///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2019-2020 Edouard Griffiths, F4EXB <f4exb06@gmail.com>          //
//                                                                               //
// 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 as version 3 of the License, or                  //
// (at your option) any later version.                                           //
//                                                                               //
// This program 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 V3 for more details.                               //
//                                                                               //
// You should have received a copy of the GNU General Public License             //
// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
///////////////////////////////////////////////////////////////////////////////////

#ifndef INCLUDE_INTERFEROMETERCORR_H
#define INCLUDE_INTERFEROMETERCORR_H

#include <complex>
#include <QObject>

#include "dsp/dsptypes.h"
#include "dsp/fftwindow.h"

#include "interferometersettings.h"

class FFTEngine;

class InterferometerCorrelator : public QObject {
  	Q_OBJECT
public:
    InterferometerCorrelator(int fftSize);
    ~InterferometerCorrelator();

    void setCorrType(InterferometerSettings::CorrelationType corrType) { m_corrType = corrType; }
    InterferometerSettings::CorrelationType getCorrType() const { return m_corrType; }
    bool performCorr( //!< Returns true if results were produced
        const SampleVector& data0,
        unsigned int size0,
        const SampleVector& data1,
        unsigned int size1
    );
    int getFullFFTSize() const { return 2*m_fftSize; }
    void setPhase(int phase);

    SampleVector m_scorr; //!< raw correlation result (spectrum) - Sample vector expected
    SampleVector m_tcorr; //!< correlation result (time or spectrum inverse FFT) - Sample vector expected
    int m_processed;      //!< number of samples processed at the end of correlation
    int m_remaining[2];   //!< number of samples remaining per member at the end of correlation

signals:
    void dataReady(int start, int stop);

private:
    bool performOpCorr( //!< Returns true if results were produced
        const SampleVector& data0,
        unsigned int size0,
        const SampleVector& data1,
        unsigned int size1,
        Sample sampleOp(const Sample& a, const Sample& b)
    );
    bool performIFFTCorr( //!< Returns true if results were produced
        const SampleVector& data0,
        unsigned int size0,
        const SampleVector& data1,
        unsigned int size1,
        bool star = false
    );
    bool performIFFT2Corr( //!< Returns true if results were produced
        const SampleVector& data0,
        unsigned int size0,
        const SampleVector& data1,
        unsigned int size1
    );
    bool performFFTProd( //!< Returns true if results were produced
        const SampleVector& data0,
        unsigned int size0,
        const SampleVector& data1,
        unsigned int size1
    );
    void adjustSCorrSize(int size);
    void adjustTCorrSize(int size);

    InterferometerSettings::CorrelationType m_corrType;
    unsigned int m_fftSize;          //!< FFT length
    FFTEngine *m_fft[2];             //!< FFT engines (double FFT)
    FFTEngine *m_invFFT;             //!< Inverse FFT engine (double FFT)
    FFTEngine *m_fft2[2];            //!< FFT engines
    FFTEngine *m_invFFT2;            //!< Inverse FFT engine
    unsigned int m_fftSequences[2];  //!< FFT factory engine sequences
    unsigned int m_invFFTSequence;   //!< Inverse FFT engine sequence
    unsigned int m_fft2Sequences[2]; //!< FFT engines sequences
    unsigned int m_invFFT2Sequence;  //!< Inverse FFT engine sequence
    FFTWindow m_window;              //!< FFT window
    std::complex<float> *m_dataj;    //!< conjuate of FFT transform
    SampleVector m_data0w;           //!< windowed data 0
    SampleVector m_data1w;           //!< windowed data 1
    SampleVector m_data1p;           //!< data1 with phase correction
    int m_scorrSize;                 //!< spectrum correlations vector size
    int m_tcorrSize;                 //!< time correlations vector size
    int m_phase;   //!< phase correction
    int64_t m_sin; //!< scaled sine of phase correction
    int64_t m_cos; //!< scaled cosine of phase correction
};

#endif // INCLUDE_INTERFEROMETERCORR_H