/***************************************************************************

    source::worx raDIYo
    Copyright © 2020-2022 c.holzheuer
    chris@sourceworx.org

    This program 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 2 of the License, or
    (at your option) any later version.

***************************************************************************/


#ifndef SWFFTCALC_H
#define SWFFTCALC_H

#include <complex>
#include <iostream>
#include <valarray>

#include <QObject>
#include <QThread>
#include <QAudioFormat>
#include <QAudioProbe>
#include <QAudioDeviceInfo>
#include <QElapsedTimer>

#include <raDIYoglobals.h>

// Scale PCM value to [-1.0, 1.0]
qreal xpcmToReal(qint16 pcm);




/**
 * @brief Berechnet mittels FFT ein Spectrum
 * aus dem @see @QAudioBuffer. Das Spectrum wird beim
 * Abspielen eines Songs angezeigt.
 * @see SWSpectrumWidget
 * @see SWPlayerControl
 */

class SWFFTCalc : public QObject
{

    Q_OBJECT

public:

    explicit SWFFTCalc( QObject* parent = nullptr );
    virtual ~SWFFTCalc();

signals:

    void spectrumReady( const SWValVec& spectrum );

public slots:

    void onAudioProbed( const QAudioBuffer& audiobuffer );

protected:

    using Complex = std::complex<double>;
    using CArray  = std::valarray<Complex>;

    void bareFFT( CArray& x );

    static constexpr const int SWNumSamples = 4096;
    const double PI = 3.141592653589793238460;

    // Fudge factor used to calculate the spectrum bar heights
    //const qreal SpectrumAnalyserMultiplier = 0.15;
    const qreal SWFudgeFactor = 0.17;


    int           _bufferDuration = 0;
    QElapsedTimer _timer;
    SWValVec      _frames;
    SWValVec      _hannWindow;
    // überdenken: geht das so schneller?
    // SWValVec _logscale;
    SWValVec     _spectrum;
    CArray       _complexFrame;

};


#endif // SWFFTCALC_H