/* ========================================
 *  ResEQ2 - ResEQ2.h
 *  Copyright (c) airwindows, Airwindows uses the MIT license
 * ======================================== */

#include "ResEQ2.h"

#ifdef SHR3D_SFX_CORE_AIRWINDOWS

namespace airwinconsolidated::ResEQ2 {

void ResEQ2::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();
	int cycleEnd = floor(overallscale);
	if (cycleEnd < 1) cycleEnd = 1;
	if (cycleEnd > 4) cycleEnd = 4;
	//this is going to be 2 for 88.1 or 96k, 3 for silly people, 4 for 176 or 192k
	
	//begin ResEQ2 Mid Boost
	double freqMPeak = pow(A+0.15,3);
	double amountMPeak = pow(B,2);
	int maxMPeak = (amountMPeak*63.0)+1;
	if ((freqMPeak != prevfreqMPeak)||(amountMPeak != prevamountMPeak)) {
		for (int x = 0; x < maxMPeak; x++) {
			if (((double)x*freqMPeak) < M_PI_4) f[x] = sin(((double)x*freqMPeak)*4.0)*freqMPeak*sin(((double)(maxMPeak-x)/(double)maxMPeak)*M_PI_2);
			else f[x] = cos((double)x*freqMPeak)*freqMPeak*sin(((double)(maxMPeak-x)/(double)maxMPeak)*M_PI_2);
		}
		prevfreqMPeak = freqMPeak; prevamountMPeak = amountMPeak;
	}//end ResEQ2 Mid Boost
    
    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;
		
		//begin ResEQ2 Mid Boost
		mpc++; if (mpc < 1 || mpc > 2001) mpc = 1;
		mpkL[mpc] = inputSampleL;
		mpkR[mpc] = inputSampleR;
		double midMPeakL = 0.0;
		double midMPeakR = 0.0;
		for (int x = 0; x < maxMPeak; x++) {
			int y = x*cycleEnd;
			switch (cycleEnd)
			{
				case 1: 
					midMPeakL += (mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x]);
					midMPeakR += (mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x]); break;
				case 2: 
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.5);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.5); y--;
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.5);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.5); break;
				case 3: 
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.333);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.333); y--;
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.333);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.333); y--;
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.333);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.333); break;
				case 4: 
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25); y--;
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25); y--;
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25); y--;
					midMPeakL += ((mpkL[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25);
					midMPeakR += ((mpkR[(mpc-y)+((mpc-y < 1)?2001:0)] * f[x])*0.25); //break
			}
		}
		inputSampleL = (midMPeakL*amountMPeak)+((1.5-amountMPeak>1.0)?inputSampleL:inputSampleL*(1.5-amountMPeak));
		inputSampleR = (midMPeakR*amountMPeak)+((1.5-amountMPeak>1.0)?inputSampleR:inputSampleR*(1.5-amountMPeak));
		//end ResEQ2 Mid Boost
		
		//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
