WIP voice channels

src/app/voice.ts

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+import {derived, get, writable} from "svelte/store"
+import * as nip19 from "nostr-tools/nip19"
+import {SignJWT} from "jose"
+import {Room, RoomEvent} from "livekit-client"
+import {now} from "@welshman/lib"
+import {makeEvent, normalizeRelayUrl, getTag} from "@welshman/util"
+import {pubkey, publishThunk} from "@welshman/app"
+import {deriveEventsForUrl, displayRoom} from "@app/core/state"
+
+export const LIVE_ACTIVITY = 30311
+export const ROOM_PRESENCE = 10312
+
+const LIVEKIT_URL = import.meta.env.VITE_LIVEKIT_URL || ""
+const LIVEKIT_API_KEY = import.meta.env.VITE_LIVEKIT_API_KEY || ""
+const LIVEKIT_API_SECRET = import.meta.env.VITE_LIVEKIT_API_SECRET || ""
+const PRESENCE_INTERVAL_MS = 60_000
+const PRESENCE_EXPIRY_S = 300
+
+export type VoiceSession = {
+  url: string
+  h: string
+  room: Room
+  muted: boolean
+}
+
+export const currentVoiceSession = writable<VoiceSession | undefined>(undefined)
+
+const makeLivekitRoomName = (url: string, h: string) =>
+  `${normalizeRelayUrl(url)}:${h}`.replace(/[^a-zA-Z0-9_-]/g, "_")
+
+const generateToken = async (roomName: string, identity: string) => {
+  const secret = new TextEncoder().encode(LIVEKIT_API_SECRET)
+  const jwt = await new SignJWT({
+    video: {roomJoin: true, room: roomName, canPublish: true, canSubscribe: true},
+    sub: identity,
+    iss: LIVEKIT_API_KEY,
+    jti: identity,
+  })
+    .setProtectedHeader({alg: "HS256"})
+    .setIssuedAt()
+    .setExpirationTime("6h")
+    .sign(secret)
+
+  return jwt
+}
+
+export const deriveVoiceParticipants = (url: string, h: string) =>
+  derived(deriveEventsForUrl(url, [{kinds: [ROOM_PRESENCE]}]), $events => {
+    const cutoff = now() - PRESENCE_EXPIRY_S
+    const pubkeys: string[] = []
+
+    for (const event of $events) {
+      if (event.created_at < cutoff) continue
+
+      const aTag = getTag("a", event.tags)
+      if (!aTag) continue
+
+      const [, , dTag] = aTag[1].split(":")
+      if (dTag === h) {
+        pubkeys.push(event.pubkey)
+      }
+    }
+
+    return pubkeys
+  })
+
+const publishLiveActivity = (url: string, h: string, status: "live" | "ended") => {
+  const pk = get(pubkey)!
+  const title = displayRoom(url, h)
+  const event = makeEvent(LIVE_ACTIVITY, {
+    tags: [
+      ["d", h],
+      ["h", h],
+      ["title", title],
+      ["service", LIVEKIT_URL],
+      ["status", status],
+      ["starts", String(now())],
+      ["p", pk, "", "Host"],
+    ],
+  })
+
+  return publishThunk({event, relays: [url]})
+}
+
+const publishPresence = (url: string, h: string) => {
+  const pk = get(pubkey)!
+  const aTag = `${LIVE_ACTIVITY}:${pk}:${h}`
+  const event = makeEvent(ROOM_PRESENCE, {
+    tags: [["a", aTag, url, "root"]],
+  })
+
+  return publishThunk({event, relays: [url]})
+}
+
+const deletePresence = (url: string) => {
+  const event = makeEvent(ROOM_PRESENCE, {tags: []})
+
+  return publishThunk({event, relays: [url]})
+}
+
+let presenceInterval: ReturnType<typeof setInterval> | undefined
+
+const startPresenceHeartbeat = (url: string, h: string) => {
+  stopPresenceHeartbeat()
+  publishPresence(url, h)
+  presenceInterval = setInterval(() => publishPresence(url, h), PRESENCE_INTERVAL_MS)
+}
+
+const stopPresenceHeartbeat = () => {
+  if (presenceInterval) {
+    clearInterval(presenceInterval)
+    presenceInterval = undefined
+  }
+}
+
+export const joinVoiceRoom = async (url: string, h: string) => {
+  const session = get(currentVoiceSession)
+
+  if (session) {
+    if (session.url === url && session.h === h) return
+    await leaveVoiceRoom()
+  }
+
+  const pk = get(pubkey)!
+  const identity = nip19.npubEncode(pk)
+  const roomName = makeLivekitRoomName(url, h)
+  const token = await generateToken(roomName, identity)
+
+  const room = new Room({
+    adaptiveStream: true,
+    dynacast: true,
+  })
+
+  room.on(RoomEvent.Disconnected, () => {
+    currentVoiceSession.set(undefined)
+    stopPresenceHeartbeat()
+  })
+
+  await room.connect(LIVEKIT_URL, token)
+  await room.localParticipant.setMicrophoneEnabled(true)
+
+  currentVoiceSession.set({url, h, room, muted: false})
+
+  publishLiveActivity(url, h, "live")
+  startPresenceHeartbeat(url, h)
+}
+
+export const leaveVoiceRoom = async () => {
+  const session = get(currentVoiceSession)
+  if (!session) return
+
+  stopPresenceHeartbeat()
+  session.room.disconnect()
+  deletePresence(session.url)
+  publishLiveActivity(session.url, session.h, "ended")
+  currentVoiceSession.set(undefined)
+}
+
+export const toggleMute = () => {
+  const session = get(currentVoiceSession)
+  if (!session) return
+
+  const muted = !session.muted
+  session.room.localParticipant.setMicrophoneEnabled(!muted)
+  currentVoiceSession.set({...session, muted})
+}
+
+export const toggleDeafen = () => {
+  const session = get(currentVoiceSession)
+  if (!session) return
+
+  for (const participant of session.room.remoteParticipants.values()) {
+    for (const pub of participant.audioTrackPublications.values()) {
+      pub.setEnabled(!pub.isEnabled)
+    }
+  }
+}