Initial group calling support

ts/types/Calling.ts

@@ -1,6 +1,16 @@
 // Copyright 2020 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
+export enum CallMode {
+  None,
+  Direct,
+  Group,
+}
+
+// Ideally, we would import many of these directly from RingRTC. But because Storybook
+//   cannot import RingRTC (as it runs in the browser), we have these copies. That also
+//   means we have to convert the "real" enum to our enum in some cases.
+
 // Must be kept in sync with RingRTC.CallState
 export enum CallState {
   Prering = 'init',
@@ -31,6 +41,36 @@ export enum CallEndedReason {
   CallerIsNotMultiring = 'CallerIsNotMultiring',
 }
 
+// Must be kept in sync with RingRTC's ConnectionState
+export enum GroupCallConnectionState {
+  NotConnected = 0,
+  Connecting = 1,
+  Connected = 2,
+  Reconnecting = 3,
+}
+
+// Must be kept in sync with RingRTC's JoinState
+export enum GroupCallJoinState {
+  NotJoined = 0,
+  Joining = 1,
+  Joined = 2,
+}
+
+// Should match RingRTC's CanvasVideoRenderer
+interface Ref<T> {
+  readonly current: T | null;
+}
+export interface CanvasVideoRenderer {
+  setCanvas(canvas: Ref<HTMLCanvasElement> | undefined): void;
+  enable(source: VideoFrameSource): void;
+  disable(): void;
+}
+
+// Should match RingRTC's VideoFrameSource
+export interface VideoFrameSource {
+  receiveVideoFrame(buffer: ArrayBuffer): [number, number] | undefined;
+}
+
 // Must be kept in sync with RingRTC.AudioDevice
 export interface AudioDevice {
   // Device name.