/***************************************************************************
 *   Copyright (C) 2006 by Ilya Kotov                                      *
 *   forkotov02@hotmail.ru                                                 *
 *                                                                         *
 *   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.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <QPainter>

#include "skin.h"
#include "eqgraph.h"

EQGraph::EQGraph ( QWidget *parent )
      : PixmapWidget ( parent )
{
   m_skin = Skin::getPointer();
   setPixmap ( m_skin->getEqPart ( Skin::EQ_GRAPH ) );
   clear();
   draw();
   connect ( m_skin, SIGNAL ( skinChanged() ), this, SLOT ( updateSkin() ) );
}


EQGraph::~EQGraph()
{}

void EQGraph::addValue ( int value )
{
   if ( m_values.size() >= 10 )
      return;
   m_values.append ( value );
   if ( m_values.size() == 10 )
   {
      draw();
   }
}

void EQGraph::clear ()
{
   m_values.clear();
   update();
}

void EQGraph::init_spline ( double * x, double * y, int n, double * y2 )
{
   int i, k;
   double p, qn, sig, un, *u;

   //u = ( gfloat * ) g_malloc ( n * sizeof ( gfloat ) );
   u = new double[n];

   y2[0] = u[0] = 0.0;

   for ( i = 1; i < n - 1; i++ )
   {
      sig = ( ( double ) x[i] - x[i - 1] ) / ( ( double ) x[i + 1] - x[i - 1] );
      p = sig * y2[i - 1] + 2.0;
      y2[i] = ( sig - 1.0 ) / p;
      u[i] =
          ( ( ( double ) y[i + 1] - y[i] ) / ( x[i + 1] - x[i] ) ) -
          ( ( ( double ) y[i] - y[i - 1] ) / ( x[i] - x[i - 1] ) );
      u[i] = ( 6.0 * u[i] / ( x[i + 1] - x[i - 1] ) - sig * u[i - 1] ) / p;
   }
   qn = un = 0.0;

   y2[n - 1] = ( un - qn * u[n - 2] ) / ( qn * y2[n - 2] + 1.0 );
   for ( k = n - 2; k >= 0; k-- )
      y2[k] = y2[k] * y2[k + 1] + u[k];
   //g_free ( u );
   delete[] u;
}

double EQGraph::eval_spline ( double xa[], double ya[], double y2a[], int n, double x )
{
   int klo, khi, k;
   double h, b, a;

   klo = 0;
   khi = n - 1;
   while ( khi - klo > 1 )
   {
      k = ( khi + klo ) >> 1;
      if ( xa[k] > x )
         khi = k;
      else
         klo = k;
   }
   h = xa[khi] - xa[klo];
   a = ( xa[khi] - x ) / h;
   b = ( x - xa[klo] ) / h;
   return ( a * ya[klo] + b * ya[khi] +
            ( ( a * a * a - a ) * y2a[klo] +
              ( b * b * b - b ) * y2a[khi] ) * ( h * h ) / 6.0 );
}

void EQGraph::draw()
{
   if(m_values.size()!=10)
   {
       setPixmap ( m_skin->getEqPart ( Skin::EQ_GRAPH ) );
       return;
   }

   int i, y, ymin, ymax, py = 0;
   double x[] = { 0, 11, 23, 35, 47, 59, 71, 83, 97, 109 }, yf[10];
   double *bands = new double[10];

   for ( int i = 0; i<10; ++i )
   {
      bands[i] = m_values.at ( i );
   }
   QPixmap pixmap = m_skin->getEqPart ( Skin::EQ_GRAPH );

   init_spline ( x, bands, 10, yf );
   for ( i = 0; i < 109; i++ )
   {
      y = 9 -
          ( int ) ( ( eval_spline ( x, bands, yf, 10, i ) *
                      9.0 ) / 20.0 );
      if ( y < 0 )
         y = 0;
      if ( y > 18 )
         y = 18;
      if ( !i )
         py = y;
      if ( y < py )
      {
         ymin = y;
         ymax = py;
      }
      else
      {
         ymin = py;
         ymax = y;
      }
      py = y;

      QPainter paint ( &pixmap );
      paint.drawPixmap ( i, y, m_skin->getEqSpline ( y ) ) ;


   }
   setPixmap ( pixmap );
   delete [] bands;
}

void EQGraph::updateSkin()
{
   draw();
}