package main

import (
	"fmt"
	"io/ioutil"
	"os"

	"github.com/bovarysme/adpcm"
	"github.com/go-audio/audio"
	"github.com/go-audio/wav"
	"github.com/pkg/errors"
)

// This program is for compare data size of pcm and adpcm, it takes a wav file and compresses and encodes it to adpcm,
// the adpcm byte array is stored as a file and then the adpcm is decoded and the result saved as final.wav

func main() {
	//open wav
	wavPath := "out.wav"
	f, err := os.Open(wavPath)
	if err != nil {
		panic(err)
	}
	defer f.Close()
	//decode wav
	dec := wav.NewDecoder(f)
	if !dec.IsValidFile() {
		panic(errors.Errorf("invalid WAV file %q", wavPath))
	}
	sampleRate, nchannels, bps := int(dec.SampleRate), int(dec.NumChans), int(dec.BitDepth)
	buf, err := dec.FullPCMBuffer()
	if err != nil {
		panic(err)
	}
	//encode adpcm
	var comp []byte
	adpcm.Encode(buf.Data, &comp)
	// save to file
	pcmPath := "out.adpcm"
	err = ioutil.WriteFile(pcmPath, comp, 0644)
	if err != nil {
		panic(err)
	}
	//decode adpcm
	var decoded []int
	deco := adpcm.NewDecoder(nchannels)
	deco.Decode(comp, &decoded)

	//encode wav and save to file
	finalWavPath := "final.wav"
	of, err := os.Create(finalWavPath)
	if err != nil {
		panic(err)
	}
	defer of.Close()

	sampleBytes := bps / 8

	// normal uncompressed WAV format
	wavformat := 1

	enc := wav.NewEncoder(of, sampleRate, bps, nchannels, wavformat)

	format := &audio.Format{
		NumChannels: nchannels,
		SampleRate:  sampleRate,
	}

	intBuf := &audio.IntBuffer{Data: decoded, Format: format, SourceBitDepth: sampleBytes * 8}

	if err := enc.Write(intBuf); err != nil {
		panic(err)
	}

	if err := enc.Close(); err != nil {
		panic(err)
	}
	fmt.Printf("Saved audio to %s\n", finalWavPath)

}