/*
   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.
*/

/* This algorithm was developped by A. de Cheveigne 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
 *
 * This implementation is using an FFT to compute the square difference
 * function, which allows spectral weighting 
 * 
 */

#include "aubio_priv.h"
#include "sample.h"
#include "mathutils.h"
#include "fft.h"
#include "pitchyinfft.h"

struct _aubio_pitchyinfft_t {
        uint_t bufsize;
        uint_t rate;
	fvec_t * win;
	fvec_t * winput;
	cvec_t * res;
	fvec_t * sqrmag;
	fvec_t * weight;
	cvec_t * fftout;
	aubio_mfft_t * fft;
	fvec_t * yinfft;
};

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->bufsize      = bufsize;
  p->winput       = new_fvec(bufsize,1);
  p->fft          = new_aubio_mfft(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_fvec(bufsize,1);
  aubio_window(p->win->data[0], 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_mfft_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][(p->fftout->length-1)*2-l] = 
	  	SQR(p->fftout->norm[0][l]);
	  p->sqrmag->data[0][l] *= p->weight->data[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_mfft_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+1]*COS(res->phas[0][tau+1]); 
	  tmp += yin->data[0][tau];
	  yin->data[0][tau] *= tau/tmp;
  }
  tau = vec_min_elem(yin); 
  if (yin->data[0][tau] < tol) {
	  /* no interpolation */
	  //return tau+2;
	  /* 3 point quadratic interpolation */
	  //return vec_quadint_min(yin,tau,1);
	  /* additional check nlikely octave doubling in higher frequencies */
	  if (tau>35) {
		  return vec_quadint_min(yin,tau,1)+1;
	  } else {
		  /* should compare the minimum value of each interpolated peaks */
		  halfperiod = FLOOR(tau/2+.5);
		  if (yin->data[0][halfperiod] < tol)
			  return vec_quadint_min(yin,halfperiod,1)+1;
		  else
			  return vec_quadint_min(yin,tau,1)+1;
	  }
  } else
	  return 0;
}

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