Tweak gormlak movement slightly

- Don't let gormlaks run into things like walls or each other
- Add a small element of randomness to gormlaks' motion
- Increase gormlaks' vision by a large amount

src/Xanthous/AI/Gormlak.hs

@@ -6,25 +6,43 @@ import           Xanthous.Prelude hiding (lines)
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 import           Data.Coerce
 import           Control.Monad.State
+import           Control.Monad.Random
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-import           Xanthous.Data (Positioned(..))
+import           Xanthous.Data (Positioned(..), positioned)
+import           Xanthous.Data.EntityMap
 import qualified Xanthous.Entities.Creature as Creature
 import           Xanthous.Entities.Creature (Creature)
+import           Xanthous.Entities.Character (Character)
 import qualified Xanthous.Entities.RawTypes as Raw
 import           Xanthous.Entities (Entity(..), Brain(..), brainVia)
-import           Xanthous.Game.State (entities, GameState)
+import           Xanthous.Game.State (entities, GameState, entityIs)
+import           Xanthous.Game.Lenses (Collision(..), collisionAt)
 import           Xanthous.Data.EntityMap.Graphics (linesOfSight)
+import           Xanthous.Random
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-stepGormlak :: MonadState GameState m => Positioned Creature -> m (Positioned Creature)
-stepGormlak (Positioned pos creature) = do
+stepGormlak
+  :: (MonadState GameState m, MonadRandom m)
+  => Positioned Creature
+  -> m (Positioned Creature)
+stepGormlak pe@(Positioned pos creature) = do
   lines <- uses entities $ linesOfSight pos (Creature.visionRadius creature)
+  line <- choose $ weightedBy length lines
+  -- traceShowM ("current position", pos)
+  -- traceShowM ("lines", (headMay <=< tailMay) <$> lines)
   let newPos = fromMaybe pos
                $ fmap fst
-               . headMay <=< tailMay <=< headMay
-               . sortOn (Down . length)
-               $ lines
-  pure $ Positioned newPos creature
+               . headMay
+               =<< tailMay
+               =<< line
+  collisionAt newPos >>= \case
+    Nothing -> pure $ Positioned newPos creature
+    Just Stop -> pure pe
+    Just Combat -> do
+      ents <- use $ entities . atPosition newPos
+      if | any (entityIs @Creature) ents -> pure pe
+         | any (entityIs @Character) ents -> undefined
+         | otherwise -> pure pe
 
 newtype GormlakBrain = GormlakBrain Creature