package main

import (
	"io"
	"log"
	"os"

	"github.com/kkdai/youtube/v2"
)

const ItagM4AAudio = 140

func main() {
	var client youtube.Client

	videoID := "s_oJYdRlrv0"

	video, err := client.GetVideo(videoID)
	if err != nil {
		log.Fatal(err)
	}

	format := video.Formats.FindByItag(ItagM4AAudio)
	stream, _, err := client.GetStream(video, format)
	if err != nil {
		log.Fatal(err)
	}

	file, err := os.Create("out.m4a")
	if err != nil {
		log.Fatal(err)
	}

	defer file.Close()

	_, err = io.Copy(file, stream)

	if err != nil {
		log.Fatal(err)
	}

	log.Println("done")
}