feat(FN-4225): add mobile double-tap to select graph task nodes

Adds touch double-tap detection to the node drag hook, enabling mobile-friendly interactions on the graph canvas, with coverage in the node drag and GraphTaskNode test suites.

Fusion-Task-Id: FN-4225

plugins/fusion-plugin-dependency-graph/src/__tests__/useNodeDrag.test.ts

@@ -1,6 +1,6 @@
 import { act, renderHook } from "@testing-library/react";
 import type React from "react";
-import { describe, expect, it, vi } from "vitest";
+import { afterEach, describe, expect, it, vi } from "vitest";
 import { __internal, useNodeDrag } from "../hooks/useNodeDrag";
 
 function pointerEvent(overrides: Partial<PointerEvent> = {}) {
@@ -12,15 +12,23 @@ function pointerEvent(overrides: Partial<PointerEvent> = {}) {
   return {
     isPrimary: true,
     pointerId: 1,
+    pointerType: "mouse",
     clientX: 0,
     clientY: 0,
+    timeStamp: 0,
+    defaultPrevented: false,
     stopPropagation: vi.fn(),
+    preventDefault: vi.fn(),
     currentTarget: target,
     ...overrides,
   } as unknown as React.PointerEvent<HTMLElement>;
 }
 
 describe("useNodeDrag", () => {
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it("transitions pending to dragging and back on pointer up", () => {
     const onPositionChange = vi.fn();
     const onDragStateChange = vi.fn();
@@ -79,16 +87,99 @@ describe("useNodeDrag", () => {
     expect(result.current.isDragging).toBe(false);
   });
 
-  it("ignores pointer interactions when dragging is disabled", () => {
+  it("ignores position updates when dragging is disabled", () => {
     const onPositionChange = vi.fn();
     const { result } = renderHook(() =>
       useNodeDrag({ taskId: "A", position: { x: 0, y: 0 }, scale: 1, canDrag: false, onPositionChange }),
     );
 
-    act(() => result.current.onPointerDown(pointerEvent()));
-    act(() => result.current.onPointerMove(pointerEvent({ clientX: 8, clientY: 0 })));
+    act(() => result.current.onPointerDown(pointerEvent({ pointerType: "touch", timeStamp: 100 })));
+    act(() => result.current.onPointerMove(pointerEvent({ pointerType: "touch", clientX: 8, clientY: 0, timeStamp: 120 })));
 
     expect(result.current.isDragging).toBe(false);
     expect(onPositionChange).not.toHaveBeenCalled();
   });
+
+  it("fires onDoubleTap for qualifying touch taps and suppresses the follow-up click", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const onDoubleTap = vi.fn();
+    const { result } = renderHook(() =>
+      useNodeDrag({ taskId: "A", position: { x: 0, y: 0 }, scale: 1, canDrag: false, onPositionChange: vi.fn(), onDoubleTap }),
+    );
+
+    const firstDown = pointerEvent({ pointerId: 1, pointerType: "touch", clientX: 12, clientY: 16 });
+    const firstUp = pointerEvent({ pointerId: 1, pointerType: "touch", clientX: 12, clientY: 16, currentTarget: firstDown.currentTarget });
+    const secondDown = pointerEvent({ pointerId: 2, pointerType: "touch", clientX: 18, clientY: 20 });
+    const secondUp = pointerEvent({ pointerId: 2, pointerType: "touch", clientX: 18, clientY: 20, currentTarget: secondDown.currentTarget });
+
+    act(() => result.current.onPointerDown(firstDown));
+    act(() => result.current.onPointerUp(firstUp));
+    act(() => vi.advanceTimersByTime(120));
+    act(() => result.current.onPointerDown(secondDown));
+    act(() => result.current.onPointerUp(secondUp));
+
+    expect(onDoubleTap).toHaveBeenCalledTimes(1);
+    expect(secondUp.preventDefault).toHaveBeenCalledTimes(1);
+
+    const clickEvent = {
+      preventDefault: vi.fn(),
+      stopPropagation: vi.fn(),
+    } as unknown as React.MouseEvent<HTMLElement>;
+    act(() => result.current.onClickCapture(clickEvent));
+    expect(clickEvent.preventDefault).toHaveBeenCalledTimes(1);
+    expect(clickEvent.stopPropagation).toHaveBeenCalledTimes(1);
+  });
+
+  it("does not fire onDoubleTap when the second tap is too late", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const onDoubleTap = vi.fn();
+    const { result } = renderHook(() =>
+      useNodeDrag({ taskId: "A", position: { x: 0, y: 0 }, scale: 1, canDrag: false, onPositionChange: vi.fn(), onDoubleTap }),
+    );
+
+    act(() => result.current.onPointerDown(pointerEvent({ pointerId: 1, pointerType: "touch" })));
+    act(() => result.current.onPointerUp(pointerEvent({ pointerId: 1, pointerType: "touch" })));
+    act(() => vi.advanceTimersByTime(320));
+    act(() => result.current.onPointerDown(pointerEvent({ pointerId: 2, pointerType: "touch" })));
+    act(() => result.current.onPointerUp(pointerEvent({ pointerId: 2, pointerType: "touch" })));
+
+    expect(onDoubleTap).not.toHaveBeenCalled();
+  });
+
+  it("does not fire onDoubleTap for mouse pointer events", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const onDoubleTap = vi.fn();
+    const { result } = renderHook(() =>
+      useNodeDrag({ taskId: "A", position: { x: 0, y: 0 }, scale: 1, canDrag: false, onPositionChange: vi.fn(), onDoubleTap }),
+    );
+
+    act(() => result.current.onPointerDown(pointerEvent({ pointerId: 1, pointerType: "mouse" })));
+    act(() => result.current.onPointerUp(pointerEvent({ pointerId: 1, pointerType: "mouse" })));
+    act(() => vi.advanceTimersByTime(120));
+    act(() => result.current.onPointerDown(pointerEvent({ pointerId: 2, pointerType: "mouse" })));
+    act(() => result.current.onPointerUp(pointerEvent({ pointerId: 2, pointerType: "mouse" })));
+
+    expect(onDoubleTap).not.toHaveBeenCalled();
+  });
+
+  it("does not fire onDoubleTap after movement reaches the drag threshold", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const onDoubleTap = vi.fn();
+    const { result } = renderHook(() =>
+      useNodeDrag({ taskId: "A", position: { x: 0, y: 0 }, scale: 1, canDrag: false, onPositionChange: vi.fn(), onDoubleTap }),
+    );
+
+    act(() => result.current.onPointerDown(pointerEvent({ pointerId: 1, pointerType: "touch", clientX: 0, clientY: 0 })));
+    act(() => result.current.onPointerMove(pointerEvent({ pointerId: 1, pointerType: "touch", clientX: __internal.DRAG_THRESHOLD_PX, clientY: 0 })));
+    act(() => result.current.onPointerUp(pointerEvent({ pointerId: 1, pointerType: "touch", clientX: __internal.DRAG_THRESHOLD_PX, clientY: 0 })));
+    act(() => vi.advanceTimersByTime(120));
+    act(() => result.current.onPointerDown(pointerEvent({ pointerId: 2, pointerType: "touch", clientX: 0, clientY: 0 })));
+    act(() => result.current.onPointerUp(pointerEvent({ pointerId: 2, pointerType: "touch", clientX: 0, clientY: 0 })));
+
+    expect(onDoubleTap).not.toHaveBeenCalled();
+  });
 });