feat(server): expose main credit stat to reflect only album artist | artist credit (#4268)

* attempt using artist | albumartist

* add primary stats, expose to ND and Subsonic

* response to feedback (1)

* address feedback part 1

* fix docs and artist show

* fix migration order

---------

Co-authored-by: Deluan Quintão <deluan@navidrome.org>

db/migrations/20250701010106_add_participant_stats_to_all_artists.sql

@@ -0,0 +1,65 @@
+-- +goose Up
+-- +goose StatementBegin
+WITH artist_role_counters AS (
+    SELECT jt.atom AS artist_id,
+            substr(
+                    replace(jt.path, '$.', ''),
+                    1,
+                    CASE WHEN instr(replace(jt.path, '$.', ''), '[') > 0
+                            THEN instr(replace(jt.path, '$.', ''), '[') - 1
+                        ELSE length(replace(jt.path, '$.', ''))
+                        END
+            ) AS role,
+            count(DISTINCT mf.album_id) AS album_count,
+            count(mf.id) AS count,
+            sum(mf.size) AS size
+    FROM media_file mf
+    JOIN json_tree(mf.participants) jt ON jt.key = 'id' AND jt.atom IS NOT NULL
+    GROUP BY jt.atom, role
+),
+artist_total_counters AS (
+    SELECT mfa.artist_id,
+            'total' AS role,
+            count(DISTINCT mf.album_id) AS album_count,
+            count(DISTINCT mf.id) AS count,
+            sum(mf.size) AS size
+    FROM media_file_artists mfa
+    JOIN media_file mf ON mfa.media_file_id = mf.id
+    GROUP BY mfa.artist_id
+),
+artist_participant_counter AS (
+    SELECT mfa.artist_id,
+        'maincredit' AS role,
+        count(DISTINCT mf.album_id) AS album_count,
+        count(DISTINCT mf.id) AS count,
+        sum(mf.size) AS size
+    FROM media_file_artists mfa
+    JOIN media_file mf ON mfa.media_file_id = mf.id
+    AND mfa.role IN ('albumartist', 'artist')
+    GROUP BY mfa.artist_id
+),
+combined_counters AS (
+    SELECT artist_id, role, album_count, count, size FROM artist_role_counters
+    UNION
+    SELECT artist_id, role, album_count, count, size FROM artist_total_counters
+    UNION
+    SELECT artist_id, role, album_count, count, size FROM artist_participant_counter
+),
+artist_counters AS (
+    SELECT artist_id AS id,
+            json_group_object(
+                    replace(role, '"', ''),
+                    json_object('a', album_count, 'm', count, 's', size)
+            ) AS counters
+    FROM combined_counters
+    GROUP BY artist_id
+)
+UPDATE artist
+SET stats = coalesce((SELECT counters FROM artist_counters ac WHERE ac.id = artist.id), '{}'),
+    updated_at = datetime(current_timestamp, 'localtime')
+WHERE artist.id <> '';
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+-- +goose StatementEnd

model/participants.go

@@ -25,6 +25,8 @@ var (
 	RoleRemixer     = Role{"remixer"}
 	RoleDJMixer     = Role{"djmixer"}
 	RolePerformer   = Role{"performer"}
+	// RoleMainCredit is a credit where the artist is an album artist or artist
+	RoleMainCredit = Role{"maincredit"}
 )
 
 var AllRoles = map[string]Role{
@@ -41,6 +43,7 @@ var AllRoles = map[string]Role{
 	RoleRemixer.role:     RoleRemixer,
 	RoleDJMixer.role:     RoleDJMixer,
 	RolePerformer.role:   RolePerformer,
+	RoleMainCredit.role:  RoleMainCredit,
 }
 
 // Role represents the role of an artist in a track or album.

persistence/artist_repository.go

@@ -124,6 +124,11 @@ func NewArtistRepository(ctx context.Context, db dbx.Builder) model.ArtistReposi
 		"song_count":  "stats->>'total'->>'m'",
 		"album_count": "stats->>'total'->>'a'",
 		"size":        "stats->>'total'->>'s'",
+
+		// Stats by credits that are currently available
+		"maincredit_song_count":  "stats->>'maincredit'->>'m'",
+		"maincredit_album_count": "stats->>'maincredit'->>'a'",
+		"maincredit_size":        "stats->>'maincredit'->>'a'",
 	})
 	return r
 }
@@ -348,13 +353,27 @@ func (r *artistRepository) RefreshStats(allArtists bool) (int64, error) {
                sum(mf.size) AS size
         FROM media_file_artists mfa
         JOIN media_file mf ON mfa.media_file_id = mf.id
-        WHERE mfa.artist_id IN (TOTAL_IDS_PLACEHOLDER) -- Will replace with actual placeholders
+        WHERE mfa.artist_id IN (ROLE_IDS_PLACEHOLDER) -- Will replace with actual placeholders
+        GROUP BY mfa.artist_id
+    ),
+    artist_participant_counter AS (
+        SELECT mfa.artist_id,
+            'maincredit' AS role,
+            count(DISTINCT mf.album_id) AS album_count,
+            count(DISTINCT mf.id) AS count,
+            sum(mf.size) AS size
+        FROM media_file_artists mfa
+        JOIN media_file mf ON mfa.media_file_id = mf.id
+        WHERE mfa.artist_id IN (ROLE_IDS_PLACEHOLDER) -- Will replace with actual placeholders
+        AND mfa.role IN ('albumartist', 'artist')
         GROUP BY mfa.artist_id
     ),
     combined_counters AS (
         SELECT artist_id, role, album_count, count, size FROM artist_role_counters
         UNION
         SELECT artist_id, role, album_count, count, size FROM artist_total_counters
+        UNION
+        SELECT artist_id, role, album_count, count, size FROM artist_participant_counter
     ),
     artist_counters AS (
         SELECT artist_id AS id,
@@ -368,7 +387,7 @@ func (r *artistRepository) RefreshStats(allArtists bool) (int64, error) {
     UPDATE artist
     SET stats = coalesce((SELECT counters FROM artist_counters ac WHERE ac.id = artist.id), '{}'),
        updated_at = datetime(current_timestamp, 'localtime')
-    WHERE artist.id IN (UPDATE_IDS_PLACEHOLDER) AND artist.id <> '';` // Will replace with actual placeholders
+    WHERE artist.id IN (ROLE_IDS_PLACEHOLDER) AND artist.id <> '';` // Will replace with actual placeholders
 
 	var totalRowsAffected int64 = 0
 	const batchSize = 1000
@@ -387,21 +406,16 @@ func (r *artistRepository) RefreshStats(allArtists bool) (int64, error) {
 		inClause := strings.Join(placeholders, ",")
 
 		// Replace the placeholder markers with actual SQL placeholders
-		batchSQL := strings.Replace(batchUpdateStatsSQL, "ROLE_IDS_PLACEHOLDER", inClause, 1)
+		batchSQL := strings.Replace(batchUpdateStatsSQL, "ROLE_IDS_PLACEHOLDER", inClause, 4)
-		batchSQL = strings.Replace(batchSQL, "TOTAL_IDS_PLACEHOLDER", inClause, 1)
-		batchSQL = strings.Replace(batchSQL, "UPDATE_IDS_PLACEHOLDER", inClause, 1)
 
-		// Create a single parameter array with all IDs (repeated 3 times for each IN clause)
+		// Create a single parameter array with all IDs (repeated 4 times for each IN clause)
-		// We need to repeat each ID 3 times (once for each IN clause)
+		// We need to repeat each ID 4 times (once for each IN clause)
-		var args []interface{}
+		args := make([]any, 4*len(artistIDBatch))
-		for _, id := range artistIDBatch {
+		for idx, id := range artistIDBatch {
-			args = append(args, id) // For ROLE_IDS_PLACEHOLDER
+			for i := range 4 {
-		}
+				startIdx := i * len(artistIDBatch)
-		for _, id := range artistIDBatch {
+				args[startIdx+idx] = id
-			args = append(args, id) // For TOTAL_IDS_PLACEHOLDER
+			}
-		}
-		for _, id := range artistIDBatch {
-			args = append(args, id) // For UPDATE_IDS_PLACEHOLDER
 		}
 
 		// Now use Expr with the expanded SQL and all parameters

server/subsonic/browsing.go

@@ -397,7 +397,7 @@ func (api *Router) buildArtistDirectory(ctx context.Context, artist *model.Artis
 	if artist.PlayCount > 0 {
 		dir.Played = artist.PlayDate
 	}
-	dir.AlbumCount = int32(artist.AlbumCount)
+	dir.AlbumCount = getArtistAlbumCount(artist)
 	dir.UserRating = int32(artist.Rating)
 	if artist.Starred {
 		dir.Starred = artist.StarredAt

server/subsonic/helpers.go

@@ -77,18 +77,16 @@ func sortName(sortName, orderName string) string {
 	return orderName
 }
 
-func getArtistAlbumCount(a model.Artist) int32 {
+func getArtistAlbumCount(a *model.Artist) int32 {
-	albumStats := a.Stats[model.RoleAlbumArtist]
-
 	// If ArtistParticipations are set, then `getArtist` will return albums
-	// where the artist is an album artist OR artist. While it may be an underestimate,
+	// where the artist is an album artist OR artist. Use the custom stat
-	// guess the count by taking a max of the album artist and artist count. This is
+	// main credit for this calculation.
-	// guaranteed to be <= the actual count.
 	// Otherwise, return just the roles as album artist (precise)
 	if conf.Server.Subsonic.ArtistParticipations {
-		artistStats := a.Stats[model.RoleArtist]
+		mainCreditStats := a.Stats[model.RoleMainCredit]
-		return int32(max(artistStats.AlbumCount, albumStats.AlbumCount))
+		return int32(mainCreditStats.AlbumCount)
 	} else {
+		albumStats := a.Stats[model.RoleAlbumArtist]
 		return int32(albumStats.AlbumCount)
 	}
 }
@@ -111,7 +109,7 @@ func toArtistID3(r *http.Request, a model.Artist) responses.ArtistID3 {
 	artist := responses.ArtistID3{
 		Id:             a.ID,
 		Name:           a.Name,
-		AlbumCount:     getArtistAlbumCount(a),
+		AlbumCount:     getArtistAlbumCount(&a),
 		CoverArt:       a.CoverArtID().String(),
 		ArtistImageUrl: public.ImageURL(r, a.CoverArtID(), 600),
 		UserRating:     int32(a.Rating),

server/subsonic/helpers_test.go

@@ -145,7 +145,7 @@ var _ = Describe("helpers", func() {
 				model.RoleAlbumArtist: {
 					AlbumCount: 3,
 				},
-				model.RoleArtist: {
+				model.RoleMainCredit: {
 					AlbumCount: 4,
 				},
 			},
@@ -153,13 +153,13 @@ var _ = Describe("helpers", func() {
 
 		It("Handles album count without artist participations", func() {
 			conf.Server.Subsonic.ArtistParticipations = false
-			result := getArtistAlbumCount(artist)
+			result := getArtistAlbumCount(&artist)
 			Expect(result).To(Equal(int32(3)))
 		})
 
 		It("Handles album count without with participations", func() {
 			conf.Server.Subsonic.ArtistParticipations = true
-			result := getArtistAlbumCount(artist)
+			result := getArtistAlbumCount(&artist)
 			Expect(result).To(Equal(int32(4)))
 		})
 	})

ui/src/artist/ArtistShow.jsx

@@ -96,10 +96,10 @@ const ArtistShowLayout = (props) => {
   let perPage = 0
   let pagination = null
 
-  const count = Math.max(
+  // Use the main credit count instead of total count, as this is a precise measure
-    record?.stats?.['albumartist']?.albumCount || 0,
+  // of the number of albums where the artist is credited as an album artist OR
-    record?.stats?.['artist']?.albumCount ?? 0,
+  // artist
-  )
+  const count = record?.stats?.['maincredit']?.albumCount || 0
 
   if (count > maxPerPage) {
     perPage = Math.trunc(maxPerPage / perPageOptions[0]) * perPageOptions[0]

ui/src/i18n/en.json

@@ -124,7 +124,8 @@
         "mixer": "Mixer |||| Mixers",
         "remixer": "Remixer |||| Remixers",
         "djmixer": "DJ Mixer |||| DJ Mixers",
-        "performer": "Performer |||| Performers"
+        "performer": "Performer |||| Performers",
+        "maincredit": "Album Artist or Artist |||| Album Artists or Artists"
       },
       "actions": {
         "topSongs": "Top Songs",