{- | Applies a diff to a decklist. If a card doesn't exist during a change in copies it is ignored.
| This is ignored because we don't have a concept of default category.
-}
-- applyDiff :: DeckDiff -> DeckList -> DeckList
-- applyDiff [] ys = ys
-- applyDiff (x : xs) decklist =
--     case x of
--         Add a -> applyDiff xs (insert a decklist)
--         Remove a -> delete a decklist
--         ChangeCard name newQuan newCat ->
--             let newQuantity = newQuan . quantity <$> card 
--                 newCategory = card <$> newCat
--                 cardQuantity = fromIntegral . unrefine . runNumber . quantity
--                 card = Deck.find name decklist
--                 -- choice =
--                 --     either
--                 --         (const $ applyDiff (Remove name : xs) decklist)
--                 --         (\quantity -> update (\(x', _) -> (x', PositiveNumber quantity)) name decklist)
--                 -- choiceFind =
--                 --     maybe
--                 --         decklist
--                 --         (choice . refine . fromIntegral . newQuantity . cardQuantity)
--              in choiceFind card