feat(base): add pure next-cell navigation helper

apps/client/src/ee/base/utils/grid-cell-nav.ts

@@ -0,0 +1,33 @@
+import { CellCoord } from "@/ee/base/types/base.types";
+
+export function computeNextCell(
+  rowIds: string[],
+  colIds: string[],
+  current: CellCoord,
+  rowDelta: number,
+  colDelta: number,
+  wrap: boolean,
+): CellCoord | null {
+  const colIndex = colIds.indexOf(current.propertyId);
+  const rowIndex = rowIds.indexOf(current.rowId);
+  if (colIndex === -1 || rowIndex === -1) return null;
+
+  let nextCol = colIndex + colDelta;
+  let nextRow = rowIndex + rowDelta;
+
+  if (wrap) {
+    if (nextCol < 0) {
+      nextCol = colIds.length - 1;
+      nextRow -= 1;
+    } else if (nextCol >= colIds.length) {
+      nextCol = 0;
+      nextRow += 1;
+    }
+  } else if (nextCol < 0 || nextCol >= colIds.length) {
+    return null;
+  }
+
+  if (nextRow < 0 || nextRow >= rowIds.length) return null;
+
+  return { rowId: rowIds[nextRow], propertyId: colIds[nextCol] };
+}