config

type Configuration interface {
	FileName() string
	Marshal() ([]byte, error)
	Unmarshal([]byte) error
}

type Library struct {
	Name   string // NOTICE: it's a unique id, it's determined by users or default, not the basename of the dirpath
	Path   string // complete path
	Tracks []Track
}

type LibraryConfiguration struct {
	Libraries []Library
}

type Track struct {
	BaseFile file
	Format   string
	Title    string // unlike filename, title comes from encoded tag info
	Album    string
	Artist   string // or artist list
	Genre    string // or genre list
	Year     string
	Sum      string // sha256 sum of the track, serving as the unique id
}