feat(agents): support multiple languages for Last.fm and Deezer metadata (#4952)

* feat(lastfm): support multiple languages for album and artist info retrieval

Signed-off-by: Deluan <deluan@navidrome.org>

* fix(lastfm): improve content validation for album and artist descriptions

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(lastfm): remove single language test and clarify languages field in configuration

Signed-off-by: Deluan <deluan@navidrome.org>

* feat(deezer): support multiple languages for artist bio retrieval

Signed-off-by: Deluan <deluan@navidrome.org>

* refactor(lastfm): rename ignoredBiographies to ignoredContent for clarity

Signed-off-by: Deluan <deluan@navidrome.org>

---------

Signed-off-by: Deluan <deluan@navidrome.org>

adapters/deezer/client.go

@@ -29,14 +29,12 @@ type httpDoer interface {
 
 type client struct {
 	httpDoer httpDoer
-	language string
 	jwt      jwtToken
 }
 
-func newClient(hc httpDoer, language string) *client {
+func newClient(hc httpDoer) *client {
 	return &client{
 		httpDoer: hc,
-		language: language,
 	}
 }
 
@@ -129,7 +127,7 @@ const pipeAPIURL = "https://pipe.deezer.com/api"
 
 var strictPolicy = bluemonday.StrictPolicy()
 
-func (c *client) getArtistBio(ctx context.Context, artistID int) (string, error) {
+func (c *client) getArtistBio(ctx context.Context, artistID int, lang string) (string, error) {
 	jwt, err := c.getJWT(ctx)
 	if err != nil {
 		return "", fmt.Errorf("deezer: failed to get JWT: %w", err)
@@ -160,10 +158,10 @@ func (c *client) getArtistBio(ctx context.Context, artistID int) (string, error)
 	}
 
 	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("Accept-Language", c.language)
+	req.Header.Set("Accept-Language", lang)
 	req.Header.Set("Authorization", "Bearer "+jwt)
 
-	log.Trace(ctx, "Fetching Deezer artist biography via GraphQL", "artistId", artistID, "language", c.language)
+	log.Trace(ctx, "Fetching Deezer artist biography via GraphQL", "artistId", artistID, "language", lang)
 	resp, err := c.httpDoer.Do(req)
 	if err != nil {
 		return "", err

adapters/deezer/client_auth_test.go

@@ -21,7 +21,7 @@ var _ = Describe("JWT Authentication", func() {
 
 	BeforeEach(func() {
 		httpClient = &fakeHttpClient{}
-		client = newClient(httpClient, "en")
+		client = newClient(httpClient)
 		ctx = context.Background()
 	})
 

adapters/deezer/client_test.go

@@ -18,7 +18,7 @@ var _ = Describe("client", func() {
 
 	BeforeEach(func() {
 		httpClient = &fakeHttpClient{}
-		client = newClient(httpClient, "en")
+		client = newClient(httpClient)
 	})
 
 	Describe("ArtistImages", func() {
@@ -78,40 +78,33 @@ var _ = Describe("client", func() {
 		})
 
 		It("returns artist bio from a successful request", func() {
-			f, err := os.Open("tests/fixtures/deezer.artist.bio.json")
+			f, err := os.Open("tests/fixtures/deezer.artist.bio.en.json")
 			Expect(err).To(BeNil())
 			httpClient.mock("https://pipe.deezer.com/api", http.Response{Body: f, StatusCode: 200})
 
-			bio, err := client.getArtistBio(GinkgoT().Context(), 27)
+			bio, err := client.getArtistBio(GinkgoT().Context(), 27, "en")
 			Expect(err).To(BeNil())
 			Expect(bio).To(ContainSubstring("Schoolmates Thomas and Guy-Manuel"))
 			Expect(bio).ToNot(ContainSubstring("<p>"))
 			Expect(bio).ToNot(ContainSubstring("</p>"))
 		})
 
-		It("uses the configured language", func() {
-			client = newClient(httpClient, "fr")
-			// Mock JWT token for the new client instance with a valid JWT
-			testJWT := createTestJWT(5 * time.Minute)
-			httpClient.mock("https://auth.deezer.com/login/anonymous", http.Response{
-				StatusCode: 200,
-				Body:       io.NopCloser(bytes.NewBufferString(fmt.Sprintf(`{"jwt":"%s","refresh_token":""}`, testJWT))),
-			})
-			f, err := os.Open("tests/fixtures/deezer.artist.bio.json")
+		It("uses the provided language", func() {
+			f, err := os.Open("tests/fixtures/deezer.artist.bio.fr.json")
 			Expect(err).To(BeNil())
 			httpClient.mock("https://pipe.deezer.com/api", http.Response{Body: f, StatusCode: 200})
 
-			_, err = client.getArtistBio(GinkgoT().Context(), 27)
+			_, err = client.getArtistBio(GinkgoT().Context(), 27, "fr")
 			Expect(err).To(BeNil())
 			Expect(httpClient.lastRequest.Header.Get("Accept-Language")).To(Equal("fr"))
 		})
 
 		It("includes the JWT token in the request", func() {
-			f, err := os.Open("tests/fixtures/deezer.artist.bio.json")
+			f, err := os.Open("tests/fixtures/deezer.artist.bio.en.json")
 			Expect(err).To(BeNil())
 			httpClient.mock("https://pipe.deezer.com/api", http.Response{Body: f, StatusCode: 200})
 
-			_, err = client.getArtistBio(GinkgoT().Context(), 27)
+			_, err = client.getArtistBio(GinkgoT().Context(), 27, "en")
 			Expect(err).To(BeNil())
 			// Verify that the Authorization header has the Bearer token format
 			authHeader := httpClient.lastRequest.Header.Get("Authorization")
@@ -142,7 +135,7 @@ var _ = Describe("client", func() {
 				Body:       io.NopCloser(bytes.NewBufferString(errorResponse)),
 			})
 
-			_, err := client.getArtistBio(GinkgoT().Context(), 999)
+			_, err := client.getArtistBio(GinkgoT().Context(), 999, "en")
 			Expect(err).To(HaveOccurred())
 			Expect(err.Error()).To(ContainSubstring("GraphQL error"))
 			Expect(err.Error()).To(ContainSubstring("Artist not found"))
@@ -164,7 +157,7 @@ var _ = Describe("client", func() {
 				Body:       io.NopCloser(bytes.NewBufferString(emptyBioResponse)),
 			})
 
-			_, err := client.getArtistBio(GinkgoT().Context(), 27)
+			_, err := client.getArtistBio(GinkgoT().Context(), 27, "en")
 			Expect(err).To(MatchError("deezer: biography not found"))
 		})
 
@@ -174,7 +167,7 @@ var _ = Describe("client", func() {
 				Body:       io.NopCloser(bytes.NewBufferString(`{"error":"Internal server error"}`)),
 			})
 
-			_, err := client.getArtistBio(GinkgoT().Context(), 27)
+			_, err := client.getArtistBio(GinkgoT().Context(), 27, "en")
 			Expect(err).To(HaveOccurred())
 			Expect(err.Error()).To(ContainSubstring("failed to get JWT"))
 		})
@@ -187,7 +180,7 @@ var _ = Describe("client", func() {
 				Body:       io.NopCloser(bytes.NewBufferString(fmt.Sprintf(`{"jwt":"%s","refresh_token":""}`, expiredJWT))),
 			})
 
-			_, err := client.getArtistBio(GinkgoT().Context(), 27)
+			_, err := client.getArtistBio(GinkgoT().Context(), 27, "en")
 			Expect(err).To(HaveOccurred())
 			Expect(err.Error()).To(ContainSubstring("JWT token already expired or expires too soon"))
 		})

adapters/deezer/deezer.go

@@ -26,15 +26,19 @@ const deezerArtistSearchLimit = 50
 type deezerAgent struct {
 	dataStore model.DataStore
 	client    *client
+	languages []string
 }
 
 func deezerConstructor(dataStore model.DataStore) agents.Interface {
-	agent := &deezerAgent{dataStore: dataStore}
+	agent := &deezerAgent{
+		dataStore: dataStore,
+		languages: conf.Server.Deezer.Languages,
+	}
 	httpClient := &http.Client{
 		Timeout: consts.DefaultHttpClientTimeOut,
 	}
 	cachedHttpClient := cache.NewHTTPClient(httpClient, consts.DefaultHttpClientTimeOut)
-	agent.client = newClient(cachedHttpClient, conf.Server.Deezer.Language)
+	agent.client = newClient(cachedHttpClient)
 	return agent
 }
 
@@ -149,7 +153,14 @@ func (s *deezerAgent) GetArtistBiography(ctx context.Context, _, name, _ string)
 		return "", err
 	}
 
-	return s.client.getArtistBio(ctx, artist.ID)
+	for _, lang := range s.languages {
+		bio, err := s.client.getArtistBio(ctx, artist.ID, lang)
+		if err == nil && bio != "" {
+			return bio, nil
+		}
+		log.Debug(ctx, "Deezer/artist.bio returned empty/error, trying next language", "artist", name, "lang", lang, err)
+	}
+	return "", agents.ErrNotFound
 }
 
 func init() {

adapters/deezer/deezer_test.go

@@ -0,0 +1,171 @@
+package deezer
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/conf/configtest"
+	"github.com/navidrome/navidrome/core/agents"
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("deezerAgent", func() {
+	var ctx context.Context
+
+	BeforeEach(func() {
+		ctx = context.Background()
+		DeferCleanup(configtest.SetupConfig())
+		conf.Server.Deezer.Enabled = true
+	})
+
+	Describe("deezerConstructor", func() {
+		It("uses configured languages", func() {
+			conf.Server.Deezer.Languages = []string{"pt", "en"}
+			agent := deezerConstructor(&tests.MockDataStore{}).(*deezerAgent)
+			Expect(agent.languages).To(Equal([]string{"pt", "en"}))
+		})
+	})
+
+	Describe("GetArtistBiography - Language Fallback", func() {
+		var agent *deezerAgent
+		var httpClient *langAwareHttpClient
+
+		BeforeEach(func() {
+			httpClient = newLangAwareHttpClient()
+
+			// Mock search artist (returns Michael Jackson)
+			fSearch, _ := os.Open("tests/fixtures/deezer.search.artist.json")
+			httpClient.searchResponse = &http.Response{Body: fSearch, StatusCode: 200}
+
+			// Mock JWT token
+			testJWT := createTestJWT(5 * time.Minute)
+			httpClient.jwtResponse = &http.Response{
+				StatusCode: 200,
+				Body:       io.NopCloser(bytes.NewBufferString(fmt.Sprintf(`{"jwt":"%s","refresh_token":""}`, testJWT))),
+			}
+		})
+
+		setupAgent := func(languages []string) {
+			conf.Server.Deezer.Languages = languages
+			agent = &deezerAgent{
+				dataStore: &tests.MockDataStore{},
+				client:    newClient(httpClient),
+				languages: languages,
+			}
+		}
+
+		It("returns content in first language when available (1 bio API call)", func() {
+			setupAgent([]string{"fr", "en"})
+
+			// French biography available
+			fFr, _ := os.Open("tests/fixtures/deezer.artist.bio.fr.json")
+			httpClient.bioResponses["fr"] = &http.Response{Body: fFr, StatusCode: 200}
+
+			bio, err := agent.GetArtistBiography(ctx, "", "Michael Jackson", "")
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(bio).To(ContainSubstring("Guy-Manuel de Homem Christo et Thomas Bangalter"))
+			Expect(httpClient.bioRequestCount).To(Equal(1))
+			Expect(httpClient.bioRequests[0].Header.Get("Accept-Language")).To(Equal("fr"))
+		})
+
+		It("falls back to second language when first returns empty (2 bio API calls)", func() {
+			setupAgent([]string{"ja", "en"})
+
+			// Japanese returns empty biography
+			fJa, _ := os.Open("tests/fixtures/deezer.artist.bio.empty.json")
+			httpClient.bioResponses["ja"] = &http.Response{Body: fJa, StatusCode: 200}
+			// English returns full biography
+			fEn, _ := os.Open("tests/fixtures/deezer.artist.bio.en.json")
+			httpClient.bioResponses["en"] = &http.Response{Body: fEn, StatusCode: 200}
+
+			bio, err := agent.GetArtistBiography(ctx, "", "Michael Jackson", "")
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(bio).To(ContainSubstring("Schoolmates Thomas and Guy-Manuel"))
+			Expect(httpClient.bioRequestCount).To(Equal(2))
+			Expect(httpClient.bioRequests[0].Header.Get("Accept-Language")).To(Equal("ja"))
+			Expect(httpClient.bioRequests[1].Header.Get("Accept-Language")).To(Equal("en"))
+		})
+
+		It("returns ErrNotFound when all languages return empty", func() {
+			setupAgent([]string{"ja", "xx"})
+
+			// Both languages return empty biography
+			fJa, _ := os.Open("tests/fixtures/deezer.artist.bio.empty.json")
+			httpClient.bioResponses["ja"] = &http.Response{Body: fJa, StatusCode: 200}
+			fXx, _ := os.Open("tests/fixtures/deezer.artist.bio.empty.json")
+			httpClient.bioResponses["xx"] = &http.Response{Body: fXx, StatusCode: 200}
+
+			_, err := agent.GetArtistBiography(ctx, "", "Michael Jackson", "")
+
+			Expect(err).To(MatchError(agents.ErrNotFound))
+			Expect(httpClient.bioRequestCount).To(Equal(2))
+		})
+	})
+})
+
+// langAwareHttpClient is a mock HTTP client that returns different responses based on the Accept-Language header
+type langAwareHttpClient struct {
+	searchResponse  *http.Response
+	jwtResponse     *http.Response
+	bioResponses    map[string]*http.Response
+	bioRequests     []*http.Request
+	bioRequestCount int
+}
+
+func newLangAwareHttpClient() *langAwareHttpClient {
+	return &langAwareHttpClient{
+		bioResponses: make(map[string]*http.Response),
+		bioRequests:  make([]*http.Request, 0),
+	}
+}
+
+func (c *langAwareHttpClient) Do(req *http.Request) (*http.Response, error) {
+	// Handle search artist request
+	if req.URL.Host == "api.deezer.com" && req.URL.Path == "/search/artist" {
+		if c.searchResponse != nil {
+			return c.searchResponse, nil
+		}
+		return &http.Response{
+			StatusCode: 200,
+			Body:       io.NopCloser(bytes.NewBufferString(`{"data":[],"total":0}`)),
+		}, nil
+	}
+
+	// Handle JWT token request
+	if req.URL.Host == "auth.deezer.com" && req.URL.Path == "/login/anonymous" {
+		if c.jwtResponse != nil {
+			return c.jwtResponse, nil
+		}
+		return &http.Response{
+			StatusCode: 500,
+			Body:       io.NopCloser(bytes.NewBufferString(`{"error":"no mock"}`)),
+		}, nil
+	}
+
+	// Handle bio request (GraphQL API)
+	if req.URL.Host == "pipe.deezer.com" && req.URL.Path == "/api" {
+		c.bioRequestCount++
+		c.bioRequests = append(c.bioRequests, req)
+		lang := req.Header.Get("Accept-Language")
+		if resp, ok := c.bioResponses[lang]; ok {
+			return resp, nil
+		}
+		// Return empty bio by default
+		return &http.Response{
+			StatusCode: 200,
+			Body:       io.NopCloser(bytes.NewBufferString(`{"data":{"artist":{"bio":{"full":""}}}}`)),
+		}, nil
+	}
+
+	panic("URL not mocked: " + req.URL.String())
+}

adapters/lastfm/agent.go

@@ -26,8 +26,8 @@ const (
 	sessionKeyProperty = "LastFMSessionKey"
 )
 
-var ignoredBiographies = []string{
-	// Unknown Artist
+var ignoredContent = []string{
+	// Empty Artist/Album
 	`<a href="https://www.last.fm/music/`,
 }
 
@@ -36,7 +36,7 @@ type lastfmAgent struct {
 	sessionKeys  *agents.SessionKeys
 	apiKey       string
 	secret       string
-	lang         string
+	languages    []string
 	client       *client
 	httpClient   httpDoer
 	getInfoMutex sync.Mutex
@@ -48,7 +48,7 @@ func lastFMConstructor(ds model.DataStore) *lastfmAgent {
 	}
 	l := &lastfmAgent{
 		ds:          ds,
-		lang:        conf.Server.LastFM.Language,
+		languages:   conf.Server.LastFM.Languages,
 		apiKey:      conf.Server.LastFM.ApiKey,
 		secret:      conf.Server.LastFM.Secret,
 		sessionKeys: &agents.SessionKeys{DataStore: ds, KeyName: sessionKeyProperty},
@@ -58,7 +58,7 @@ func lastFMConstructor(ds model.DataStore) *lastfmAgent {
 	}
 	chc := cache.NewHTTPClient(hc, consts.DefaultHttpClientTimeOut)
 	l.httpClient = chc
-	l.client = newClient(l.apiKey, l.secret, l.lang, chc)
+	l.client = newClient(l.apiKey, l.secret, chc)
 	return l
 }
 
@@ -68,22 +68,47 @@ func (l *lastfmAgent) AgentName() string {
 
 var imageRegex = regexp.MustCompile(`u\/(\d+)`)
 
-func (l *lastfmAgent) GetAlbumInfo(ctx context.Context, name, artist, mbid string) (*agents.AlbumInfo, error) {
-	a, err := l.callAlbumGetInfo(ctx, name, artist, mbid)
-	if err != nil {
-		return nil, err
+// isValidContent checks if content is non-empty and not in the ignored list
+func isValidContent(content string) bool {
+	content = strings.TrimSpace(content)
+	if content == "" {
+		return false
 	}
+	for _, ign := range ignoredContent {
+		if strings.HasPrefix(content, ign) {
+			return false
+		}
+	}
+	return true
+}
 
-	return &agents.AlbumInfo{
-		Name:        a.Name,
-		MBID:        a.MBID,
-		Description: a.Description.Summary,
-		URL:         a.URL,
-	}, nil
+func (l *lastfmAgent) GetAlbumInfo(ctx context.Context, name, artist, mbid string) (*agents.AlbumInfo, error) {
+	var a *Album
+	var resp agents.AlbumInfo
+	for _, lang := range l.languages {
+		var err error
+		a, err = l.callAlbumGetInfo(ctx, name, artist, mbid, lang)
+		if err != nil {
+			return nil, err
+		}
+		resp.Name = a.Name
+		resp.MBID = a.MBID
+		resp.URL = a.URL
+		if isValidContent(a.Description.Summary) {
+			resp.Description = strings.TrimSpace(a.Description.Summary)
+			return &resp, nil
+		}
+		log.Debug(ctx, "LastFM/album.getInfo returned empty/ignored description, trying next language", "album", name, "artist", artist, "lang", lang)
+	}
+	// This condition should not be hit (languages default to ["en"]), but just in case
+	if a == nil {
+		return nil, agents.ErrNotFound
+	}
+	return &resp, nil
 }
 
 func (l *lastfmAgent) GetAlbumImages(ctx context.Context, name, artist, mbid string) ([]agents.ExternalImage, error) {
-	a, err := l.callAlbumGetInfo(ctx, name, artist, mbid)
+	a, err := l.callAlbumGetInfo(ctx, name, artist, mbid, l.languages[0])
 	if err != nil {
 		return nil, err
 	}
@@ -118,7 +143,7 @@ func (l *lastfmAgent) GetAlbumImages(ctx context.Context, name, artist, mbid str
 }
 
 func (l *lastfmAgent) GetArtistMBID(ctx context.Context, id string, name string) (string, error) {
-	a, err := l.callArtistGetInfo(ctx, name)
+	a, err := l.callArtistGetInfo(ctx, name, l.languages[0])
 	if err != nil {
 		return "", err
 	}
@@ -129,7 +154,7 @@ func (l *lastfmAgent) GetArtistMBID(ctx context.Context, id string, name string)
 }
 
 func (l *lastfmAgent) GetArtistURL(ctx context.Context, id, name, mbid string) (string, error) {
-	a, err := l.callArtistGetInfo(ctx, name)
+	a, err := l.callArtistGetInfo(ctx, name, l.languages[0])
 	if err != nil {
 		return "", err
 	}
@@ -140,20 +165,17 @@ func (l *lastfmAgent) GetArtistURL(ctx context.Context, id, name, mbid string) (
 }
 
 func (l *lastfmAgent) GetArtistBiography(ctx context.Context, id, name, mbid string) (string, error) {
-	a, err := l.callArtistGetInfo(ctx, name)
-	if err != nil {
-		return "", err
-	}
-	a.Bio.Summary = strings.TrimSpace(a.Bio.Summary)
-	if a.Bio.Summary == "" {
-		return "", agents.ErrNotFound
-	}
-	for _, ign := range ignoredBiographies {
-		if strings.HasPrefix(a.Bio.Summary, ign) {
-			return "", nil
+	for _, lang := range l.languages {
+		a, err := l.callArtistGetInfo(ctx, name, lang)
+		if err != nil {
+			return "", err
 		}
+		if isValidContent(a.Bio.Summary) {
+			return strings.TrimSpace(a.Bio.Summary), nil
+		}
+		log.Debug(ctx, "LastFM/artist.getInfo returned empty/ignored biography, trying next language", "artist", name, "lang", lang)
 	}
-	return a.Bio.Summary, nil
+	return "", agents.ErrNotFound
 }
 
 func (l *lastfmAgent) GetSimilarArtists(ctx context.Context, id, name, mbid string, limit int) ([]agents.Artist, error) {
@@ -219,7 +241,7 @@ var (
 
 func (l *lastfmAgent) GetArtistImages(ctx context.Context, _, name, mbid string) ([]agents.ExternalImage, error) {
 	log.Debug(ctx, "Getting artist images from Last.fm", "name", name)
-	a, err := l.callArtistGetInfo(ctx, name)
+	a, err := l.callArtistGetInfo(ctx, name, l.languages[0])
 	if err != nil {
 		return nil, fmt.Errorf("get artist info: %w", err)
 	}
@@ -259,14 +281,14 @@ func (l *lastfmAgent) GetArtistImages(ctx context.Context, _, name, mbid string)
 	return res, nil
 }
 
-func (l *lastfmAgent) callAlbumGetInfo(ctx context.Context, name, artist, mbid string) (*Album, error) {
-	a, err := l.client.albumGetInfo(ctx, name, artist, mbid)
+func (l *lastfmAgent) callAlbumGetInfo(ctx context.Context, name, artist, mbid string, lang string) (*Album, error) {
+	a, err := l.client.albumGetInfo(ctx, name, artist, mbid, lang)
 	var lfErr *lastFMError
 	isLastFMError := errors.As(err, &lfErr)
 
 	if mbid != "" && (isLastFMError && lfErr.Code == 6) {
 		log.Debug(ctx, "LastFM/album.getInfo could not find album by mbid, trying again", "album", name, "mbid", mbid)
-		return l.callAlbumGetInfo(ctx, name, artist, "")
+		return l.callAlbumGetInfo(ctx, name, artist, "", lang)
 	}
 
 	if err != nil {
@@ -280,11 +302,11 @@ func (l *lastfmAgent) callAlbumGetInfo(ctx context.Context, name, artist, mbid s
 	return a, nil
 }
 
-func (l *lastfmAgent) callArtistGetInfo(ctx context.Context, name string) (*Artist, error) {
+func (l *lastfmAgent) callArtistGetInfo(ctx context.Context, name string, lang string) (*Artist, error) {
 	l.getInfoMutex.Lock()
 	defer l.getInfoMutex.Unlock()
 
-	a, err := l.client.artistGetInfo(ctx, name)
+	a, err := l.client.artistGetInfo(ctx, name, lang)
 	if err != nil {
 		log.Error(ctx, "Error calling LastFM/artist.getInfo", "artist", name, err)
 		return nil, err

adapters/lastfm/agent_test.go

@@ -39,12 +39,12 @@ var _ = Describe("lastfmAgent", func() {
 	})
 	Describe("lastFMConstructor", func() {
 		When("Agent is properly configured", func() {
-			It("uses configured api key and language", func() {
-				conf.Server.LastFM.Language = "pt"
+			It("uses configured api key and languages", func() {
+				conf.Server.LastFM.Languages = []string{"pt", "en"}
 				agent := lastFMConstructor(ds)
 				Expect(agent.apiKey).To(Equal("123"))
 				Expect(agent.secret).To(Equal("secret"))
-				Expect(agent.lang).To(Equal("pt"))
+				Expect(agent.languages).To(Equal([]string{"pt", "en"}))
 			})
 		})
 		When("Agent is disabled", func() {
@@ -72,7 +72,7 @@ var _ = Describe("lastfmAgent", func() {
 		var httpClient *tests.FakeHttpClient
 		BeforeEach(func() {
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			client := newClient("API_KEY", "SECRET", httpClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 		})
@@ -102,12 +102,129 @@ var _ = Describe("lastfmAgent", func() {
 		})
 	})
 
+	Describe("Language Fallback", func() {
+		Describe("GetArtistBiography", func() {
+			var agent *lastfmAgent
+			var httpClient *langAwareHttpClient
+
+			BeforeEach(func() {
+				httpClient = newLangAwareHttpClient()
+			})
+
+			It("returns content in first language when available (1 API call)", func() {
+				conf.Server.LastFM.Languages = []string{"pt", "en"}
+				agent = lastFMConstructor(ds)
+				agent.client = newClient("API_KEY", "SECRET", httpClient)
+
+				// Portuguese biography available
+				f, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+				httpClient.responses["pt"] = http.Response{Body: f, StatusCode: 200}
+
+				bio, err := agent.GetArtistBiography(ctx, "123", "U2", "")
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(bio).To(ContainSubstring("U2 é uma das mais importantes bandas de rock"))
+				Expect(httpClient.requestCount).To(Equal(1))
+				Expect(httpClient.requests[0].URL.Query().Get("lang")).To(Equal("pt"))
+			})
+
+			It("falls back to second language when first returns empty (2 API calls)", func() {
+				conf.Server.LastFM.Languages = []string{"ja", "en"}
+				agent = lastFMConstructor(ds)
+				agent.client = newClient("API_KEY", "SECRET", httpClient)
+
+				// Japanese returns empty/ignored biography (actual Last.fm response with just "Read more" link)
+				fJa, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.empty.json")
+				httpClient.responses["ja"] = http.Response{Body: fJa, StatusCode: 200}
+				// English returns full biography
+				fEn, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.en.json")
+				httpClient.responses["en"] = http.Response{Body: fEn, StatusCode: 200}
+
+				bio, err := agent.GetArtistBiography(ctx, "123", "Legião Urbana", "")
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(bio).To(ContainSubstring("Legião Urbana was a Brazilian post-punk band"))
+				Expect(httpClient.requestCount).To(Equal(2))
+				Expect(httpClient.requests[0].URL.Query().Get("lang")).To(Equal("ja"))
+				Expect(httpClient.requests[1].URL.Query().Get("lang")).To(Equal("en"))
+			})
+
+			It("returns ErrNotFound when all languages return empty", func() {
+				conf.Server.LastFM.Languages = []string{"ja", "xx"}
+				agent = lastFMConstructor(ds)
+				agent.client = newClient("API_KEY", "SECRET", httpClient)
+
+				// Both languages return empty/ignored biography (using actual Last.fm response format)
+				fJa, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.empty.json")
+				httpClient.responses["ja"] = http.Response{Body: fJa, StatusCode: 200}
+				// Second language also returns empty
+				fXx, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.empty.json")
+				httpClient.responses["xx"] = http.Response{Body: fXx, StatusCode: 200}
+
+				_, err := agent.GetArtistBiography(ctx, "123", "Legião Urbana", "")
+
+				Expect(err).To(MatchError(agents.ErrNotFound))
+				Expect(httpClient.requestCount).To(Equal(2))
+			})
+		})
+
+		Describe("GetAlbumInfo", func() {
+			var agent *lastfmAgent
+			var httpClient *langAwareHttpClient
+
+			BeforeEach(func() {
+				httpClient = newLangAwareHttpClient()
+			})
+
+			It("falls back to second language when first returns empty description (2 API calls)", func() {
+				conf.Server.LastFM.Languages = []string{"ja", "en"}
+				agent = lastFMConstructor(ds)
+				agent.client = newClient("API_KEY", "SECRET", httpClient)
+
+				// Japanese returns album without wiki/description (actual Last.fm response)
+				fJa, _ := os.Open("tests/fixtures/lastfm.album.getinfo.empty.json")
+				httpClient.responses["ja"] = http.Response{Body: fJa, StatusCode: 200}
+				// English returns album with description
+				fEn, _ := os.Open("tests/fixtures/lastfm.album.getinfo.en.json")
+				httpClient.responses["en"] = http.Response{Body: fEn, StatusCode: 200}
+
+				albumInfo, err := agent.GetAlbumInfo(ctx, "Dois", "Legião Urbana", "")
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(albumInfo.Name).To(Equal("Dois"))
+				Expect(albumInfo.Description).To(ContainSubstring("segundo álbum de estúdio"))
+				Expect(httpClient.requestCount).To(Equal(2))
+				Expect(httpClient.requests[0].URL.Query().Get("lang")).To(Equal("ja"))
+				Expect(httpClient.requests[1].URL.Query().Get("lang")).To(Equal("en"))
+			})
+
+			It("returns album without description when all languages return empty", func() {
+				conf.Server.LastFM.Languages = []string{"ja", "xx"}
+				agent = lastFMConstructor(ds)
+				agent.client = newClient("API_KEY", "SECRET", httpClient)
+
+				// Both languages return album without description
+				fJa, _ := os.Open("tests/fixtures/lastfm.album.getinfo.empty.json")
+				httpClient.responses["ja"] = http.Response{Body: fJa, StatusCode: 200}
+				fXx, _ := os.Open("tests/fixtures/lastfm.album.getinfo.empty.json")
+				httpClient.responses["xx"] = http.Response{Body: fXx, StatusCode: 200}
+
+				albumInfo, err := agent.GetAlbumInfo(ctx, "Dois", "Legião Urbana", "")
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(albumInfo.Name).To(Equal("Dois"))
+				Expect(albumInfo.Description).To(BeEmpty())
+				Expect(httpClient.requestCount).To(Equal(2))
+			})
+		})
+	})
+
 	Describe("GetSimilarArtists", func() {
 		var agent *lastfmAgent
 		var httpClient *tests.FakeHttpClient
 		BeforeEach(func() {
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			client := newClient("API_KEY", "SECRET", httpClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 		})
@@ -145,7 +262,7 @@ var _ = Describe("lastfmAgent", func() {
 		var httpClient *tests.FakeHttpClient
 		BeforeEach(func() {
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			client := newClient("API_KEY", "SECRET", httpClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 		})
@@ -183,7 +300,7 @@ var _ = Describe("lastfmAgent", func() {
 		var httpClient *tests.FakeHttpClient
 		BeforeEach(func() {
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			client := newClient("API_KEY", "SECRET", httpClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 		})
@@ -233,7 +350,7 @@ var _ = Describe("lastfmAgent", func() {
 		BeforeEach(func() {
 			_ = ds.UserProps(ctx).Put("user-1", sessionKeyProperty, "SK-1")
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "en", httpClient)
+			client := newClient("API_KEY", "SECRET", httpClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 			track = &model.MediaFile{
@@ -407,7 +524,7 @@ var _ = Describe("lastfmAgent", func() {
 		var httpClient *tests.FakeHttpClient
 		BeforeEach(func() {
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			client := newClient("API_KEY", "SECRET", httpClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 		})
@@ -477,7 +594,7 @@ var _ = Describe("lastfmAgent", func() {
 		BeforeEach(func() {
 			apiClient = &tests.FakeHttpClient{}
 			httpClient = &tests.FakeHttpClient{}
-			client := newClient("API_KEY", "SECRET", "pt", apiClient)
+			client := newClient("API_KEY", "SECRET", apiClient)
 			agent = lastFMConstructor(ds)
 			agent.client = client
 			agent.httpClient = httpClient
@@ -538,3 +655,31 @@ var _ = Describe("lastfmAgent", func() {
 		})
 	})
 })
+
+// langAwareHttpClient is a mock HTTP client that returns different responses based on the lang parameter
+type langAwareHttpClient struct {
+	responses    map[string]http.Response
+	requests     []*http.Request
+	requestCount int
+}
+
+func newLangAwareHttpClient() *langAwareHttpClient {
+	return &langAwareHttpClient{
+		responses: make(map[string]http.Response),
+		requests:  make([]*http.Request, 0),
+	}
+}
+
+func (c *langAwareHttpClient) Do(req *http.Request) (*http.Response, error) {
+	c.requestCount++
+	c.requests = append(c.requests, req)
+	lang := req.URL.Query().Get("lang")
+	if resp, ok := c.responses[lang]; ok {
+		return &resp, nil
+	}
+	// Return default empty response if no specific response is configured
+	return &http.Response{
+		StatusCode: 200,
+		Body:       io.NopCloser(bytes.NewBufferString(`{}`)),
+	}, nil
+}

adapters/lastfm/auth_router.go

@@ -44,7 +44,7 @@ func NewRouter(ds model.DataStore) *Router {
 	hc := &http.Client{
 		Timeout: consts.DefaultHttpClientTimeOut,
 	}
-	r.client = newClient(r.apiKey, r.secret, "en", hc)
+	r.client = newClient(r.apiKey, r.secret, hc)
 	return r
 }
 

adapters/lastfm/client.go

@@ -34,24 +34,23 @@ type httpDoer interface {
 	Do(req *http.Request) (*http.Response, error)
 }
 
-func newClient(apiKey string, secret string, lang string, hc httpDoer) *client {
-	return &client{apiKey, secret, lang, hc}
+func newClient(apiKey string, secret string, hc httpDoer) *client {
+	return &client{apiKey, secret, hc}
 }
 
 type client struct {
 	apiKey string
 	secret string
-	lang   string
 	hc     httpDoer
 }
 
-func (c *client) albumGetInfo(ctx context.Context, name string, artist string, mbid string) (*Album, error) {
+func (c *client) albumGetInfo(ctx context.Context, name string, artist string, mbid string, lang string) (*Album, error) {
 	params := url.Values{}
 	params.Add("method", "album.getInfo")
 	params.Add("album", name)
 	params.Add("artist", artist)
 	params.Add("mbid", mbid)
-	params.Add("lang", c.lang)
+	params.Add("lang", lang)
 	response, err := c.makeRequest(ctx, http.MethodGet, params, false)
 	if err != nil {
 		return nil, err
@@ -59,11 +58,11 @@ func (c *client) albumGetInfo(ctx context.Context, name string, artist string, m
 	return &response.Album, nil
 }
 
-func (c *client) artistGetInfo(ctx context.Context, name string) (*Artist, error) {
+func (c *client) artistGetInfo(ctx context.Context, name string, lang string) (*Artist, error) {
 	params := url.Values{}
 	params.Add("method", "artist.getInfo")
 	params.Add("artist", name)
-	params.Add("lang", c.lang)
+	params.Add("lang", lang)
 	response, err := c.makeRequest(ctx, http.MethodGet, params, false)
 	if err != nil {
 		return nil, err

adapters/lastfm/client_test.go

@@ -22,7 +22,7 @@ var _ = Describe("client", func() {
 
 	BeforeEach(func() {
 		httpClient = &tests.FakeHttpClient{}
-		client = newClient("API_KEY", "SECRET", "pt", httpClient)
+		client = newClient("API_KEY", "SECRET", httpClient)
 	})
 
 	Describe("albumGetInfo", func() {
@@ -30,7 +30,7 @@ var _ = Describe("client", func() {
 			f, _ := os.Open("tests/fixtures/lastfm.album.getinfo.json")
 			httpClient.Res = http.Response{Body: f, StatusCode: 200}
 
-			album, err := client.albumGetInfo(context.Background(), "Believe", "U2", "mbid-1234")
+			album, err := client.albumGetInfo(context.Background(), "Believe", "U2", "mbid-1234", "pt")
 			Expect(err).To(BeNil())
 			Expect(album.Name).To(Equal("Believe"))
 			Expect(httpClient.SavedRequest.URL.String()).To(Equal(apiBaseUrl + "?album=Believe&api_key=API_KEY&artist=U2&format=json&lang=pt&mbid=mbid-1234&method=album.getInfo"))
@@ -42,7 +42,7 @@ var _ = Describe("client", func() {
 			f, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
 			httpClient.Res = http.Response{Body: f, StatusCode: 200}
 
-			artist, err := client.artistGetInfo(context.Background(), "U2")
+			artist, err := client.artistGetInfo(context.Background(), "U2", "pt")
 			Expect(err).To(BeNil())
 			Expect(artist.Name).To(Equal("U2"))
 			Expect(httpClient.SavedRequest.URL.String()).To(Equal(apiBaseUrl + "?api_key=API_KEY&artist=U2&format=json&lang=pt&method=artist.getInfo"))
@@ -54,7 +54,7 @@ var _ = Describe("client", func() {
 				StatusCode: 500,
 			}
 
-			_, err := client.artistGetInfo(context.Background(), "U2")
+			_, err := client.artistGetInfo(context.Background(), "U2", "pt")
 			Expect(err).To(MatchError("last.fm http status: (500)"))
 		})
 
@@ -64,7 +64,7 @@ var _ = Describe("client", func() {
 				StatusCode: 400,
 			}
 
-			_, err := client.artistGetInfo(context.Background(), "U2")
+			_, err := client.artistGetInfo(context.Background(), "U2", "pt")
 			Expect(err).To(MatchError(&lastFMError{Code: 3, Message: "Invalid Method - No method with that name in this package"}))
 		})
 
@@ -74,14 +74,14 @@ var _ = Describe("client", func() {
 				StatusCode: 200,
 			}
 
-			_, err := client.artistGetInfo(context.Background(), "U2")
+			_, err := client.artistGetInfo(context.Background(), "U2", "pt")
 			Expect(err).To(MatchError(&lastFMError{Code: 6, Message: "The artist you supplied could not be found"}))
 		})
 
 		It("fails if HttpClient.Do() returns error", func() {
 			httpClient.Err = errors.New("generic error")
 
-			_, err := client.artistGetInfo(context.Background(), "U2")
+			_, err := client.artistGetInfo(context.Background(), "U2", "pt")
 			Expect(err).To(MatchError("generic error"))
 		})
 
@@ -91,7 +91,7 @@ var _ = Describe("client", func() {
 				StatusCode: 200,
 			}
 
-			_, err := client.artistGetInfo(context.Background(), "U2")
+			_, err := client.artistGetInfo(context.Background(), "U2", "pt")
 			Expect(err).To(MatchError("invalid character '<' looking for beginning of value"))
 		})
 

conf/configuration.go

@@ -175,6 +175,9 @@ type lastfmOptions struct {
 	Secret                  string
 	Language                string
 	ScrobbleFirstArtistOnly bool
+
+	// Computed values
+	Languages []string // Computed from Language, split by comma
 }
 
 type spotifyOptions struct {
@@ -185,6 +188,9 @@ type spotifyOptions struct {
 type deezerOptions struct {
 	Enabled  bool
 	Language string
+
+	// Computed values
+	Languages []string // Computed from Language, split by comma
 }
 
 type listenBrainzOptions struct {
@@ -374,6 +380,12 @@ func Load(noConfigDump bool) {
 	Server.PID.Album = cmp.Or(Server.PID.Album, consts.DefaultAlbumPID)
 	Server.PID.Track = cmp.Or(Server.PID.Track, consts.DefaultTrackPID)
 
+	// Parse LastFM.Language into Languages slice (comma-separated, with fallback to DefaultInfoLanguage)
+	Server.LastFM.Languages = parseLanguages(Server.LastFM.Language)
+
+	// Parse Deezer.Language into Languages slice (comma-separated, with fallback to DefaultInfoLanguage)
+	Server.Deezer.Languages = parseLanguages(Server.Deezer.Language)
+
 	logDeprecatedOptions("Scanner.GenreSeparators", "")
 	logDeprecatedOptions("Scanner.GroupAlbumReleases", "")
 	logDeprecatedOptions("DevEnableBufferedScrobble", "") // Deprecated: Buffered scrobbling is now always enabled and this option is ignored
@@ -462,6 +474,22 @@ func validatePlaylistsPath() error {
 	return nil
 }
 
+// parseLanguages parses a comma-separated language string into a slice.
+// It trims whitespace from each entry and ensures at least [DefaultInfoLanguage] is returned.
+func parseLanguages(lang string) []string {
+	var languages []string
+	for _, l := range strings.Split(lang, ",") {
+		l = strings.TrimSpace(l)
+		if l != "" {
+			languages = append(languages, l)
+		}
+	}
+	if len(languages) == 0 {
+		return []string{consts.DefaultInfoLanguage}
+	}
+	return languages
+}
+
 func validatePurgeMissingOption() error {
 	allowedValues := []string{consts.PurgeMissingNever, consts.PurgeMissingAlways, consts.PurgeMissingFull}
 	valid := false
@@ -618,14 +646,14 @@ func setViperDefaults() {
 	viper.SetDefault("subsonic.legacyclients", "DSub,SubMusic")
 	viper.SetDefault("agents", "lastfm,spotify,deezer")
 	viper.SetDefault("lastfm.enabled", true)
-	viper.SetDefault("lastfm.language", "en")
+	viper.SetDefault("lastfm.language", consts.DefaultInfoLanguage)
 	viper.SetDefault("lastfm.apikey", "")
 	viper.SetDefault("lastfm.secret", "")
 	viper.SetDefault("lastfm.scrobblefirstartistonly", false)
 	viper.SetDefault("spotify.id", "")
 	viper.SetDefault("spotify.secret", "")
 	viper.SetDefault("deezer.enabled", true)
-	viper.SetDefault("deezer.language", "en")
+	viper.SetDefault("deezer.language", consts.DefaultInfoLanguage)
 	viper.SetDefault("listenbrainz.enabled", true)
 	viper.SetDefault("listenbrainz.baseurl", "https://api.listenbrainz.org/1/")
 	viper.SetDefault("enablescrobblehistory", true)

conf/configuration_test.go

@@ -26,6 +26,32 @@ var _ = Describe("Configuration", func() {
 		conf.ResetConf()
 	})
 
+	Describe("ParseLanguages", func() {
+		It("parses single language", func() {
+			Expect(conf.ParseLanguages("en")).To(Equal([]string{"en"}))
+		})
+
+		It("parses multiple comma-separated languages", func() {
+			Expect(conf.ParseLanguages("pt,en")).To(Equal([]string{"pt", "en"}))
+		})
+
+		It("trims whitespace from languages", func() {
+			Expect(conf.ParseLanguages(" pt , en ")).To(Equal([]string{"pt", "en"}))
+		})
+
+		It("returns default 'en' when empty", func() {
+			Expect(conf.ParseLanguages("")).To(Equal([]string{"en"}))
+		})
+
+		It("returns default 'en' when only whitespace", func() {
+			Expect(conf.ParseLanguages("   ")).To(Equal([]string{"en"}))
+		})
+
+		It("handles multiple languages with various spacing", func() {
+			Expect(conf.ParseLanguages("ja, pt, en")).To(Equal([]string{"ja", "pt", "en"}))
+		})
+	})
+
 	DescribeTable("should load configuration from",
 		func(format string) {
 			filename := filepath.Join("testdata", "cfg."+format)

conf/export_test.go

@@ -5,3 +5,5 @@ func ResetConf() {
 }
 
 var SetViperDefaults = setViperDefaults
+
+var ParseLanguages = parseLanguages

consts/consts.go

@@ -56,6 +56,8 @@ const (
 
 	ServerReadHeaderTimeout = 3 * time.Second
 
+	DefaultInfoLanguage = "en"
+
 	ArtistInfoTimeToLive      = 24 * time.Hour
 	AlbumInfoTimeToLive       = 7 * 24 * time.Hour
 	UpdateLastAccessFrequency = time.Minute

tests/fixtures/deezer.artist.bio.empty.json

@@ -0,0 +1,10 @@
+{
+  "data": {
+    "artist": {
+      "bio": null
+    }
+  },
+  "extensions": {
+    "queryCost": 3
+  }
+}

tests/fixtures/deezer.artist.bio.en.json

@@ -0,0 +1,12 @@
+{
+  "data": {
+    "artist": {
+      "bio": {
+        "full": "<p>Schoolmates Thomas and Guy-Manuel began their career in 1992 with the indie rock trio Darlin' (named after The Beach Boys song) but were scathingly dismissed by Melody Maker magazine as \"daft punk.\" Turning to house-inspired electronica, they used the put down as a name for their DJ-ing partnership and became a hugely successful and influential dance act. First major single <em>\"Da Funk\"</em> was accompanied by a Spike Jonze-directed video and more success followed with global dance floor anthem <em>\"Around the World,\" \"One More Time,\"</em> and <em>\"Harder, Faster, Better, Stronger\"</em> - which was sampled by Kanye West for his hit <em>\"Stronger.\"</em> Albums <em>Homework</em> (1997), <em>Discovery</em> (2001) and <em>Human After All</em> (2005) all made the UK Top 10 establishing a style of simple, Chicago house-inspired grooves exploding into a robotic, rave sound.</p>"
+      }
+    }
+  },
+  "extensions": {
+    "queryCost": 3
+  }
+}

tests/fixtures/deezer.artist.bio.fr.json

@@ -0,0 +1,12 @@
+{
+  "data": {
+    "artist": {
+      "bio": {
+        "full": "Guy-Manuel de Homem Christo et Thomas Bangalter se rencontrent en 1987 au lycée Carnot de Paris. Partageant une même passion pour la musique, les deux amis fondent en 1992 Darlin', un groupe de rock influencé par les Stooges et MC5, dont la production sera taxée par un critique de la presse anglaise de «daft punk» (« punk idiot »). <br />\n<br />\nDécouragés face à l'apathie du milieu rock, ils décident un peu plus tard de se lancer à corps perdus dans le courant Techno alors en pleine explosion. Arrive alors la découverte de la House, des clubs et des raves, dont une en particulier qui déterminera leur avenir : en 1993 est organisé à EuroDisney une rave où notre duo rencontre les dirigeants du label techno écossais Soma."
+      }
+    }
+  },
+  "extensions": {
+    "queryCost": 3
+  }
+}

tests/fixtures/deezer.artist.bio.json

@@ -1,9 +0,0 @@
-{
-  "data": {
-    "artist": {
-      "bio": {
-        "full": "<p>Schoolmates Thomas and Guy-Manuel began their career in 1992 with the indie rock trio Darlin' (named after The Beach Boys song) but were scathingly dismissed by Melody Maker magazine as \"daft punk.\" Turning to house-inspired electronica, they used the put down as a name for their DJ-ing partnership and became a hugely successful and influential dance act.</p>"
-      }
-    }
-  }
-}