fix(gs/xanthous): Preserve character state when going up stairs r/2996

Carry over everything except the character's position when going up
stairs, so that eg the character doesn't lose everything they picked up
and instantly heal to full when going up a level.

Change-Id: I08513578a72f2410a363bbadbb273d95826a3f1b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3766
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

1 files changed, 7 insertions, 1 deletions

diff --git a/users/grfn/xanthous/src/Xanthous/App.hs b/users/grfn/xanthous/src/Xanthous/App.hs
index 689a6a35ca30..bb6d6cf4ddda 100644
--- a/users/grfn/xanthous/src/Xanthous/App.hs
+++ b/users/grfn/xanthous/src/Xanthous/App.hs
@@ -353,7 +353,13 @@ handleCommand GoUp = do
   hasStairs <- uses entitiesAtCharacter $ elem (SomeEntity UpStaircase)
   if hasStairs
   then uses levels prevLevel >>= \case
-    Just levs' -> levels .= levs'
+    Just levs' -> do
+      cEID <- use characterEntityID
+      pCharacter <- entities . at cEID <<.= Nothing
+      levels .= levs'
+      charPos <- use characterPosition
+      entities . at cEID .= pCharacter
+      characterPosition .= charPos
     Nothing ->
       -- TODO in nethack, this leaves the game. Maybe something similar here?
       say_ ["cant", "goUp"]