import { CellRef, cellRefEquals } from "../../types";

export type CellRange = [start: CellRef, end: CellRef];

export interface GridSelection {
  activeCellRef: CellRef;
  range?: CellRange;
}

export function extendSelection(
  selection: GridSelection | undefined,
  cellRef: CellRef,
): GridSelection {
  if (!selection || cellRefEquals(selection.activeCellRef, cellRef)) {
    return { activeCellRef: cellRef };
  }

  if (selection.range) {
    return { ...selection, range: [selection.range[0], cellRef] };
  }

  return { ...selection, range: [selection.activeCellRef, cellRef] };
}