// License: BSD 3 Clause
// Copyright (C) 2012, Google Inc. All rights reserved.
// Copyright (C) 2015+, The LabSound Authors. All rights reserved.

#ifndef PeriodicWave_h
#define PeriodicWave_h

#include "LabSound/core/AudioArray.h"
#include "LabSound/core/AudioNode.h"

#include <memory>
#include <vector>

namespace lab
{

class PeriodicWave
{
public:
    PeriodicWave(const float sampleRate, OscillatorType basicWaveform);
    PeriodicWave(const float sampleRate, OscillatorType basicWaveform, std::vector<float> & real, std::vector<float> & imag);

    ~PeriodicWave();

    // Returns pointers to the lower and higher wavetable data for the pitch range containing
    // the given fundamental frequency. These two tables are in adjacent "pitch" ranges
    // where the higher table will have the maximum number of partials which won't alias when played back
    // at this fundamental frequency. The lower wavetable is the next range containing fewer partials than the higher wavetable.
    // Interpolation between these two tables can be made according to tableInterpolationFactor.
    // Where values from 0 -> 1 interpolate between lower -> higher.
    void waveDataForFundamentalFrequency(float, float *& lowerWaveData, float *& higherWaveData, float & tableInterpolationFactor);

    // Returns the scalar multiplier to the oscillator frequency to calculate wave table phase increment.
    float rateScale() const { return m_rateScale; }

    unsigned periodicWaveSize() const;

private:
    void generateBasicWaveform(OscillatorType);

    int m_numberOfRanges;
    float m_centsPerRange;

    // The lowest frequency (in Hertz) where playback will include all of the partials.
    // Playing back lower than this frequency will gradually lose more high-frequency information.
    // This frequency is quite low (~10Hz @ 44.1KHz)
    float m_lowestFundamentalFrequency;
    float m_sampleRate;
    float m_rateScale;

    int numberOfRanges() const { return m_numberOfRanges; }

    // Maximum possible number of partials (before culling).
    int maxNumberOfPartials() const;

    int numberOfPartialsForRange(int rangeIndex) const;

    // Creates tables based on numberOfComponents Fourier coefficients.
    void createBandLimitedTables(const float * real, const float * imag, int numberOfComponents);

    std::vector<std::unique_ptr<AudioFloatArray>> m_bandLimitedTables;
};

}  // namespace lab

#endif  // PeriodicWave_h