From e79a1dec22f7da174cd2e3e7884ed535c67bc7fb Mon Sep 17 00:00:00 2001
From: Victor Giers <mail@victorgiers.com>
Date: Mon, 27 Apr 2026 15:42:22 +0200
Subject: [PATCH] Refactor simulation state management using dedicated
 controller

---
 src/app/App.tsx | 99 ++++++++-----------------------------------------
 1 file changed, 16 insertions(+), 83 deletions(-)

diff --git a/src/app/App.tsx b/src/app/App.tsx
index b6ea5544..1de1f4c7 100644
--- a/src/app/App.tsx
+++ b/src/app/App.tsx
@@ -3957,96 +3957,29 @@ export function App({ store, initialStatusMessage }: AppProps) {
   }, [editorState.projectDocument.time]);
 
   useEffect(() => {
-    setEditorSimulationClockOverride((currentClock) => {
-      if (currentClock === null) {
-        return null;
-      }
+    return editorSimulationController.subscribeUiSnapshot(
+      setEditorSimulationSnapshot
+    );
+  }, [editorSimulationController]);
 
-      const reconfiguredClock = reconfigureRuntimeClockState(
-        currentClock,
-        editorState.projectDocument.time
-      );
-
-      return areRuntimeClockStatesEqual(currentClock, reconfiguredClock)
-        ? currentClock
-        : reconfiguredClock;
+  useEffect(() => {
+    editorSimulationController.updateInputs({
+      document: editorState.document,
+      loadedModelAssets
     });
-  }, [editorState.projectDocument.time.dayLengthMinutes]);
-
-  useEffect(() => {
-    if (editorState.toolMode !== "play") {
-      return;
-    }
-
-    setEditorSimulationPlaying(false);
-  }, [editorState.toolMode]);
-
-  useEffect(() => {
-    if (editorState.toolMode === "play" || !editorSimulationPlaying) {
-      return;
-    }
-
-    let animationFrame = 0;
-    let previousFrameTime: number | null = null;
-
-    const tick = (timestamp: number) => {
-      if (previousFrameTime !== null) {
-        const dtSeconds = Math.min(
-          0.25,
-          (timestamp - previousFrameTime) / 1000
-        );
-        setEditorSimulationClockOverride((currentClock) =>
-          advanceRuntimeClockState(
-            currentClock ??
-              createRuntimeClockState(editorState.projectDocument.time),
-            dtSeconds
-          )
-        );
-      }
-
-      previousFrameTime = timestamp;
-      animationFrame = window.requestAnimationFrame(tick);
-    };
-
-    animationFrame = window.requestAnimationFrame(tick);
-
-    return () => {
-      if (animationFrame !== 0) {
-        window.cancelAnimationFrame(animationFrame);
-      }
-    };
-  }, [
-    editorSimulationPlaying,
-    editorState.projectDocument.time,
-    editorState.toolMode
-  ]);
+  }, [editorSimulationController, editorState.document, loadedModelAssets]);
 
   useEffect(() => {
     if (editorState.toolMode === "play") {
-      return;
+      editorSimulationController.pause();
     }
+  }, [editorSimulationController, editorState.toolMode]);
 
-    try {
-      const nextEditorSimulationScene = applyResolvedControlStateToRuntimeScene(
-        buildRuntimeSceneFromDocument(editorState.document, {
-          loadedModelAssets,
-          runtimeClock: editorSimulationClock
-        })
-      );
-      setEditorSimulationScene(nextEditorSimulationScene);
-      setEditorSimulationMessage(null);
-    } catch (error) {
-      setEditorSimulationScene(null);
-      setEditorSimulationMessage(getErrorMessage(error));
-    }
-  }, [
-    editorSimulationClock.dayCount,
-    editorSimulationClock.dayLengthMinutes,
-    editorSimulationClock.timeOfDayHours,
-    editorState.document,
-    editorState.toolMode,
-    loadedModelAssets
-  ]);
+  useEffect(() => {
+    return () => {
+      editorSimulationController.dispose();
+    };
+  }, [editorSimulationController]);
 
   useEffect(() => {
     if (selectedScheduleRoutineId === null) {