fix bug on hour fold update

src/components/GridStore.tsx

@@ -9,14 +9,13 @@ import { create } from "zustand";
 import {
   DEFAULT_BOUNDS,
   addFold,
-  foldAt,
-  normalizeFolds,
+  unfoldStrip,
   type Bounds,
   type FitLayout,
   type Fold,
 } from "../grid/fit";
 import { loadFolds, saveFolds } from "../grid/folds";
-import { bandAt, type Placed } from "./GridModel";
+import { bandAt, busyHours, type Placed } from "./GridModel";
 
 export type DragMode = "create" | "move" | "resize-start" | "resize-end";
 
@@ -82,9 +81,7 @@ export const useGrid = create<GridState>((set, get) => ({
     set({ folds });
   },
   unfold: (range) => {
-    const folds = saveFolds(
-      normalizeFolds(get().folds).filter((f) => f.end <= range.start || f.start >= range.end),
-    );
+    const folds = saveFolds(unfoldStrip(get().folds, busyHours(get().items), range));
     // An out-of-bounds band has no fold to remove, so widening the floor is what holds it open.
     const base = get().floor ?? get().layout?.bounds ?? DEFAULT_BOUNDS;
     set({
@@ -93,7 +90,7 @@ export const useGrid = create<GridState>((set, get) => ({
     });
   },
   toggleFold: (hour) => {
-    const { layout, hoverHour, items, folds } = get();
+    const { layout, hoverHour, items } = get();
     if (!layout) return;
     const at = hour ?? hoverHour;
     if (at === null || at === undefined) return;
@@ -103,11 +100,8 @@ export const useGrid = create<GridState>((set, get) => ({
       get().unfold({ start: segment.start / 60, end: segment.end / 60 });
       return;
     }
-    if (foldAt(folds, h)) {
-      get().unfold({ start: h, end: h + 1 });
-      return;
-    }
-    get().fold(bandAt(items, layout.bounds, h));
+    const band = bandAt(items, layout.bounds, h);
+    if (band) get().fold(band);
   },
   unfoldAll: () => {
     saveFolds([]);