export type SelectionType =
  | "replace"
  | "intersection"
  | "difference"
  | "symmetricDifference";

export function updateSelection<T extends string | number>(
  currentIds: T[],
  newIds: T | T[] | undefined,
  selectionType: SelectionType
) {
  const ids =
    newIds === undefined ? [] : Array.isArray(newIds) ? newIds : [newIds];

  switch (selectionType) {
    case "intersection":
      currentIds.push(...ids.filter((id) => !currentIds.includes(id)));
      return;
    case "difference":
      ids.forEach((id) => {
        const selectedIndex = currentIds.indexOf(id);
        currentIds.splice(selectedIndex, 1);
      });
      return;
    case "replace":
      // Update currentIds array in-place
      currentIds.length = 0;
      currentIds.push(...ids);
      return;
    case "symmetricDifference":
      ids.forEach((id) => {
        const selectedIndex = currentIds.indexOf(id);
        if (selectedIndex === -1) {
          currentIds.push(id);
        } else {
          currentIds.splice(selectedIndex, 1);
        }
      });
      return;
  }
}

export function makeSelection(
  a: string[],
  b: string[],
  selectionType: SelectionType
): string[] {
  const selection = [...a];
  updateSelection(selection, b, selectionType);
  return selection;
}

export function updateSelectionWithItem(
  selection: string[],
  elementId: string | undefined,
  shiftKey: boolean
) {
  if (elementId) {
    if (selection.includes(elementId)) {
      if (shiftKey && selection.length !== 1) {
        return makeSelection(selection, [elementId], "difference");
      } else {
        return selection;
      }
    } else {
      return makeSelection(
        selection,
        [elementId],
        shiftKey ? "intersection" : "replace"
      );
    }
  } else {
    return [];
  }
}