feat(dees-dashboardgrid): implement collision detection during widget swap to prevent overlaps

test/test.dashboardgrid-layout.node.ts

@@ -0,0 +1,28 @@
+import { tap, expect } from '@push.rocks/tapbundle';
+
+import {
+  resolveWidgetPlacement,
+  collectCollisions,
+} from '../ts_web/elements/dees-dashboardgrid/layout.ts';
+import type { DashboardWidget } from '../ts_web/elements/dees-dashboardgrid/types.ts';
+
+tap.test('dashboardgrid does not overlap widgets after swap attempt', async () => {
+  const widgets: DashboardWidget[] = [
+    { id: 'w0', x: 6, y: 5, w: 1, h: 3 },
+    { id: 'w1', x: 6, y: 1, w: 1, h: 3 },
+    { id: 'w2', x: 3, y: 0, w: 2, h: 2 },
+    { id: 'w3', x: 9, y: 0, w: 1, h: 2 },
+    { id: 'w4', x: 4, y: 3, w: 1, h: 2 },
+  ];
+
+  const placement = resolveWidgetPlacement(widgets, 'w0', { x: 6, y: 3 }, 12);
+  expect(placement).toBeTruthy();
+
+  const layout = placement!.widgets;
+  for (const widget of layout) {
+    const collisions = collectCollisions(layout, widget, widget.x, widget.y, widget.w, widget.h);
+    expect(collisions).toBeEmptyArray();
+  }
+});
+
+export default tap.start();