Implement volume control #830 (#994)

Co-authored-by: Max Isom <hi@maxisom.me>

src/services/player.ts

@@ -8,7 +8,7 @@ import shuffle from 'array-shuffle';
 import {
   AudioPlayer,
   AudioPlayerState,
-  AudioPlayerStatus,
+  AudioPlayerStatus, AudioResource,
   createAudioPlayer,
   createAudioResource, DiscordGatewayAdapterCreator,
   joinVoiceChannel,
@@ -59,6 +59,8 @@ export interface PlayerEvents {
 
 type YTDLVideoFormat = videoFormat & {loudnessDb?: number};
 
+export const DEFAULT_VOLUME = 100;
+
 export default class {
   public voiceConnection: VoiceConnection | null = null;
   public status = STATUS.PAUSED;
@@ -69,6 +71,9 @@ export default class {
   private queue: QueuedSong[] = [];
   private queuePosition = 0;
   private audioPlayer: AudioPlayer | null = null;
+  private audioResource: AudioResource | null = null;
+  private volume?: number;
+  private defaultVolume: number = DEFAULT_VOLUME;
   private nowPlaying: QueuedSong | null = null;
   private playPositionInterval: NodeJS.Timeout | undefined;
   private lastSongURL = '';
@@ -83,6 +88,11 @@ export default class {
   }
 
   async connect(channel: VoiceChannel): Promise<void> {
+    // Always get freshest default volume setting value
+    const settings = await getGuildSettings(this.guildId);
+    const {defaultVolume = DEFAULT_VOLUME} = settings;
+    this.defaultVolume = defaultVolume;
+
     this.voiceConnection = joinVoiceChannel({
       channelId: channel.id,
       guildId: channel.guild.id,
@@ -120,6 +130,7 @@ export default class {
 
       this.voiceConnection = null;
       this.audioPlayer = null;
+      this.audioResource = null;
     }
   }
 
@@ -155,9 +166,7 @@ export default class {
       },
     });
     this.voiceConnection.subscribe(this.audioPlayer);
-    this.audioPlayer.play(createAudioResource(stream, {
-      inputType: StreamType.WebmOpus,
-    }));
+    this.playAudioPlayerResource(this.createAudioStream(stream));
     this.attachListeners();
     this.startTrackingPosition(positionSeconds);
 
@@ -220,11 +229,7 @@ export default class {
         },
       });
       this.voiceConnection.subscribe(this.audioPlayer);
-      const resource = createAudioResource(stream, {
-        inputType: StreamType.WebmOpus,
-      });
-
-      this.audioPlayer.play(resource);
+      this.playAudioPlayerResource(this.createAudioStream(stream));
 
       this.attachListeners();
 
@@ -408,6 +413,17 @@ export default class {
     return this.queue[this.queuePosition + to];
   }
 
+  setVolume(level: number): void {
+    // Level should be a number between 0 and 100 = 0% => 100%
+    this.volume = level;
+    this.setAudioPlayerVolume(level);
+  }
+
+  getVolume(): number {
+    // Only use default volume if player volume is not already set (in the event of a reconnect we shouldn't reset)
+    return this.volume ?? this.defaultVolume;
+  }
+
   private getHashForCache(url: string): string {
     return hasha(url);
   }
@@ -610,4 +626,24 @@ export default class {
       resolve(returnedStream);
     });
   }
+
+  private createAudioStream(stream: Readable) {
+    return createAudioResource(stream, {
+      inputType: StreamType.WebmOpus,
+      inlineVolume: true,
+    });
+  }
+
+  private playAudioPlayerResource(resource: AudioResource) {
+    if (this.audioPlayer !== null) {
+      this.audioResource = resource;
+      this.setAudioPlayerVolume();
+      this.audioPlayer.play(this.audioResource);
+    }
+  }
+
+  private setAudioPlayerVolume(level?: number) {
+    // Audio resource expects a float between 0 and 1 to represent level percentage
+    this.audioResource?.volume?.setVolume((level ?? this.getVolume()) / 100);
+  }
 }