/* -*- 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 2007-2022 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.
*/

#include "R3StretcherImpl.h"

#include "../common/VectorOpsComplex.h"

#include <array>

namespace RubberBand {

R3StretcherImpl::R3StretcherImpl(Parameters parameters,
                                 double initialTimeRatio,
                                 double initialPitchScale) :
    m_parameters(parameters),
    m_timeRatio(initialTimeRatio),
    m_pitchScale(initialPitchScale),
    m_guide(Guide::Parameters(m_parameters.sampleRate, parameters.logger)),
    m_guideConfiguration(m_guide.getConfiguration()),
    m_channelAssembly(m_parameters.channels),
    m_troughPicker(m_guideConfiguration.classificationFftSize / 2 + 1),
    m_inhop(1),
    m_prevOuthop(1),
    m_draining(false)
{
    BinSegmenter::Parameters segmenterParameters
        (m_guideConfiguration.classificationFftSize,
         m_parameters.sampleRate);
    BinClassifier::Parameters classifierParameters
        (m_guideConfiguration.classificationFftSize / 2 + 1,
         9, 1, 10, 2.0, 2.0, 1.0e-7);

    int inRingBufferSize = m_guideConfiguration.longestFftSize * 2;
    int outRingBufferSize = m_guideConfiguration.longestFftSize * 16;

    for (int c = 0; c < m_parameters.channels; ++c) {
        m_channelData.push_back(std::make_shared<ChannelData>
                                (segmenterParameters,
                                 classifierParameters,
                                 m_guideConfiguration.longestFftSize,
                                 inRingBufferSize,
                                 outRingBufferSize));
        for (auto band: m_guideConfiguration.fftBandLimits) {
            int fftSize = band.fftSize;
            m_channelData[c]->scales[fftSize] =
                std::make_shared<ChannelScaleData>
                (fftSize, m_guideConfiguration.longestFftSize);
        }
    }
        
    for (auto band: m_guideConfiguration.fftBandLimits) {
        int fftSize = band.fftSize;
        GuidedPhaseAdvance::Parameters guidedParameters
            (fftSize, m_parameters.sampleRate, m_parameters.channels,
             m_parameters.logger);
        m_scaleData[fftSize] = std::make_shared<ScaleData>(guidedParameters);
    }

    m_calculator = std::unique_ptr<StretchCalculator>
        (new StretchCalculator(int(round(m_parameters.sampleRate)), //!!! which is a double...
                               1, false)); // no fixed inputIncrement

    Resampler::Parameters resamplerParameters;
    resamplerParameters.quality = Resampler::FastestTolerable;
    resamplerParameters.dynamism = Resampler::RatioOftenChanging;
    resamplerParameters.ratioChange = Resampler::SmoothRatioChange;
    resamplerParameters.initialSampleRate = m_parameters.sampleRate;
    resamplerParameters.maxBufferSize = m_guideConfiguration.longestFftSize; //!!!???
    m_resampler = std::unique_ptr<Resampler>
        (new Resampler(resamplerParameters, m_parameters.channels));
        
    calculateHop();

    m_prevOuthop = int(round(m_inhop * getEffectiveRatio()));
}

void
R3StretcherImpl::setTimeRatio(double ratio)
{
    m_timeRatio = ratio;
    calculateHop();
}

void
R3StretcherImpl::setPitchScale(double scale)
{
    m_pitchScale = scale;
    calculateHop();
}

void
R3StretcherImpl::calculateHop()
{
    double ratio = getEffectiveRatio();
    double proposedOuthop = 256;
    
    if (ratio > 1.0) {
        double inhop = proposedOuthop / ratio;
        if (inhop < 1.0) {
            m_parameters.logger("WARNING: Extreme ratio yields ideal inhop < 1, results may be suspect");
            m_inhop = 1;
        } else {
            m_inhop = int(round(inhop));
        }
    } else {
        double inhop = std::min(proposedOuthop / ratio, 340.0);
        m_inhop = int(round(inhop));
    }
}

double
R3StretcherImpl::getTimeRatio() const
{
    return m_timeRatio;
}

double
R3StretcherImpl::getPitchScale() const
{
    return m_pitchScale;
}

size_t
R3StretcherImpl::getLatency() const
{
    return 0; //!!!
}

size_t
R3StretcherImpl::getChannelCount() const
{
    return m_parameters.channels;
}

void
R3StretcherImpl::reset()
{
    //!!!
}

size_t
R3StretcherImpl::getSamplesRequired() const
{
    int longest = m_guideConfiguration.longestFftSize;
    size_t rs = m_channelData[0]->inbuf->getReadSpace();
    if (rs < longest) {
        return longest - rs;
    } else {
        return 0;
    }
}

//!!! __attribute__((annotate("realtime")))
void
R3StretcherImpl::process(const float *const *input, size_t samples, bool final)
{
    //!!! todo: final

//!!!    m_parameters.logger("process called");
    if (final) {
//        m_parameters.logger("final = true");
        m_draining = true;
    }
    
    bool allConsumed = false;

    size_t ws = m_channelData[0]->inbuf->getWriteSpace();
    if (samples > ws) {
        //!!! check this
        m_parameters.logger("R3StretcherImpl::process: WARNING: Forced to increase input buffer size. Either setMaxProcessSize was not properly called or process is being called repeatedly without retrieve.");
        size_t newSize = m_channelData[0]->inbuf->getSize() - ws + samples;
        for (int c = 0; c < m_parameters.channels; ++c) {
            m_channelData[c]->inbuf =
                std::unique_ptr<RingBuffer<float>>
                (m_channelData[c]->inbuf->resized(newSize));
        }
    }

    for (int c = 0; c < m_parameters.channels; ++c) {
        m_channelData[c]->inbuf->write(input[c], samples);
    }

    consume();
}

//!!! __attribute__((annotate("realtime")))
int
R3StretcherImpl::available() const
{
//!!!    m_parameters.logger("available called");
    int av = int(m_channelData[0]->outbuf->getReadSpace());
    if (av == 0 && m_draining) return -1;
    else return av;
}

//!!! __attribute__((annotate("realtime")))
size_t
R3StretcherImpl::retrieve(float *const *output, size_t samples) const
{
//!!!    m_parameters.logger("retrieve called");
    size_t got = samples;
    
    for (size_t c = 0; c < m_parameters.channels; ++c) {
        size_t gotHere = m_channelData[c]->outbuf->read(output[c], got);
        if (gotHere < got) {
            if (c > 0) {
                m_parameters.logger("R3StretcherImpl::retrieve: WARNING: channel imbalance detected");
            }
            got = gotHere;
        }
    }

    return got;
}

void
R3StretcherImpl::consume()
{
    double ratio = getEffectiveRatio();
    int longest = m_guideConfiguration.longestFftSize;
    int channels = m_parameters.channels;

    m_calculator->setDebugLevel(3);
    
    int outhop = m_calculator->calculateSingle(ratio,
                                               1.0 / m_pitchScale,
                                               1.f,
                                               m_inhop,
                                               longest,
                                               longest);

    std::cout << "outhop = " << outhop << std::endl;

    while (m_channelData.at(0)->outbuf->getWriteSpace() >= outhop) {

        // NB our ChannelData, ScaleData, and ChannelScaleData maps
        // contain shared_ptrs; whenever we retain one of them in a
        // variable, we do so by reference to avoid copying the
        // shared_ptr (as that is not realtime safe). Same goes for
        // the map iterators

        int readSpace = m_channelData.at(0)->inbuf->getReadSpace();
        if (readSpace < longest) {
            if (m_draining) {
                if (readSpace == 0) {
                    break;
                }
            } else {
                break;
            }
        }

        // Analysis
        
        for (int c = 0; c < channels; ++c) {
            analyseChannel(c, m_prevOuthop);
        }

        // Phase update. This is synchronised across all channels
        
        for (auto &it : m_channelData[0]->scales) {
            int fftSize = it.first;
            for (int c = 0; c < channels; ++c) {
                auto &cd = m_channelData.at(c);
                auto &scale = cd->scales.at(fftSize);
                m_channelAssembly.mag[c] = scale->mag.data();
                m_channelAssembly.phase[c] = scale->phase.data();
                m_channelAssembly.guidance[c] = &cd->guidance;
                m_channelAssembly.outPhase[c] = scale->advancedPhase.data();
            }
            m_scaleData.at(fftSize)->guided.advance
                (m_channelAssembly.outPhase.data(),
                 m_channelAssembly.mag.data(),
                 m_channelAssembly.phase.data(),
                 m_guideConfiguration,
                 m_channelAssembly.guidance.data(),
                 m_inhop,
                 outhop);
        }

        // Resynthesis
        
        for (int c = 0; c < channels; ++c) {
            synthesiseChannel(c, outhop);
        }

        // Resample

        int resampledCount = 0;
        if (m_resampler) {
            for (int c = 0; c < channels; ++c) {
                auto &cd = m_channelData.at(c);
                m_channelAssembly.mixdown[c] = cd->mixdown.data();
                m_channelAssembly.resampled[c] = cd->resampled.data();
            }
            resampledCount = m_resampler->resample
                (m_channelAssembly.resampled.data(),
                 m_channelData[0]->resampled.size(),
                 m_channelAssembly.mixdown.data(),
                 outhop,
                 1.0 / m_pitchScale,
                 m_draining && readSpace < longest);
        }

        // Emit

        for (int c = 0; c < channels; ++c) {
            auto &cd = m_channelData.at(c);
            if (m_resampler) {
                cd->outbuf->write(cd->resampled.data(), resampledCount);
            } else {
                cd->outbuf->write(cd->mixdown.data(), outhop);
            }
        
            int readSpace = cd->inbuf->getReadSpace();
            if (readSpace < m_inhop) {
                // This should happen only when draining
                cd->inbuf->skip(readSpace);
            } else {
                cd->inbuf->skip(m_inhop);
            }
        }
    }

    m_prevOuthop = outhop;
}

void
R3StretcherImpl::analyseChannel(int c, int prevOuthop)
{
    int longest = m_guideConfiguration.longestFftSize;
    int classify = m_guideConfiguration.classificationFftSize;

    auto &cd = m_channelData.at(c);
    double *buf = cd->scales.at(longest)->timeDomain.data();

    int readSpace = cd->inbuf->getReadSpace();
    if (readSpace < longest) {
        cd->inbuf->peek(buf, readSpace);
        v_zero(buf + readSpace, longest - readSpace);
    } else {
        cd->inbuf->peek(buf, longest);
    }
    
    // We have a single unwindowed frame at the longest FFT
    // size ("scale"). Populate the shorter FFT sizes from the
    // centre of it, windowing as we copy. The classification
    // scale is handled separately because it has readahead,
    // so skip it here as well as the longest. (In practice
    // this means we are probably only populating one scale)

    for (auto &it: cd->scales) {
        int fftSize = it.first;
        if (fftSize == classify || fftSize == longest) continue;
        int offset = (longest - fftSize) / 2;
        m_scaleData.at(fftSize)->analysisWindow.cut
            (buf + offset, it.second->timeDomain.data());
    }

    // The classification scale has a one-hop readahead (note
    // that inhop is fixed), so populate its current data from
    // the readahead and the readahead from further down the
    // long unwindowed frame.

    auto &classifyScale = cd->scales.at(classify);
    ClassificationReadaheadData &readahead = cd->readahead;

    m_scaleData.at(classify)->analysisWindow.cut
        (buf + (longest - classify) / 2 + m_inhop,
         readahead.timeDomain.data());
            
    // Finally window the longest scale
    m_scaleData.at(longest)->analysisWindow.cut(buf);

    // FFT shift, forward FFT, and carry out cartesian-polar
    // conversion for each FFT size.

    // For the classification scale we need magnitudes for the
    // full range (polar only in a subset) and we operate in
    // the readahead, pulling current values from the existing
    // readahead

    v_fftshift(readahead.timeDomain.data(), classify);

    v_copy(classifyScale->mag.data(),
           readahead.mag.data(),
           classifyScale->bufSize);
            
    v_copy(classifyScale->phase.data(),
           readahead.phase.data(),
           classifyScale->bufSize);

    m_scaleData.at(classify)->fft.forward(readahead.timeDomain.data(),
                                          classifyScale->real.data(),
                                          classifyScale->imag.data());

    for (const auto &b : m_guideConfiguration.fftBandLimits) {
        if (b.fftSize == classify) {
            if (b.b0min > 0) {
                v_cartesian_to_magnitudes(readahead.mag.data(),
                                          classifyScale->real.data(),
                                          classifyScale->imag.data(),
                                          b.b0min);
            }
                    
            v_cartesian_to_polar(readahead.mag.data() + b.b0min,
                                 readahead.phase.data() + b.b0min,
                                 classifyScale->real.data() + b.b0min,
                                 classifyScale->imag.data() + b.b0min,
                                 b.b1max - b.b0min);
                    
            if (b.b1max < classify/2 + 1) {
                v_cartesian_to_magnitudes
                    (readahead.mag.data() + b.b1max,
                     classifyScale->real.data() + b.b1max,
                     classifyScale->imag.data() + b.b1max,
                     classify/2 + 1 - b.b1max);
            }
                    
            v_scale(classifyScale->mag.data(),
                    1.0 / double(classify),
                    classifyScale->mag.size());
            break;
        }
    }

    // For the others we operate directly in the scale data
    // and restrict the range for cartesian-polar conversion
            
    for (auto &it: cd->scales) {
        int fftSize = it.first;
        if (fftSize == classify) continue;
        auto &scale = it.second;

        v_fftshift(scale->timeDomain.data(), fftSize);

        m_scaleData.at(fftSize)->fft.forward(scale->timeDomain.data(),
                                             scale->real.data(),
                                             scale->imag.data());

        //!!! This should be a map
        for (const auto &b : m_guideConfiguration.fftBandLimits) {
            if (b.fftSize == fftSize) {
                v_cartesian_to_polar(scale->mag.data() + b.b0min,
                                     scale->phase.data() + b.b0min,
                                     scale->real.data() + b.b0min,
                                     scale->imag.data() + b.b0min,
                                     b.b1max - b.b0min);
                v_scale(scale->mag.data() + b.b0min,
                        1.0 / double(fftSize),
                        b.b1max - b.b0min);
                break;
            }
        }
    }

    // Use the classification scale to get a bin segmentation
    // and calculate the adaptive frequency guide for this
    // channel
    cd->prevSegmentation = cd->segmentation;
    cd->segmentation = cd->nextSegmentation;
    cd->nextSegmentation = cd->segmenter->segment(readahead.mag.data());

    m_troughPicker.findNearestAndNextPeaks
        (classifyScale->mag.data(), 3, nullptr,
         classifyScale->troughs.data());
            
    double instantaneousRatio = double(prevOuthop) / double(m_inhop);
    m_guide.calculate(instantaneousRatio,
                      classifyScale->mag.data(),
                      classifyScale->troughs.data(),
                      classifyScale->prevMag.data(),
                      cd->segmentation,
                      cd->prevSegmentation,
                      cd->nextSegmentation,
                      cd->guidance);
}

void
R3StretcherImpl::synthesiseChannel(int c, int outhop)
{
    int longest = m_guideConfiguration.longestFftSize;

    auto &cd = m_channelData.at(c);

    for (auto &it : cd->scales) {
        auto &scale = it.second;
        int bufSize = scale->bufSize;
        // copy to prevMag before filtering
        v_copy(scale->prevMag.data(),
               scale->mag.data(),
               bufSize);
    }
        
    for (const auto &band : cd->guidance.fftBands) {
        int fftSize = band.fftSize;
        auto &scale = cd->scales.at(fftSize);
        auto &scaleData = m_scaleData.at(fftSize);

        //!!! messy and slow, but leave it until we've
        //!!! discovered whether we need a window accumulator
        //!!! (we probably do)
        int analysisWindowSize = scaleData->analysisWindow.getSize();
        int synthesisWindowSize = scaleData->synthesisWindow.getSize();
        int offset = (analysisWindowSize - synthesisWindowSize) / 2;
        double winscale = 0.0;
        for (int i = 0; i < synthesisWindowSize; ++i) {
            winscale += scaleData->analysisWindow.getValue(i + offset) *
                scaleData->synthesisWindow.getValue(i);
        }
        winscale = double(outhop) / winscale;

        // The frequency filter is applied naively in the
        // frequency domain. Aliasing is reduced by the
        // shorter resynthesis window
                
        double factor = m_parameters.sampleRate / double(fftSize);
        for (int i = 0; i < fftSize/2 + 1; ++i) {
            double f = double(i) * factor;
            if (f >= band.f0 && f < band.f1) {
                //!!! check the mod 2 bit from stretch-fn
                scale->mag[i] *= winscale;
            } else {
                scale->mag[i] = 0.f;
            }
        }
    }

    // Resynthesise each FFT size (scale) individually, then
    // sum. This is easier to manage scaling for in situations
    // with a varying resynthesis hop
            
    for (auto &it : cd->scales) {
        int fftSize = it.first;
        auto &scale = it.second;
        auto &scaleData = m_scaleData.at(fftSize);
                
        for (const auto &b : m_guideConfiguration.fftBandLimits) {
            if (b.fftSize == fftSize) {
                int offset = b.b0min;
                v_zero(scale->real.data(), fftSize/2 + 1);
                v_zero(scale->imag.data(), fftSize/2 + 1);
                v_polar_to_cartesian
                    (scale->real.data() + offset,
                     scale->imag.data() + offset,
                     scale->mag.data() + offset,
                     scale->advancedPhase.data() + offset,
                     b.b1max - offset);
                break;
            }
        }

        scaleData->fft.inverse(scale->real.data(),
                               scale->imag.data(),
                               scale->timeDomain.data());

        v_fftshift(scale->timeDomain.data(), fftSize);

        // Synthesis window is shorter than analysis window,
        // so copy and cut only from the middle of the
        // time-domain frame; and the accumulator length
        // always matches the longest FFT size, so as to make
        // mixing straightforward, so there is an additional
        // offset needed for the target
                
        int synthesisWindowSize = scaleData->synthesisWindow.getSize();
        int fromOffset = (fftSize - synthesisWindowSize) / 2;
        int toOffset = (longest - synthesisWindowSize) / 2;

        scaleData->synthesisWindow.cutAndAdd
            (scale->timeDomain.data() + fromOffset,
             scale->accumulator.data() + toOffset);
    }

    // Mix this channel and move the accumulator along
            
    float *mixptr = cd->mixdown.data();
    v_zero(mixptr, outhop);

    for (auto &it : cd->scales) {
        auto &scale = it.second;

        double *accptr = scale->accumulator.data();
        for (int i = 0; i < outhop; ++i) {
            mixptr[i] += float(accptr[i]);
        }

        int n = scale->accumulator.size() - outhop;
        v_move(accptr, accptr + outhop, n);
        v_zero(accptr + n, outhop);
    }
}

}