Improve left use equipment interaction with general equipment

src/Dodge/Creature/Impulse/UseItem.hs

@@ -22,7 +22,7 @@ itemEffect :: Creature -> Item -> World -> World
 itemEffect cr it w = case it ^? itUse of
     Just RightUse {_rUse = eff,_useMods = usemods} 
                     -> hammerTest $ foldr ($) eff usemods it cr
-    Just LeftUse {} -> setuhamdown $ lhammer setEquipLeftItem
+    Just LeftUse {} -> setuhamdown $ lhammer (setEquipLeftItem)
     Just EquipUse{} -> setuhamdown $ lhammer $ toggleEquipmentAt (_crInvSel cr) it
     -- ConsumeUse will cause problems if the item is not selected
     Just (ConsumeUse eff) -> setuhamdown $ hammerTest $ eff it cr . rmInvItem (_crID cr) (_crInvSel cr)
@@ -37,7 +37,15 @@ itemEffect cr it w = case it ^? itUse of
         _ -> id
     setEquipLeftItem cr' = case _crLeftInvSel cr' of
         Just i | i == _crInvSel cr' -> cr' & crLeftInvSel .~ Nothing
+            & crInvEquipped . at i .~ Nothing
+            -- if the following causes an exception we have reached a state that
+            -- should not be possible
+            & crEquipment . at (_crInvEquipped cr' IM.! i) .~ Nothing
+        -- Just i -> cr' & crLeftInvSel ?~ _crInvSel cr' 
+        -- should left use equipment be removed if replaced by left use
+        -- equipment that uses a different site?
         _ -> cr' & crLeftInvSel ?~ _crInvSel cr'
+            & equipUsingSiteCheck (_crInvSel cr') it
     setuhamdown = creatures . ix (_crID cr) . crHammerPosition .~ HammerDown
 
 toggleEquipmentAt :: Int -> Item -> Creature -> Creature
@@ -46,6 +54,12 @@ toggleEquipmentAt invid itm cr = case cr ^? crInvEquipped . ix invid of
         & crEquipment . at epos .~ Nothing
     Nothing -> equipUsingSite invid itm cr
 
+-- | First check if the item is already equiped, then do nothing
+equipUsingSiteCheck :: Int -> Item -> Creature -> Creature
+equipUsingSiteCheck invid itm cr
+    | isJust (cr ^? crInvEquipped . ix invid) = cr
+    | otherwise = equipUsingSite invid itm cr
+
 equipUsingSite :: Int -> Item -> Creature -> Creature
 equipUsingSite invid itm cr = cr
     & crInvEquipped . at invid ?~ epos
@@ -55,7 +69,10 @@ equipUsingSite invid itm cr = cr
     epos = eqSiteToPos cr (_eqSite $ _itUse itm)
     removeOtherEquipment = case cr ^? crEquipment . ix epos of
         Nothing -> id
-        Just oid -> crInvEquipped . at oid .~ Nothing
+        Just oid -> (crInvEquipped . at oid .~ Nothing) . removeIfLUse oid
+    removeIfLUse oid
+        | _crLeftInvSel cr == Just oid = crLeftInvSel .~ Nothing
+        | otherwise = id
 
 eqSiteToPos :: Creature -> EquipSite -> EquipPosition
 eqSiteToPos cr es = case es of
@@ -80,5 +97,7 @@ useLeftItem cid w
   where
     cr = _creatures w IM.! cid
     itmShouldBeUsed = isJust (cr ^? crInv . ix (_crInvSel cr) . itUse . cUse)
-        || isJust (cr ^? crInv . ix (_crInvSel cr) . itUse . eqUse)
+        || ( isJust (cr ^? crInv . ix (_crInvSel cr) . itUse . eqUse)
+            && _crLeftInvSel cr /= Just (_crInvSel cr)
+            )
     -- TODO determine itmShouldBeUsed with reference to config options