From 73ee088605409cb01ef36b12418e45962a9d6c45 Mon Sep 17 00:00:00 2001
From: Half-Shot <will@half-shot.uk>
Date: Mon, 9 Dec 2024 15:19:27 +0000
Subject: [PATCH] Use call view model for hand raised reactions

---
 src/room/CallEventAudioRenderer.tsx | 20 ++++++--------------
 src/state/CallViewModel.ts          | 26 +++++++++++++++++++++++---
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/src/room/CallEventAudioRenderer.tsx b/src/room/CallEventAudioRenderer.tsx
index 6f4f0359..6412d23e 100644
--- a/src/room/CallEventAudioRenderer.tsx
+++ b/src/room/CallEventAudioRenderer.tsx
@@ -6,7 +6,7 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { ReactNode, useDeferredValue, useEffect, useMemo } from "react";
-import { filter, interval, throttle } from "rxjs";
+import { filter, interval, map, scan, throttle } from "rxjs";
 
 import { CallViewModel } from "../state/CallViewModel";
 import joinCallSoundMp3 from "../sound/join_call.mp3";
@@ -51,19 +51,6 @@ export function CallEventAudioRenderer({
   });
   const audioEngineRef = useLatest(audioEngineCtx);
 
-  const { raisedHands } = useReactions();
-  const raisedHandCount = useMemo(
-    () => Object.keys(raisedHands).length,
-    [raisedHands],
-  );
-  const previousRaisedHandCount = useDeferredValue(raisedHandCount);
-
-  useEffect(() => {
-    if (audioEngineRef.current && previousRaisedHandCount < raisedHandCount) {
-      audioEngineRef.current.playSound("raiseHand");
-    }
-  }, [audioEngineRef, previousRaisedHandCount, raisedHandCount]);
-
   useEffect(() => {
     const joinSub = vm.memberChanges
       .pipe(
@@ -89,9 +76,14 @@ export function CallEventAudioRenderer({
         audioEngineRef.current?.playSound("left");
       });
 
+    const handRaisedSub = vm.handRaised.subscribe(() => {
+      audioEngineRef.current?.playSound("raiseHand");
+    });
+
     return (): void => {
       joinSub.unsubscribe();
       leftSub.unsubscribe();
+      handRaisedSub.unsubscribe();
     };
   }, [audioEngineRef, vm]);
 
diff --git a/src/state/CallViewModel.ts b/src/state/CallViewModel.ts
index d9f12348..df56fb00 100644
--- a/src/state/CallViewModel.ts
+++ b/src/state/CallViewModel.ts
@@ -26,7 +26,6 @@ import {
   Subject,
   combineLatest,
   concat,
-  distinct,
   distinctUntilChanged,
   filter,
   forkJoin,
@@ -1099,13 +1098,16 @@ export class CallViewModel extends ViewModel {
   );
 
   public readonly handsRaised = new Subject<Record<string, Date>>();
-  public readonly reactions = new Subject<Record<string, ReactionOption>>();
+  private readonly reactions = new Subject<Record<string, ReactionOption>>();
 
   public updateReactions(data: ReturnType<typeof useReactions>) {
     this.handsRaised.next(data.raisedHands);
     this.reactions.next(data.reactions);
   }
 
+  /**
+   * Emits an array of reactions that should be visible on the screen.
+   */
   public readonly visibleReactions = showReactions.value
     .pipe(switchMap((show) => (show ? this.reactions : of({}))))
     .pipe(
@@ -1125,6 +1127,9 @@ export class CallViewModel extends ViewModel {
     )
     .pipe(this.scope.state());
 
+  /**
+   * Emits an array of reactions that should be played.
+   */
   public readonly audibleReactions = playReactionsSound.value
     .pipe(
       switchMap((show) =>
@@ -1147,10 +1152,25 @@ export class CallViewModel extends ViewModel {
         { playing: [], newSounds: [] },
       ),
       map((v) => v.newSounds),
-      distinct(),
     )
     .pipe(this.scope.state());
 
+  /**
+   * Emits an event every time a new hand is raised in
+   * the call.
+   */
+  public readonly handRaised = this.handsRaised.pipe(
+    map((v) => Object.keys(v).length),
+    scan(
+      (acc, newValue) => ({
+        value: newValue,
+        playSounds: newValue > acc.value,
+      }),
+      { value: 0, playSounds: false },
+    ),
+    filter((v) => v.playSounds),
+  );
+
   public constructor(
     // A call is permanently tied to a single Matrix room and LiveKit room
     private readonly matrixRTCSession: MatrixRTCSession,