Add better control over substreams.

src/utils/camera.ts

@@ -28,12 +28,21 @@ export function getCameraID(
  * Get all cameras that depend on a given camera.
  * @param cameraManager The camera manager.
  * @param cameraID ID of the target camera.
- * @returns A set of dependent cameraIDs or null.
+ * @returns A set of dependent cameraIDs or null (since JS sets guarantee order,
+ * the first item in the set is guaranteed to be the cameraID itself).
  */
-export const getAllDependentCameras = (
+export function getAllDependentCameras(
+  cameraManager: CameraManager,
+  cameraID: string,
+): Set<string>;
+export function getAllDependentCameras(
   cameraManager?: CameraManager,
   cameraID?: string,
-): Set<string> | null => {
+): Set<string> | null;
+export function getAllDependentCameras(
+  cameraManager?: CameraManager,
+  cameraID?: string,
+): Set<string> | null {
   if (!cameraManager || !cameraID) {
     return null;
   }
@@ -45,9 +54,7 @@ export const getAllDependentCameras = (
     if (cameraConfig) {
       cameraIDs.add(cameraID);
       const dependentCameras: Set<string> = new Set();
-      (cameraConfig.dependencies.cameras || []).forEach((item) =>
-        dependentCameras.add(item),
-      );
+      cameraConfig.dependencies.cameras.forEach((item) => dependentCameras.add(item));
       if (cameraConfig.dependencies.all_cameras) {
         cameras.forEach((_, key) => dependentCameras.add(key));
       }
@@ -62,4 +69,4 @@ export const getAllDependentCameras = (
     getDependentCameras(cameraID);
   }
   return cameraIDs;
-};
+}

src/utils/substream.ts

@@ -0,0 +1,48 @@
+import { CameraManager } from '../camera-manager/manager';
+import { View } from '../view/view';
+import { getAllDependentCameras } from './camera';
+
+export const createViewWithSelectedSubstream = (
+  view: View,
+  substreamID: string,
+): View | null => {
+  const overrides: Map<string, string> = view.context?.live?.overrides ?? new Map();
+  overrides.set(view.camera, substreamID);
+  return view.clone().mergeInContext({
+    live: { overrides: overrides },
+  });
+};
+
+export const createViewWithoutSubstream = (view: View): View => {
+  const newView = view.clone();
+  const overrides: Map<string, string> | undefined = newView.context?.live?.overrides;
+  if (overrides && overrides.has(view.camera)) {
+    newView.context?.live?.overrides?.delete(view.camera);
+  }
+  return newView;
+};
+
+export const hasSubstream = (view: View): boolean => {
+  const override = view?.context?.live?.overrides?.get(view.camera);
+  return !!override && override !== view.camera;
+};
+
+export const createViewWithNextStream = (
+  cameraManager: CameraManager,
+  view: View,
+): View => {
+  const dependencies = [...getAllDependentCameras(cameraManager, view.camera)];
+  if (dependencies.length <= 1) {
+    return view.clone();
+  }
+
+  const newView = view.clone();
+  const overrides: Map<string, string> = newView.context?.live?.overrides ?? new Map();
+  const currentOverride = overrides.get(newView.camera) ?? newView.camera;
+  const currentIndex = dependencies.indexOf(currentOverride);
+  const newIndex = currentIndex < 0 ? 0 : (currentIndex + 1) % dependencies.length;
+  overrides.set(view.camera, dependencies[newIndex]);
+  newView.mergeInContext({ live: { overrides: overrides } });
+
+  return newView;
+};