// Fetch returns a group from the collection with the given path.
func (l *Library) Fetch(c index.Collection, path []string) (group, error) {
if len(path) == 0 {
return build(c, index.Key("Root")), nil
}
var g index.Group = c
k := index.Key(path[0])
g = c.Get(k)
if g == nil {
return group{}, fmt.Errorf("invalid path: near '%v'", path[0])
}
index.Sort(g.Tracks(), index.MultiSort(index.SortByInt("DiscNumber"), index.SortByInt("TrackNumber")))
g = index.Transform(g, index.SplitList("Artist", "AlbumArtist", "Composer"))
c = index.Collect(g, index.ByPrefix("Name"))
g = index.SubTransform(c, index.TrimEnumPrefix)
g = index.SumGroupIntAttr("TotalTime", g)
commonFields := []attr.Interface{
attr.String("Album"),
attr.Strings("Artist"),
attr.Strings("AlbumArtist"),
attr.Strings("Composer"),
attr.Int("Year"),
attr.Int("BitRate"),
attr.Int("DiscNumber"),
}
g = index.CommonGroupAttr(commonFields, g)
g = index.RemoveEmptyCollections(g)
for i, p := range path[1:] {
var ok bool
c, ok = g.(index.Collection)
if !ok {
return group{}, fmt.Errorf("retrieved Group is not a Collection")
}
k = index.Key(p)
g = c.Get(k)
if g == nil {
return group{}, fmt.Errorf("invalid path near '%v'", path[1:][i])
}
if _, ok = g.(index.Collection); !ok {
if i == len(path[1:])-1 {
break
}
return group{}, fmt.Errorf("retrieved Group isn't a Collection: %v", p)
}
}
if g == nil {
return group{}, fmt.Errorf("could not find group")
}
g = index.FirstTrackAttr(attr.String("ID"), g)
return build(g, k), nil
}
func buildCollection(h group, c index.Collection) group {
getField := func(f string, g index.Group, c index.Collection) interface{} {
if StringSliceEqual(g.Field(f), c.Field(f)) {
return nil
}
return g.Field(f)
}
for _, k := range c.Keys() {
g := c.Get(k)
g = index.FirstTrackAttr(attr.Strings("AlbumArtist"), g)
g = index.CommonGroupAttr([]attr.Interface{attr.Strings("Artist")}, g)
h.Groups = append(h.Groups, group{
Name: g.Name(),
Key: k,
AlbumArtist: getField("AlbumArtist", g, c),
Artist: getField("Artist", g, c),
})
}
return h
}
