misc: Move Jellyfin Artist iterator to separate file

backend/mediaprovider/jellyfin/artistiterator.go

@@ -0,0 +1,55 @@
+package jellyfin
+
+import (
+	"github.com/dweymouth/go-jellyfin"
+	"github.com/dweymouth/supersonic/backend/mediaprovider"
+	"github.com/dweymouth/supersonic/backend/mediaprovider/helpers"
+	"github.com/dweymouth/supersonic/sharedutil"
+)
+
+const (
+	ArtistSortNameAZ string = "Name (A-Z)"
+)
+
+func (j *jellyfinMediaProvider) ArtistSortOrders() []string {
+	return []string{
+		ArtistSortNameAZ,
+	}
+}
+
+func (j *jellyfinMediaProvider) IterateArtists(sortOrder string, filter mediaprovider.ArtistFilter) mediaprovider.ArtistIterator {
+	var jfSort jellyfin.Sort
+
+	if sortOrder == "" {
+		sortOrder = ArtistSortNameAZ // default
+	}
+	switch sortOrder {
+	case ArtistSortNameAZ:
+		jfSort.Field = jellyfin.SortByName
+		jfSort.Mode = jellyfin.SortAsc
+	}
+
+	fetcher := func(offs, limit int) ([]*mediaprovider.Artist, error) {
+		ar, err := j.client.GetAlbumArtists(jellyfin.QueryOpts{
+			Sort:   jfSort,
+			Paging: jellyfin.Paging{StartIndex: offs, Limit: limit},
+		})
+		if err != nil {
+			return nil, err
+		}
+		return sharedutil.MapSlice(ar, toArtist), nil
+	}
+
+	return helpers.NewArtistIterator(fetcher, filter, j.prefetchCoverCB)
+}
+
+func (j *jellyfinMediaProvider) SearchArtists(searchQuery string, filter mediaprovider.ArtistFilter) mediaprovider.ArtistIterator {
+	fetcher := func(offs, limit int) ([]*mediaprovider.Artist, error) {
+		sr, err := j.client.Search(searchQuery, jellyfin.TypeArtist, jellyfin.Paging{StartIndex: offs, Limit: limit})
+		if err != nil {
+			return nil, err
+		}
+		return sharedutil.MapSlice(sr.Artists, toArtist), nil
+	}
+	return helpers.NewArtistIterator(fetcher, filter, j.prefetchCoverCB)
+}