/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Rubber Band Library
    An audio time-stretching and pitch-shifting library.
    Copyright 2007-2023 Particular Programs Ltd.

    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.  See the file
    COPYING included with this distribution for more information.

    Alternatively, if you have a valid commercial licence for the
    Rubber Band Library obtained by agreement with the copyright
    holders, you may redistribute and/or modify it under the terms
    described in that licence.

    If you wish to distribute code using the Rubber Band Library
    under terms other than those of the GNU General Public License,
    you must obtain a valid commercial licence before doing so.
*/

#ifndef RUBBERBAND_R3_STRETCHERIMPL_H
#define RUBBERBAND_R3_STRETCHERIMPL_H

#include "BinSegmenter.h"
#include "Guide.h"
#include "Peak.h"
#include "PhaseAdvance.h"

#include "../common/StretchCalculator.h"
#include "../common/Resampler.h"
#include "../common/FFT.h"
#include "../common/FixedVector.h"
#include "../common/Allocators.h"
#include "../common/Window.h"
#include "../common/VectorOpsComplex.h"
#include "../common/Log.h"

#include "../../rubberband/RubberBandStretcher.h"

#include <map>
#include <memory>

namespace RubberBand
{

class R3Stretcher
{
public:
    struct Parameters {
        double sampleRate;
        int channels;
        RubberBandStretcher::Options options;
        Parameters(double _sampleRate, int _channels,
                   RubberBandStretcher::Options _options) :
            sampleRate(_sampleRate), channels(_channels), options(_options) { }
    };
    
    R3Stretcher(Parameters parameters,
                double initialTimeRatio,
                double initialPitchScale,
                Log log);
    ~R3Stretcher() { }

    void reset();
    
    void setTimeRatio(double ratio);
    void setPitchScale(double scale);
    void setFormantScale(double scale);

    double getTimeRatio() const;
    double getPitchScale() const;
    double getFormantScale() const;

    void setKeyFrameMap(const std::map<size_t, size_t> &);

    void setFormantOption(RubberBandStretcher::Options);
    void setPitchOption(RubberBandStretcher::Options);
    
    void study(const float *const *input, size_t samples, bool final);
    size_t getSamplesRequired() const;
    void process(const float *const *input, size_t samples, bool final);
    int available() const;
    size_t retrieve(float *const *output, size_t samples) const;

    size_t getPreferredStartPad() const;
    size_t getStartDelay() const;
    
    size_t getChannelCount() const;

    void setExpectedInputDuration(size_t samples);
    void setMaxProcessSize(size_t samples);
    
    void setDebugLevel(int level) {
        m_log.setDebugLevel(level);
        for (auto &sd : m_scaleData) {
            sd.second->guided.setDebugLevel(level);
        }
        m_guide.setDebugLevel(level);
        m_calculator->setDebugLevel(level);
    }

protected:
    struct Limits {
        int minPreferredOuthop;
        int maxPreferredOuthop;
        int minInhop;
        int maxInhopWithReadahead;
        int maxInhop;
        Limits(RubberBandStretcher::Options options, double rate) :
            // commented values are results when rate = 44100 or 48000
            minPreferredOuthop(roundUpDiv(rate, 512)), // 128
            maxPreferredOuthop(roundUpDiv(rate, 128)), // 512
            minInhop(1),
            maxInhopWithReadahead(roundUpDiv(rate, 64)), // 1024
            maxInhop(roundUpDiv(rate, 32)) {             // 2048
            if (options & RubberBandStretcher::OptionWindowShort) {
                // See note in calculateHop
                minPreferredOuthop = roundUpDiv(rate, 256); // 256
                maxPreferredOuthop = (roundUpDiv(rate, 128) * 5) / 4; // 640
                maxInhopWithReadahead = roundUpDiv(rate, 128); // 512
                maxInhop = (roundUpDiv(rate, 64) * 3) / 2; // 1536
            }
        }
    };
    
    struct ClassificationReadaheadData {
        FixedVector<process_t> timeDomain;
        FixedVector<process_t> mag;
        FixedVector<process_t> phase;
        ClassificationReadaheadData(int _fftSize) :
            timeDomain(_fftSize, 0.f),
            mag(_fftSize/2 + 1, 0.f),
            phase(_fftSize/2 + 1, 0.f)
        { }

    private:
        ClassificationReadaheadData(const ClassificationReadaheadData &) =delete;
        ClassificationReadaheadData &operator=(const ClassificationReadaheadData &) =delete;
    };
    
    struct ChannelScaleData {
        int fftSize;
        int bufSize; // size of every freq-domain array here: fftSize/2 + 1
        FixedVector<process_t> timeDomain;
        FixedVector<process_t> real;
        FixedVector<process_t> imag;
        FixedVector<process_t> mag;
        FixedVector<process_t> phase;
        FixedVector<process_t> advancedPhase;
        FixedVector<process_t> prevMag;
        FixedVector<process_t> pendingKick;
        FixedVector<process_t> accumulator;
        int accumulatorFill;

        ChannelScaleData(int _fftSize, int _longestFftSize) :
            fftSize(_fftSize),
            bufSize(fftSize/2 + 1),
            timeDomain(fftSize, 0.f),
            real(bufSize, 0.f),
            imag(bufSize, 0.f),
            mag(bufSize, 0.f),
            phase(bufSize, 0.f),
            advancedPhase(bufSize, 0.f),
            prevMag(bufSize, 0.f),
            pendingKick(bufSize, 0.f),
            accumulator(_longestFftSize, 0.f),
            accumulatorFill(0)
        { }

        void reset() {
            v_zero(prevMag.data(), prevMag.size());
            v_zero(pendingKick.data(), pendingKick.size());
            v_zero(accumulator.data(), accumulator.size());
            accumulatorFill = 0;
        }

    private:
        ChannelScaleData(const ChannelScaleData &) =delete;
        ChannelScaleData &operator=(const ChannelScaleData &) =delete;
    };

    struct FormantData {
        int fftSize;
        FixedVector<process_t> cepstra;
        FixedVector<process_t> envelope;
        FixedVector<process_t> spare;

        FormantData(int _fftSize) :
            fftSize(_fftSize),
            cepstra(_fftSize, 0.0),
            envelope(_fftSize/2 + 1, 0.0),
            spare(_fftSize/2 + 1, 0.0) { }

        process_t envelopeAt(process_t bin) const {
            int b0 = int(floor(bin)), b1 = int(ceil(bin));
            if (b0 < 0 || b0 > fftSize/2) {
                return 0.0;
            } else if (b1 == b0 || b1 > fftSize/2) {
                return envelope.at(b0);
            } else {
                process_t diff = bin - process_t(b0);
                return envelope.at(b0) * (1.0 - diff) + envelope.at(b1) * diff;
            }
        }
    };

    struct ChannelData {
        std::map<int, std::shared_ptr<ChannelScaleData>> scales;
        FixedVector<process_t> windowSource;
        ClassificationReadaheadData readahead;
        bool haveReadahead;
        std::unique_ptr<BinClassifier> classifier;
        FixedVector<BinClassifier::Classification> classification;
        FixedVector<BinClassifier::Classification> nextClassification;
        std::unique_ptr<BinSegmenter> segmenter;
        BinSegmenter::Segmentation segmentation;
        BinSegmenter::Segmentation prevSegmentation;
        BinSegmenter::Segmentation nextSegmentation;
        Guide::Guidance guidance;
        FixedVector<float> mixdown;
        FixedVector<float> resampled;
        std::unique_ptr<RingBuffer<float>> inbuf;
        std::unique_ptr<RingBuffer<float>> outbuf;
        std::unique_ptr<FormantData> formant;
        ChannelData(BinSegmenter::Parameters segmenterParameters,
                    BinClassifier::Parameters classifierParameters,
                    int /*!!! longestFftSize */,
                    int windowSourceSize,
                    int inRingBufferSize,
                    int outRingBufferSize) :
            scales(),
            windowSource(windowSourceSize, 0.0),
            readahead(segmenterParameters.fftSize),
            haveReadahead(false),
            classifier(new BinClassifier(classifierParameters)),
            classification(classifierParameters.binCount,
                           BinClassifier::Classification::Residual),
            nextClassification(classifierParameters.binCount,
                               BinClassifier::Classification::Residual),
            segmenter(new BinSegmenter(segmenterParameters)),
            segmentation(), prevSegmentation(), nextSegmentation(),
            mixdown(inRingBufferSize, 0.f),
            resampled(outRingBufferSize, 0.f),
            inbuf(new RingBuffer<float>(inRingBufferSize)),
            outbuf(new RingBuffer<float>(outRingBufferSize)),
            formant(new FormantData(segmenterParameters.fftSize)) { }
        void reset() {
            haveReadahead = false;
            classifier->reset();
            segmentation = BinSegmenter::Segmentation();
            prevSegmentation = BinSegmenter::Segmentation();
            nextSegmentation = BinSegmenter::Segmentation();
            for (size_t i = 0; i < nextClassification.size(); ++i) {
                nextClassification[i] = BinClassifier::Classification::Residual;
            }
            inbuf->reset();
            outbuf->reset();
            for (auto &s : scales) {
                s.second->reset();
            }
        }
    };

    struct ChannelAssembly {
        // Vectors of bare pointers, used to package container data
        // from different channels into arguments for PhaseAdvance
        FixedVector<const float *> input;
        FixedVector<process_t *> mag;
        FixedVector<process_t *> phase;
        FixedVector<process_t *> prevMag;
        FixedVector<Guide::Guidance *> guidance;
        FixedVector<process_t *> outPhase;
        FixedVector<float *> mixdown;
        FixedVector<float *> resampled;
        ChannelAssembly(int channels) :
            input(channels, nullptr),
            mag(channels, nullptr), phase(channels, nullptr),
            prevMag(channels, nullptr), guidance(channels, nullptr),
            outPhase(channels, nullptr), mixdown(channels, nullptr),
            resampled(channels, nullptr) { }
    };

    struct ScaleData {
        int fftSize;
        bool singleWindowMode;
        FFT fft;
        Window<process_t> analysisWindow;
        Window<process_t> synthesisWindow;
        process_t windowScaleFactor;
        GuidedPhaseAdvance guided;

        ScaleData(GuidedPhaseAdvance::Parameters guidedParameters,
                  Log log) :
            fftSize(guidedParameters.fftSize),
            singleWindowMode(guidedParameters.singleWindowMode),
            fft(fftSize),
            analysisWindow(analysisWindowShape(),
                           analysisWindowLength()),
            synthesisWindow(synthesisWindowShape(),
                            synthesisWindowLength()),
            windowScaleFactor(0.0),
            guided(guidedParameters, log)
        {
            int asz = analysisWindow.getSize(), ssz = synthesisWindow.getSize();
            int off = (asz - ssz) / 2;
            for (int i = 0; i < ssz; ++i) {
                windowScaleFactor += analysisWindow.getValue(i + off) *
                    synthesisWindow.getValue(i);
            }
        }

        WindowType analysisWindowShape();
        int analysisWindowLength();
        WindowType synthesisWindowShape();
        int synthesisWindowLength();
    };
    
    Log m_log;
    Parameters m_parameters;
    const Limits m_limits;

    std::atomic<double> m_timeRatio;
    std::atomic<double> m_pitchScale;
    std::atomic<double> m_formantScale;
    
    std::vector<std::shared_ptr<ChannelData>> m_channelData;
    std::map<int, std::shared_ptr<ScaleData>> m_scaleData;
    Guide m_guide;
    Guide::Configuration m_guideConfiguration;
    ChannelAssembly m_channelAssembly;
    std::unique_ptr<StretchCalculator> m_calculator;
    std::unique_ptr<Resampler> m_resampler;
    bool m_useReadahead;
    std::atomic<int> m_inhop;
    int m_prevInhop;
    int m_prevOuthop;
    uint32_t m_unityCount;
    int m_startSkip;

    size_t m_studyInputDuration;
    size_t m_suppliedInputDuration;
    size_t m_totalTargetDuration;
    size_t m_consumedInputDuration;
    size_t m_lastKeyFrameSurpassed;
    size_t m_totalOutputDuration;
    std::map<size_t, size_t> m_keyFrameMap;
    
    enum class ProcessMode {
        JustCreated,
        Studying,
        Processing,
        Finished
    };
    ProcessMode m_mode;

    void initialise();
    void prepareInput(const float *const *input, int ix, int n);
    void consume();
    void createResampler();
    void calculateHop();
    void updateRatioFromMap();
    void analyseChannel(int channel, int inhop, int prevInhop, int prevOuthop);
    void analyseFormant(int channel);
    void adjustFormant(int channel);
    void adjustPreKick(int channel);
    void synthesiseChannel(int channel, int outhop, bool draining);

    struct ToPolarSpec {
        int magFromBin;
        int magBinCount;
        int polarFromBin;
        int polarBinCount;
    };

    Parameters validateSampleRate(const Parameters &params) {
        Parameters validated { params };
        double minRate = 8000.0, maxRate = 192000.0;
        if (params.sampleRate < minRate) {
            m_log.log(0, "R3Stretcher: WARNING: Unsupported sample rate", params.sampleRate);
            m_log.log(0, "R3Stretcher: Minimum rate is", minRate);
            validated.sampleRate = minRate;
        } else if (params.sampleRate > maxRate) {
            m_log.log(0, "R3Stretcher: WARNING: Unsupported sample rate", params.sampleRate);
            m_log.log(0, "R3Stretcher: Maximum rate is", maxRate);
            validated.sampleRate = maxRate;
        }
        return validated;
    }
    
    void convertToPolar(process_t *mag, process_t *phase,
                        const process_t *real, const process_t *imag,
                        const ToPolarSpec &s) const {
        v_cartesian_to_polar(mag + s.polarFromBin,
                             phase + s.polarFromBin,
                             real + s.polarFromBin,
                             imag + s.polarFromBin,
                             s.polarBinCount);
        if (s.magFromBin < s.polarFromBin) {
            v_cartesian_to_magnitudes(mag + s.magFromBin,
                                      real + s.magFromBin,
                                      imag + s.magFromBin,
                                      s.polarFromBin - s.magFromBin);
        }
        if (s.magFromBin + s.magBinCount > s.polarFromBin + s.polarBinCount) {
            v_cartesian_to_magnitudes(mag + s.polarFromBin + s.polarBinCount,
                                      real + s.polarFromBin + s.polarBinCount,
                                      imag + s.polarFromBin + s.polarBinCount,
                                      s.magFromBin + s.magBinCount -
                                      s.polarFromBin - s.polarBinCount);
        }
    }
    
    double getEffectiveRatio() const {
        return m_timeRatio * m_pitchScale;
    }

    bool isRealTime() const {
        return m_parameters.options &
            RubberBandStretcher::OptionProcessRealTime;
    }

    void areWeResampling(bool *before, bool *after) const {

        if (before) *before = false;
        if (after) *after = false;

        // Some of the logic about when/whether to resample may have
        // already been decided, because we might not have a
        // resampler. This call is for the processing path, we don't
        // make big decisions here and can't be saying we should
        // resample if there is no resampler
        if (!m_resampler) return;

        // In offline mode we always ignore the OptionPitch setting
        // and resample afterwards, like OptionPitchHighConsistency
        // (except that we don't resample for ratio of 1.0). This is
        // because (a) the initial algorithm was developed and tested
        // that way, (b) R2 works that way and nobody has ever
        // complained, and (c) otherwise for the command-line tool
        // (which is probably the most common way to use RB offline)
        // we would have to choose between defaulting to lower-quality
        // OptionPitchHighSpeed or offering yet another setting, both
        // of which are undesirable.
        
        if (!isRealTime()) {
            if (m_pitchScale != 1.0) {
                // Offline, any pitch scale
                if (after) *after = true;
            }
        } else if (m_parameters.options &
                   RubberBandStretcher::OptionPitchHighConsistency) {
            // RT, any pitch scale, HC
            if (after) *after = true;
            
        } else if (m_pitchScale != 1.0) {

            bool hq = (m_parameters.options &
                       RubberBandStretcher::OptionPitchHighQuality);
            // We already handled OptionPitchHighConsistency, so if
            // !hq then we must be HighSpeed
            if (m_pitchScale > 1.0) {
                if (hq) {
                    if (after) *after = true;
                } else {
                    if (before) *before = true;
                }
            } else if (m_pitchScale < 1.0) {
                if (hq) {
                    if (before) *before = true;
                } else {
                    if (after) *after = true;
                }
            }
        }
    }        

    bool useMidSide() const {
        return m_parameters.channels == 2 &&
            (m_parameters.options &
             RubberBandStretcher::OptionChannelsTogether);
    }
    
    bool isSingleWindowed() const {
        return m_parameters.options &
            RubberBandStretcher::OptionWindowShort;
    }

    int getWindowSourceSize() const {
        int sz = m_guideConfiguration.classificationFftSize +
            m_limits.maxInhopWithReadahead;
        if (m_guideConfiguration.longestFftSize > sz) {
            return m_guideConfiguration.longestFftSize;
        } else {
            return sz;
        }
    }
};

}

#endif
