fix: align subsonic artist and album response shapes

internal/subsonic/service.go

@@ -1,7 +1,10 @@
 package subsonic
 
 import (
+	"sort"
+	"strings"
 	"time"
+	"unicode"
 
 	"github.com/benya/temporserv/internal/library"
 	"github.com/benya/temporserv/internal/playlist"
@@ -18,7 +21,7 @@ type Response struct {
 	Type          string         `json:"type"`
 	Server        string         `json:"serverVersion"`
 	OpenAPI       bool           `json:"openSubsonic"`
-	Artists       []ArtistRef    `json:"artists,omitempty"`
+	Artists       *Artists       `json:"artists,omitempty"`
 	Artist        *ArtistFull    `json:"artist,omitempty"`
 	Album         *AlbumFull     `json:"album,omitempty"`
 	AlbumList2    *AlbumList2    `json:"albumList2,omitempty"`
@@ -42,6 +45,15 @@ type ArtistRef struct {
 	Name string `json:"name"`
 }
 
+type Artists struct {
+	Index []ArtistIndex `json:"index,omitempty"`
+}
+
+type ArtistIndex struct {
+	Name   string      `json:"name"`
+	Artist []ArtistRef `json:"artist,omitempty"`
+}
+
 type SongRef struct {
 	ID       string `json:"id"`
 	Title    string `json:"title"`
@@ -62,10 +74,11 @@ type ArtistFull struct {
 
 type AlbumRef struct {
 	ID       string `json:"id"`
-	Name     string `json:"name"`
+	Title    string `json:"title"`
 	Artist   string `json:"artist"`
 	ArtistID string `json:"artistId"`
 	Year     int    `json:"year,omitempty"`
+	Genre    string `json:"genre,omitempty"`
 	CoverArt string `json:"coverArt,omitempty"`
 }
 
@@ -194,12 +207,34 @@ func PingResponse() Envelope {
 
 func ArtistsResponse(artists []library.Artist) Envelope {
 	response := PingResponse()
+	groups := map[string][]ArtistRef{}
 	for _, artist := range artists {
-		response.SubsonicResponse.Artists = append(response.SubsonicResponse.Artists, ArtistRef{
+		initial := "#"
+		name := []rune(strings.TrimSpace(artist.Name))
+		if len(name) > 0 {
+			first := unicode.ToUpper(name[0])
+			if unicode.IsLetter(first) {
+				initial = string(first)
+			}
+		}
+		groups[initial] = append(groups[initial], ArtistRef{
 			ID:   artist.ID,
 			Name: artist.Name,
 		})
 	}
+	keys := make([]string, 0, len(groups))
+	for key := range groups {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	payload := &Artists{}
+	for _, key := range keys {
+		payload.Index = append(payload.Index, ArtistIndex{
+			Name:   key,
+			Artist: groups[key],
+		})
+	}
+	response.SubsonicResponse.Artists = payload
 	return response
 }
 
@@ -230,10 +265,11 @@ func ArtistResponse(artist library.ArtistDetail) Envelope {
 	for _, album := range artist.Albums {
 		item.Albums = append(item.Albums, AlbumRef{
 			ID:       album.ID,
-			Name:     album.Title,
+			Title:    album.Title,
 			Artist:   album.ArtistName,
 			ArtistID: album.ArtistID,
 			Year:     album.Year,
+			Genre:    album.Genre,
 			CoverArt: album.CoverArtID,
 		})
 	}
@@ -253,10 +289,11 @@ func Search3Response(results library.SearchResults) Envelope {
 	for _, album := range results.Albums {
 		payload.Album = append(payload.Album, AlbumRef{
 			ID:       album.ID,
-			Name:     album.Title,
+			Title:    album.Title,
 			Artist:   album.ArtistName,
 			ArtistID: album.ArtistID,
 			Year:     album.Year,
+			Genre:    album.Genre,
 			CoverArt: album.CoverArtID,
 		})
 	}
@@ -287,10 +324,11 @@ func Starred2Response(results library.StarredResults) Envelope {
 	for _, album := range results.Albums {
 		payload.Album = append(payload.Album, AlbumRef{
 			ID:       album.ID,
-			Name:     album.Title,
+			Title:    album.Title,
 			Artist:   album.ArtistName,
 			ArtistID: album.ArtistID,
 			Year:     album.Year,
+			Genre:    album.Genre,
 			CoverArt: album.CoverArtID,
 		})
 	}
@@ -384,10 +422,11 @@ func AlbumList2Response(albums []library.Album) Envelope {
 	for _, album := range albums {
 		payload.Album = append(payload.Album, AlbumRef{
 			ID:       album.ID,
-			Name:     album.Title,
+			Title:    album.Title,
 			Artist:   album.ArtistName,
 			ArtistID: album.ArtistID,
 			Year:     album.Year,
+			Genre:    album.Genre,
 			CoverArt: album.CoverArtID,
 		})
 	}