From 9618108f2a936918bfcd6c30b17e01180e31fbf5 Mon Sep 17 00:00:00 2001
From: lb-a <lb-a@tuta.io>
Date: Thu, 30 Apr 2026 12:00:58 +0200
Subject: [PATCH] performance: exclude lyrics if they are not enabled

---
 internal/app/app.go               |  4 ++++
 internal/download/downloader.go   |  3 +++
 internal/provider/tidal/client.go | 39 +++++++++++++++++++++++--------
 3 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/internal/app/app.go b/internal/app/app.go
index a347344..888f6a4 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -121,6 +121,10 @@ func New(cfg *config.Config) (*Main, error) {
 	}, nil
 }
 
+// downloaderMaxConnsPerHost picks the per-host idle connection cap for the
+// shared download client. We floor at 16 so artwork/manifest fetches and
+// concurrent track downloads to the same CDN host can reuse keep-alive
+// sockets even when the user configured a tiny max_connections.
 func downloaderMaxConnsPerHost(maxConnections int) int {
 	if maxConnections > 16 {
 		return maxConnections
diff --git a/internal/download/downloader.go b/internal/download/downloader.go
index e9a3b44..4daa53d 100644
--- a/internal/download/downloader.go
+++ b/internal/download/downloader.go
@@ -31,6 +31,9 @@ type Downloader struct {
 	barStarted   atomic.Int32
 }
 
+// downloadBufferSize sizes HTTP-to-disk copies. 1 MiB cuts read/write syscalls
+// ~32x vs Go's default 32 KiB io.Copy buffer, which matters for multi-MB FLAC
+// streams off CDNs that can sustain high per-connection throughput.
 const downloadBufferSize = 1 << 20
 
 func New() *Downloader {
diff --git a/internal/provider/tidal/client.go b/internal/provider/tidal/client.go
index d411991..a49c180 100644
--- a/internal/provider/tidal/client.go
+++ b/internal/provider/tidal/client.go
@@ -209,12 +209,17 @@ func (c *Client) GetMetadata(ctx context.Context, item, mediaType string) (map[s
 		if album, ok := resp["album"].(map[string]any); ok {
 			enrichTidalImage(album)
 		}
-		if lyrics, lrc := c.fetchTrackLyrics(ctx, item); lyrics != "" || lrc != "" {
-			if lyrics != "" {
-				resp["lyrics"] = lyrics
-			}
-			if lrc != "" {
-				resp["lyrics_synced"] = lrc
+		// Lyrics live on a separate endpoint, so fetching them costs an extra
+		// rate-limited roundtrip per track. Users who don't embed lyrics can
+		// opt out via metadata.exclude = ["lyrics"].
+		if !c.lyricsExcluded() {
+			if lyrics, lrc := c.fetchTrackLyrics(ctx, item); lyrics != "" || lrc != "" {
+				if lyrics != "" {
+					resp["lyrics"] = lyrics
+				}
+				if lrc != "" {
+					resp["lyrics_synced"] = lrc
+				}
 			}
 		}
 	}
@@ -222,6 +227,15 @@ func (c *Client) GetMetadata(ctx context.Context, item, mediaType string) (map[s
 	return resp, nil
 }
 
+func (c *Client) lyricsExcluded() bool {
+	for _, k := range c.cfg.Session.Metadata.Exclude {
+		if strings.EqualFold(strings.TrimSpace(k), "lyrics") {
+			return true
+		}
+	}
+	return false
+}
+
 func (c *Client) fetchTrackLyrics(ctx context.Context, trackID string) (string, string) {
 	params := url.Values{}
 	params.Set("deviceType", "PHONE")
@@ -277,10 +291,11 @@ func (c *Client) GetDownloadable(ctx context.Context, trackID string, quality in
 	}
 
 	if c.cfg.Session.Tidal.PreferAtmos {
-		if c.trackSupportsAtmos(ctx, trackID) {
-			if d, _ := c.getAtmosDownloadable(ctx, trackID); d != nil {
-				return d, nil
-			}
+		// No tracks/{id} pre-check: getAtmosDownloadable already validates
+		// each candidate response via playbackLooksAtmos and falls back
+		// through the format-specific trackManifests paths.
+		if d, _ := c.getAtmosDownloadable(ctx, trackID); d != nil {
+			return d, nil
 		}
 	}
 
@@ -295,6 +310,10 @@ func (c *Client) GetDownloadable(ctx context.Context, trackID string, quality in
 	}
 	if status == http.StatusOK {
 		if d := downloadableFromPlaybackManifest(resp); d != nil {
+			// Tidal's playbackinfo sometimes returns an m4a (HIGH/AAC)
+			// stream even when LOSSLESS+ was requested. There is no
+			// lossless m4a tier, so retry via the openAPI v2 manifest
+			// before settling for the downgrade.
 			if quality >= 2 && d.Extension == "m4a" {
 				if strict, strictErr := c.getDownloadableFromTrackManifest(ctx, trackID, quality); strictErr == nil && strict != nil {
 					return strict, nil