t)44100.;
      while (freq > freqs[j]) {
        j +=1;
            }
      a0 = weight[j-1];
      f0 = freqs[j-1];
            a1 = weight[j];
      f1 = freqs[j];
      if (f0 == f1) { // just in case
        p->weight->data[0][i] = a0;
      } else if (f0 == 0) { // y = ax+b
        p->weight->data[0][i] = (a1-a0)/f1*freq + a0;
      } else {
        p->weight->data[0][i] = (a1-a0)/(f1-f0)*freq +
          (a0 - (a1 - a0)/(f1/f0 - 1.));
      }
      while (freq > freqs[j]) {
        j +=1;
      }
      //AUBIO_DBG("%f\n",p->weight->data[0][i]);
      p->weight->data[0][i] = DB2LIN(p->weight->data[0][i]);
      //p->weight->data[0][i] = SQRT(DB2LIN(p->weight->data[0][i]));
    }
  }
  return p;
}

smpl_t aubio_pitchyinfft_detect(aubio_pitchyinfft_t * p, fvec_t * input, smpl_t tol) {
  uint_t tau, l = 0;
  uint_t halfperiod;
  smpl_t tmp = 0, sum = 0;
  cvec_t * res = (cvec_t *)p->res;
  fvec_t * yin = (fvec_t *)p->yinfft;
  for (l=0; l < input->length; l++){
    p->winput->data[0][l] = p->win->data[0][l] * input->data[0][l];
  }
  aubio_fft_do(p->fft,p->winput,p->fftout);
  for (l=0; l < p->fftout->length; l++){
    p->sqrmag->data[0][l] = SQR(p->fftout->norm[0][l]);
    p->sqrmag->data[0][l] *= p->weight->data[0][l];
  }
  for (l=1; l < p->fftout->length; l++){
    p->sqrmag->data[0][(p->fftout->length-1)*2-l] =
     SQR(p->fftout->norm[0][l]);
    p->sqrmag->data[0][(p->fftout->length-1)*2-l] *=
     p->weight->data[0][l];
  }
  for (l=0; l < p->sqrmag->length/2+1; l++) {
    sum += p->sqrmag->data[0][l];
  }
  sum *= 2.;
  aubio_fft_do(p->fft,p->sqrmag,res);
  yin->data[0][0] = 1.;
  for (tau=1; tau < yin->length; tau++) {
    yin->data[0][tau] = sum -
      res->norm[0][tau]*COS(res->phas[0][tau]);
    tmp += yin->data[0][tau];
    yin->data[0][tau] *= tau/tmp;
  }
  tau = fvec_min_elem(yin);
  if (yin->data[0][tau] < tol) {
    /* no interpolation */
    //return tau;
    /* 3 point quadratic interpolation */
    //return fvec_quadint_min(yin,tau,1);
    /* additional check for (unlikely) octave doubling in higher frequencies */
    if (tau>35) {
      return fvec_quadint(yin,tau,1);
    } else {
      /* should compare the minimum value of each interpolated peaks */
      halfperiod = FLOOR(tau/2+.5);
      if (yin->data[0][halfperiod] < tol)
        return fvec_quadint(yin,halfperiod,1);
      else
        return fvec_quadint(yin,tau,1);
    }
  } else
    return 0.;
}

void del_aubio_pitchyinfft(aubio_pitchyinfft_t *p){
  del_fvec(p->win);
  del_aubio_fft(p->fft);
  del_fvec(p->yinfft);
  del_fvec(p->sqrmag);
  del_cvec(p->res);
  del_cvec(p->fftout);
  del_fvec(p->winput);
  del_fvec(p->weight);
  AUBIO_FREE(p);
}