feat: refactor sidebar to nested draggable lists with long-press gesture arbitration

packages/app/src/utils/sidebar-gesture-arbitration.test.ts

@@ -0,0 +1,78 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  decideLongPressMove,
+  shouldOpenContextMenuOnPressOut,
+} from "./sidebar-gesture-arbitration";
+
+describe("decideLongPressMove", () => {
+  it("keeps long press pending for small movement before long-press arm", () => {
+    expect(
+      decideLongPressMove({
+        longPressArmed: false,
+        didStartDrag: false,
+        startPoint: { x: 0, y: 0 },
+        currentPoint: { x: 3, y: 2 },
+      })
+    ).toBe("none");
+  });
+
+  it("cancels long press when movement exceeds cancel slop before arm", () => {
+    expect(
+      decideLongPressMove({
+        longPressArmed: false,
+        didStartDrag: false,
+        startPoint: { x: 0, y: 0 },
+        currentPoint: { x: 12, y: 0 },
+      })
+    ).toBe("cancel_long_press");
+  });
+
+  it("starts drag when movement exceeds drag slop after long-press arm", () => {
+    expect(
+      decideLongPressMove({
+        longPressArmed: true,
+        didStartDrag: false,
+        startPoint: { x: 0, y: 0 },
+        currentPoint: { x: 0, y: 9 },
+      })
+    ).toBe("start_drag");
+  });
+
+  it("does nothing when drag already started", () => {
+    expect(
+      decideLongPressMove({
+        longPressArmed: true,
+        didStartDrag: true,
+        startPoint: { x: 0, y: 0 },
+        currentPoint: { x: 20, y: 20 },
+      })
+    ).toBe("none");
+  });
+});
+
+describe("shouldOpenContextMenuOnPressOut", () => {
+  it("opens menu only when long-press is armed and drag did not start", () => {
+    expect(
+      shouldOpenContextMenuOnPressOut({
+        longPressArmed: true,
+        didStartDrag: false,
+      })
+    ).toBe(true);
+
+    expect(
+      shouldOpenContextMenuOnPressOut({
+        longPressArmed: false,
+        didStartDrag: false,
+      })
+    ).toBe(false);
+
+    expect(
+      shouldOpenContextMenuOnPressOut({
+        longPressArmed: true,
+        didStartDrag: true,
+      })
+    ).toBe(false);
+  });
+});
+