Genre priorities for album covers section

src/db.rs

@@ -594,8 +594,8 @@ pub fn top_genres(conn: &Connection, period: &str, limit: i64) -> Result<Vec<Top
         // Deprioritised genres (e.g. "ambient") always rank below specific
         // genres regardless of play count. They still appear in the list if
         // they are the only genres present.
-        let a_dep = is_deprioritised(&a.genre);
-        let b_dep = is_deprioritised(&b.genre);
+        let a_dep = is_deprioritised_genre(&a.genre);
+        let b_dep = is_deprioritised_genre(&b.genre);
         match (a_dep, b_dep) {
             (true, false) => std::cmp::Ordering::Greater,
             (false, true) => std::cmp::Ordering::Less,
@@ -743,7 +743,7 @@ pub fn uncached_albums(conn: &Connection) -> Result<Vec<UncachedAlbum>> {
 /// Single-word genres ("rock", "electronic", "ambient") are broad descriptors
 /// that appear as secondary tags on many artists. Multi-word genres ("prog
 /// rock", "alternative metal") are more specific and should rank first.
-fn is_deprioritised(genre: &str) -> bool {
+pub fn is_deprioritised_genre(genre: &str) -> bool {
     canonical_genre_key(genre).split_whitespace().count() < 2
 }
 

src/report.rs

@@ -1539,16 +1539,23 @@ fn html_attr_escape(s: &str) -> String {
     html_escape(s).replace('"', """)
 }
 
-/// Split a comma-separated genre list and keep only the first `max_labels`
-/// cleaned labels.
+/// Split a comma-separated genre list and return the top `max_labels` labels,
+/// applying the same deprioritisation rule as `top_genres`: multi-word genres
+/// rank before single-word broad descriptors ("rock", "electronic", etc.).
 fn top_genre_labels(genre_csv: &str, max_labels: usize) -> Vec<String> {
-    genre_csv
+    let mut labels: Vec<String> = genre_csv
         .split(',')
         .map(str::trim)
         .filter(|s| !s.is_empty())
-        .take(max_labels)
         .map(|s| s.to_string())
-        .collect()
+        .collect();
+
+    // Stable sort so that multi-word genres always precede single-word ones,
+    // preserving the original MusicBrainz order within each group.
+    labels.sort_by_key(|g| db::is_deprioritised_genre(g));
+
+    labels.truncate(max_labels);
+    labels
 }
 
 // ---------------------------------------------------------------------------
@@ -1610,6 +1617,9 @@ mod tests {
 
     #[test]
     fn test_top_genre_labels_caps_to_three() {
+        // "alternative rock" and "industrial" are multi-word → rank first.
+        // "electronic" and "darkwave" are single-word → deprioritised.
+        // With limit 3 we get both multi-word genres + one single-word.
         let labels = top_genre_labels("alternative rock, electronic, industrial, darkwave", 3);
         assert_eq!(
             labels,