Extract scene registry helpers

src/main.js

@@ -2,30 +2,13 @@
   const { Engine, Render, Runner, World, Body, Constraint, Events, Vector } =
     Matter;
 
-  const { scenes = [], defaultSceneId } = window.PhysilinksScenes || {};
-  const getSceneById = (sceneId) =>
-    scenes.find((candidate) => candidate.id === sceneId) || null;
-
-  const getSceneIdFromUrl = () => {
-    try {
-      const params = new URLSearchParams(window.location.search);
-      const urlScene = params.get("scene");
-      return getSceneById(urlScene) ? urlScene : null;
-    } catch (err) {
-      return null;
-    }
-  };
-
-  const setSceneIdInUrl = (sceneId) => {
-    if (!sceneId) return;
-    try {
-      const url = new URL(window.location.href);
-      url.searchParams.set("scene", sceneId);
-      history.replaceState({}, "", `${url.pathname}${url.search}${url.hash}`);
-    } catch (err) {
-      // ignore history failures (blocked or unsupported)
-    }
-  };
+  const {
+    scenes = [],
+    defaultSceneId,
+    order: sceneOrder = [],
+  } = window.PhysilinksScenes || {};
+  const { getSceneById, getSceneIdFromUrl, setSceneIdInUrl, getNextSceneId } =
+    window.PhysilinksSceneRegistry || {};
 
   const defaultMessageConfig = {
     durationMs: 4200,
@@ -206,28 +189,6 @@
     updateHud();
   };
 
-  const getNextSceneId = () => {
-    const order = window.PhysilinksScenes?.order || [];
-    const currentId = currentScene?.id;
-    const orderedExisting = order.filter((id) =>
-      scenes.some((s) => s.id === id),
-    );
-    if (orderedExisting.length > 0 && currentId) {
-      const idx = orderedExisting.indexOf(currentId);
-      if (idx >= 0 && idx < orderedExisting.length - 1) {
-        return orderedExisting[idx + 1];
-      }
-      if (idx === orderedExisting.length - 1) {
-        return orderedExisting[0];
-      }
-    }
-    const fallbackIdx = scenes.findIndex((s) => s.id === currentId);
-    if (fallbackIdx >= 0 && fallbackIdx < scenes.length - 1) {
-      return scenes[fallbackIdx + 1].id;
-    }
-    return scenes[0]?.id || defaultSceneId;
-  };
-
   const chain = {
     active: false,
     color: null,
@@ -782,7 +743,12 @@
     onPauseToggle: () => setPaused(!isPaused),
     onRestart: restartGame,
     onSceneChange: (id) => applyScene(id),
-    onWinNext: () => applyScene(getNextSceneId()),
+    onWinNext: () =>
+      applyScene(
+        getNextSceneId
+          ? getNextSceneId(scenes, sceneOrder, currentScene) || currentScene?.id
+          : currentScene?.id,
+      ),
   });
   ui.setSceneOptions(
     scenes,

src/scene-registry.js

@@ -0,0 +1,53 @@
+(() => {
+  const getSceneById = (scenes, sceneId) =>
+    scenes.find((candidate) => candidate.id === sceneId) || null;
+
+  const getSceneIdFromUrl = (scenes) => {
+    try {
+      const params = new URLSearchParams(window.location.search);
+      const urlScene = params.get("scene");
+      return getSceneById(scenes, urlScene) ? urlScene : null;
+    } catch (err) {
+      return null;
+    }
+  };
+
+  const setSceneIdInUrl = (sceneId) => {
+    if (!sceneId) return;
+    try {
+      const url = new URL(window.location.href);
+      url.searchParams.set("scene", sceneId);
+      history.replaceState({}, "", `${url.pathname}${url.search}${url.hash}`);
+    } catch (err) {
+      // ignore history failures (blocked or unsupported)
+    }
+  };
+
+  const getNextSceneId = (scenes, order, currentScene) => {
+    const currentId = currentScene?.id;
+    const orderedExisting = order.filter((id) =>
+      scenes.some((s) => s.id === id),
+    );
+    if (orderedExisting.length > 0 && currentId) {
+      const idx = orderedExisting.indexOf(currentId);
+      if (idx >= 0 && idx < orderedExisting.length - 1) {
+        return orderedExisting[idx + 1];
+      }
+      if (idx === orderedExisting.length - 1) {
+        return orderedExisting[0];
+      }
+    }
+    const fallbackIdx = scenes.findIndex((s) => s.id === currentId);
+    if (fallbackIdx >= 0 && fallbackIdx < scenes.length - 1) {
+      return scenes[fallbackIdx + 1].id;
+    }
+    return scenes[0]?.id || null;
+  };
+
+  window.PhysilinksSceneRegistry = {
+    getSceneById,
+    getSceneIdFromUrl,
+    setSceneIdInUrl,
+    getNextSceneId,
+  };
+})();