/* ========================================
 *  Channel5 - Channel5.h
 *  Copyright (c) 2016 airwindows, Airwindows uses the MIT license
 * ======================================== */

#include "Channel5.h"

#ifdef SHR3D_SFX_CORE_AIRWINDOWS

namespace airwinconsolidated::Channel5 {

void Channel5::processBlock(float **inputs, float **outputs, int sampleFrames) 
{
    float* in1  =  inputs[0];
    float* in2  =  inputs[1];
    float* out1 = outputs[0];
    float* out2 = outputs[1];
	
	double overallscale = 1.0;
	overallscale /= 44100.0;
	overallscale *= getSampleRate();	
	const double localiirAmount = iirAmount / overallscale;
	const double localthreshold = threshold / overallscale;
	const double density = pow(drive,2); //this doesn't relate to the plugins Density and Drive much

    while (--sampleFrames >= 0)
    {
		double inputSampleL = *in1;
		double inputSampleR = *in2;
		
		
		if (fpFlip)
		{
			iirSampleLA = (iirSampleLA * (1 - localiirAmount)) + (inputSampleL * localiirAmount);
			inputSampleL = inputSampleL - iirSampleLA;
			iirSampleRA = (iirSampleRA * (1 - localiirAmount)) + (inputSampleR * localiirAmount);
			inputSampleR = inputSampleR - iirSampleRA;
		}
		else
		{
			iirSampleLB = (iirSampleLB * (1 - localiirAmount)) + (inputSampleL * localiirAmount);
			inputSampleL = inputSampleL - iirSampleLB;
			iirSampleRB = (iirSampleRB * (1 - localiirAmount)) + (inputSampleR * localiirAmount);
			inputSampleR = inputSampleR - iirSampleRB;
		}
		//highpass section
		
		double bridgerectifier = fabs(inputSampleL)*1.57079633;
		if (bridgerectifier > 1.57079633) bridgerectifier = 1.0;
		else bridgerectifier = sin(bridgerectifier);
		if (inputSampleL > 0) inputSampleL = (inputSampleL*(1-density))+(bridgerectifier*density);
		else inputSampleL = (inputSampleL*(1-density))-(bridgerectifier*density);
		
		bridgerectifier = fabs(inputSampleR)*1.57079633;
		if (bridgerectifier > 1.57079633) bridgerectifier = 1.0;
		else bridgerectifier = sin(bridgerectifier);
		if (inputSampleR > 0) inputSampleR = (inputSampleR*(1-density))+(bridgerectifier*density);
		else inputSampleR = (inputSampleR*(1-density))-(bridgerectifier*density);
		//drive section
		
		double clamp = inputSampleL - lastSampleL;
		if (clamp > localthreshold)
			inputSampleL = lastSampleL + localthreshold;
		if (-clamp > localthreshold)
			inputSampleL = lastSampleL - localthreshold;
		lastSampleL = inputSampleL;
		
		clamp = inputSampleR - lastSampleR;
		if (clamp > localthreshold)
			inputSampleR = lastSampleR + localthreshold;
		if (-clamp > localthreshold)
			inputSampleR = lastSampleR - localthreshold;
		lastSampleR = inputSampleR;
		//slew section
		fpFlip = !fpFlip;
		
		if (output < 1.0) {
			inputSampleL *= output;
			inputSampleR *= output;
		}
		
		//noise shaping to 32-bit floating point
		float fpTemp = inputSampleL;
		fpNShapeL += (inputSampleL-fpTemp);
		inputSampleL += fpNShapeL;
		//if this confuses you look at the wordlength for fpTemp :)
		fpTemp = inputSampleR;
		fpNShapeR += (inputSampleR-fpTemp);
		inputSampleR += fpNShapeR;
		//for deeper space and warmth, we try a non-oscillating noise shaping
		//that is kind of ruthless: it will forever retain the rounding errors
		//except we'll dial it back a hair at the end of every buffer processed
		//end noise shaping on 32 bit output
		
		*out1 = float(inputSampleL);
		*out2 = float(inputSampleR);
		
		in1++;
		in2++;
		out1++;
		out2++;
    }
	fpNShapeL *= 0.999999;
	fpNShapeR *= 0.999999;
	//we will just delicately dial back the FP noise shaping, not even every sample
	//this is a good place to put subtle 'no runaway' calculations, though bear in mind
	//that it will be called more often when you use shorter sample buffers in the DAW.
	//So, very low latency operation will call these calculations more often.	
}

} // end namespace

#endif // SHR3D_SFX_CORE_AIRWINDOWS
