Fixes for reliability of playback and fade-in support.

Author: JustinFreitas

src/main/kotlin/dev/arbjerg/ukulele/api/PlayerController.kt

@@ -22,7 +22,7 @@ class PlayerController(
     val botProps: BotProps
 ) {
 
-
+    private val log = org.slf4j.LoggerFactory.getLogger(PlayerController::class.java)
 
     @GetMapping("/guilds")
     fun getGuilds(): List<GuildDto> {
@@ -97,7 +97,7 @@ class PlayerController(
         }
 
         var identifiers = (body["url"] ?: "").split("|")
-// ... (rest of play method logic)
+        // ... (rest of play method logic)
         if (identifiers.isNotEmpty() && identifiers.first().isEmpty()) {
             identifiers = botProps.playlist.split("|")
         }
@@ -106,35 +106,43 @@ class PlayerController(
 
         identifiers.forEach { identifier ->
             val matcher = pattern.matcher(identifier)
+            var source = identifier
+            var queueLabel = ""
             if (matcher.find() && matcher.groupCount() == 2) {
-                // val queueLabel = if (matcher.group(1) != null) matcher.group(1) else ""
-                val source = if (matcher.group(2) != null) matcher.group(2) else ""
-                
-                if (source.isNotEmpty()) {
-                    apm.loadItemOrdered(player, source, object : AudioLoadResultHandler {
-                        override fun trackLoaded(track: AudioTrack) {
-                            if (botProps.prependQueueLabelToTitle && matcher.group(1) != null) {
-                                track.info.title = "${matcher.group(1)} - ${track.info.title}"
-                            }
-                            player.add(track)
+                if (matcher.group(1) != null) queueLabel = matcher.group(1)
+                if (matcher.group(2) != null) source = matcher.group(2)
+            } else {
+                log.warn("Pattern match failed for identifier: '{}', attempting to load as raw URL", identifier)
+            }
+            
+            if (source.isNotEmpty()) {
+                apm.loadItemOrdered(player, source, object : AudioLoadResultHandler {
+                    override fun trackLoaded(track: AudioTrack) {
+                        if (botProps.prependQueueLabelToTitle && queueLabel.isNotEmpty()) {
+                            track.info.title = "$queueLabel - ${track.info.title}"
                         }
-
-                        override fun playlistLoaded(playlist: AudioPlaylist) {
-                            if (playlist.isSearchResult) {
-                                val track = playlist.tracks.first()
-                                if (botProps.prependQueueLabelToTitle && matcher.group(1) != null) {
-                                    track.info.title = "${matcher.group(1)} - ${track.info.title}"
-                                }
-                                player.add(track)
-                            } else {
-                                player.add(*playlist.tracks.toTypedArray())
+                        player.add(track)
+                    }
+
+                    override fun playlistLoaded(playlist: AudioPlaylist) {
+                        if (playlist.isSearchResult) {
+                            val track = playlist.tracks.first()
+                            if (botProps.prependQueueLabelToTitle && queueLabel.isNotEmpty()) {
+                                track.info.title = "$queueLabel - ${track.info.title}"
                             }
+                            player.add(track)
+                        } else {
+                            player.add(*playlist.tracks.toTypedArray())
                         }
-
-                        override fun noMatches() {}
-                        override fun loadFailed(exception: FriendlyException) {}
-                    })
-                }
+                    }
+
+                    override fun noMatches() {
+                        log.warn("No matches found for source: {}", source)
+                    }
+                    override fun loadFailed(exception: FriendlyException) {
+                        log.error("Load failed for source: {}", source, exception)
+                    }
+                })
             }
         }
     }

src/main/kotlin/dev/arbjerg/ukulele/audio/Player.kt

@@ -197,6 +197,9 @@ class Player(private val beans: Beans, guildProperties: GuildProperties) : Audio
         // Reset the volume to the current guild volume config
         player.volume = scaleVolume(this.volume)
 
+        // Only apply queue label volume if the guild volume is not zero.
+        // This allows the client (e.g. ukulele-remote) to perform a seamless fade-in by
+        // starting the track at zero volume.
         if (this.volume > 0 && (!beans.botProps.normalization || !track.isReplayGainApplied())) {
             adjustVolumeFromQueueLabelVolumeMatcher(player, track)
         }