update to the playlists. testing

shanty-playlist/src/selection.rs

@@ -11,6 +11,8 @@ pub fn generate_playlist(
     candidates: &[Candidate],
     n: usize,
     seed_names: &HashSet<String>,
+    max_artists: Option<u8>,
+    skip_seed_enforcement: bool,
 ) -> Vec<Candidate> {
     if candidates.is_empty() {
         return Vec::new();
@@ -20,8 +22,14 @@ pub fn generate_playlist(
     let mut pool: Vec<&Candidate> = candidates.iter().collect();
     let mut result: Vec<Candidate> = Vec::new();
     let mut artist_counts: HashMap<String, usize> = HashMap::new();
+    let mut distinct_artists_set: HashSet<String> = HashSet::new();
+    let max_distinct = max_artists.map(|m| (m as usize).max(1));
 
-    let seed_min = (n / 10).max(1);
+    let seed_min = if skip_seed_enforcement {
+        0
+    } else {
+        (n / 10).max(1)
+    };
 
     let distinct_artists: usize = {
         let mut seen = HashSet::new();
@@ -54,6 +62,13 @@ pub fn generate_playlist(
             .iter()
             .enumerate()
             .filter(|(_, c)| {
+                // Max distinct artists: reject new artists once we hit the cap
+                if let Some(max) = max_distinct
+                    && distinct_artists_set.len() >= max
+                    && !distinct_artists_set.contains(&c.artist)
+                {
+                    return false;
+                }
                 if force_seed {
                     seed_names.contains(&c.artist)
                 } else {
@@ -79,6 +94,7 @@ pub fn generate_playlist(
         let picked = indices[dist.sample(&mut rng)];
         let track = pool.remove(picked);
         *artist_counts.entry(track.artist.clone()).or_insert(0) += 1;
+        distinct_artists_set.insert(track.artist.clone());
         result.push(Candidate {
             score: track.score,
             artist: track.artist.clone(),