CardCollection setCards(CardCollection oldCards, CardCollection newCards, TrackableProperty key) {
if (newCards == null || newCards.isEmpty()) { // avoid storing empty collections
set(key, null);
return null;
}
set(key, CardView.getCollection(newCards)); // TODO prevent overwriting list if not necessary
return newCards;
}
void updateTargetCards(SpellAbilityStackInstance si) {
set(
TrackableProperty.TargetCards,
CardView.getCollection(si.getTargetChoices().getTargetCards()));
}