update to the playlists. testing

shanty-playlist/src/lib.rs

@@ -9,5 +9,9 @@ pub mod selection;
 pub mod strategies;
 pub mod types;
 
-pub use strategies::{PlaylistError, genre_based, random, similar_artists, smart, to_m3u};
-pub use types::{Candidate, PlaylistRequest, PlaylistResult, PlaylistTrack, SmartRules};
+pub use strategies::{
+    CountryLookup, PlaylistError, genre_based, random, similar_artists, smart, to_m3u,
+};
+pub use types::{
+    Candidate, PlaylistRequest, PlaylistResult, PlaylistTrack, SimilarConfig, SmartRules,
+};

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
 }

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(),

shanty-playlist/src/strategies.rs

@@ -1,4 +1,6 @@
 use std::collections::{HashMap, HashSet};
+use std::future::Future;
+use std::pin::Pin;
 
 use sea_orm::DatabaseConnection;
 use shanty_data::{PopularTrack, SimilarArtist, SimilarArtistFetcher};
@@ -12,6 +14,16 @@ use crate::types::*;
 /// Cache TTL: 7 days in seconds.
 const CACHE_TTL: i64 = 7 * 24 * 3600;
 
+/// Trait for looking up an artist's country by MBID.
+/// Implementations should return quickly (local DB or cache), never blocking
+/// on rate-limited remote APIs during playlist generation.
+pub trait CountryLookup: Send + Sync {
+    fn get_country<'a>(
+        &'a self,
+        mbid: &'a str,
+    ) -> Pin<Box<dyn Future<Output = Option<String>> + Send + 'a>>;
+}
+
 /// Generate a playlist based on similar artists (the primary strategy).
 ///
 /// Flow:
@@ -26,9 +38,8 @@ pub async fn similar_artists(
     conn: &DatabaseConnection,
     fetcher: &impl SimilarArtistFetcher,
     seed_artists: Vec<String>,
-    count: usize,
-    popularity_bias: u8,
-    ordering: &str,
+    config: &SimilarConfig,
+    _country_fetcher: Option<&dyn CountryLookup>,
 ) -> Result<PlaylistResult, PlaylistError> {
     if seed_artists.is_empty() {
         return Err(PlaylistError::InvalidInput(
@@ -37,25 +48,32 @@ pub async fn similar_artists(
     }
 
     let num_seeds = seed_artists.len() as f64;
+    let seed_similarity = config.seed_weight as f64 * 0.2;
 
     // Merge similar artists from all seeds: key -> (name, total_score)
     let mut merged: HashMap<String, (String, f64)> = HashMap::new();
     // Track resolved seed names for enforcement (use DB names, not raw input)
     let mut resolved_seed_names: HashSet<String> = HashSet::new();
+    // Track which keys are seeds (for country filter)
+    let mut seed_keys: HashSet<String> = HashSet::new();
 
     for seed in &seed_artists {
         // Resolve the seed artist: try name lookup in DB
         let (artist_name, artist_mbid) = resolve_artist(conn, seed).await?;
         resolved_seed_names.insert(artist_name.clone());
 
-        // Insert the seed itself with score 1.0
         let key = artist_mbid
             .clone()
             .unwrap_or_else(|| artist_name.to_lowercase());
-        let entry = merged
-            .entry(key)
-            .or_insert_with(|| (artist_name.clone(), 0.0));
-        entry.1 += 1.0;
+        seed_keys.insert(key.clone());
+
+        // Insert the seed itself with configured weight
+        if seed_similarity > 0.0 {
+            let entry = merged
+                .entry(key.clone())
+                .or_insert_with(|| (artist_name.clone(), 0.0));
+            entry.1 += seed_similarity;
+        }
 
         // Fetch similar artists (cached or fresh)
         let similar = fetch_cached_similar(conn, fetcher, &artist_name, artist_mbid.as_deref())
@@ -71,11 +89,41 @@ pub async fn similar_artists(
         }
     }
 
-    // Normalize scores by seed count
-    let artists: Vec<(String, String, f64)> = merged
+    // Normalize scores by seed count, sort by similarity descending
+    let mut artists: Vec<(String, String, f64)> = merged
         .into_iter()
         .map(|(key, (name, total))| (key, name, total / num_seeds))
         .collect();
+    artists.sort_by(|a, b| b.2.partial_cmp(&a.2).unwrap_or(std::cmp::Ordering::Equal));
+
+    // Apply discovery range: truncate to pool size
+    let pool_size = discovery_pool_size(config.discovery_range);
+    artists.truncate(pool_size);
+
+    // Country filter: only keep artists from the same countries as seeds
+    if config.country_filter
+        && let Some(cf) = _country_fetcher
+    {
+        let mut seed_countries: HashSet<String> = HashSet::new();
+        for key in &seed_keys {
+            if let Some(country) = cf.get_country(key).await {
+                seed_countries.insert(country);
+            }
+        }
+
+        if !seed_countries.is_empty() {
+            let mut filtered = Vec::new();
+            for entry in artists {
+                let country = cf.get_country(&entry.0).await;
+                match country {
+                    Some(c) if seed_countries.contains(&c) => filtered.push(entry),
+                    None => filtered.push(entry), // unknown = pass through
+                    _ => {}                       // known but different = exclude
+                }
+            }
+            artists = filtered;
+        }
+    }
 
     // Build track and top-track maps for scoring
     let mut tracks_by_artist: HashMap<String, Vec<shanty_db::entities::track::Model>> =
@@ -104,7 +152,9 @@ pub async fn similar_artists(
         &artists,
         &tracks_by_artist,
         &top_tracks_by_artist,
-        popularity_bias,
+        config.popularity_bias,
+        config.global_popularity,
+        config.max_tracks_per_artist,
     );
 
     // Convert to candidates
@@ -123,10 +173,17 @@ pub async fn similar_artists(
         .collect();
 
     // Select (use resolved DB names for seed enforcement, not raw input)
-    let selected = selection::generate_playlist(&candidates, count, &resolved_seed_names);
+    let skip_seed_enforcement = config.seed_weight == 0;
+    let selected = selection::generate_playlist(
+        &candidates,
+        config.count,
+        &resolved_seed_names,
+        config.max_artists,
+        skip_seed_enforcement,
+    );
 
     // Order
-    let ordered = apply_ordering(selected, ordering);
+    let ordered = apply_ordering(selected, &config.ordering);
 
     Ok(PlaylistResult {
         tracks: candidates_to_tracks(ordered),
@@ -135,6 +192,14 @@ pub async fn similar_artists(
     })
 }
 
+/// Map discovery_range (0-10) to artist pool size.
+/// 0 -> 15, 5 -> ~100, 10 -> 500 (exponential curve).
+fn discovery_pool_size(range: u8) -> usize {
+    let r = range.min(10) as f64;
+    let size = 15.0 * (500.0_f64 / 15.0).powf(r / 10.0);
+    size.round() as usize
+}
+
 /// Generate a genre-based playlist.
 pub async fn genre_based(
     conn: &DatabaseConnection,
@@ -176,7 +241,7 @@ pub async fn genre_based(
         .collect();
 
     let seed_names = HashSet::new();
-    let selected = selection::generate_playlist(&candidates, count, &seed_names);
+    let selected = selection::generate_playlist(&candidates, count, &seed_names, None, true);
     let ordered = apply_ordering(selected, ordering);
 
     Ok(PlaylistResult {
@@ -306,7 +371,7 @@ pub async fn smart(
         .collect();
 
     let seed_names = HashSet::new();
-    let selected = selection::generate_playlist(&candidates, count, &seed_names);
+    let selected = selection::generate_playlist(&candidates, count, &seed_names, None, true);
     let ordered = ordering::interleave_artists(selected);
 
     Ok(PlaylistResult {

shanty-playlist/src/types.rs

@@ -17,6 +17,58 @@ pub struct PlaylistRequest {
     pub ordering: String,
     #[serde(default)]
     pub rules: Option<SmartRules>,
+
+    /// Discovery range: how many similar artists to consider (0-10).
+    /// 0 = focused (~15), 10 = wide open (~500). Default: 5.
+    #[serde(default)]
+    pub discovery_range: Option<u8>,
+    /// Global popularity weighting (0-10). 0 = off, 10 = strong bias toward
+    /// globally popular tracks across all artists. Default: 0.
+    #[serde(default)]
+    pub global_popularity: Option<u8>,
+    /// Filter to same countries as seed artists. Default: false.
+    #[serde(default)]
+    pub country_filter: Option<bool>,
+    /// Seed artist weight (0-10). 0 = exclude seeds, 5 = normal (similarity 1.0),
+    /// 10 = double weight (similarity 2.0). Default: 5.
+    #[serde(default)]
+    pub seed_weight: Option<u8>,
+    /// Explicit per-artist track cap. None or 0 = auto (derived from popularity_bias).
+    #[serde(default)]
+    pub max_tracks_per_artist: Option<u8>,
+    /// Maximum distinct artists in the result. None or 0 = unlimited.
+    #[serde(default)]
+    pub max_artists: Option<u8>,
+}
+
+/// Resolved configuration for the similar-artists strategy.
+#[derive(Debug, Clone)]
+pub struct SimilarConfig {
+    pub count: usize,
+    pub popularity_bias: u8,
+    pub ordering: String,
+    pub discovery_range: u8,
+    pub global_popularity: u8,
+    pub country_filter: bool,
+    pub seed_weight: u8,
+    pub max_tracks_per_artist: Option<u8>,
+    pub max_artists: Option<u8>,
+}
+
+impl SimilarConfig {
+    pub fn from_request(req: &PlaylistRequest) -> Self {
+        Self {
+            count: req.count,
+            popularity_bias: req.popularity_bias,
+            ordering: req.ordering.clone(),
+            discovery_range: req.discovery_range.unwrap_or(5),
+            global_popularity: req.global_popularity.unwrap_or(0),
+            country_filter: req.country_filter.unwrap_or(false),
+            seed_weight: req.seed_weight.unwrap_or(5),
+            max_tracks_per_artist: req.max_tracks_per_artist.filter(|&v| v > 0),
+            max_artists: req.max_artists.filter(|&v| v > 0),
+        }
+    }
 }
 
 fn default_count() -> usize {