Prevent selection of unselectable items when scrolling

src/Dodge/Combine.hs

@@ -6,7 +6,7 @@ module Dodge.Combine (
 ) where
 
 import Dodge.Data.Universe
-import Regex
+--import Regex
 import Dodge.DisplayInventory
 import Dodge.Render.HUD
 import Dodge.SelectionList
@@ -53,7 +53,6 @@ combineItemListYouX = map (first $ concatMap g) . lookupItems . yourInv
 
 combineList :: World -> [SelectionItem CombinableItem]
 combineList w = case combineList' w of
-    -- [] -> [SelectionInfo ["No possible combinations"] 1 False 0 white 0]
     [] -> [SelectionInfo ["No possible combinations"] 1 False white 0]
     xs -> xs
 
@@ -140,22 +139,26 @@ toggleCombineInv uv = case uv ^? uvWorld . hud . hudElement . subInventory of
 
 enterCombineInv :: Configuration -> World -> World
 enterCombineInv cfig w = w & hud . hudElement . subInventory .~ CombineInventory 
-    cm
+    cm'
     Nothing 
     sss
     --(updateCombineSelections w cfig sss)
   where
-    cm = IM.fromAscList $ zip [0..] $ combineList w
+    cm' = IM.fromAscList $ zip [0..] $ combineList' w 
+    cm | null cm' = IM.singleton 0 $ SelectionInfo ["No possible combinations"] 1 False white 0
+       | otherwise = cm'
     sss = SelectionSections  
         { _sssSections = IM.singleton 0 combsection
-        , _sssSelPos = Just (0,0)
+        , _sssSelPos = selpos
         }
+    selpos | null cm' = Nothing
+       | otherwise = Just (0,0)
     availablelines = getAvailableListLines secondColumnParams cfig
     combsection = updateSection cm (Just 0) availablelines combinationssection'
     combinationssection' = SelectionSection
         { _ssItems = cm
         , _ssCursor = do
-            (i,si) <- IM.lookupMin cm
+            (_,si) <- IM.lookupMin cm
             return $ SectionCursor 0 (length (_siPictures si)) (_siColor si)
         , _ssMinSize = 5
         , _ssOffset = 0