//	Copyright (c) 2010 Martin Eastwood
//  This code is distributed under the terms of the GNU General Public License

//  MVerb is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  at your option) any later version.
//
//  MVerb is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this MVerb.  If not, see <http://www.gnu.org/licenses/>.

#ifndef EMVERB_H
#define EMVERB_H

#include <cmath>
#include <cstring>

//forward declaration
template<typename T, int maxLength> class Allpass;
template<typename T, int maxLength> class StaticAllpassFourTap;
template<typename T, int maxLength> class StaticDelayLine;
template<typename T, int maxLength> class StaticDelayLineFourTap;
template<typename T, int maxLength> class StaticDelayLineEightTap;
template<typename T, int OverSampleCount> class StateVariable;

template<typename T>
class MVerb
{
private:
    Allpass<T, 96000> allpass[4];
    StaticAllpassFourTap<T, 96000> allpassFourTap[4];
    StateVariable<T,4> bandwidthFilter[2];
    StateVariable<T,4> damping[2];
    StaticDelayLine<T, 96000> predelay;
    StaticDelayLineFourTap<T, 96000> staticDelayLine[4];
    StaticDelayLineEightTap<T, 96000> earlyReflectionsDelayLine[2];
    T SampleRate, DampingFreq, Density1, Density2, BandwidthFreq, PreDelayTime, Decay, Gain, Mix, EarlyMix, Size;
    T MixSmooth, EarlyLateSmooth, BandwidthSmooth, DampingSmooth, PredelaySmooth, SizeSmooth, DensitySmooth, DecaySmooth;
    T PreviousLeftTank, PreviousRightTank;
    int ControlRate, ControlRateCounter;

public:
    enum
    {
        DAMPINGFREQ=0,
        DENSITY,
        BANDWIDTHFREQ,
        DECAY,
        PREDELAY,
        SIZE,
        GAIN,
        MIX,
        EARLYMIX,
        NUM_PARAMS
    };

    MVerb(){
        DampingFreq = 18000.;
        BandwidthFreq = 18000.;
        SampleRate = 44100.;
        Decay = 0.5;
        Gain = 1.;
        Mix = 1.;
        Size = 1.;
        EarlyMix = 1.;
        PreviousLeftTank = 0.;
        PreviousRightTank = 0.;
        PreDelayTime = 100 * (SampleRate / 1000);
        MixSmooth = EarlyLateSmooth = BandwidthSmooth = DampingSmooth = PredelaySmooth = SizeSmooth = DecaySmooth = DensitySmooth = 0.;
        ControlRate = SampleRate / 1000;
        ControlRateCounter = 0;
        reset();
    }

    ~MVerb(){
        //nowt to do here
    }

    void process(const T **inputs, T **outputs, int sampleFrames){
        T OneOverSampleFrames = 1. / sampleFrames;
        T MixDelta	= (Mix - MixSmooth) * OneOverSampleFrames;
        T EarlyLateDelta = (EarlyMix - EarlyLateSmooth) * OneOverSampleFrames;
        T BandwidthDelta = (((BandwidthFreq * 18400.) + 100.) - BandwidthSmooth) * OneOverSampleFrames;
        T DampingDelta = (((DampingFreq * 18400.) + 100.) - DampingSmooth) * OneOverSampleFrames;
        T PredelayDelta = ((PreDelayTime * 200 * (SampleRate / 1000)) - PredelaySmooth) * OneOverSampleFrames;
        T SizeDelta	= (Size - SizeSmooth) * OneOverSampleFrames;
        T DecayDelta = (((0.7995f * Decay) + 0.005) - DecaySmooth) * OneOverSampleFrames;
        T DensityDelta = (((0.7995f * Density1) + 0.005) - DensitySmooth) * OneOverSampleFrames;
        for(int i=0;i<sampleFrames;++i){
            T left = inputs[0][i];
            T right = inputs[1][i];
            MixSmooth += MixDelta;
            EarlyLateSmooth += EarlyLateDelta;
            BandwidthSmooth += BandwidthDelta;
            DampingSmooth += DampingDelta;
            PredelaySmooth += PredelayDelta;
            SizeSmooth += SizeDelta;
            DecaySmooth += DecayDelta;
            DensitySmooth += DensityDelta;
            if (ControlRateCounter >= ControlRate){
                ControlRateCounter = 0;
                bandwidthFilter[0].Frequency(BandwidthSmooth);
                bandwidthFilter[1].Frequency(BandwidthSmooth);
                damping[0].Frequency(DampingSmooth);
                damping[1].Frequency(DampingSmooth);
            }
            ++ControlRateCounter;
            predelay.SetLength(PredelaySmooth);
            Density2 = DecaySmooth + 0.15;
            if (Density2 > 0.5)
                Density2 = 0.5;
            if (Density2 < 0.25)
                Density2 = 0.25;
            allpassFourTap[1].SetFeedback(Density2);
            allpassFourTap[3].SetFeedback(Density2);
            allpassFourTap[0].SetFeedback(Density1);
            allpassFourTap[2].SetFeedback(Density1);
            T bandwidthLeft = bandwidthFilter[0](left) ;
            T bandwidthRight = bandwidthFilter[1](right) ;
            T earlyReflectionsL = earlyReflectionsDelayLine[0] ( bandwidthLeft * 0.5 + bandwidthRight * 0.3 )
                    + earlyReflectionsDelayLine[0].GetIndex(2) * 0.6
                    + earlyReflectionsDelayLine[0].GetIndex(3) * 0.4
                    + earlyReflectionsDelayLine[0].GetIndex(4) * 0.3
                    + earlyReflectionsDelayLine[0].GetIndex(5) * 0.3
                    + earlyReflectionsDelayLine[0].GetIndex(6) * 0.1
                    + earlyReflectionsDelayLine[0].GetIndex(7) * 0.1
                    + ( bandwidthLeft * 0.4 + bandwidthRight * 0.2 ) * 0.5 ;
            T earlyReflectionsR = earlyReflectionsDelayLine[1] ( bandwidthLeft * 0.3 + bandwidthRight * 0.5 )
                    + earlyReflectionsDelayLine[1].GetIndex(2) * 0.6
                    + earlyReflectionsDelayLine[1].GetIndex(3) * 0.4
                    + earlyReflectionsDelayLine[1].GetIndex(4) * 0.3
                    + earlyReflectionsDelayLine[1].GetIndex(5) * 0.3
                    + earlyReflectionsDelayLine[1].GetIndex(6) * 0.1
                    + earlyReflectionsDelayLine[1].GetIndex(7) * 0.1
                    + ( bandwidthLeft * 0.2 + bandwidthRight * 0.4 ) * 0.5 ;
            T predelayMonoInput = predelay(( bandwidthRight + bandwidthLeft ) * 0.5f);
            T smearedInput = predelayMonoInput;
            for(int j=0;j<4;j++)
                smearedInput = allpass[j] ( smearedInput );
            T leftTank = allpassFourTap[0] ( smearedInput + PreviousRightTank ) ;
            leftTank = staticDelayLine[0] (leftTank);
            leftTank = damping[0](leftTank);
            leftTank = allpassFourTap[1](leftTank);
            leftTank = staticDelayLine[1](leftTank);
            T rightTank = allpassFourTap[2] (smearedInput + PreviousLeftTank) ;
            rightTank = staticDelayLine[2](rightTank);
            rightTank = damping[1] (rightTank);
            rightTank = allpassFourTap[3](rightTank);
            rightTank = staticDelayLine[3](rightTank);
            PreviousLeftTank = leftTank * DecaySmooth;
            PreviousRightTank = rightTank * DecaySmooth;
            T accumulatorL = (0.6*staticDelayLine[2].GetIndex(1))
                    +(0.6*staticDelayLine[2].GetIndex(2))
                    -(0.6*allpassFourTap[3].GetIndex(1))
                    +(0.6*staticDelayLine[3].GetIndex(1))
                    -(0.6*staticDelayLine[0].GetIndex(1))
                    -(0.6*allpassFourTap[1].GetIndex(1))
                    -(0.6*staticDelayLine[1].GetIndex(1));
            T accumulatorR = (0.6*staticDelayLine[0].GetIndex(2))
                    +(0.6*staticDelayLine[0].GetIndex(3))
                    -(0.6*allpassFourTap[1].GetIndex(2))
                    +(0.6*staticDelayLine[1].GetIndex(2))
                    -(0.6*staticDelayLine[2].GetIndex(3))
                    -(0.6*allpassFourTap[3].GetIndex(2))
                    -(0.6*staticDelayLine[3].GetIndex(2));
            accumulatorL = ((accumulatorL * EarlyMix) + ((1 - EarlyMix) * earlyReflectionsL));
            accumulatorR = ((accumulatorR * EarlyMix) + ((1 - EarlyMix) * earlyReflectionsR));
            left = ( left + MixSmooth * ( accumulatorL - left ) ) * Gain;
            right = ( right + MixSmooth * ( accumulatorR - right ) ) * Gain;
            outputs[0][i] = left;
            outputs[1][i] = right;
        }
    }

    void reset(){
        ControlRateCounter = 0;
        bandwidthFilter[0].SetSampleRate (SampleRate );
        bandwidthFilter[1].SetSampleRate (SampleRate );
        bandwidthFilter[0].Reset();
        bandwidthFilter[1].Reset();
        damping[0].SetSampleRate (SampleRate );
        damping[1].SetSampleRate (SampleRate );
        damping[0].Reset();
        damping[1].Reset();
        predelay.Clear();
        predelay.SetLength(PreDelayTime);
        allpass[0].Clear();
        allpass[1].Clear();
        allpass[2].Clear();
        allpass[3].Clear();
        allpass[0].SetLength (0.0048 * SampleRate);
        allpass[1].SetLength (0.0036 * SampleRate);
        allpass[2].SetLength (0.0127 * SampleRate);
        allpass[3].SetLength (0.0093 * SampleRate);
        allpass[0].SetFeedback (0.75);
        allpass[1].SetFeedback (0.75);
        allpass[2].SetFeedback (0.625);
        allpass[3].SetFeedback (0.625);
        allpassFourTap[0].Clear();
        allpassFourTap[1].Clear();
        allpassFourTap[2].Clear();
        allpassFourTap[3].Clear();
        allpassFourTap[0].SetLength(0.020 * SampleRate * Size);
        allpassFourTap[1].SetLength(0.060 * SampleRate * Size);
        allpassFourTap[2].SetLength(0.030 * SampleRate * Size);
        allpassFourTap[3].SetLength(0.089 * SampleRate * Size);
        allpassFourTap[0].SetFeedback(Density1);
        allpassFourTap[1].SetFeedback(Density2);
        allpassFourTap[2].SetFeedback(Density1);
        allpassFourTap[3].SetFeedback(Density2);
        allpassFourTap[0].SetIndex(0,0,0,0);
        allpassFourTap[1].SetIndex(0,0.006 * SampleRate * Size, 0.041 * SampleRate * Size, 0);
        allpassFourTap[2].SetIndex(0,0,0,0);
        allpassFourTap[3].SetIndex(0,0.031 * SampleRate * Size, 0.011 * SampleRate * Size, 0);
        staticDelayLine[0].Clear();
        staticDelayLine[1].Clear();
        staticDelayLine[2].Clear();
        staticDelayLine[3].Clear();
        staticDelayLine[0].SetLength(0.15 * SampleRate * Size);
        staticDelayLine[1].SetLength(0.12 * SampleRate * Size);
        staticDelayLine[2].SetLength(0.14 * SampleRate * Size);
        staticDelayLine[3].SetLength(0.11 * SampleRate * Size);
        staticDelayLine[0].SetIndex(0, 0.067 * SampleRate * Size, 0.011 * SampleRate * Size , 0.121 * SampleRate * Size);
        staticDelayLine[1].SetIndex(0, 0.036 * SampleRate * Size, 0.089 * SampleRate * Size , 0);
        staticDelayLine[2].SetIndex(0, 0.0089 * SampleRate * Size, 0.099 * SampleRate * Size , 0);
        staticDelayLine[3].SetIndex(0, 0.067 * SampleRate * Size, 0.0041 * SampleRate * Size , 0);
        earlyReflectionsDelayLine[0].Clear();
        earlyReflectionsDelayLine[1].Clear();
        earlyReflectionsDelayLine[0].SetLength(0.089 * SampleRate);
        earlyReflectionsDelayLine[0].SetIndex (0, 0.0199*SampleRate, 0.0219*SampleRate, 0.0354*SampleRate,0.0389*SampleRate, 0.0414*SampleRate, 0.0692*SampleRate, 0);
        earlyReflectionsDelayLine[1].SetLength(0.069 * SampleRate);
        earlyReflectionsDelayLine[1].SetIndex (0, 0.0099*SampleRate, 0.011*SampleRate, 0.0182*SampleRate,0.0189*SampleRate, 0.0213*SampleRate, 0.0431*SampleRate, 0);
    }

    void setParameter(int index, T value){
        switch(index){
        case DAMPINGFREQ:
            DampingFreq =  /* 1. - */ value; // FIXME?
            break;
        case DENSITY:
            Density1 = value;
            break;
        case BANDWIDTHFREQ:
            BandwidthFreq = value;
            break;
        case PREDELAY:
            PreDelayTime = value;
            break;
        case SIZE:
            Size = value;
            allpassFourTap[0].Clear();
            allpassFourTap[1].Clear();
            allpassFourTap[2].Clear();
            allpassFourTap[3].Clear();
            allpassFourTap[0].SetLength(0.020 * SampleRate * Size);
            allpassFourTap[1].SetLength(0.060 * SampleRate * Size);
            allpassFourTap[2].SetLength(0.030 * SampleRate * Size);
            allpassFourTap[3].SetLength(0.089 * SampleRate * Size);
            allpassFourTap[1].SetIndex(0,0.006 * SampleRate * Size, 0.041 * SampleRate * Size, 0);
            allpassFourTap[3].SetIndex(0,0.031 * SampleRate * Size, 0.011 * SampleRate * Size, 0);
            staticDelayLine[0].Clear();
            staticDelayLine[1].Clear();
            staticDelayLine[2].Clear();
            staticDelayLine[3].Clear();
            staticDelayLine[0].SetLength(0.15 * SampleRate * Size);
            staticDelayLine[1].SetLength(0.12 * SampleRate * Size);
            staticDelayLine[2].SetLength(0.14 * SampleRate * Size);
            staticDelayLine[3].SetLength(0.11 * SampleRate * Size);
            staticDelayLine[0].SetIndex(0, 0.067 * SampleRate * Size, 0.011 * SampleRate * Size , 0.121 * SampleRate * Size);
            staticDelayLine[1].SetIndex(0, 0.036 * SampleRate * Size, 0.089 * SampleRate * Size , 0);
            staticDelayLine[2].SetIndex(0, 0.0089 * SampleRate * Size, 0.099 * SampleRate * Size , 0);
            staticDelayLine[3].SetIndex(0, 0.067 * SampleRate * Size, 0.0041 * SampleRate * Size , 0);
            break;
        case DECAY:
            Decay = value;
            break;
        case GAIN:
            Gain = value;
            break;
        case MIX:
            Mix = value;
            break;
        case EARLYMIX:
            EarlyMix = value;
            break;
        }
    }

    float getParameter(int index) const{
        switch(index){
        case DAMPINGFREQ:
            return DampingFreq;
            break;
        case DENSITY:
            return Density1;
            break;
        case BANDWIDTHFREQ:
            return BandwidthFreq;
            break;
        case PREDELAY:
            return PreDelayTime;
            break;
        case SIZE:
            return Size;
            break;
        case DECAY:
            return Decay;
            break;
        case GAIN:
            return Gain;
            break;
        case MIX:
            return Mix;
            break;
        case EARLYMIX:
            return EarlyMix;
            break;
        default: return 0.f;
            break;

        }
    }

    void setSampleRate(T sr){
        SampleRate = sr;
        ControlRate = SampleRate / 1000;
        reset();
    }
};



template<typename T, int maxLength>
class Allpass
{
private:
    T buffer[maxLength];
    int index;
    int Length;
    T Feedback;

public:
    Allpass()
    {
        SetLength ( maxLength - 1 );
        Clear();
        Feedback = 0.5;
    }

    T operator()(T input)
    {
        T output;
        T bufout;
        bufout = buffer[index];
        T temp = input * -Feedback;
        output = bufout + temp;
        buffer[index] = input + ((bufout+temp)*Feedback);
        if(++index>=Length) index = 0;
        return output;
    }

    void SetLength (int Length)
    {
        if( Length >= maxLength )
            Length = maxLength;
        if( Length < 0 )
            Length = 0;

        this->Length = Length;
    }

    void SetFeedback(T feedback)
    {
        Feedback = feedback;
    }

    void Clear()
    {
        std::memset(buffer, 0, sizeof(buffer));
        index = 0;
    }

    int GetLength() const
    {
        return Length;
    }
};

template<typename T, int maxLength>
class StaticAllpassFourTap
{
private:
    T buffer[maxLength];
    int index1, index2, index3, index4;
    int Length;
    T Feedback;

public:
    StaticAllpassFourTap()
    {
        SetLength ( maxLength - 1 );
        Clear();
        Feedback = 0.5;
    }

    T operator()(T input)
    {
        T output;
        T bufout;

        bufout = buffer[index1];
        T temp = input * -Feedback;
        output = bufout + temp;
        buffer[index1] = input + ((bufout+temp)*Feedback);

        if(++index1>=Length)
            index1 = 0;
        if(++index2 >= Length)
            index2 = 0;
        if(++index3 >= Length)
            index3 = 0;
        if(++index4 >= Length)
            index4 = 0;

        return output;
    }

    void SetIndex (int Index1, int Index2, int Index3, int Index4)
    {
        index1 = Index1;
        index2 = Index2;
        index3 = Index3;
        index4 = Index4;
    }

    T GetIndex (int Index)
    {
        switch (Index)
        {
        case 0:
            return buffer[index1];
            break;
        case 1:
            return buffer[index2];
            break;
        case 2:
            return buffer[index3];
            break;
        case 3:
            return buffer[index4];
            break;
        default:
            return buffer[index1];
            break;
        }
    }

    void SetLength (int Length)
    {
        if( Length >= maxLength )
            Length = maxLength;
        if( Length < 0 )
            Length = 0;

        this->Length = Length;
    }


    void Clear()
    {
        std::memset(buffer, 0, sizeof(buffer));
        index1 = index2  = index3 = index4 = 0;
    }

    void SetFeedback(T feedback)
    {
        Feedback = feedback;
    }

    int GetLength() const
    {
        return Length;
    }
};

template<typename T, int maxLength>
class StaticDelayLine
{
private:
    T buffer[maxLength];
    int index;
    int Length;
    T Feedback;

public:
    StaticDelayLine()
    {
        SetLength ( maxLength - 1 );
        Clear();
    }

    T operator()(T input)
    {
        T output = buffer[index];
        buffer[index++] = input;
        if(index >= Length)
            index = 0;
        return output;
    }

    void SetLength (int Length)
    {
        if( Length >= maxLength )
            Length = maxLength;
        if( Length < 0 )
            Length = 0;

        this->Length = Length;
    }

    void Clear()
    {
        std::memset(buffer, 0, sizeof(buffer));
        index = 0;
    }

    int GetLength() const
    {
        return Length;
    }
};

template<typename T, int maxLength>
class StaticDelayLineFourTap
{
private:
    T buffer[maxLength];
    int index1, index2, index3, index4;
    int Length;
    T Feedback;

public:
    StaticDelayLineFourTap()
    {
        SetLength ( maxLength - 1 );
        Clear();
    }

    //get ouput and iterate
    T operator()(T input)
    {
        T output = buffer[index1];
        buffer[index1++] = input;
        if(index1 >= Length)
            index1 = 0;
        if(++index2 >= Length)
            index2 = 0;
        if(++index3 >= Length)
            index3 = 0;
        if(++index4 >= Length)
            index4 = 0;
        return output;
    }

    void SetIndex (int Index1, int Index2, int Index3, int Index4)
    {
        index1 = Index1;
        index2 = Index2;
        index3 = Index3;
        index4 = Index4;
    }


    T GetIndex (int Index)
    {
        switch (Index)
        {
        case 0:
            return buffer[index1];
            break;
        case 1:
            return buffer[index2];
            break;
        case 2:
            return buffer[index3];
            break;
        case 3:
            return buffer[index4];
            break;
        default:
            return buffer[index1];
            break;
        }
    }


    void SetLength (int Length)
    {
        if( Length >= maxLength )
            Length = maxLength;
        if( Length < 0 )
            Length = 0;

        this->Length = Length;
    }


    void Clear()
    {
        std::memset(buffer, 0, sizeof(buffer));
        index1 = index2  = index3 = index4 = 0;
    }


    int GetLength() const
    {
        return Length;
    }
};

template<typename T, int maxLength>
class StaticDelayLineEightTap
{
private:
    T buffer[maxLength];
    int index1, index2, index3, index4, index5, index6, index7, index8;
    int Length;
    T Feedback;

public:
    StaticDelayLineEightTap()
    {
        SetLength ( maxLength - 1 );
        Clear();
    }

    //get ouput and iterate
    T operator()(T input)
    {
        T output = buffer[index1];
        buffer[index1++] = input;
        if(index1 >= Length)
            index1 = 0;
        if(++index2 >= Length)
            index2 = 0;
        if(++index3 >= Length)
            index3 = 0;
        if(++index4 >= Length)
            index4 = 0;
        if(++index5 >= Length)
            index5 = 0;
        if(++index6 >= Length)
            index6 = 0;
        if(++index7 >= Length)
            index7 = 0;
        if(++index8 >= Length)
            index8 = 0;
        return output;

    }

    void SetIndex (int Index1, int Index2, int Index3, int Index4, int Index5, int Index6, int Index7, int Index8)
    {
        index1 = Index1;
        index2 = Index2;
        index3 = Index3;
        index4 = Index4;
        index5 = Index5;
        index6 = Index6;
        index7 = Index7;
        index8 = Index8;
    }


    T GetIndex (int Index)
    {
        switch (Index)
        {
        case 0:
            return buffer[index1];
            break;
        case 1:
            return buffer[index2];
            break;
        case 2:
            return buffer[index3];
            break;
        case 3:
            return buffer[index4];
            break;
        case 4:
            return buffer[index5];
            break;
        case 5:
            return buffer[index6];
            break;
        case 6:
            return buffer[index7];
            break;
        case 7:
            return buffer[index8];
            break;
        default:
            return buffer[index1];
            break;
        }
    }

    void SetLength (int Length)
    {
        if( Length >= maxLength )
            Length = maxLength;
        if( Length < 0 )
            Length = 0;

        this->Length = Length;
    }


    void Clear()
    {
        std::memset(buffer, 0, sizeof(buffer));
        index1 = index2  = index3 = index4 = index5 = index6 = index7 = index8 = 0;
    }


    int GetLength() const
    {
        return Length;
    }
};

template<typename T, int OverSampleCount>
class StateVariable
{
public:

    enum FilterType
    {
        LOWPASS,
        HIGHPASS,
        BANDPASS,
        NOTCH,
        FilterTypeCount
    };

private:

    T sampleRate;
    T frequency;
    T q;
    T f;

    T low;
    T high;
    T band;
    T notch;

    T *out;

public:
    StateVariable()
    {
        SetSampleRate(44100.);
        Frequency(1000.);
        Resonance(0);
        Type(LOWPASS);
        Reset();
    }

    T operator()(T input)
    {
        for(unsigned int i = 0; i < OverSampleCount; i++)
        {
            low += f * band + 1e-25;
            high = input - low - q * band;
            band += f * high;
            notch = low + high;
        }
        return *out;
    }

    void Reset()
    {
        low = high = band = notch = 0;
    }

    void SetSampleRate(T sampleRate)
    {
        this->sampleRate = sampleRate * OverSampleCount;
        UpdateCoefficient();
    }

    void Frequency(T frequency)
    {
        this->frequency = frequency;
        UpdateCoefficient();
    }

    void Resonance(T resonance)
    {
        this->q = 2 - 2 * resonance;
    }

    void Type(int type)
    {
        switch(type)
        {
        case LOWPASS:
            out = &low;
            break;

        case HIGHPASS:
            out = &high;
            break;

        case BANDPASS:
            out = &band;
            break;

        case NOTCH:
            out = &notch;
            break;

        default:
            out = &low;
            break;
        }
    }

private:
    void UpdateCoefficient()
    {
        f = 2. * std::sin(M_PI * frequency / sampleRate);
    }
};
#endif