/***************************************************/
/*! \class JCRev
    \brief John Chowning's reverberator class.

    This class takes a monophonic input signal and produces a stereo
    output signal.  It is derived from the CLM JCRev function, which
    is based on the use of networks of simple allpass and comb delay
    filters.  This class implements three series allpass units,
    followed by four parallel comb filters, and two decorrelation
    delay lines in parallel at the output.

    by Perry R. Cook and Gary P. Scavone, 1995 - 2009.
*/
/***************************************************/

#include "JCRev.h"
#include <cmath>

namespace stk {

JCRev :: JCRev( StkFloat T60 )
{
  lastFrame_.resize( 1, 2, 0.0 ); // resize lastFrame_ for stereo output

  // Delay lengths for 44100 Hz sample rate.
  int lengths[9] = {1777, 1847, 1993, 2137, 389, 127, 43, 211, 179};
  double scaler = Stk::sampleRate() / 44100.0;

  int delay, i;
  if ( scaler != 1.0 ) {
    for ( i=0; i<9; i++ ) {
      delay = (int) floor( scaler * lengths[i] );
      if ( (delay & 1) == 0) delay++;
      while ( !this->isPrime(delay) ) delay += 2;
      lengths[i] = delay;
    }
  }

  for ( i=0; i<3; i++ ) {
	  allpassDelays_[i].setMaximumDelay( lengths[i+4] );
	  allpassDelays_[i].setDelay( lengths[i+4] );
  }

  for ( i=0; i<4; i++ ) {
    combDelays_[i].setMaximumDelay( lengths[i] );
    combDelays_[i].setDelay( lengths[i] );
  }

  this->setT60( T60 );
  outLeftDelay_.setMaximumDelay( lengths[7] );
  outLeftDelay_.setDelay( lengths[7] );
  outRightDelay_.setMaximumDelay( lengths[8] );
  outRightDelay_.setDelay( lengths[8] );
  allpassCoefficient_ = 0.7;
  effectMix_ = 0.3;
  this->clear();
}

void JCRev :: clear()
{
  allpassDelays_[0].clear();
  allpassDelays_[1].clear();
  allpassDelays_[2].clear();
  combDelays_[0].clear();
  combDelays_[1].clear();
  combDelays_[2].clear();
  combDelays_[3].clear();
  outRightDelay_.clear();
  outLeftDelay_.clear();
  lastFrame_[0] = 0.0;
  lastFrame_[1] = 0.0;
}

void JCRev :: setT60( StkFloat T60 )
{
  for ( int i=0; i<4; i++ )
    combCoefficient_[i] = pow(10.0, (-3.0 * combDelays_[i].getDelay() / (T60 * Stk::sampleRate())));
}

StkFrames& JCRev :: tick( StkFrames& frames, unsigned int channel )
{
#if defined(_STK_DEBUG_)
  if ( channel >= frames.channels() - 1 ) {
    errorString_ << "JCRev::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif

  StkFloat *samples = &frames[channel];
  unsigned int hop = frames.channels();
  for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
    *samples = tick( *samples );
    *samples++;
    *samples = lastFrame_[1];
  }

  return frames;
}

StkFrames& JCRev :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
{
#if defined(_STK_DEBUG_)
  if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() - 1 ) {
    errorString_ << "JCRev::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif

  StkFloat *iSamples = &iFrames[iChannel];
  StkFloat *oSamples = &oFrames[oChannel];
  unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
  for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
    *oSamples++ = tick( *iSamples );
    *oSamples = lastFrame_[1];
  }

  return iFrames;
}

} // stk namespace