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

#include "DeHiss.h"

#ifdef SHR3D_SFX_CORE_AIRWINDOWS

namespace airwinconsolidated::DeHiss {

void DeHiss::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();

	double meanAL;
	double meanBL;
	double meanOutL = 0;
	double meanLastL;
	double averageL[5];
	
	double meanAR;
	double meanBR;
	double meanOutR = 0;
	double meanLastR;
	double averageR[5];
	
	double threshold = pow(A,9);
	double wet = B;
    
    while (--sampleFrames >= 0)
    {
		double inputSampleL = *in1;
		double inputSampleR = *in2;
		if (fabs(inputSampleL)<1.18e-23) inputSampleL = fpdL * 1.18e-17;
		if (fabs(inputSampleR)<1.18e-23) inputSampleR = fpdR * 1.18e-17;
		double drySampleL = inputSampleL;
		double drySampleR = inputSampleR;
		
		//begin L
		storedL[1] = storedL[0];
		storedL[0] = inputSampleL;
		diffL[5] = diffL[4];
		diffL[4] = diffL[3];
		diffL[3] = diffL[2];
		diffL[2] = diffL[1];
		diffL[1] = diffL[0];
		diffL[0] = storedL[0] - storedL[1];
		
		averageL[4] = (diffL[0] + diffL[1] + diffL[2] + diffL[3] + diffL[4] + diffL[5])/6.0;
		averageL[3] = (diffL[0] + diffL[1] + diffL[2] + diffL[3] + diffL[4])/5.0;
		averageL[2] = (diffL[0] + diffL[1] + diffL[2] + diffL[3])/4.0;
		averageL[1] = (diffL[0] + diffL[1] + diffL[2])/3.0;
		averageL[0] = (diffL[0] + diffL[1])/2.0;
		
		meanAL = diffL[0];
		meanBL = diffL[0];
		if (fabs(averageL[4]) < fabs(meanBL)) {meanAL = meanBL; meanBL = averageL[4];}
		if (fabs(averageL[3]) < fabs(meanBL)) {meanAL = meanBL; meanBL = averageL[3];}
		if (fabs(averageL[2]) < fabs(meanBL)) {meanAL = meanBL; meanBL = averageL[2];}
		if (fabs(averageL[1]) < fabs(meanBL)) {meanAL = meanBL; meanBL = averageL[1];}
		if (fabs(averageL[0]) < fabs(meanBL)) {meanAL = meanBL; meanBL = averageL[0];}
		meanLastL = meanOutL;
		meanOutL = ((meanAL+meanBL)/2.0);
		
		if (rawL > 0) rawL -= 0.001;
		if (fabs(inputSampleL) > threshold) {gateL = 1.0; rawL = 2.0;}
		else {gateL = (gateL * 0.999); if (threshold > 0) gateL += ((fabs(inputSampleL)/threshold) * 0.001);}
		
		if ((fabs(meanOutL) > threshold) || (fabs(meanLastL) > threshold)){}
		else storedL[0] = storedL[1] + (meanOutL * gateL);
		
		if (rawL < 1) inputSampleL = (inputSampleL * rawL) + (storedL[0] * (1-rawL));
		//end L
		
		//begin R
		storedR[1] = storedR[0];
		storedR[0] = inputSampleR;
		diffR[5] = diffR[4];
		diffR[4] = diffR[3];
		diffR[3] = diffR[2];
		diffR[2] = diffR[1];
		diffR[1] = diffR[0];
		diffR[0] = storedR[0] - storedR[1];
		
		averageR[4] = (diffR[0] + diffR[1] + diffR[2] + diffR[3] + diffR[4] + diffR[5])/6.0;
		averageR[3] = (diffR[0] + diffR[1] + diffR[2] + diffR[3] + diffR[4])/5.0;
		averageR[2] = (diffR[0] + diffR[1] + diffR[2] + diffR[3])/4.0;
		averageR[1] = (diffR[0] + diffR[1] + diffR[2])/3.0;
		averageR[0] = (diffR[0] + diffR[1])/2.0;
		
		meanAR = diffR[0];
		meanBR = diffR[0];
		if (fabs(averageR[4]) < fabs(meanBR)) {meanAR = meanBR; meanBR = averageR[4];}
		if (fabs(averageR[3]) < fabs(meanBR)) {meanAR = meanBR; meanBR = averageR[3];}
		if (fabs(averageR[2]) < fabs(meanBR)) {meanAR = meanBR; meanBR = averageR[2];}
		if (fabs(averageR[1]) < fabs(meanBR)) {meanAR = meanBR; meanBR = averageR[1];}
		if (fabs(averageR[0]) < fabs(meanBR)) {meanAR = meanBR; meanBR = averageR[0];}
		meanLastR = meanOutR;
		meanOutR = ((meanAR+meanBR)/2.0);
		
		if (rawR > 0) rawR -= 0.001;
		if (fabs(inputSampleR) > threshold) {gateR = 1.0; rawR = 2.0;}
		else {gateR = (gateR * 0.999); if (threshold > 0) gateR += ((fabs(inputSampleR)/threshold) * 0.001);}
		
		if ((fabs(meanOutR) > threshold) || (fabs(meanLastR) > threshold)){}
		else storedR[0] = storedR[1] + (meanOutR * gateR);
		
		if (rawR < 1) inputSampleR = (inputSampleR * rawR) + (storedR[0] * (1-rawR));
		//end R
		
		if (wet !=1.0) {
			inputSampleL = (inputSampleL * wet) + (drySampleL * (1.0-wet));
			inputSampleR = (inputSampleR * wet) + (drySampleR * (1.0-wet));
		}
		
		//begin 32 bit stereo floating point dither
		int expon; frexpf((float)inputSampleL, &expon);
		fpdL ^= fpdL << 13; fpdL ^= fpdL >> 17; fpdL ^= fpdL << 5;
		inputSampleL += double((double(fpdL)-uint32_t(0x7fffffff)) * 5.5e-36l * pow(2.0,expon+62.0));
		frexpf((float)inputSampleR, &expon);
		fpdR ^= fpdR << 13; fpdR ^= fpdR >> 17; fpdR ^= fpdR << 5;
		inputSampleR += double((double(fpdR)-uint32_t(0x7fffffff)) * 5.5e-36l * pow(2.0,expon+62.0));
		//end 32 bit stereo floating point dither
		
		*out1 = float(inputSampleL);
		*out2 = float(inputSampleR);

		in1++;
		in2++;
		out1++;
		out2++;
    }
}

} // end namespace

#endif // SHR3D_SFX_CORE_AIRWINDOWS
