several small ui updates, plus hopefully a track-matching fix

frontend/src/pages/playlists.rs

@@ -41,7 +41,7 @@ pub fn playlists_page() -> Html {
     let seed_input = use_state(String::new);
     let seed_focused = use_state(|| false);
     let seeds = use_state(Vec::<String>::new);
-    let count = use_state(|| 50usize);
+    let count = use_state(|| 30usize);
     let popularity_bias = use_state(|| 5u8);
     let ordering = use_state(|| "interleave".to_string());
     let discovery_range = use_state(|| 5u8);
@@ -129,11 +129,23 @@ pub fn playlists_page() -> Html {
                     ordering: ordering_val,
                     rules: None,
                     discovery_range: Some(discovery_range_val),
-                    global_popularity: if global_popularity_val > 0 { Some(global_popularity_val) } else { None },
+                    global_popularity: if global_popularity_val > 0 {
+                        Some(global_popularity_val)
+                    } else {
+                        None
+                    },
                     country_filter: if country_filter_val { Some(true) } else { None },
                     seed_weight: Some(seed_weight_val),
-                    max_tracks_per_artist: if max_tpa_val > 0 { Some(max_tpa_val) } else { None },
-                    max_artists: if max_artists_val > 0 { Some(max_artists_val) } else { None },
+                    max_tracks_per_artist: if max_tpa_val > 0 {
+                        Some(max_tpa_val)
+                    } else {
+                        None
+                    },
+                    max_artists: if max_artists_val > 0 {
+                        Some(max_artists_val)
+                    } else {
+                        None
+                    },
                 };
 
                 match api::generate_playlist(&req).await {
@@ -437,7 +449,11 @@ pub fn playlists_page() -> Html {
                             }
                         })}
                     </div>
-                    <label>{ format!("Popularity Bias: {}", *popularity_bias) }</label>
+                    <label class="tooltip-wrap">
+                        { format!("Popularity Bias: {}", *popularity_bias) }
+                        <span class="tooltip-icon">{ "?" }</span>
+                        <span class="tooltip-text">{ "Controls how much to prefer an artist's popular tracks over deep cuts. 0 = all tracks equally likely, 10 = heavily favor their most-played songs." }</span>
+                    </label>
                     <input
                         type="range"
                         min="0" max="10"
@@ -452,8 +468,11 @@ pub fn playlists_page() -> Html {
                             })
                         }}
                     />
-                    <label>{ format!("Discovery Range: {}", *discovery_range) }
+                    <label class="tooltip-wrap">
+                        { format!("Discovery Range: {}", *discovery_range) }
                         <span class="text-sm text-muted">{ if *discovery_range <= 3 { " (focused)" } else if *discovery_range >= 7 { " (wide)" } else { "" } }</span>
+                        <span class="tooltip-icon">{ "?" }</span>
+                        <span class="tooltip-text">{ "How far from your seeds to explore. Low = only the most closely related artists. High = cast a wide net into loosely connected artists." }</span>
                     </label>
                     <input
                         type="range"
@@ -469,8 +488,11 @@ pub fn playlists_page() -> Html {
                             })
                         }}
                     />
-                    <label>{ format!("Seed Weight: {}", *seed_weight) }
+                    <label class="tooltip-wrap">
+                        { format!("Seed Weight: {}", *seed_weight) }
                         <span class="text-sm text-muted">{ if *seed_weight == 0 { " (exclude seeds)" } else if *seed_weight >= 8 { " (heavy)" } else { "" } }</span>
+                        <span class="tooltip-icon">{ "?" }</span>
+                        <span class="tooltip-text">{ "How much your seed artists themselves should appear in the playlist. 0 = only discoveries (seeds excluded), 5 = normal, 10 = seeds appear heavily." }</span>
                     </label>
                     <input
                         type="range"
@@ -486,8 +508,11 @@ pub fn playlists_page() -> Html {
                             })
                         }}
                     />
-                    <label>{ format!("Global Popularity: {}", *global_popularity) }
+                    <label class="tooltip-wrap">
+                        { format!("Global Popularity: {}", *global_popularity) }
                         <span class="text-sm text-muted">{ if *global_popularity == 0 { " (off)" } else { "" } }</span>
+                        <span class="tooltip-icon">{ "?" }</span>
+                        <span class="tooltip-text">{ "Boost tracks that are globally popular across all artists. Unlike Popularity Bias (which is per-artist), this favors well-known songs regardless of which artist they belong to." }</span>
                     </label>
                     <input
                         type="range"
@@ -503,24 +528,30 @@ pub fn playlists_page() -> Html {
                             })
                         }}
                     />
-                    <div class="form-group">
-                        <label>
-                            <input type="checkbox"
-                                checked={*country_filter}
-                                onchange={{
-                                    let cf = country_filter.clone();
-                                    Callback::from(move |e: Event| {
-                                        let input: HtmlInputElement = e.target_unchecked_into();
-                                        cf.set(input.checked());
-                                    })
-                                }}
-                            />
-                            { " Same countries as seed artists" }
-                        </label>
-                    </div>
-                    <div style="display: flex; gap: 1rem;">
-                        <div class="form-group" style="flex: 1;">
-                            <label>{ "Max Per Artist" }</label>
+                    <div class="playlist-controls-row">
+                        <div class="form-group">
+                            <label class="tooltip-wrap" style="white-space: nowrap;">
+                                <input type="checkbox"
+                                    checked={*country_filter}
+                                    onchange={{
+                                        let cf = country_filter.clone();
+                                        Callback::from(move |e: Event| {
+                                            let input: HtmlInputElement = e.target_unchecked_into();
+                                            cf.set(input.checked());
+                                        })
+                                    }}
+                                />
+                                { " Same countries" }
+                                <span class="tooltip-icon">{ "?" }</span>
+                                <span class="tooltip-text">{ "Only include artists from the same countries as your seed artists. Useful for getting music in a particular language. Requires a local MusicBrainz database for best results." }</span>
+                            </label>
+                        </div>
+                        <div class="form-group">
+                            <label class="tooltip-wrap">
+                                { "Max Per Artist" }
+                                <span class="tooltip-icon">{ "?" }</span>
+                                <span class="tooltip-text">{ "Maximum number of tracks from any single artist. 'Auto' ties this to the Popularity Bias setting." }</span>
+                            </label>
                             <select onchange={{
                                 let mtpa = max_tracks_per_artist.clone();
                                 Callback::from(move |e: Event| {
@@ -538,8 +569,12 @@ pub fn playlists_page() -> Html {
                                 })}
                             </select>
                         </div>
-                        <div class="form-group" style="flex: 1;">
-                            <label>{ "Max Artists" }</label>
+                        <div class="form-group">
+                            <label class="tooltip-wrap">
+                                { "Max Artists" }
+                                <span class="tooltip-icon">{ "?" }</span>
+                                <span class="tooltip-text">{ "Limit how many different artists appear in the playlist. Lower values give a tighter, more focused mix." }</span>
+                            </label>
                             <select onchange={{
                                 let ma = max_artists.clone();
                                 Callback::from(move |e: Event| {
@@ -557,20 +592,24 @@ pub fn playlists_page() -> Html {
                                 })}
                             </select>
                         </div>
-                    </div>
-                    <div class="form-group">
-                        <label>{ "Track Order" }</label>
-                        <select onchange={{
-                            let ord = ordering.clone();
-                            Callback::from(move |e: Event| {
-                                let select: HtmlSelectElement = e.target_unchecked_into();
-                                ord.set(select.value());
-                            })
-                        }}>
-                            <option value="interleave" selected={*ordering == "interleave"}>{ "Interleave (spread artists)" }</option>
-                            <option value="score" selected={*ordering == "score"}>{ "By Score (best first)" }</option>
-                            <option value="random" selected={*ordering == "random"}>{ "Random" }</option>
-                        </select>
+                        <div class="form-group">
+                            <label class="tooltip-wrap">
+                                { "Track Order" }
+                                <span class="tooltip-icon">{ "?" }</span>
+                                <span class="tooltip-text">{ "How to arrange tracks in the final playlist. Interleave spreads artists evenly, By Score puts the best matches first, Random shuffles everything." }</span>
+                            </label>
+                            <select onchange={{
+                                let ord = ordering.clone();
+                                Callback::from(move |e: Event| {
+                                    let select: HtmlSelectElement = e.target_unchecked_into();
+                                    ord.set(select.value());
+                                })
+                            }}>
+                                <option value="interleave" selected={*ordering == "interleave"}>{ "Interleave" }</option>
+                                <option value="score" selected={*ordering == "score"}>{ "By Score" }</option>
+                                <option value="random" selected={*ordering == "random"}>{ "Random" }</option>
+                            </select>
+                        </div>
                     </div>
                 </div>
             }
@@ -632,8 +671,12 @@ pub fn playlists_page() -> Html {
                     { strategy_inputs }
 
                     <div class="form-group">
-                        <label>{ format!("Count: {}", *count) }</label>
-                        <input type="range" min="10" max="200" step="10"
+                        <label class="tooltip-wrap">
+                            { format!("Count: {}", *count) }
+                            <span class="tooltip-icon">{ "?" }</span>
+                            <span class="tooltip-text">{ "Total number of tracks to include in the generated playlist." }</span>
+                        </label>
+                        <input type="range" min="10" max="100" step="5"
                             value={count.to_string()}
                             oninput={{
                                 let count = count.clone();

frontend/src/types.rs

@@ -377,7 +377,7 @@ pub struct GenerateRequest {
 }
 
 fn default_playlist_count() -> usize {
-    50
+    30
 }
 
 fn default_popularity_bias() -> u8 {

frontend/style.css

@@ -447,6 +447,59 @@ tr[draggable="true"]:active { cursor: grabbing; }
     .artist-photo { width: 80px; height: 80px; }
     .scroll-track { width: 18px; }
     .scroll-track-letter { font-size: 0.7rem; }
+    .playlist-controls-row { grid-template-columns: repeat(2, 1fr); }
+}
+
+/* Tooltips */
+.tooltip-wrap {
+    position: relative;
+    display: inline-flex;
+    align-items: center;
+    gap: 0.3rem;
+}
+.tooltip-icon {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 15px;
+    height: 15px;
+    border-radius: 50%;
+    background: var(--border);
+    color: var(--text-muted);
+    font-size: 0.65rem;
+    font-weight: bold;
+    cursor: help;
+    flex-shrink: 0;
+}
+.tooltip-text {
+    visibility: hidden;
+    opacity: 0;
+    position: absolute;
+    bottom: calc(100% + 6px);
+    left: 0;
+    width: 240px;
+    padding: 0.5rem 0.6rem;
+    background: var(--bg-tertiary);
+    color: var(--text-primary);
+    border: 1px solid var(--border);
+    border-radius: 6px;
+    font-size: 0.75rem;
+    line-height: 1.4;
+    z-index: 50;
+    pointer-events: none;
+    transition: opacity 0.15s;
+}
+.tooltip-wrap:hover .tooltip-text {
+    visibility: visible;
+    opacity: 1;
+}
+
+/* Playlist controls row */
+.playlist-controls-row {
+    display: grid;
+    grid-template-columns: repeat(4, 1fr);
+    gap: 1rem;
+    align-items: end;
 }
 
 /* Alphabetical scroll track — fixed to right edge next to browser scrollbar */

src/routes/subsonic/browsing.rs

@@ -2,6 +2,7 @@ use actix_web::{HttpRequest, HttpResponse, web};
 use std::collections::BTreeMap;
 
 use shanty_db::queries;
+use shanty_playlist::SimilarConfig;
 
 use crate::state::AppState;
 
@@ -995,3 +996,121 @@ pub async fn get_artist_info2(req: HttpRequest, state: web::Data<AppState>) -> H
         }),
     )
 }
+
+/// GET /rest/getSimilarSongs2[.view]
+pub async fn get_similar_songs2(req: HttpRequest, state: web::Data<AppState>) -> HttpResponse {
+    let (params, _user) = match authenticate(&req, &state).await {
+        Ok(v) => v,
+        Err(resp) => return resp,
+    };
+
+    let id_str = match get_query_param(&req, "id") {
+        Some(id) => id,
+        None => {
+            return response::error(
+                &params.format,
+                response::ERROR_MISSING_PARAM,
+                "missing required parameter: id",
+            );
+        }
+    };
+
+    let (_prefix, artist_id) = match parse_subsonic_id(&id_str) {
+        Some(v) => v,
+        None => {
+            return response::error(
+                &params.format,
+                response::ERROR_NOT_FOUND,
+                "invalid artist id",
+            );
+        }
+    };
+
+    let artist = match queries::artists::get_by_id(state.db.conn(), artist_id).await {
+        Ok(a) => a,
+        Err(_) => {
+            return response::error(
+                &params.format,
+                response::ERROR_NOT_FOUND,
+                "artist not found",
+            );
+        }
+    };
+
+    let count: usize = get_query_param(&req, "count")
+        .and_then(|v| v.parse().ok())
+        .unwrap_or(50);
+
+    // Need a Last.fm API key for similar artist lookups
+    let config = state.config.read().await;
+    let lastfm_key = config.metadata.lastfm_api_key.clone();
+    drop(config);
+
+    let api_key = match lastfm_key {
+        Some(k) if !k.is_empty() => k,
+        _ => {
+            return response::ok(
+                &params.format,
+                serde_json::json!({ "similarSongs2": { "song": [] } }),
+            );
+        }
+    };
+
+    let fetcher = match shanty_data::LastFmSimilarFetcher::new(api_key) {
+        Ok(f) => f,
+        Err(_) => {
+            return response::ok(
+                &params.format,
+                serde_json::json!({ "similarSongs2": { "song": [] } }),
+            );
+        }
+    };
+
+    let similar_config = SimilarConfig {
+        count,
+        popularity_bias: 5,
+        ordering: "random".to_string(),
+        discovery_range: 5,
+        global_popularity: 0,
+        country_filter: false,
+        seed_weight: 3,
+        max_tracks_per_artist: None,
+        max_artists: None,
+    };
+
+    let result = shanty_playlist::similar_artists(
+        state.db.conn(),
+        &fetcher,
+        vec![artist.name],
+        &similar_config,
+        None,
+    )
+    .await;
+
+    let songs: Vec<serde_json::Value> = match result {
+        Ok(playlist) => {
+            let mut songs = Vec::new();
+            for pt in &playlist.tracks {
+                if let Ok(track) =
+                    queries::tracks::get_by_id(state.db.conn(), pt.track_id).await
+                {
+                    songs.push(
+                        serde_json::to_value(SubsonicChild::from_track(&track))
+                            .unwrap_or_default(),
+                    );
+                }
+            }
+            songs
+        }
+        Err(_) => vec![],
+    };
+
+    response::ok(
+        &params.format,
+        serde_json::json!({
+            "similarSongs2": {
+                "song": songs,
+            }
+        }),
+    )
+}

src/routes/subsonic/mod.rs

@@ -73,6 +73,14 @@ pub fn configure(cfg: &mut web::ServiceConfig) {
                 "/getArtistInfo2.view",
                 web::get().to(browsing::get_artist_info2),
             )
+            .route(
+                "/getSimilarSongs2",
+                web::get().to(browsing::get_similar_songs2),
+            )
+            .route(
+                "/getSimilarSongs2.view",
+                web::get().to(browsing::get_similar_songs2),
+            )
             // Search
             .route("/search3", web::get().to(search::search3))
             .route("/search3.view", web::get().to(search::search3))