fix: use request track count, better mix artist similar songs

The plugin used a config value for the track count to return for
GetSimilarSongsByTrack, and returned everything for
GetSimilarSongsByArtist. This ignores the "count" parameter in the
request, which indicates how many songs the player wants.

This change makes use of this parameter and removes the plugin config
value to be better match what navidrome expects, and have one less thing
for users to configure / worry about.

For GetSimilarSongsByTrack we simply use the parameter from the query
and keep the same logic.

For GetSimilarSongsByArtist, however, no limit was implemented. Before
this change the plugin returned tracks in "clumps": a few tracks for
artist1, a few tracks for artist2, etc. I changed the logic to instead
alternate between the "base artist" (from the request) and related
artists, stopping when we have the desired number of tracks. This IMHO
better emulates the "radio" features of popular streaming services.

Author: ShimmerGlass

main.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/url"
+	"slices"
 	"strconv"
 
 	"github.com/navidrome/navidrome/plugins/pdk/go/metadata"
@@ -13,15 +14,13 @@ import (
 // Configuration keys (must match manifest.json)
 const (
 	configAPIUrl              = "apiUrl"
-	configTrackCount          = "trackCount"
 	configEliminateDuplicates = "eliminateDuplicates"
 	configRadiusSimilarity    = "radiusSimilarity"
 )
 
 // Default values
 const (
 	defaultAPIUrl              = "http://192.168.3.203:8000"
-	defaultTrackCount          = 200
 	defaultArtistSimilarCount  = 10
 	defaultEliminateDuplicates = true
 	defaultRadiusSimilarity    = true
@@ -81,17 +80,16 @@ func (p *audioMusePlugin) GetSimilarSongsByTrack(input metadata.SimilarSongsByTr
 
 	// Read configuration
 	apiBaseURL := getConfigString(configAPIUrl, defaultAPIUrl)
-	trackCount := getConfigInt(configTrackCount, defaultTrackCount)
 	eliminateDuplicates := getConfigBool(configEliminateDuplicates, defaultEliminateDuplicates)
 	radiusSimilarity := getConfigBool(configRadiusSimilarity, defaultRadiusSimilarity)
 
 	pdk.Log(pdk.LogDebug, fmt.Sprintf("[AudioMuse] Config - API URL: %s, TrackCount: %d, EliminateDuplicates: %v, RadiusSimilarity: %v",
-		apiBaseURL, trackCount, eliminateDuplicates, radiusSimilarity))
+		apiBaseURL, input.Count, eliminateDuplicates, radiusSimilarity))
 
 	// Build the API URL with query parameters
 	params := url.Values{}
 	params.Set("item_id", input.ID)
-	params.Set("n", strconv.Itoa(trackCount))
+	params.Set("n", strconv.Itoa(int(input.Count)))
 	params.Set("eliminate_duplicates", strconv.FormatBool(eliminateDuplicates))
 	params.Set("radius_similarity", strconv.FormatBool(radiusSimilarity))
 
@@ -151,37 +149,69 @@ func (p *audioMusePlugin) GetSimilarSongsByArtist(input metadata.SimilarSongsByA
 		return nil, err
 	}
 
-	// Collect unique song IDs preserving order
-	songIDs := make([]string, 0)
 	seen := make(map[string]bool)
 
+	// songSlices contains artist songs in alternating order: [baseArtist, relatedArtist1, baseArtist, relatedArtist2, ...]
+	songSlices := [][]metadata.SongRef{}
+
 	for _, a := range artists {
+		var artist1Songs, artist2Songs []metadata.SongRef
+
 		for _, cm := range a.ComponentMatches {
 			for _, s := range cm.Artist1RepresentativeSongs {
+
 				if s.ItemID == "" {
 					continue
 				}
-				if !seen[s.ItemID] {
-					seen[s.ItemID] = true
-					songIDs = append(songIDs, s.ItemID)
+				if seen[s.ItemID] {
+					continue
 				}
+
+				seen[s.ItemID] = true
+				artist1Songs = append(artist1Songs, metadata.SongRef{ID: s.ItemID, Name: s.Title})
 			}
+
 			for _, s := range cm.Artist2RepresentativeSongs {
 				if s.ItemID == "" {
 					continue
 				}
-				if !seen[s.ItemID] {
-					seen[s.ItemID] = true
-					songIDs = append(songIDs, s.ItemID)
+
+				if seen[s.ItemID] {
+					continue
 				}
+
+				seen[s.ItemID] = true
+				artist2Songs = append(artist2Songs, metadata.SongRef{ID: s.ItemID, Name: s.Title})
 			}
 		}
+
+		if len(artist1Songs) > 0 {
+			songSlices = append(songSlices, artist1Songs)
+		}
+		if len(artist2Songs) > 0 {
+			songSlices = append(songSlices, artist2Songs)
+		}
 	}
 
-	// Build SongRef list (names not always available)
-	songs := make([]metadata.SongRef, 0, len(songIDs))
-	for _, id := range songIDs {
-		songs = append(songs, metadata.SongRef{ID: id})
+	songs := make([]metadata.SongRef, 0, input.Count)
+
+	// get songs from our slices until we have enough or we ran out
+	artistID := 0
+	for len(songs) < int(input.Count) && len(songSlices) > 0 {
+		song := songSlices[artistID][0] // take a song
+		songs = append(songs, song)
+
+		songSlices[artistID] = songSlices[artistID][1:] // remove it from the pool
+
+		if len(songSlices[artistID]) == 0 {
+			// this slice has no more songs, remove it
+			songSlices = slices.Delete(songSlices, artistID, artistID+1)
+		} else {
+			// else, go to the next slice
+			artistID++
+		}
+
+		artistID = artistID % len(songSlices) // loop around if needed
 	}
 
 	pdk.Log(pdk.LogInfo, fmt.Sprintf("[AudioMuse] Returning %d artist-related songs to Navidrome", len(songs)))

manifest.json

@@ -15,14 +15,6 @@
           "description": "Base URL for the AudioMuse-AI server (e.g., http://192.168.3.203:8000).",
           "default": "http://192.168.3.203:8000"
         },
-        "trackCount": {
-          "type": "integer",
-          "title": "Number of Similar Tracks",
-          "description": "Maximum number of similar tracks to return. Default: 200",
-          "default": 200,
-          "minimum": 10,
-          "maximum": 500
-        },
         "artistSimilarCount": {
           "type": "integer",
           "title": "Number of Similar Artists",
@@ -62,10 +54,6 @@
           "type": "Group",
           "label": "Song Instant Mix",
           "elements": [
-            {
-              "type": "Control",
-              "scope": "#/properties/trackCount"
-            },
             {
               "type": "HorizontalLayout",
               "elements": [
@@ -100,7 +88,9 @@
     },
     "http": {
       "reason": "To call AudioMuse-AI API for similar tracks",
-      "requiredHosts": ["*"]
+      "requiredHosts": [
+        "*"
+      ]
     }
   }
-}
+}