fix(room): preserve Viewer capacity across sharing generations (#307)

src/client/pages/HostPage.tsx

@@ -821,15 +821,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
     commitViewerQualityEvidence(peerId, null);
   }
 
-  function clearAllViewerQualityEvidence(): void {
-    viewerQualityEvidenceTimersRef.current.forEach((timer) =>
-      window.clearTimeout(timer),
-    );
-    viewerQualityEvidenceTimersRef.current.clear();
-    viewerQualityEvidenceRef.current = new Map();
-    setViewerQualityEvidence(new Map());
-  }
-
   function acceptViewerQualityEvidence(evidence: ViewerQualityEvidence): void {
     const peer = peersRef.current.get(evidence.viewerPeerId);
     const directSnapshot = peer?.getSnapshot() ?? null;
@@ -1395,7 +1386,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
       setViewerPasswordEnabled(message.viewerPasswordEnabled);
       setViewerPasswordDraft(authenticatedProfile.roomPassword ?? "");
       setViewerPasswordVisible(false);
-      clearAllViewerQualityEvidence();
       setSfuStandbyUrl(
         "sfuStandbyUrl" in message ? message.sfuStandbyUrl : null,
       );

src/client/webrtc/host-peer.ts

@@ -682,9 +682,9 @@ export class HostPeer {
     }
     switch (this.limitationReason) {
       case "bandwidth":
-        return "此发送连接持续按带宽估计降低分辨率或帧率";
+        return "当前连接带宽受限，画质已自动降低";
       case "cpu":
-        return "此发送连接持续因编码性能降低分辨率或帧率";
+        return "编码性能受限，画质已自动降低";
       case "other":
         return "浏览器持续报告其他画质限制";
       default:

src/server/hybrid-media-router.ts

@@ -918,11 +918,22 @@ export class HybridMediaRouter {
     this.options.deleteConnectionId(roomId, peerId);
     if (room?.controller?.confirmDeparture(peerId, this.now())) {
       this.requestPump(roomId);
+    } else if (room && !room.controller && room.advertisedCapacityByViewer.size === 0) {
+      this.rooms.delete(roomId);
     }
   }
 
   stopRoom(roomId: string): void {
+    const capacities = new Map(
+      this.rooms.get(roomId)?.advertisedCapacityByViewer ?? [],
+    );
     this.clearRoom(roomId);
+    if (capacities.size > 0) {
+      const room = this.room(roomId);
+      for (const [peerId, capacity] of capacities) {
+        room.advertisedCapacityByViewer.set(peerId, capacity);
+      }
+    }
   }
 
   deleteRoom(roomId: string): void {