refactor: control character from scene (#58551)

client/src/templates/Challenges/components/scene/character.tsx

@@ -3,13 +3,14 @@ import { Characters, CharacterPosition } from '../../../../redux/prop-types';
 import { characterAssets } from './scene-assets';
 
 import './character.css';
+import { SceneSubject } from './scene-subject';
 
 interface CharacterProps {
   position: CharacterPosition;
   opacity: number;
   name: Characters;
-  isBlinking: boolean;
   isTalking: boolean;
+  sceneSubject: SceneSubject;
 }
 
 interface CharacterStyles {
@@ -27,29 +28,43 @@ export function Character({
   position,
   opacity,
   name,
-  isBlinking,
-  isTalking
+  isTalking,
+  sceneSubject
 }: CharacterProps): JSX.Element {
   const [eyesAreOpen, setEyesAreOpen] = useState(true);
   const [mouthIsOpen, setMouthIsOpen] = useState(false);
+  const [isPlaying, setIsPlaying] = useState(false);
+
+  const onNotify = (eventType: 'play' | 'stop') => {
+    if (eventType === 'play') {
+      setIsPlaying(true);
+    } else {
+      setIsPlaying(false);
+    }
+  };
 
   useEffect(() => {
-    let blinkIntervalId: NodeJS.Timeout;
+    sceneSubject.attach(onNotify);
+    return () => {
+      sceneSubject.detach(onNotify);
+    };
+  }, [sceneSubject]);
+
+  useEffect(() => {
+    if (!isPlaying) return;
     let blinkTimeoutId: NodeJS.Timeout;
 
-    if (isBlinking) {
-      const blinkPeriod = getRandomInt(2000, 5000);
-      blinkIntervalId = setInterval(() => {
-        const blinkJitter = getRandomInt(0, 1000);
-        blinkTimeoutId = setTimeout(() => {
-          setEyesAreOpen(false);
+    const blinkPeriod = getRandomInt(2000, 5000);
+    const blinkIntervalId = setInterval(() => {
+      const blinkJitter = getRandomInt(0, 1000);
+      blinkTimeoutId = setTimeout(() => {
+        setEyesAreOpen(false);
 
-          blinkTimeoutId = setTimeout(() => {
-            setEyesAreOpen(true);
-          }, 30); // always unblink after 30ms
-        }, blinkJitter);
-      }, blinkPeriod);
-    }
+        blinkTimeoutId = setTimeout(() => {
+          setEyesAreOpen(true);
+        }, 30); // always unblink after 30ms
+      }, blinkJitter);
+    }, blinkPeriod);
 
     // Clear intervals when component is unmounted or conditions change
     return () => {
@@ -57,9 +72,10 @@ export function Character({
       clearInterval(blinkIntervalId);
       clearTimeout(blinkTimeoutId);
     };
-  }, [isBlinking]);
+  }, [isPlaying]);
 
   useEffect(() => {
+    if (!isPlaying) return;
     let talkIntervalId: NodeJS.Timeout;
     let mouthOpenTimeoutId: NodeJS.Timeout;
     let mouthCloseTimeoutId: NodeJS.Timeout;
@@ -91,7 +107,7 @@ export function Character({
       clearTimeout(mouthOpenTimeoutId);
       clearTimeout(mouthCloseTimeoutId);
     };
-  }, [isTalking]);
+  }, [isTalking, isPlaying]);
 
   const characterWrapStyles: CharacterStyles = {
     opacity

client/src/templates/Challenges/components/scene/scene-subject.tsx

@@ -1,4 +1,4 @@
-type Observer = () => void;
+type Observer = (eventType: 'play' | 'stop') => void;
 
 export class SceneSubject {
   #observers: Observer[];
@@ -16,7 +16,7 @@ export class SceneSubject {
 
   // For now, we don't need to pass any data to the observers, so notify()
   // doesn't take any arguments.
-  notify() {
-    this.#observers.forEach(observer => observer());
+  notify(eventType: 'play' | 'stop') {
+    this.#observers.forEach(observer => observer(eventType));
   }
 }

client/src/templates/Challenges/components/scene/scene.tsx

@@ -153,7 +153,7 @@ export function Scene({
     canPauseRef.current = false;
   };
 
-  const playScene = useCallback(() => {
+  const handlePlay = useCallback(() => {
     const updateCurrentTime = () => {
       const time = Date.now() - startRef.current;
       setCurrentTime(time);
@@ -207,9 +207,9 @@ export function Scene({
       },
       duration + sToMs(audio.startTime)
     );
-  }, [isPlaying, sceneIsReady, audio, duration]);
+  }, [audio, duration, isPlaying, sceneIsReady]);
 
-  const resetScene = useCallback(() => {
+  const handleStop = useCallback(() => {
     usedCommandsRef.current.clear();
     pause();
     audioRef.current.currentTime = audio.startTimestamp || 0;
@@ -222,12 +222,27 @@ export function Scene({
     setBackground(initBackground);
   }, [audio, initCharacters, initBackground]);
 
+  const onNotify = useCallback(
+    (eventType: 'play' | 'stop') => {
+      if (eventType === 'play') {
+        handlePlay();
+      } else {
+        handleStop();
+      }
+    },
+    [handlePlay, handleStop]
+  );
+
+  const resetScene = useCallback(() => {
+    sceneSubject.notify('stop');
+  }, [sceneSubject]);
+
   useEffect(() => {
-    sceneSubject.attach(playScene);
+    sceneSubject.attach(onNotify);
     return () => {
-      sceneSubject.detach(playScene);
+      sceneSubject.detach(onNotify);
     };
-  }, [playScene, sceneSubject]);
+  }, [onNotify, sceneSubject]);
 
   useEffect(() => {
     if (isEmpty(sortedCommands)) return;
@@ -306,8 +321,8 @@ export function Scene({
                     name={character}
                     position={position}
                     opacity={opacity}
+                    sceneSubject={sceneSubject}
                     isTalking={isTalking}
-                    isBlinking={isPlaying}
                   />
                 );
               }
@@ -328,7 +343,7 @@ export function Scene({
               <div className='scene-start-screen'>
                 <button
                   className='scene-start-btn scene-play-btn'
-                  onClick={() => sceneSubject.notify()}
+                  onClick={() => sceneSubject.notify('play')}
                 >
                   <img
                     src={`${images}/play-button.png`}

client/src/templates/Challenges/generic/show.tsx

@@ -198,7 +198,7 @@ const ShowGeneric = ({
     <Hotkeys
       executeChallenge={handleSubmit}
       containerRef={container}
-      playScene={scene ? () => sceneSubject.notify() : undefined}
+      playScene={scene ? () => sceneSubject.notify('play') : undefined}
     >
       <LearnLayout>
         <Helmet