Add file

src/Dodge/Inventory/CheckSlots.hs

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+module Dodge.Inventory.CheckSlots where
+import Dodge.Data
+import Dodge.Base.You
+
+--import Control.Lens
+import qualified Data.IntMap.Strict 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 >= _itInvSize it 
+                = Just $ maybe 0 ((+1) . fst) $ IM.lookupMax inv
+    | otherwise = Nothing
+  where 
+    ycr = you w
+    inv = _crInv ycr
+
+crNumFreeSlots :: Creature -> Int
+crNumFreeSlots cr = _crInvCapacity cr - invSize (_crInv cr)
+
+crInvSize :: Creature -> Int
+crInvSize = invSize . _crInv
+
+invSize :: IM.IntMap Item -> Int
+invSize = sum . fmap _itInvSize