chore: monorepo setup (#7175)

packages/voice/src/DataStore.ts

@@ -0,0 +1,189 @@
+import { GatewayOpcodes } from 'discord-api-types/v9';
+import type { AudioPlayer } from './audio';
+import type { VoiceConnection } from './VoiceConnection';
+
+export interface JoinConfig {
+	guildId: string;
+	channelId: string | null;
+	selfDeaf: boolean;
+	selfMute: boolean;
+	group: string;
+}
+
+/**
+ * Sends a voice state update to the main websocket shard of a guild, to indicate joining/leaving/moving across
+ * voice channels.
+ *
+ * @param config - The configuration to use when joining the voice channel
+ */
+export function createJoinVoiceChannelPayload(config: JoinConfig) {
+	return {
+		op: GatewayOpcodes.VoiceStateUpdate,
+		d: {
+			guild_id: config.guildId,
+			channel_id: config.channelId,
+			self_deaf: config.selfDeaf,
+			self_mute: config.selfMute,
+		},
+	};
+}
+
+// Voice Connections
+const groups = new Map<string, Map<string, VoiceConnection>>();
+groups.set('default', new Map());
+
+function getOrCreateGroup(group: string) {
+	const existing = groups.get(group);
+	if (existing) return existing;
+	const map = new Map<string, VoiceConnection>();
+	groups.set(group, map);
+	return map;
+}
+
+/**
+ * Retrieves the map of group names to maps of voice connections. By default, all voice connections
+ * are created under the 'default' group.
+ *
+ * @returns The group map
+ */
+export function getGroups() {
+	return groups;
+}
+
+/**
+ * Retrieves all the voice connections under the 'default' group.
+ *
+ * @param group - The group to look up
+ *
+ * @returns The map of voice connections
+ */
+export function getVoiceConnections(group?: 'default'): Map<string, VoiceConnection>;
+
+/**
+ * Retrieves all the voice connections under the given group name.
+ *
+ * @param group - The group to look up
+ *
+ * @returns The map of voice connections
+ */
+export function getVoiceConnections(group: string): Map<string, VoiceConnection> | undefined;
+
+/**
+ * Retrieves all the voice connections under the given group name. Defaults to the 'default' group.
+ *
+ * @param group - The group to look up
+ *
+ * @returns The map of voice connections
+ */
+export function getVoiceConnections(group = 'default') {
+	return groups.get(group);
+}
+
+/**
+ * Finds a voice connection with the given guild id and group. Defaults to the 'default' group.
+ *
+ * @param guildId - The guild id of the voice connection
+ * @param group - the group that the voice connection was registered with
+ *
+ * @returns The voice connection, if it exists
+ */
+export function getVoiceConnection(guildId: string, group = 'default') {
+	return getVoiceConnections(group)?.get(guildId);
+}
+
+export function untrackVoiceConnection(voiceConnection: VoiceConnection) {
+	return getVoiceConnections(voiceConnection.joinConfig.group)?.delete(voiceConnection.joinConfig.guildId);
+}
+
+export function trackVoiceConnection(voiceConnection: VoiceConnection) {
+	return getOrCreateGroup(voiceConnection.joinConfig.group).set(voiceConnection.joinConfig.guildId, voiceConnection);
+}
+
+// Audio Players
+
+// Each audio packet is 20ms long
+const FRAME_LENGTH = 20;
+
+let audioCycleInterval: NodeJS.Timeout | undefined;
+let nextTime = -1;
+
+/**
+ * A list of created audio players that are still active and haven't been destroyed.
+ */
+const audioPlayers: AudioPlayer[] = [];
+
+/**
+ * Called roughly every 20 milliseconds. Dispatches audio from all players, and then gets the players to prepare
+ * the next audio frame.
+ */
+function audioCycleStep() {
+	if (nextTime === -1) return;
+
+	nextTime += FRAME_LENGTH;
+	const available = audioPlayers.filter((player) => player.checkPlayable());
+
+	// eslint-disable-next-line @typescript-eslint/dot-notation
+	available.forEach((player) => player['_stepDispatch']());
+
+	prepareNextAudioFrame(available);
+}
+
+/**
+ * Recursively gets the players that have been passed as parameters to prepare audio frames that can be played
+ * at the start of the next cycle.
+ */
+function prepareNextAudioFrame(players: AudioPlayer[]) {
+	const nextPlayer = players.shift();
+
+	if (!nextPlayer) {
+		if (nextTime !== -1) {
+			audioCycleInterval = setTimeout(() => audioCycleStep(), nextTime - Date.now());
+		}
+		return;
+	}
+
+	// eslint-disable-next-line @typescript-eslint/dot-notation
+	nextPlayer['_stepPrepare']();
+
+	// setImmediate to avoid long audio player chains blocking other scheduled tasks
+	setImmediate(() => prepareNextAudioFrame(players));
+}
+
+/**
+ * Checks whether or not the given audio player is being driven by the data store clock.
+ *
+ * @param target - The target to test for
+ *
+ * @returns `true` if it is being tracked, `false` otherwise
+ */
+export function hasAudioPlayer(target: AudioPlayer) {
+	return audioPlayers.includes(target);
+}
+
+/**
+ * Adds an audio player to the data store tracking list, if it isn't already there.
+ *
+ * @param player - The player to track
+ */
+export function addAudioPlayer(player: AudioPlayer) {
+	if (hasAudioPlayer(player)) return player;
+	audioPlayers.push(player);
+	if (audioPlayers.length === 1) {
+		nextTime = Date.now();
+		setImmediate(() => audioCycleStep());
+	}
+	return player;
+}
+
+/**
+ * Removes an audio player from the data store tracking list, if it is present there.
+ */
+export function deleteAudioPlayer(player: AudioPlayer) {
+	const index = audioPlayers.indexOf(player);
+	if (index === -1) return;
+	audioPlayers.splice(index, 1);
+	if (audioPlayers.length === 0) {
+		nextTime = -1;
+		if (typeof audioCycleInterval !== 'undefined') clearTimeout(audioCycleInterval);
+	}
+}