Added a popularity adjuster

src/main.rs

@@ -28,7 +28,7 @@ fn db_path() -> PathBuf {
 fn usage(program: &str) -> ! {
     eprintln!("Usage:");
     eprintln!("  {program} index [-v] [-f] <directory>");
-    eprintln!("  {program} build [-v] [-m|-a] [-s|-r] [-n COUNT] [file]");
+    eprintln!("  {program} build [-v] [-m|-a] [-s|-r] [-n COUNT] [-p LEVEL] [file]");
     std::process::exit(1);
 }
 
@@ -154,8 +154,9 @@ fn cmd_build(args: &[String]) {
         std::process::exit(1);
     }
 
-    // Parse -n COUNT
+    // Parse -n COUNT and -p LEVEL
     let mut count: usize = 20;
+    let mut popularity_bias: u8 = 5;
     let mut rest: Vec<&String> = Vec::new();
     let mut iter = args.iter().skip(2);
     while let Some(arg) = iter.next() {
@@ -175,13 +176,27 @@ fn cmd_build(args: &[String]) {
                     std::process::exit(1);
                 }
             }
+        } else if arg == "-p" {
+            match iter.next() {
+                Some(val) => match val.parse::<u8>() {
+                    Ok(n) if n <= 10 => popularity_bias = n,
+                    _ => {
+                        eprintln!("Error: -p requires an integer 0-10");
+                        std::process::exit(1);
+                    }
+                },
+                None => {
+                    eprintln!("Error: -p requires a value");
+                    std::process::exit(1);
+                }
+            }
         } else {
             rest.push(arg);
         }
     }
 
     if rest.len() > 1 {
-        eprintln!("Usage: {} build [-v] [-m|-a] [-s|-r] [-n COUNT] [file]", args[0]);
+        eprintln!("Usage: {} build [-v] [-m|-a] [-s|-r] [-n COUNT] [-p LEVEL] [file]", args[0]);
         std::process::exit(1);
     }
 
@@ -224,9 +239,13 @@ fn cmd_build(args: &[String]) {
         }
     };
 
-    build_playlist(&conn, &artist_mbid, &seed_name, count, verbose, mpd, airsonic, shuffle, random);
+    build_playlist(&conn, &artist_mbid, &seed_name, count, verbose, mpd, airsonic, shuffle, random, popularity_bias);
 }
 
+const POPULARITY_EXPONENTS: [f64; 11] = [
+    0.0, 0.03, 0.08, 0.15, 0.25, 0.35, 0.55, 0.85, 1.30, 1.80, 2.50,
+];
+
 fn build_playlist(
     conn: &rusqlite::Connection,
     artist_mbid: &str,
@@ -237,6 +256,7 @@ fn build_playlist(
     airsonic: bool,
     shuffle: bool,
     random: bool,
+    popularity_bias: u8,
 ) {
     let similar = match db::get_available_similar_artists(conn, artist_mbid) {
         Ok(a) => a,
@@ -302,13 +322,13 @@ fn build_playlist(
             let Some(playcount) = playcount else { continue };
 
             let popularity = if playcount > 0 {
-                (playcount as f64 / max_playcount as f64).powf(0.15)
+                (playcount as f64 / max_playcount as f64).powf(POPULARITY_EXPONENTS[popularity_bias as usize])
             } else {
                 0.0
             };
 
             let similarity = (match_score.exp()) / std::f64::consts::E;
-            let total = similarity * (1.0 + popularity);
+            let total = similarity * popularity;
             playlist.push((total, popularity, similarity, name.clone(), track_path.clone()));
         }
     }
@@ -337,12 +357,10 @@ fn build_playlist(
 
     let tracks: Vec<String> = selected.iter().map(|(_, _, p)| p.clone()).collect();
 
-    let local_dir = env::var("LOCAL_MUSIC_DIR").unwrap_or_default();
-
     if mpd {
-        let mpd_dir = env::var("MPD_MUSIC_DIR").unwrap_or_default();
-        if local_dir.is_empty() || mpd_dir.is_empty() {
-            eprintln!("Error: LOCAL_MUSIC_DIR and MPD_MUSIC_DIR must be set");
+        let music_dir = env::var("MPD_MUSIC_DIR").unwrap_or_default();
+        if music_dir.is_empty() {
+            eprintln!("Error: MPD_MUSIC_DIR not set");
             std::process::exit(1);
         }
         let mut client = match mpd::MpdClient::connect() {
@@ -352,7 +370,7 @@ fn build_playlist(
                 std::process::exit(1);
             }
         };
-        client.queue_playlist(&tracks, &local_dir, &mpd_dir);
+        client.queue_playlist(&tracks, &music_dir);
     } else if airsonic {
         let client = match airsonic::AirsonicClient::new() {
             Ok(c) => c,

src/mpd.rs

@@ -83,7 +83,7 @@ impl MpdClient {
         }
     }
 
-    pub fn queue_playlist(&mut self, tracks: &[String], local_dir: &str, mpd_dir: &str) {
+    pub fn queue_playlist(&mut self, tracks: &[String], music_dir: &str) {
         if let Err(e) = self.send_command("clear") {
             eprintln!("MPD clear: {e}");
             return;
@@ -92,7 +92,7 @@ impl MpdClient {
         let mut failed: Vec<String> = Vec::new();
 
         for track in tracks {
-            let uri = Self::track_to_uri(track, local_dir, mpd_dir);
+            let uri = Self::track_to_uri(track, music_dir);
             let escaped = uri.replace('\\', "\\\\").replace('"', "\\\"");
             if self.send_command(&format!("add \"{escaped}\"")).is_err() {
                 failed.push(uri.to_string());
@@ -117,12 +117,10 @@ impl MpdClient {
         }
     }
 
-    fn track_to_uri(track: &str, local_dir: &str, mpd_dir: &str) -> String {
-        let relative = track
-            .strip_prefix(local_dir)
+    fn track_to_uri<'a>(track: &'a str, music_dir: &str) -> &'a str {
+        track
+            .strip_prefix(music_dir)
             .map(|p| p.trim_start_matches('/'))
-            .unwrap_or(track);
-        let mpd_base = mpd_dir.trim_end_matches('/');
-        format!("{mpd_base}/{relative}")
+            .unwrap_or(track)
     }
 }