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

#include "Chorus.h"

#ifdef SHR3D_SFX_CORE_AIRWINDOWS

namespace airwinconsolidated::Chorus {

void Chorus::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 speed = pow(A,4) * 0.001;
	speed *= overallscale;
	int loopLimit = (int)(totalsamples * 0.499);
	int count;
	double range = pow(B,4) * loopLimit * 0.499;
	double wet = C;
	double modulation = range*wet;
	//removed extra dry variable
	double tupi = 3.141592653589793238 * 2.0;
	double offset;
	//this is a double buffer so we will be splitting it in two
	

	double inputSampleL;
	double inputSampleR;
	double drySampleL;
	double drySampleR;
	
    while (--sampleFrames >= 0)
    {
		inputSampleL = *in1;
		inputSampleR = *in2;
		if (fabs(inputSampleL)<1.18e-23) inputSampleL = fpdL * 1.18e-17;
		if (fabs(inputSampleR)<1.18e-23) inputSampleR = fpdR * 1.18e-17;
		drySampleL = inputSampleL;
		drySampleR = inputSampleR;

		airFactorL = airPrevL - inputSampleL;
		if (fpFlip) {airEvenL += airFactorL; airOddL -= airFactorL; airFactorL = airEvenL;}
		else {airOddL += airFactorL; airEvenL -= airFactorL; airFactorL = airOddL;}
		airOddL = (airOddL - ((airOddL - airEvenL)/256.0)) / 1.0001;
		airEvenL = (airEvenL - ((airEvenL - airOddL)/256.0)) / 1.0001;
		airPrevL = inputSampleL;
		inputSampleL += (airFactorL*wet);
		//air, compensates for loss of highs in flanger's interpolation

		airFactorR = airPrevR - inputSampleR;
		if (fpFlip) {airEvenR += airFactorR; airOddR -= airFactorR; airFactorR = airEvenR;}
		else {airOddR += airFactorR; airEvenR -= airFactorR; airFactorR = airOddR;}
		airOddR = (airOddR - ((airOddR - airEvenR)/256.0)) / 1.0001;
		airEvenR = (airEvenR - ((airEvenR - airOddR)/256.0)) / 1.0001;
		airPrevR = inputSampleR;
		inputSampleR += (airFactorR*wet);
		//air, compensates for loss of highs in flanger's interpolation
		
		if (gcount < 1 || gcount > loopLimit) {gcount = loopLimit;}
		count = gcount;
		dL[count+loopLimit] = dL[count] = inputSampleL;
		dR[count+loopLimit] = dR[count] = inputSampleR;
		gcount--;
		//double buffer
		
		offset = range + (modulation * sin(sweep));
		count += (int)floor(offset);
		
		inputSampleL = dL[count] * (1-(offset-floor(offset))); //less as value moves away from .0
		inputSampleL += dL[count+1]; //we can assume always using this in one way or another?
		inputSampleL += (dL[count+2] * (offset-floor(offset))); //greater as value moves away from .0
		inputSampleL -= (((dL[count]-dL[count+1])-(dL[count+1]-dL[count+2]))/50); //interpolation hacks 'r us
		
		inputSampleR = dR[count] * (1-(offset-floor(offset))); //less as value moves away from .0
		inputSampleR += dR[count+1]; //we can assume always using this in one way or another?
		inputSampleR += (dR[count+2] * (offset-floor(offset))); //greater as value moves away from .0
		inputSampleR -= (((dR[count]-dR[count+1])-(dR[count+1]-dR[count+2]))/50); //interpolation hacks 'r us
		
		inputSampleL *= 0.5; //to get a comparable level
		inputSampleR *= 0.5; //to get a comparable level
		//sliding
		
		sweep += speed;
		if (sweep > tupi){sweep -= tupi;}
		//still scrolling through the samples, remember
		
		if (wet !=1.0) {
			inputSampleL = (inputSampleL * wet) + (drySampleL * (1.0-wet));
			inputSampleR = (inputSampleR * wet) + (drySampleR * (1.0-wet));
		}
		fpFlip = !fpFlip;

		//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
