1 files changed, 23 insertions, 9 deletions
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Item.hs b/users/grfn/xanthous/src/Xanthous/Entities/Item.hs
index b50a5eab80..6647c42731 100644
--- a/users/grfn/xanthous/src/Xanthous/Entities/Item.hs
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Item.hs
@@ -1,49 +1,63 @@
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE RecordWildCards #-}
 --------------------------------------------------------------------------------
 module Xanthous.Entities.Item
   ( Item(..)
   , itemType
+  , density
+  , volume
   , newWithType
   , isEdible
+  , weight
   ) where
 --------------------------------------------------------------------------------
 import           Xanthous.Prelude
-import           Test.QuickCheck
+import           Test.QuickCheck (Arbitrary, CoArbitrary, Function)
 import           Data.Aeson (ToJSON, FromJSON)
 import           Data.Aeson.Generic.DerivingVia
+import           Control.Monad.Random (MonadRandom)
 --------------------------------------------------------------------------------
-import           Xanthous.Entities.RawTypes hiding (Item, description, isEdible)
+import           Xanthous.Entities.RawTypes (ItemType)
 import qualified Xanthous.Entities.RawTypes as Raw
 import           Xanthous.Game.State
+import           Xanthous.Data (Grams, Per, Cubic, Meters, (|*|))
+import           Xanthous.Util.QuickCheck (GenericArbitrary(GenericArbitrary))
+import           Xanthous.Random (choose, FiniteInterval(..))
 --------------------------------------------------------------------------------
 
 data Item = Item
   { _itemType :: ItemType
+  , _density  :: Grams `Per` Cubic Meters
+  , _volume   :: Cubic Meters
   }
   deriving stock (Eq, Show, Ord, Generic)
   deriving anyclass (NFData, CoArbitrary, Function)
   deriving Draw via DrawRawChar "_itemType" Item
+  deriving Arbitrary via GenericArbitrary Item
   deriving (ToJSON, FromJSON)
        via WithOptions '[ FieldLabelModifier '[Drop 1] ]
                        Item
 makeLenses ''Item
 
-{-# ANN Item ("HLint: ignore Use newtype instead of data" :: String )#-}
-
 -- deriving via (Brainless Item) instance Brain Item
 instance Brain Item where step = brainVia Brainless
 
-instance Arbitrary Item where
-  arbitrary = Item <$> arbitrary
-
 instance Entity Item where
   description = view $ itemType . Raw.description
   entityChar = view $ itemType . Raw.char
   entityCollision = const Nothing
 
-newWithType :: ItemType -> Item
-newWithType = Item
+newWithType :: MonadRandom m => ItemType -> m Item
+newWithType _itemType = do
+  _density <- choose . FiniteInterval $ _itemType ^. Raw.density
+  _volume  <- choose . FiniteInterval $ _itemType ^. Raw.volume
+  pure Item {..}
 
 isEdible :: Item -> Bool
 isEdible = Raw.isEdible . view itemType
+
+-- | The weight of this item, calculated by multiplying its volume by the
+-- density of its material
+weight :: Item -> Grams
+weight item = (item ^. density) |*| (item ^. volume)