update to the playlists. testing

shanty-playlist/src/scoring.rs

@@ -21,6 +21,8 @@ pub fn score_tracks(
     tracks_by_artist: &HashMap<String, Vec<Track>>,
     top_tracks_by_artist: &HashMap<String, Vec<PopularTrack>>,
     popularity_bias: u8,
+    _global_popularity: u8,
+    max_tracks_per_artist: Option<u8>,
 ) -> Vec<ScoredTrack> {
     let bias = popularity_bias.min(10) as usize;
     let mut scored = Vec::new();
@@ -108,7 +110,9 @@ pub fn score_tracks(
         by_artist.entry(key).or_default().push(t);
     }
 
-    let cap = if popularity_bias == 0 {
+    let cap = if let Some(explicit) = max_tracks_per_artist {
+        Some((explicit as usize).max(1))
+    } else if popularity_bias == 0 {
         None
     } else {
         let b = popularity_bias as f64;
@@ -147,5 +151,49 @@ pub fn score_tracks(
         }
     }
 
-    by_artist.into_values().flatten().collect()
+    let mut result: Vec<ScoredTrack> = by_artist.into_values().flatten().collect();
+
+    // Step 3: Apply global popularity weighting
+    if _global_popularity > 0 {
+        let gp = _global_popularity.min(10) as usize;
+        let gp_exponent = POPULARITY_EXPONENTS[gp];
+        let gp_strength = _global_popularity as f64 / 10.0;
+
+        // Find max playcount across ALL artists
+        let global_max: u64 = top_tracks_by_artist
+            .values()
+            .flat_map(|tracks| tracks.iter().map(|t| t.playcount))
+            .max()
+            .unwrap_or(1)
+            .max(1);
+
+        // Build a global playcount lookup (lowercase name -> max playcount)
+        let mut global_playcounts: HashMap<String, u64> = HashMap::new();
+        for tracks in top_tracks_by_artist.values() {
+            for t in tracks {
+                let key = t.name.to_lowercase();
+                global_playcounts
+                    .entry(key)
+                    .and_modify(|c| *c = (*c).max(t.playcount))
+                    .or_insert(t.playcount);
+            }
+        }
+
+        for t in &mut result {
+            let playcount = t
+                .title
+                .as_ref()
+                .and_then(|title| global_playcounts.get(&title.to_lowercase()).copied())
+                .unwrap_or(0);
+
+            if playcount > 0 {
+                let global_pop = (playcount as f64 / global_max as f64).powf(gp_exponent);
+                // lerp(1.0, global_pop, gp_strength)
+                let factor = 1.0 + gp_strength * (global_pop - 1.0);
+                t.score *= factor;
+            }
+        }
+    }
+
+    result
 }