feat(voice): support per-client conversation mode state

packages/server/src/clients/connection-manager.ts

@@ -0,0 +1,128 @@
+import type { Logger } from "../logger"
+
+const STALE_CONNECTION_TIMEOUT_MS = 45000
+const STALE_SWEEP_INTERVAL_MS = 5000
+
+export interface ClientConnectionRef {
+  clientId: string
+  connectionId: string
+}
+
+export interface ClientConnectionRecord extends ClientConnectionRef {
+  key: string
+  connectedAt: number
+  lastSeenAt: number
+}
+
+type ConnectionChangeEvent = {
+  type: "connected" | "disconnected"
+  connection: ClientConnectionRecord
+  reason?: string
+}
+
+interface RegisteredConnection extends ClientConnectionRecord {
+  close: () => void
+}
+
+export class ClientConnectionManager {
+  private readonly connections = new Map<string, RegisteredConnection>()
+  private readonly subscribers = new Set<(event: ConnectionChangeEvent) => void>()
+  private readonly sweepTimer: NodeJS.Timeout
+
+  constructor(private readonly logger: Logger) {
+    this.sweepTimer = setInterval(() => this.sweepStaleConnections(), STALE_SWEEP_INTERVAL_MS)
+    this.sweepTimer.unref?.()
+  }
+
+  shutdown(): void {
+    clearInterval(this.sweepTimer)
+    for (const connection of Array.from(this.connections.values())) {
+      this.disconnect(connection.key, "shutdown", false)
+    }
+  }
+
+  subscribe(listener: (event: ConnectionChangeEvent) => void): () => void {
+    this.subscribers.add(listener)
+    return () => this.subscribers.delete(listener)
+  }
+
+  register(input: ClientConnectionRef & { close: () => void }): () => void {
+    const key = getConnectionKey(input)
+    const now = Date.now()
+    const existing = this.connections.get(key)
+
+    if (existing) {
+      this.logger.debug({ clientId: input.clientId, connectionId: input.connectionId }, "Replacing existing client connection")
+      this.disconnect(key, "replaced")
+    }
+
+    const connection: RegisteredConnection = {
+      key,
+      clientId: input.clientId,
+      connectionId: input.connectionId,
+      connectedAt: now,
+      lastSeenAt: now,
+      close: input.close,
+    }
+    this.connections.set(key, connection)
+    this.logger.debug({ clientId: input.clientId, connectionId: input.connectionId }, "Client connected")
+    this.notify({ type: "connected", connection })
+    return () => this.disconnect(key, "closed")
+  }
+
+  pong(input: ClientConnectionRef): boolean {
+    const key = getConnectionKey(input)
+    const connection = this.connections.get(key)
+    if (!connection) {
+      this.logger.debug({ clientId: input.clientId, connectionId: input.connectionId }, "Ignoring pong for unknown client connection")
+      return false
+    }
+
+    connection.lastSeenAt = Date.now()
+    return true
+  }
+
+  isConnected(input: ClientConnectionRef): boolean {
+    return this.connections.has(getConnectionKey(input))
+  }
+
+  private sweepStaleConnections(): void {
+    const cutoff = Date.now() - STALE_CONNECTION_TIMEOUT_MS
+    for (const connection of Array.from(this.connections.values())) {
+      if (connection.lastSeenAt > cutoff) continue
+      this.logger.debug({ clientId: connection.clientId, connectionId: connection.connectionId }, "Client connection timed out")
+      this.disconnect(connection.key, "timeout")
+    }
+  }
+
+  private disconnect(key: string, reason: string, invokeClose = true): void {
+    const connection = this.connections.get(key)
+    if (!connection) return
+    this.connections.delete(key)
+    this.logger.debug({ clientId: connection.clientId, connectionId: connection.connectionId, reason }, "Client disconnected")
+
+    if (invokeClose) {
+      try {
+        connection.close()
+      } catch (error) {
+        this.logger.warn({ err: error, clientId: connection.clientId, connectionId: connection.connectionId }, "Failed to close stale client connection")
+      }
+    }
+
+    this.notify({ type: "disconnected", connection, reason })
+  }
+
+  private notify(event: ConnectionChangeEvent): void {
+    for (const subscriber of this.subscribers) {
+      try {
+        subscriber(event)
+      } catch (error) {
+        this.logger.warn({ err: error, eventType: event.type }, "Client connection subscriber failed")
+      }
+    }
+  }
+}
+
+function getConnectionKey(input: ClientConnectionRef): string {
+  return `${input.clientId}:${input.connectionId}`
+}