refactor

lib/editor/draft/useUndoStack.ts

@@ -0,0 +1,80 @@
+import { useCallback, useState } from "react";
+import type { UndoAction } from "@/lib/editor/draft/editorTypes";
+import { geometryEquals } from "@/lib/editor/draft/draftDiff";
+
+type Options = {
+    applyUndoAction: (action: UndoAction) => boolean;
+};
+
+export function useUndoStack(options: Options) {
+    const { applyUndoAction } = options;
+    const [undoStack, setUndoStack] = useState<UndoAction[]>([]);
+
+    const pushUndo = useCallback((action: UndoAction) => {
+        setUndoStack((prev) => {
+            const last = prev[prev.length - 1];
+            if (isSameUndo(last, action)) return prev;
+            return [...prev, action];
+        });
+    }, []);
+
+    const undo = useCallback(() => {
+        let applied = false;
+        setUndoStack((prev) => {
+            if (applied) return prev;
+            if (!prev.length) return prev;
+
+            const last = prev[prev.length - 1];
+            const remaining = prev.slice(0, -1);
+            applied = true;
+
+            const didApply = applyUndoAction(last);
+            return didApply ? remaining : prev;
+        });
+    }, [applyUndoAction]);
+
+    const clearUndo = useCallback(() => {
+        setUndoStack([]);
+    }, []);
+
+    return {
+        undoStack,
+        pushUndo,
+        undo,
+        clearUndo,
+    };
+}
+
+function isSameUndo(a: UndoAction | undefined, b: UndoAction) {
+    if (!a) return false;
+    if (a.type !== b.type) return false;
+    switch (a.type) {
+        case "create": {
+            const next = b as Extract<UndoAction, { type: "create" }>;
+            return a.id === next.id;
+        }
+        case "delete": {
+            const next = b as Extract<UndoAction, { type: "delete" }>;
+            return (
+                a.feature.properties.id === next.feature.properties.id &&
+                geometryEquals(a.feature.geometry, next.feature.geometry)
+            );
+        }
+        case "update": {
+            const next = b as Extract<UndoAction, { type: "update" }>;
+            return (
+                a.id === next.id &&
+                geometryEquals(a.prevGeometry, next.prevGeometry)
+            );
+        }
+        case "properties": {
+            const next = b as Extract<UndoAction, { type: "properties" }>;
+            return (
+                a.id === next.id &&
+                JSON.stringify(a.prevProperties) === JSON.stringify(next.prevProperties)
+            );
+        }
+        default:
+            return false;
+    }
+}