#pragma once

#include <algorithm>

#include "AudioMath.h"
#include "poly.h"
#include "ObjectCache.h"
#include "SinOscillator.h"

using Osc = SinOscillator<float, true>;

#ifndef _CLAMP
#define _CLAMP
namespace std {
    inline float clamp(float v, float lo, float hi)
    {
        assert(lo < hi);
        return std::min(hi, std::max(v, lo));
    }
}
#endif

/**
 * Composite for Chebyshev module.
 *
 * Performance measure for 1.0 = 42.44
 * reduced polynomial order to what we actually use (10), perf = 39.5
 */
template <class TBase>
class CHBg : public TBase
{
public:
    CHBg(struct Module * module) : TBase(module)
    {
        init();
    }
    CHBg() : TBase()
    {
        init();
    }

    enum ParamIds
    {
        PARAM_TUNE,
        PARAM_OCTAVE,
        PARAM_EXTGAIN,
        PARAM_PITCH_MOD_TRIM,
        PARAM_LINEAR_FM_TRIM,
        PARAM_EXTGAIN_TRIM,
        PARAM_FOLD,
        PARAM_SLOPE,
        PARAM_MAG_EVEN,
        PARAM_MAG_ODD,
        PARAM_H0,
        PARAM_H1,
        PARAM_H2,
        PARAM_H3,
        PARAM_H4,
        PARAM_H5,
        PARAM_H6,
        PARAM_H7,
        PARAM_H8,
        PARAM_H9,

        NUM_PARAMS
    };
    const int numHarmonics = 1 + PARAM_H9 - PARAM_H0;

    enum InputIds
    {
        CV_INPUT,
        PITCH_MOD_INPUT,
        LINEAR_FM_INPUT,
        ENV_INPUT,
        GAIN_INPUT,
        AUDIO_INPUT,
        SLOPE_INPUT,
        H0_INPUT,
        H1_INPUT,
        H2_INPUT,
        H3_INPUT,
        H4_INPUT,
        H5_INPUT,
        H6_INPUT,
        H7_INPUT,
        H8_INPUT,
        H9_INPUT,
        H10_INPUT,
        NUM_INPUTS
    };

    enum OutputIds
    {
        MIX_OUTPUT,
        NUM_OUTPUTS
    };

    enum LightIds
    {
        GAIN_GREEN_LIGHT,
        GAIN_RED_LIGHT,
        NUM_LIGHTS
    };

    /**
     * Main processing entry point. Called every sample
     */
    void step() override;

    float _freq = 0;

private:
    bool economyMode = true;        // let's default to economy mode
    int cycleCount = 1;
    int clipCount = 0;
    int signalCount = 0;
    const int clipDuration = 4000;
    float finalGain = 0;
    bool isExternalAudio = false;

    static const int polyOrder = 10;

    /**
     * The waveshaper that is the heart of this module.
     * Let's use doubles.
     */
    Poly<double, polyOrder> poly;

    /*
     * maps freq multiple to "octave".
     * In other words, log base 12.
     */
    float _octave[polyOrder];
    float getOctave(int mult) const;
    void init();

    float _volume[polyOrder] = {0};

    /**
     * Internal sine wave oscillator to drive the waveshaper
     */
    SinOscillatorParams<float> sinParams;
    SinOscillatorState<float> sinState;

    // just maps 0..1 to 0..1
    std::shared_ptr<LookupTableParams<float>> audioTaper = {ObjectCache<float>::getAudioTaper()};

    AudioMath::ScaleFun<float> gainCombiner = AudioMath::makeLinearScaler(0.f, 1.f);

    std::function<float(float)> expLookup = ObjectCache<float>::getExp2Ex();
    std::shared_ptr<LookupTableParams<float>> db2gain = ObjectCache<float>::getDb2Gain();

    /**
     * Audio taper for the slope.
     */
    AudioMath::ScaleFun<float> slopeScale =
    {AudioMath::makeLinearScaler<float>(-18, 0)};

    /**
     * do one-time calculations when sample rate changes
     */
    void internalUpdate();

    /**
     * Do all the processing to get the input waveform
     * that will be fed to the polynomials
     */
    float getInput();

    void calcVolumes(float *);

    void checkClipping(float sample);

    /**
     * Does audio taper
     * @param raw = 0..1
     * @return 0..1
     */
    float taper(float raw)
    {
        return LookupTable<float>::lookup(*audioTaper, raw, false);
    }
};

template <class TBase>
inline void  CHBg<TBase>::init()
{
    for (int i = 0; i < polyOrder; ++i) {
        _octave[i] = log2(float(i + 1));
    }
}

template <class TBase>
inline float  CHBg<TBase>::getOctave(int i) const
{
    assert(i >= 0 && i < polyOrder);
    return _octave[i];
}

template <class TBase>
inline float CHBg<TBase>::getInput()
{
    assert(TBase::engineGetSampleTime() > 0);

    // Get the frequency from the inputs.
    float pitch = 1.0f + roundf(TBase::params[PARAM_OCTAVE].value) + TBase::params[PARAM_TUNE].value / 12.0f;
    pitch += TBase::inputs[CV_INPUT].value;
    pitch += .25f * TBase::inputs[PITCH_MOD_INPUT].value *
        taper(TBase::params[PARAM_PITCH_MOD_TRIM].value);

    const float q = float(log2(261.626));       // move up to pitch range of EvenVCO
    pitch += q;
    _freq = expLookup(pitch);

    if (_freq < .01f) {
        _freq = .01f;
    }

    // Multiply in the Linear FM contribution
    _freq *= 1.0f + TBase::inputs[LINEAR_FM_INPUT].value * taper(TBase::params[PARAM_LINEAR_FM_TRIM].value);
    float time = std::clamp(_freq * TBase::engineGetSampleTime(), -.5f, 0.5f);

    Osc::setFrequency(sinParams, time);

    if (cycleCount == 0) {
    // Get the gain from the envelope generator in
    // eGain = {0 .. 10.0f }
        float eGain = TBase::inputs[ENV_INPUT].active ? TBase::inputs[ENV_INPUT].value : 10.f;
        isExternalAudio = TBase::inputs[AUDIO_INPUT].active;

        const float gainKnobValue = TBase::params[PARAM_EXTGAIN].value;
        const float gainCVValue = TBase::inputs[GAIN_INPUT].value;
        const float gainTrimValue = TBase::params[PARAM_EXTGAIN_TRIM].value;
        const float combinedGain = gainCombiner(gainCVValue, gainKnobValue, gainTrimValue);

        // tapered gain {0 .. 0.5}
        const float taperedGain = .5f * taper(combinedGain);

        // final gain 0..5
        finalGain = taperedGain * eGain;
    }

    float input = finalGain * (isExternalAudio ?
        TBase::inputs[AUDIO_INPUT].value :
        Osc::run(sinState, sinParams));

    checkClipping(input);


    // Now clip or fold to keep in -1...+1
    if (TBase::params[PARAM_FOLD].value > .5) {
        input = AudioMath::fold(input);
    } else {
        input = std::max(input, -1.f);
        input = std::min(input, 1.f);
    }

    return input;
}

/**
 * Desired behavior:
 *      If we clip, led goes red and stays red for clipDuration
 *      if not red, sign present goes green
 *      nothing - turn off
 */
template <class TBase>
inline void CHBg<TBase>::checkClipping(float input)
{
    if (input > 1) {
        // if clipping, go red
        clipCount = clipDuration;
        TBase::lights[GAIN_RED_LIGHT].value = 10;
        TBase::lights[GAIN_GREEN_LIGHT].value = 0;
    } else if (clipCount) {
        // If red,run down the clock
        clipCount--;
        if (clipCount <= 0) {
            TBase::lights[GAIN_RED_LIGHT].value = 0;
            TBase::lights[GAIN_GREEN_LIGHT].value = 0;
        }
    } else if (input > .3f) {
        // if signal present
        signalCount = clipDuration;
        TBase::lights[GAIN_GREEN_LIGHT].value = 10;
    } else if (signalCount) {
        signalCount--;
        if (signalCount <= 0) {
            TBase::lights[GAIN_GREEN_LIGHT].value = 0;
        }
    }
}

template <class TBase>
inline void CHBg<TBase>::calcVolumes(float * volumes)
{
    // first get the harmonics knobs, and scale them
    for (int i = 0; i < numHarmonics; ++i) {
        float val = taper(TBase::params[i + PARAM_H0].value);       // apply taper to the knobs

        // If input connected, scale and multiply with knob value
        if (TBase::inputs[i + H0_INPUT].active) {
            const float inputCV = TBase::inputs[i + H0_INPUT].value * .1f;
            val *= std::max(inputCV, 0.f);
        }

        volumes[i] = val;
    }

    // Second: apply the even and odd knobs
    {
        const float even = taper(TBase::params[PARAM_MAG_EVEN].value);
        const float odd = taper(TBase::params[PARAM_MAG_ODD].value);
        for (int i = 1; i < polyOrder; ++i) {
            const float mul = (i & 1) ? even : odd;     // 0 = fundamental, 1=even, 2=odd....
            volumes[i] *= mul;
        }
    }

    // Third: slope
    {
        const float slope = slopeScale(TBase::params[PARAM_SLOPE].value, TBase::inputs[SLOPE_INPUT].value, 1);

        for (int i = 0; i < polyOrder; ++i) {
            float slopeAttenDb = slope * getOctave(i);
            float slopeAtten = LookupTable<float>::lookup(*db2gain, slopeAttenDb);
            volumes[i] *= slopeAtten;
        }
    }
}

template <class TBase>
inline void CHBg<TBase>::step()
{
    if (economyMode) {
        if (--cycleCount < 0) {
            cycleCount = 3;
        }
    } else {
        cycleCount = 0;
    }

    // do all the processing to get the carrier signal
    const float input = getInput();

    if (cycleCount == 0) {
        calcVolumes(_volume);

        for (int i = 0; i < polyOrder; ++i) {
            poly.setGain(i, _volume[i]);
        }
    }


    float output = poly.run(input, std::min(finalGain, 1.f));
    TBase::outputs[MIX_OUTPUT].value = 5.0f * output;
}