Allow for more complex placement positioning

src/Dodge/Room/Link.hs

@@ -16,6 +16,7 @@ module Dodge.Room.Link
     , changeLinkTo
     , changeLinkFrom
     , randomiseOutLinks
+    , chooseOneInLink
     ) where
 import Dodge.Placement.PlaceSpot
 import Dodge.LevelGen.Data
@@ -29,6 +30,17 @@ import Control.Monad.State
 import Control.Lens
 import Data.List
 import qualified Data.Set as S
+--import System.Random
+
+chooseOneInLink :: RandomGen g => Room -> State g Room
+chooseOneInLink r = restrictToFstInLink <$> shuffleLinks r
+
+restrictToFstInLink :: Room -> Room
+restrictToFstInLink = rmLinks %~ f
+  where
+    f (rl:xs) | S.member InLink (_rlType rl) = rl : restrictLinkType InLink (const False) xs
+        | otherwise = rl : f xs
+    f [] = []
 
 {- Shuffle the initial links of a room randomly. -}
 randomiseOutLinks :: RandomGen g => Room -> State g Room