module Dodge.Inventory.CheckSlots where

import Control.Lens
import Data.Maybe
import Dodge.Base.You
import Dodge.Data.World
import Dodge.Inventory.ItemSpace
import qualified IntMapHelp as IM

{- | checks whether or not an item will fit in your inventory
 if so return Just the next slot to be used
-}
checkInvSlotsYou :: Item -> World -> Maybe Int
checkInvSlotsYou it w
    | crNumFreeSlots ycr >= ceiling (_itInvSize it) =
        Just $ findItemSlot it inv
    | otherwise = Nothing
  where
    ycr = you w
    inv = _crInv ycr

-- Assumes that the item is singular.
-- Do not want to stack floor items for now
findItemSlot :: Item -> IM.IntMap Item -> Int
findItemSlot it inv = case it ^? itUse . useAmount of
    Just _ ->
        fromMaybe newslot $ IM.findIndex (\it' -> _itType it == _itType it') inv
    _ -> newslot
  where
    newslot = maybe 0 ((+ 1) . fst) $ IM.lookupMax inv

crNumFreeSlots :: Creature -> Int
crNumFreeSlots cr = _crInvCapacity cr - invSize (_crInv cr)

crInvSize :: Creature -> Int
crInvSize = invSize . _crInv

invSize :: IM.IntMap Item -> Int
invSize = sum . fmap itSlotsTaken