feat: fix reduce motion controls

src/lib/background.ts

@@ -1,8 +1,6 @@
-const STORAGE_KEY = "background-motion-preference";
 const MOTION_QUERY = "(prefers-reduced-motion: reduce)";
 const STILL_STEPS = 5;
 
-type MotionPreference = "auto" | "off" | "on";
 type BackgroundMode = "animated" | "still" | "failed";
 
 interface BackgroundActions {
@@ -11,23 +9,7 @@ interface BackgroundActions {
   renderStill: (steps: number) => void;
 }
 
-function readPreference(): MotionPreference {
-  const stored = window.localStorage.getItem(STORAGE_KEY);
-  return stored === "off" || stored === "on" || stored === "auto"
-    ? stored
-    : "auto";
-}
-
-function writePreference(preference: MotionPreference) {
-  window.localStorage.setItem(STORAGE_KEY, preference);
-}
-
-function getMode(
-  preference: MotionPreference,
-  reducedMotion: boolean,
-): BackgroundMode {
-  if (preference === "on") return "animated";
-  if (preference === "off") return "still";
+function getMode(reducedMotion: boolean): BackgroundMode {
   return reducedMotion ? "still" : "animated";
 }
 
@@ -39,46 +21,22 @@ function applyCanvasState(mode: BackgroundMode) {
   }
 }
 
-function updateControls(
-  preference: MotionPreference,
-  mode: BackgroundMode,
-  reducedMotion: boolean,
-) {
-  const button = document.getElementById(
-    "background-toggle",
-  ) as HTMLButtonElement | null;
-  const status = document.getElementById("background-status");
-  if (!button || !status) return;
-
-  button.textContent = `motion ${preference}`;
-
-  if (mode === "failed") {
-    status.textContent = "background unavailable";
-    return;
-  }
-
-  if (mode === "still") {
-    status.textContent =
-      preference === "auto" && reducedMotion
-        ? "still frame"
-        : "background still";
-    return;
-  }
-
-  status.textContent = "background live";
-}
-
 export function initBackgroundControls(actions: BackgroundActions) {
   const media = window.matchMedia(MOTION_QUERY);
-  let preference = readPreference();
-  let mode: BackgroundMode = getMode(preference, media.matches);
+  let mode: BackgroundMode = getMode(media.matches);
+  let failed = false;
 
-  const applyMode = () => {
-    mode = getMode(preference, media.matches);
+  const applyMode = (restartAnimation = false) => {
+    if (failed) return;
+
+    mode = getMode(media.matches);
     applyCanvasState(mode);
-    updateControls(preference, mode, media.matches);
 
     if (mode === "animated") {
+      if (restartAnimation) {
+        actions.stop();
+      }
+
       actions.start();
       return;
     }
@@ -87,29 +45,34 @@ export function initBackgroundControls(actions: BackgroundActions) {
     actions.renderStill(STILL_STEPS);
   };
 
-  const button = document.getElementById(
-    "background-toggle",
-  ) as HTMLButtonElement | null;
+  const restartAnimation = () => {
+    if (document.visibilityState === "hidden" || media.matches) {
+      return;
+    }
 
-  button?.addEventListener("click", () => {
-    preference =
-      preference === "auto" ? "off" : preference === "off" ? "on" : "auto";
-    writePreference(preference);
-    applyMode();
-  });
+    applyMode(true);
+  };
 
   media.addEventListener("change", () => {
     applyMode();
   });
 
+  document.addEventListener("visibilitychange", () => {
+    restartAnimation();
+  });
+
+  window.addEventListener("pageshow", () => {
+    restartAnimation();
+  });
+
   return {
     applyInitialMode() {
       applyMode();
     },
     setFailed() {
+      failed = true;
       mode = "failed";
       applyCanvasState(mode);
-      updateControls(preference, mode, media.matches);
     },
   };
 }

src/lib/site.ts

@@ -38,9 +38,6 @@ export function renderFooter() {
         <span aria-hidden="true">|</span>
         <a href="/ssh.txt" data-native-link>ssh</a>
         <span aria-hidden="true">|</span>
-        <button type="button" id="background-toggle" class="qa-inline-action">motion auto</button>
-        <span id="background-status" class="qa-meta" aria-live="polite"></span>
-        <span aria-hidden="true">|</span>
         <a href="${mirror.href}">${mirror.label}</a>
       </div>
     </div>`;

src/styles/globals.css

@@ -352,10 +352,6 @@ a[aria-current="page"] {
   color: var(--dark-gray);
 }
 
-#background-status {
-  margin-top: 0;
-}
-
 .sr-only {
   position: absolute;
   width: 1px;