package panako

import "C"
import (
	"git.gammaspectra.live/S.O.N.G/Hibiki/cgo"
	"git.gammaspectra.live/S.O.N.G/Hibiki/utilities"
	"git.gammaspectra.live/S.O.N.G/Kirika/audio"
	"git.gammaspectra.live/S.O.N.G/goborator"
	"runtime"
	"unsafe"
)

type EventPointProcessor struct {
	audio.Sink
	instance        *Instance
	magnitudes      [][]float32
	maxMagnitudes   [][]float32
	magnitudesIndex int

	previousMaxMagnitudes map[int][]float32
	previousMagnitudes    map[int][]float32

	eventPoints  []EventPoint
	fingerprints []Fingerprint

	analysisFrameIndex           int
	maxFilterVertical            *cgo.LemireMaxClampedFilter
	maxFilterWindowSizeFrequency int
	maxFilterWindowSizeTime      int
	maxHorizontal                []float32
	bandNumber                   int
	gaborator                    *goborator.Gaborator
	pinner                       runtime.Pinner
}

func NewEventPointProcessor(instance *Instance) (*EventPointProcessor, error) {
	ob := &EventPointProcessor{
		instance:                     instance,
		magnitudesIndex:              0,
		previousMaxMagnitudes:        make(map[int][]float32),
		previousMagnitudes:           make(map[int][]float32),
		analysisFrameIndex:           0,
		maxFilterWindowSizeFrequency: instance.PointFilterMaximumFrequencyFilterSize,
		maxFilterWindowSizeTime:      instance.PointFilterMaximumTimeFilterSize,
		eventPoints:                  make([]EventPoint, 0, 8196),
		fingerprints:                 make([]Fingerprint, 0, 8196),
	}

	ob.gaborator = goborator.NewGaborator(
		instance.BlockSize,
		float64(instance.SampleRate),
		instance.GetTransformBandsPerOctave(),
		float64(instance.GetTransformMinimumFrequency()),
		float64(instance.GetTransformMaximumFrequency()),
		float64(instance.GetTransformReferenceFrequency()),
		instance.GetTransformTimeResolutionInSamples(),
	)

	ob.bandNumber = ob.gaborator.GetNumberOfBands()

	ob.magnitudes = make([][]float32, ob.maxFilterWindowSizeTime)

	ob.maxMagnitudes = make([][]float32, ob.maxFilterWindowSizeTime)
	for i := range ob.maxMagnitudes {
		ob.maxMagnitudes[i] = make([]float32, ob.bandNumber)
		ob.pinner.Pin(unsafe.SliceData(ob.maxMagnitudes[i]))
	}

	ob.maxHorizontal = make([]float32, ob.bandNumber)

	var err error
	ob.maxFilterVertical, err = cgo.NewLemireMaxClampedFilter(ob.maxFilterWindowSizeFrequency, ob.bandNumber)
	if err != nil {
		return nil, err
	}

	return ob, nil
}

func (e *EventPointProcessor) GetMagnitudes() []float32 {
	return e.magnitudes[e.magnitudesIndex]
}

func (e *EventPointProcessor) GetFingerprints() []Fingerprint {
	return e.fingerprints
}

func (e *EventPointProcessor) GetEventPoints() []EventPoint {
	return e.eventPoints
}

func (e *EventPointProcessor) Process(source audio.Source) error {
	return e.ProcessBlockChannel(source.ToFloat32().GetBlocks())
}

func (e *EventPointProcessor) ProcessBlockChannel(channel chan []float32) error {
	err := e.gaborator.GaborBlockTransform(channel, e.processResult)
	if err != nil {
		return err
	}
	e.processResultFinish()
	return nil
}

func (e *EventPointProcessor) ProcessingFinished() {
	e.gaborator.ProcessingFinished()
	if e.maxFilterVertical != nil {
		e.maxFilterVertical.Close()
		e.maxFilterVertical = nil
	}
	e.pinner.Unpin()
}

func (e *EventPointProcessor) GetLatency() int64 {
	return e.gaborator.GetLatency()
}

func (e *EventPointProcessor) processResult(currentMagnitudes []float32) {
	e.magnitudes[e.magnitudesIndex] = currentMagnitudes

	//store the frame magnitudes

	e.previousMagnitudes[e.analysisFrameIndex] = e.magnitudes[e.magnitudesIndex]
	e.pinner.Pin(unsafe.SliceData(e.magnitudes[e.magnitudesIndex]))

	//run a max filter over frequency bins
	e.maxFilterVertical.Filter(e.magnitudes[e.magnitudesIndex], e.maxMagnitudes[e.magnitudesIndex])
	//store the max filtered frequency bins
	e.previousMaxMagnitudes[e.analysisFrameIndex] = e.maxMagnitudes[e.magnitudesIndex]

	//find the horizontal maxima
	if len(e.previousMaxMagnitudes) == e.maxFilterWindowSizeTime {
		time := e.analysisFrameIndex - e.maxFilterWindowSizeTime/2

		maxFrame := e.previousMaxMagnitudes[time]
		frameMagnitudes := e.previousMagnitudes[time]

		for frequency := 2; frequency < len(frameMagnitudes)-1; frequency++ {
			maxVal := maxFrame[frequency]
			currentVal := frameMagnitudes[frequency]

			if maxVal == currentVal && currentVal != 0 {
				e.horizontalFilter(frequency)
				maxVal = e.maxHorizontal[frequency]
				if currentVal == maxVal {
					prevFrameMagnitudes := e.previousMagnitudes[time-1]
					nextFrameMagnitudes := e.previousMagnitudes[time+1]

					//add the magnitude of surrounding bins for magnitude estimates more robust against discretization effects
					totalMagnitude := frameMagnitudes[frequency] + prevFrameMagnitudes[frequency] + nextFrameMagnitudes[frequency] +
						frameMagnitudes[frequency+1] + prevFrameMagnitudes[frequency+1] + nextFrameMagnitudes[frequency+1] +
						frameMagnitudes[frequency-1] + prevFrameMagnitudes[frequency-1] + nextFrameMagnitudes[frequency-1]

					e.eventPoints = append(e.eventPoints, EventPoint{
						Time:      uint32(time),
						Frequency: uint32(frequency),
						Magnitude: totalMagnitude,
					})
				}
			}
		}

		//Remove analysis frames that are not needed any more:
		ix := e.analysisFrameIndex - e.maxFilterWindowSizeTime + 1
		delete(e.previousMaxMagnitudes, ix)
		delete(e.previousMagnitudes, ix)
	}

	//magnitude index counter
	e.magnitudesIndex++
	if e.magnitudesIndex == len(e.magnitudes) {
		e.magnitudesIndex = 0
	}

	//Increment analysis frame counter
	e.analysisFrameIndex++
}

func (e *EventPointProcessor) processResultFinish() {
	e.packEventPointsIntoFingerprints()
	e.ProcessingFinished()
}

func (e *EventPointProcessor) horizontalFilter(j int) {
	e.maxHorizontal[j] = -1000

	centerFrameIndex := e.analysisFrameIndex - e.maxFilterWindowSizeTime/2
	startFrameIndex := centerFrameIndex - e.maxFilterWindowSizeTime/2
	stopFrameIndex := centerFrameIndex + e.maxFilterWindowSizeTime/2

	// Run a horizontal max filter
	for i := startFrameIndex; i < stopFrameIndex; i++ {
		maxFrame := e.previousMaxMagnitudes[i]
		if maxFrame[j] > e.maxHorizontal[j] {
			e.maxHorizontal[j] = maxFrame[j]
		}
	}
}

func (e *EventPointProcessor) packEventPointsIntoFingerprints() {
	minFreqDistance := int64(e.instance.PointFilterMinimumFrequencyDistance)
	maxFreqDistance := int64(e.instance.PointFilterMaximumFrequencyDistance)

	minTimeDistance := int64(e.instance.PointFilterMinimumTimeDistance)
	maxTimeDistance := int64(e.instance.PointFilterMaximumTimeDistance)

	for i := range e.eventPoints {
		p1 := &e.eventPoints[i]

		index2 := i + 1
		for j := range e.eventPoints[index2:] {
			p2 := &e.eventPoints[j]

			fDiff := utilities.AbsInt64(int64(p1.Frequency) - int64(p2.Frequency))
			tDiff := int64(p2.Time) - int64(p1.Time)

			if tDiff > maxTimeDistance {
				break
			}
			if tDiff < minTimeDistance {
				continue
			}

			if fDiff < minFreqDistance {
				continue
			}
			if fDiff > maxFreqDistance {
				continue
			}
			index3 := index2 + j + 1

			for k := range e.eventPoints[index3:] {
				p3 := &e.eventPoints[k]
				fDiff = utilities.AbsInt64(int64(p2.Frequency) - int64(p3.Frequency))
				tDiff = int64(p3.Time) - int64(p2.Time)

				if tDiff > maxTimeDistance {
					break
				}
				if tDiff < minTimeDistance {
					continue
				}

				if fDiff < minFreqDistance {
					continue
				}
				if fDiff > maxFreqDistance {
					continue
				}

				e.fingerprints = append(e.fingerprints, NewFingerprint(p1, p2, p3))
			}
		}
	}
}