#pragma once
#include <stdlib.h>
#include <cstdint>
#include <cmath>

namespace trnr::lib::companding {
// ulaw compansion based on code by Chris Johnson
class ulaw {
public:
    ulaw() {
        fpd_l = 1.0; while (fpd_l < 16386) fpd_l = rand()*UINT32_MAX;
        fpd_r = 1.0; while (fpd_r < 16386) fpd_r = rand()*UINT32_MAX;
    }

    void encode_samples(double& input_sample_l, double& input_sample_r) {

        // ulaw encoding
        static int noisesource_l = 0;
        static int noisesource_r = 850010;
        int residue;
        double applyresidue;
        
        noisesource_l = noisesource_l % 1700021; noisesource_l++;
        residue = noisesource_l * noisesource_l;
        residue = residue % 170003; residue *= residue;
        residue = residue % 17011; residue *= residue;
        residue = residue % 1709; residue *= residue;
        residue = residue % 173; residue *= residue;
        residue = residue % 17;
        applyresidue = residue;
        applyresidue *= 0.00000001;
        applyresidue *= 0.00000001;
        input_sample_l += applyresidue;
        if (input_sample_l<1.2e-38 && -input_sample_l<1.2e-38) {
            input_sample_l -= applyresidue;
        }
        
        noisesource_r = noisesource_r % 1700021; noisesource_r++;
        residue = noisesource_r * noisesource_r;
        residue = residue % 170003; residue *= residue;
        residue = residue % 17011; residue *= residue;
        residue = residue % 1709; residue *= residue;
        residue = residue % 173; residue *= residue;
        residue = residue % 17;
        applyresidue = residue;
        applyresidue *= 0.00000001;
        applyresidue *= 0.00000001;
        input_sample_r += applyresidue;
        if (input_sample_r<1.2e-38 && -input_sample_r<1.2e-38) {
            input_sample_r -= applyresidue;
        }
        
        if (input_sample_l > 1.0) input_sample_l = 1.0;
        if (input_sample_l < -1.0) input_sample_l = -1.0;
        
        if (input_sample_r > 1.0) input_sample_r = 1.0;
        if (input_sample_r < -1.0) input_sample_r = -1.0;
        
        if (input_sample_l > 0) input_sample_l = log(1.0+(255*fabs(input_sample_l))) / log(256);
        if (input_sample_l < 0) input_sample_l = -log(1.0+(255*fabs(input_sample_l))) / log(256);
        
        if (input_sample_r > 0) input_sample_r = log(1.0+(255*fabs(input_sample_r))) / log(256);
        if (input_sample_r < 0) input_sample_r = -log(1.0+(255*fabs(input_sample_r))) / log(256);
    }

    void decode_samples(double& input_sample_l, double& input_sample_r) {

        // ulaw decoding
        if (fabs(input_sample_l)<1.18e-23) input_sample_l = fpd_l * 1.18e-17;
        if (fabs(input_sample_r)<1.18e-23) input_sample_r = fpd_r * 1.18e-17;
        
        if (input_sample_l > 1.0) input_sample_l = 1.0;
        if (input_sample_l < -1.0) input_sample_l = -1.0;
        
        if (input_sample_r > 1.0) input_sample_r = 1.0;
        if (input_sample_r < -1.0) input_sample_r = -1.0;
        
        if (input_sample_l > 0) input_sample_l = (pow(256,fabs(input_sample_l))-1.0) / 255;
        if (input_sample_l < 0) input_sample_l = -(pow(256,fabs(input_sample_l))-1.0) / 255;
        
        if (input_sample_r > 0) input_sample_r = (pow(256,fabs(input_sample_r))-1.0) / 255;
        if (input_sample_r < 0) input_sample_r = -(pow(256,fabs(input_sample_r))-1.0) / 255;

        // 64 bit stereo floating point dither
        fpd_l ^= fpd_l << 13; fpd_l ^= fpd_l >> 17; fpd_l ^= fpd_l << 5;
        fpd_r ^= fpd_r << 13; fpd_r ^= fpd_r >> 17; fpd_r ^= fpd_r << 5;
    }

private:
    uint32_t fpd_l;
	uint32_t fpd_r;
};
}