feat: added undo and redo functionality

test/pages/visProgPage/visualProgrammingUI/EditorUndoRedo.test.ts

@@ -0,0 +1,239 @@
+import {act} from '@testing-library/react';
+import useFlowStore from '../../../../src/pages/VisProgPage/visualProgrammingUI/VisProgStores.tsx';
+import { mockReactFlow } from '../../../setupFlowTests.ts';
+
+
+beforeAll(() => {
+  mockReactFlow();
+});
+
+describe("UndoRedo Middleware", () => {
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  test("pushSnapshot adds a snapshot to past and clears future", () => {
+    const store = useFlowStore;
+
+    store.setState({
+      nodes: [{
+        id: 'A',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'A'}
+      }],
+      edges: [],
+      past: [],
+      future: [{
+        nodes: [
+          {
+            id: 'A',
+            type: 'default',
+            position: {x: 0, y: 0},
+            data: {label: 'A'}
+          },
+        ],
+        edges: []
+      }],
+    });
+
+    act(() => {
+      store.getState().pushSnapshot();
+    })
+
+    const state = store.getState();
+    expect(state.past.length).toBe(1);
+    expect(state.past[0]).toEqual({
+      nodes: [{
+        id: 'A',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'A'}
+      }],
+      edges: []
+    });
+    expect(state.future).toEqual([]);
+  });
+
+  test("pushSnapshot does nothing during batch action", () => {
+    const store = useFlowStore;
+
+    act(() => {
+      store.setState({ isBatchAction: true });
+      store.getState().pushSnapshot();
+    })
+
+    expect(store.getState().past.length).toBe(0);
+  });
+
+  test("undo restores last snapshot and pushes current snapshot to future", () => {
+    const store = useFlowStore;
+
+    // initial state
+    store.setState({
+      nodes: [{
+        id: 'A',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'A'}
+      }],
+      edges: []
+    });
+
+    act(() => {
+      store.getState().pushSnapshot();
+
+      // modified state
+      store.setState({
+        nodes: [{
+          id: 'B',
+          type: 'default',
+          position: {x: 0, y: 0},
+          data: {label: 'B'}
+        }],
+        edges: []
+      });
+
+      store.getState().undo();
+    })
+
+    expect(store.getState().nodes).toEqual([{
+      id: 'A',
+      type: 'default',
+      position: {x: 0, y: 0},
+      data: {label: 'A'}
+    }]);
+    expect(store.getState().future.length).toBe(1);
+    expect(store.getState().future[0]).toEqual({
+      nodes: [{
+        id: 'B',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'B'}
+      }],
+      edges: []
+    });
+  });
+
+  test("undo does nothing when past is empty", () => {
+    const store = useFlowStore;
+
+    store.setState({past: []});
+
+    act(() => { store.getState().undo(); });
+
+    expect(store.getState().nodes).toEqual([]);
+    expect(store.getState().future).toEqual([]);
+  });
+
+  test("redo restores last future snapshot and pushes current to past", () => {
+    const store = useFlowStore;
+
+    // initial
+    store.setState({
+      nodes: [{
+        id: 'A',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'A'}
+      }],
+      edges: []
+    });
+
+    act(() => {
+      store.getState().pushSnapshot();
+      store.setState({
+        nodes: [{
+          id: 'B',
+          type: 'default',
+          position: {x: 0, y: 0},
+          data: {label: 'B'}
+        }],
+        edges: []
+      });
+
+
+      store.getState().undo();
+
+      // redo should restore node with id 'B'
+      store.getState().redo();
+    })
+
+    expect(store.getState().nodes).toEqual([{
+      id: 'B',
+      type: 'default',
+      position: {x: 0, y: 0},
+      data: {label: 'B'}
+    }]);
+    expect(store.getState().past.length).toBe(1); // snapshot A stored
+    expect(store.getState().past[0]).toEqual({
+      nodes: [{
+        id: 'A',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'A'}
+      }],
+      edges: []
+    });
+  });
+
+  test("redo does nothing when future is empty", () => {
+    const store = useFlowStore;
+
+    store.setState({past: []});
+    act(() => { store.getState().redo(); });
+
+    expect(store.getState().nodes).toEqual([]);
+  });
+
+  test("beginBatchAction pushes snapshot and sets isBatchAction=true", () => {
+    const store = useFlowStore;
+
+    store.setState({
+      nodes: [{
+        id: 'A',
+        type: 'default',
+        position: {x: 0, y: 0},
+        data: {label: 'A'}
+      }],
+      edges: []
+    });
+
+    act(() => { store.getState().beginBatchAction(); });
+
+    expect(store.getState().isBatchAction).toBe(true);
+    expect(store.getState().past.length).toBe(1);
+  });
+
+  test("endBatchAction sets isBatchAction=false after timeout", () => {
+    const store = useFlowStore;
+
+    store.setState({ isBatchAction: true });
+    act(() => { store.getState().endBatchAction(); });
+
+    // isBatchAction should remain true before the timer has advanced
+    expect(store.getState().isBatchAction).toBe(true);
+
+    jest.advanceTimersByTime(10);
+
+    // it should now be set to false as the timer has advanced enough
+    expect(store.getState().isBatchAction).toBe(false);
+  });
+
+  test("multiple beginBatchAction calls clear the timeout", () => {
+    const store = useFlowStore;
+
+    act(() => {
+      store.getState().beginBatchAction();
+      store.getState().endBatchAction(); // starts timeout
+      store.getState().beginBatchAction(); // should clear previous timeout
+    });
+
+
+    jest.advanceTimersByTime(10);
+
+    // After advancing the timers, isBatchAction should still be true,
+    // as the timeout should have been cleared
+    expect(store.getState().isBatchAction).toBe(true);
+  });
+});

test/setupFlowTests.ts

@@ -69,6 +69,9 @@ beforeAll(() => {
   useFlowStore.setState({
     nodes: [],
     edges: [],
+    past: [],
+    future: [],
+    isBatchAction: false,
     edgeReconnectSuccessful: true
   });
 });
@@ -78,6 +81,9 @@ afterEach(() => {
   useFlowStore.setState({
     nodes: [],
     edges: [],
+    past: [],
+    future: [],
+    isBatchAction: false,
     edgeReconnectSuccessful: true
   });
 });