Allow for getting cached players

Author: duncte123

src/main/kotlin/dev/arbjerg/lavalink/client/LavalinkClient.kt

@@ -1,9 +1,9 @@
 package dev.arbjerg.lavalink.client
 
-import dev.arbjerg.lavalink.client.loadbalancing.builtin.DefaultLoadBalancer
 import dev.arbjerg.lavalink.client.loadbalancing.ILoadBalancer
 import dev.arbjerg.lavalink.client.loadbalancing.IRegionFilter
 import dev.arbjerg.lavalink.client.loadbalancing.VoiceRegion
+import dev.arbjerg.lavalink.client.loadbalancing.builtin.DefaultLoadBalancer
 import dev.arbjerg.lavalink.internal.ReconnectTask
 import dev.arbjerg.lavalink.protocol.v4.Message
 import reactor.core.Disposable
@@ -114,7 +114,6 @@ class LavalinkClient(val userId: Long) : Closeable, Disposable {
         if (!linkMap.containsKey(guildId)) {
             val bestNode = loadBalancer.selectNode(region)
             linkMap[guildId] = Link(guildId, bestNode)
-            bestNode.playerCache[guildId] = newPlayer(bestNode, guildId.toString())
         }
 
         return linkMap[guildId]!!

src/main/kotlin/dev/arbjerg/lavalink/client/LavalinkNode.kt

@@ -141,6 +141,27 @@ class LavalinkNode(
             }
     }
 
+    /**
+     * Gets a player from the local cache. If the player is not in the local cache, it will be created.
+     *
+     * @param guildId The guild id of the player.
+     *
+     * @return The local player. This player may not exist on the [LavalinkNode] yet.
+     */
+    fun getOrCreateCachedPlayer(guildId: Long): LavalinkPlayer {
+        val cachedPlayer = playerCache[guildId]
+
+        if (cachedPlayer == null) {
+            val newPlayer = newPlayer(this, guildId.toString())
+
+            playerCache[guildId] = newPlayer
+
+            return newPlayer
+        }
+
+        return cachedPlayer
+    }
+
     fun updatePlayer(guildId: Long, updateConsumer: Consumer<PlayerUpdateBuilder>): Mono<LavalinkPlayer> {
         val update = createOrUpdatePlayer(guildId)
 
@@ -386,7 +407,14 @@ class LavalinkNode(
         }
     }
 
-    internal fun getCachedPlayer(guildId: Long): LavalinkPlayer? = playerCache[guildId]
+    /**
+     * Get a [LavalinkPlayer] from the player cache.
+     *
+     * @return The cached player, or null if not yet cached.
+     *
+     * @see [getOrCreateCachedPlayer]
+     */
+    fun getCachedPlayer(guildId: Long): LavalinkPlayer? = playerCache[guildId]
 
     override fun equals(other: Any?): Boolean {
         if (this === other) return true

src/main/kotlin/dev/arbjerg/lavalink/client/Link.kt

@@ -22,10 +22,19 @@ class Link(
         internal set
 
     /**
-     * Gets the player for this link. If the player is not cached, it will be retrieved from the server.
+     * Gets the player for this link. If the player is not cached, it will be retrieved or created on the server.
+     *
+     * If you just want a local player instead, you can use [getOrCreateCachedPlayer]
      */
     fun getPlayer() = node.getPlayer(guildId)
 
+    /**
+     * Gets the cached player for this link. If the player is not cached it will be created locally.
+     *
+     * To ensure a player also exist on the node, you can use [getPlayer]
+     */
+    fun getOrCreateCachedPlayer() = node.getOrCreateCachedPlayer(guildId)
+
     /**
      * Destroys the player for this link. This will also remove the link from the client.
      */

src/main/kotlin/dev/arbjerg/lavalink/internal/LavalinkSocket.kt

@@ -70,7 +70,9 @@ class LavalinkSocket(private val node: LavalinkNode) : WebSocketListener(), Clos
                 val update = event as Message.PlayerUpdateEvent
                 val idLong = update.guildId.toLong()
 
-                node.getCachedPlayer(idLong)?.state = update.state
+                // Create a local player on the node if we don't have one.
+                // There probably is an edge-case where this will happen.
+                node.getOrCreateCachedPlayer(idLong).state = update.state
                 node.lavalink.getLinkIfCached(idLong)?.state = if (update.state.connected) {
                     LinkState.CONNECTED
                 } else {

testbot/src/main/java/me/duncte123/testbot/JDAListener.java

@@ -39,7 +39,8 @@ public void onReady(@NotNull ReadyEvent event) {
                 Commands.slash("join", "Join the voice channel you are in."),
                 Commands.slash("leave", "Leaves the vc"),
                 Commands.slash("stop", "Stops the current track"),
-                Commands.slash("pause", "Pause or unpause the plauer"),
+                Commands.slash("pause", "Pause or unpause the player"),
+                Commands.slash("now-playing", "Shows what is currently playing"),
                 Commands.slash("play", "Play a song")
                     .addOption(
                         OptionType.STRING,
@@ -75,6 +76,27 @@ public void onSlashCommandInteraction(@NotNull SlashCommandInteractionEvent even
                 event.getJDA().getDirectAudioController().disconnect(event.getGuild());
                 event.reply("Leaving your channel!").queue();
                 break;
+            case "now-playing": {
+                final var link = this.client.getLink(event.getGuild().getIdLong());
+                final var player = link.getOrCreateCachedPlayer();
+                final var track = player.getTrack();
+
+                if (track == null) {
+                    event.reply("Nothing playing currently!").queue();
+                    break;
+                }
+
+                final var trackInfo = track.getInfo();
+
+                event.reply(
+                    "Currently playing: %s\nDuration: %s/%s".formatted(
+                        trackInfo.getTitle(),
+                        player.getPosition(),
+                        trackInfo.getLength()
+                    )
+                ).queue();
+                break;
+            }
             case "pause":
                 this.client.getLink(event.getGuild().getIdLong())
                     .getPlayer()