First (buggy) implementation of rewind gun

src/Dodge/Item/Data.hs

@@ -27,6 +27,7 @@ data ItemIdentity
     | LongGun
     | Flamethrower
     | Blinker
+    | Rewinder
     | Grenade
     | RemoteBomb
     | TeslaGun

src/Dodge/Item/Weapon/Utility.hs

@@ -1,5 +1,6 @@
 module Dodge.Item.Weapon.Utility where
 import Dodge.Data
+import Dodge.Base
 import Dodge.Default
 import Dodge.Picture.Layer
 import Dodge.Creature.Action
@@ -7,11 +8,35 @@ import Dodge.Item.Weapon.TriggerType
 import Dodge.Default.Weapon
 import Geometry
 import Picture
---import qualified IntMapHelp as IM
+import qualified IntMapHelp as IM
 import Shape
 import ShapePicture
 
 import Control.Lens
+
+rewindGun :: Item
+rewindGun = defaultGun
+    { _itName = "REWINDER"
+    , _itIdentity = Rewinder
+    , _wpMaxAmmo  = 0
+    , _wpLoadedAmmo = 0
+    , _itUse = useRewindGun 
+    , _itEffect = ItRewindEffect rewindEffect []
+    , _itLeftClickUse = Just $ \cr invid -> useRewindGun (_crInv cr IM.! invid) cr
+    }
+rewindEffect :: ItEffect -> Creature -> Int -> World -> World
+rewindEffect iteff cr invid w = w & rewindWorlds %~ (take 100 . (w' : ))
+    & creatures . ix (_crID cr) . crInv . ix invid . wpLoadedAmmo .~ length (_rewindWorlds w)
+  where
+    w' = w & rewindWorlds .~ []
+
+useRewindGun :: Item -> Creature -> World -> World
+useRewindGun it cr w = case _rewindWorlds w of
+    (_:w':ws) -> w' & keys .~ _keys w
+        & mouseButtons .~ _mouseButtons w
+        & rewindWorlds .~ ws
+    _ -> w
+
 shrinkGun :: Item
 shrinkGun = defaultGun
     { _itName = "SHRINKER"