/*
 * Author: Harry van Haaren 2013
 *         harryhaaren@gmail.com
 * 
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 */

#ifndef OPENAV_DSP_SIDECHAIN_GAIN_H
#define OPENAV_DSP_SIDECHAIN_GAIN_H

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

class SidechainGain
{
  public:
    SidechainGain(int rate);
    ~SidechainGain(){}
    
    void threshold(float t){controlThreshold = t;}
    void reduction(float r){controlReduction = r;}
    void time     (float t){controlReleaseTime = t;}
    
    void process(unsigned int n_samples, float** inputs, float** outputs);
  
  private:
    /// audio buffers
    float* audioInputL;
    float* audioInputR;
    float* audioSidechain;
    float* audioOutputL;
    float* audioOutputR;
    
    /// control signals
    float controlThreshold;
    float controlReduction;
    float controlReleaseTime;
    float controlSidechainAmp;
    
    /// filter state
    float w, a, b, g1, g2;
    
    /// last peak history
    bool nowIsAPeak;
    long peakFrameCounter;
    
    /// nframes available for countdown
    long peakCountDuration;
    
    /// control output
    float currentTarget;
};

#endif // OPENAV_DSP_SIDECHAIN_GAIN_H