package main

import "fmt"

type AudioBuffer struct {
	Buffer []int16
}

type Sink[O any] interface {
	Chain(O)
}

type Src[O any] interface {
	LinkTo(Sink[O])
}

type Filter[I, O any] interface {
	Sink[I]
	Src[O]
}

type TypePreservingFilter[IO any] interface {
	Filter[IO, IO]
}

type PipelineElement[O any] struct {
	chain func(O)
}

func (e *PipelineElement[O]) LinkTo(sink Sink[O]) {
	e.chain = sink.Chain
}

type IdentityFilter[IO any] struct {
	PipelineElement[IO] // value embedding
}

func (f *IdentityFilter[IO]) Chain(data IO) {}

type MonoConverter struct {
	PipelineElement[*AudioBuffer] // value embedding
}

func (r *MonoConverter) Chain(ab *AudioBuffer) {}

type Resampler struct {
	PipelineElement[*AudioBuffer] // value embedding
}

func (r *Resampler) Chain(ab *AudioBuffer) {}

func NewOptionalFilter[IO any]() TypePreservingFilter[IO] {
	return &IdentityFilter[IO]{}
}

func main() {
	isMono := true
	sampleRate := 48000
	apiSampleRate := 16000

	monoConverter := NewOptionalFilter[*AudioBuffer]()
	if !isMono { // dead branch
		monoConverter = &MonoConverter{}
	}

	resampler := NewOptionalFilter[*AudioBuffer]()
	if sampleRate != apiSampleRate { // taken branch
		resampler = &Resampler{}
	}

	fmt.Printf("monoConverter: %T\n", monoConverter)
	fmt.Printf("resampler:     %T\n", resampler)

	monoConverter.LinkTo(resampler) // panics
	fmt.Println("OK")
}