refactor(users/glittershark): Rename to grfn r/2485

Rename my //users directory and all places that refer to glittershark to
grfn, including nix references and documentation.

This may require some extra attention inside of gerrit's database after
it lands to allow me to actually push things.

Change-Id: I4728b7ec2c60024392c1c1fa6e0d4a59b3e266fa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2933
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: glittershark <grfn@gws.fyi>

14 files changed, 1021 insertions, 0 deletions

diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Character.hs b/users/grfn/xanthous/src/Xanthous/Entities/Character.hs
new file mode 100644
index 0000000000..c18d726a4b
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Character.hs
@@ -0,0 +1,276 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Xanthous.Entities.Character
+  ( Character(..)
+  , characterName
+  , inventory
+  , characterDamage
+  , characterHitpoints'
+  , characterHitpoints
+  , hitpointRecoveryRate
+  , speed
+
+    -- * Inventory
+  , Inventory(..)
+  , backpack
+  , wielded
+  , items
+    -- ** Wielded items
+  , Wielded(..)
+  , hands
+  , leftHand
+  , rightHand
+  , inLeftHand
+  , inRightHand
+  , doubleHanded
+  , wieldedItems
+  , WieldedItem(..)
+  , wieldedItem
+  , wieldableItem
+  , asWieldedItem
+
+    -- *
+  , mkCharacter
+  , pickUpItem
+  , isDead
+  , damage
+  ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+--------------------------------------------------------------------------------
+import           Brick
+import           Data.Aeson.Generic.DerivingVia
+import           Data.Aeson (ToJSON, FromJSON)
+import           Data.Coerce (coerce)
+import           Test.QuickCheck
+import           Test.QuickCheck.Instances.Vector ()
+import           Test.QuickCheck.Arbitrary.Generic
+--------------------------------------------------------------------------------
+import           Xanthous.Util.QuickCheck
+import           Xanthous.Game.State
+import           Xanthous.Entities.Item
+import           Xanthous.Data
+                 ( TicksPerTile, Hitpoints, Per, Ticks, (|*|), positioned
+                 , Positioned(..)
+                 )
+import           Xanthous.Entities.RawTypes (WieldableItem, wieldable)
+import qualified Xanthous.Entities.RawTypes as Raw
+--------------------------------------------------------------------------------
+
+data WieldedItem = WieldedItem
+  { _wieldedItem :: Item
+  , _wieldableItem :: WieldableItem
+    -- ^ Invariant: item ^. itemType . wieldable ≡ Just wieldableItem
+  }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+           WieldedItem
+makeFieldsNoPrefix ''WieldedItem
+
+asWieldedItem :: Prism' Item WieldedItem
+asWieldedItem = prism' hither yon
+ where
+   yon item = WieldedItem item <$> item ^. itemType . wieldable
+   hither (WieldedItem item _) = item
+
+instance Brain WieldedItem where
+  step ticks (Positioned p wi) =
+    over positioned (\i -> WieldedItem i $ wi ^. wieldableItem)
+    <$> step ticks (Positioned p $ wi ^. wieldedItem)
+
+instance Draw WieldedItem where
+  draw = draw . view wieldedItem
+
+instance Entity WieldedItem where
+  entityAttributes = entityAttributes . view wieldedItem
+  description = description . view wieldedItem
+  entityChar = entityChar . view wieldedItem
+
+instance Arbitrary WieldedItem where
+  arbitrary = genericArbitrary <&> \wi ->
+    wi & wieldedItem . itemType . wieldable ?~ wi ^. wieldableItem
+
+data Wielded
+  = DoubleHanded WieldedItem
+  | Hands { _leftHand :: !(Maybe WieldedItem)
+          , _rightHand :: !(Maybe WieldedItem)
+          }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary Wielded
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ 'SumEnc 'ObjWithSingleField ]
+           Wielded
+
+hands :: Prism' Wielded (Maybe WieldedItem, Maybe WieldedItem)
+hands = prism' (uncurry Hands) $ \case
+  Hands l r -> Just (l, r)
+  _ -> Nothing
+
+leftHand :: Traversal' Wielded WieldedItem
+leftHand = hands . _1 . _Just
+
+inLeftHand :: WieldedItem -> Wielded
+inLeftHand wi = Hands (Just wi) Nothing
+
+rightHand :: Traversal' Wielded WieldedItem
+rightHand = hands . _2 . _Just
+
+inRightHand :: WieldedItem -> Wielded
+inRightHand wi = Hands Nothing (Just wi)
+
+doubleHanded :: Prism' Wielded WieldedItem
+doubleHanded = prism' DoubleHanded $ \case
+  DoubleHanded i -> Just i
+  _ -> Nothing
+
+wieldedItems :: Traversal' Wielded WieldedItem
+wieldedItems k (DoubleHanded wielded) = DoubleHanded <$> k wielded
+wieldedItems k (Hands l r) = Hands <$> _Just k l <*> _Just k r
+
+data Inventory = Inventory
+  { _backpack :: Vector Item
+  , _wielded :: Wielded
+  }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary Inventory
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+           Inventory
+makeFieldsNoPrefix ''Inventory
+
+items :: Traversal' Inventory Item
+items k (Inventory bp w) = Inventory
+  <$> traversed k bp
+  <*> (wieldedItems . wieldedItem) k w
+
+type instance Element Inventory = Item
+
+instance MonoFunctor Inventory where
+  omap = over items
+
+instance MonoFoldable Inventory where
+  ofoldMap = foldMapOf items
+  ofoldr = foldrOf items
+  ofoldl' = foldlOf' items
+  otoList = toListOf items
+  oall = allOf items
+  oany = anyOf items
+  onull = nullOf items
+  ofoldr1Ex = foldr1Of items
+  ofoldl1Ex' = foldl1Of' items
+  headEx = headEx . toListOf items
+  lastEx = lastEx . toListOf items
+
+instance MonoTraversable Inventory where
+  otraverse = traverseOf items
+
+instance Semigroup Inventory where
+  inv₁ <> inv₂ =
+    let backpack' = inv₁ ^. backpack <> inv₂ ^. backpack
+        (wielded', backpack'') = case (inv₁ ^. wielded, inv₂ ^. wielded) of
+          (wielded₁, wielded₂@(DoubleHanded _)) ->
+            (wielded₂, backpack' <> fromList (wielded₁ ^.. wieldedItems . wieldedItem))
+          (wielded₁, wielded₂@(Hands (Just _) (Just _))) ->
+            (wielded₂, backpack' <> fromList (wielded₁ ^.. wieldedItems . wieldedItem))
+          (wielded₁, Hands Nothing Nothing) -> (wielded₁, backpack')
+          (Hands Nothing Nothing, wielded₂) -> (wielded₂, backpack')
+          (Hands (Just l₁) Nothing, Hands Nothing (Just r₂)) ->
+            (Hands (Just l₁) (Just r₂), backpack')
+          (wielded₁@(DoubleHanded _), wielded₂) ->
+            (wielded₁, backpack' <> fromList (wielded₂ ^.. wieldedItems . wieldedItem))
+          (Hands Nothing (Just r₁), Hands Nothing (Just r₂)) ->
+            (Hands Nothing (Just r₂), r₁ ^. wieldedItem <| backpack')
+          (Hands Nothing r₁, Hands (Just l₂) Nothing) ->
+            (Hands (Just l₂) r₁, backpack')
+          (Hands (Just l₁) Nothing, Hands (Just l₂) Nothing) ->
+            (Hands (Just l₂) Nothing, l₁ ^. wieldedItem <| backpack')
+          (Hands (Just l₁) (Just r₁), Hands Nothing (Just r₂)) ->
+            (Hands (Just l₁) (Just r₂), r₁ ^. wieldedItem <| backpack')
+          (Hands (Just l₁) (Just r₁), Hands (Just l₂) Nothing) ->
+            (Hands (Just l₂) (Just r₁), l₁ ^. wieldedItem <| backpack')
+    in Inventory backpack'' wielded'
+
+instance Monoid Inventory where
+  mempty = Inventory mempty $ Hands Nothing Nothing
+
+--------------------------------------------------------------------------------
+
+data Character = Character
+  { _inventory :: !Inventory
+  , _characterName :: !(Maybe Text)
+  , _characterHitpoints' :: !Double
+  , _speed :: TicksPerTile
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+           Character
+makeLenses ''Character
+
+characterHitpoints :: Character -> Hitpoints
+characterHitpoints = views characterHitpoints' floor
+
+scrollOffset :: Int
+scrollOffset = 5
+
+instance Draw Character where
+  draw _ = visibleRegion rloc rreg $ str "@"
+    where
+      rloc = Location (negate scrollOffset, negate scrollOffset)
+      rreg = (2 * scrollOffset, 2 * scrollOffset)
+  drawPriority = const maxBound -- Character should always be on top, for now
+
+instance Brain Character where
+  step ticks = (pure .) $ positioned . characterHitpoints' %~ \hp ->
+    if hp > fromIntegral initialHitpoints
+    then hp
+    else hp + hitpointRecoveryRate |*| ticks
+
+instance Entity Character where
+  description _ = "yourself"
+  entityChar _ = "@"
+
+instance Arbitrary Character where
+  arbitrary = genericArbitrary
+
+initialHitpoints :: Hitpoints
+initialHitpoints = 10
+
+hitpointRecoveryRate :: Double `Per` Ticks
+hitpointRecoveryRate = 1.0 / (15 * coerce defaultSpeed)
+
+defaultSpeed :: TicksPerTile
+defaultSpeed = 100
+
+mkCharacter :: Character
+mkCharacter = Character
+  { _inventory = mempty
+  , _characterName = Nothing
+  , _characterHitpoints' = fromIntegral initialHitpoints
+  , _speed = defaultSpeed
+  }
+
+defaultCharacterDamage :: Hitpoints
+defaultCharacterDamage = 1
+
+-- | Returns the damage that the character currently does with an attack
+-- TODO use double-handed/left-hand/right-hand here
+characterDamage :: Character -> Hitpoints
+characterDamage
+  = fromMaybe defaultCharacterDamage
+  . preview (inventory . wielded . wieldedItems . wieldableItem . Raw.damage)
+
+isDead :: Character -> Bool
+isDead = (== 0) . characterHitpoints
+
+pickUpItem :: Item -> Character -> Character
+pickUpItem it = inventory . backpack %~ (it <|)
+
+damage :: Hitpoints -> Character -> Character
+damage (fromIntegral -> amount) = characterHitpoints' %~ \case
+  n | n <= amount -> 0
+    | otherwise  -> n - amount
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Creature.hs b/users/grfn/xanthous/src/Xanthous/Entities/Creature.hs
new file mode 100644
index 0000000000..e95e9f0b98
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Creature.hs
@@ -0,0 +1,92 @@
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Entities.Creature
+  ( -- * Creature
+    Creature(..)
+    -- ** Lenses
+  , creatureType
+  , hitpoints
+  , hippocampus
+
+    -- ** Creature functions
+  , newWithType
+  , damage
+  , isDead
+  , visionRadius
+
+    -- * Hippocampus
+  , Hippocampus(..)
+    -- ** Lenses
+  , destination
+    -- ** Destination
+  , Destination(..)
+  , destinationFromPos
+    -- *** Lenses
+  , destinationPosition
+  , destinationProgress
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude
+--------------------------------------------------------------------------------
+import           Test.QuickCheck
+import           Test.QuickCheck.Arbitrary.Generic
+import           Data.Aeson.Generic.DerivingVia
+import           Data.Aeson (ToJSON, FromJSON)
+--------------------------------------------------------------------------------
+import           Xanthous.AI.Gormlak
+import           Xanthous.Entities.RawTypes hiding
+                 (Creature, description, damage)
+import qualified Xanthous.Entities.RawTypes as Raw
+import           Xanthous.Game.State
+import           Xanthous.Data
+import           Xanthous.Data.Entities
+import           Xanthous.Entities.Creature.Hippocampus
+--------------------------------------------------------------------------------
+
+data Creature = Creature
+  { _creatureType :: !CreatureType
+  , _hitpoints    :: !Hitpoints
+  , _hippocampus  :: !Hippocampus
+  }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Draw via DrawRawCharPriority "_creatureType" 1000 Creature
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       Creature
+instance Arbitrary Creature where arbitrary = genericArbitrary
+makeLenses ''Creature
+
+instance HasVisionRadius Creature where
+  visionRadius = const 50 -- TODO
+
+instance Brain Creature where
+  step = brainVia GormlakBrain
+  entityCanMove = const True
+
+instance Entity Creature where
+  entityAttributes _ = defaultEntityAttributes
+    & blocksObject .~ True
+  description = view $ creatureType . Raw.description
+  entityChar = view $ creatureType . char
+  entityCollision = const $ Just Combat
+
+--------------------------------------------------------------------------------
+
+newWithType :: CreatureType -> Creature
+newWithType _creatureType =
+  let _hitpoints = _creatureType ^. maxHitpoints
+      _hippocampus = initialHippocampus
+  in Creature {..}
+
+damage :: Hitpoints -> Creature -> Creature
+damage amount = hitpoints %~ \hp ->
+  if hp <= amount
+  then 0
+  else hp - amount
+
+isDead :: Creature -> Bool
+isDead = views hitpoints (== 0)
+
+{-# ANN module ("Hlint: ignore Use newtype instead of data" :: String) #-}
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Creature/Hippocampus.hs b/users/grfn/xanthous/src/Xanthous/Entities/Creature/Hippocampus.hs
new file mode 100644
index 0000000000..501a5b5972
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Creature/Hippocampus.hs
@@ -0,0 +1,64 @@
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Entities.Creature.Hippocampus
+  (-- * Hippocampus
+    Hippocampus(..)
+  , initialHippocampus
+    -- ** Lenses
+  , destination
+    -- ** Destination
+  , Destination(..)
+  , destinationFromPos
+    -- *** Lenses
+  , destinationPosition
+  , destinationProgress
+  )
+where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude
+--------------------------------------------------------------------------------
+import           Data.Aeson.Generic.DerivingVia
+import           Data.Aeson (ToJSON, FromJSON)
+import           Test.QuickCheck
+import           Test.QuickCheck.Arbitrary.Generic
+--------------------------------------------------------------------------------
+import           Xanthous.Data
+import           Xanthous.Util.QuickCheck
+--------------------------------------------------------------------------------
+
+
+data Destination = Destination
+  { _destinationPosition :: !Position
+    -- | The progress towards the destination, tracked as an offset from the
+    -- creature's original position.
+    --
+    -- When this value reaches >= 1, the creature has reached their destination
+  , _destinationProgress :: !Tiles
+  }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       Destination
+instance Arbitrary Destination where arbitrary = genericArbitrary
+makeLenses ''Destination
+
+destinationFromPos :: Position -> Destination
+destinationFromPos _destinationPosition =
+  let _destinationProgress = 0
+  in Destination{..}
+
+data Hippocampus = Hippocampus
+  { _destination :: !(Maybe Destination)
+  }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary Hippocampus
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       Hippocampus
+makeLenses ''Hippocampus
+
+initialHippocampus :: Hippocampus
+initialHippocampus = Hippocampus Nothing
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Draw/Util.hs b/users/grfn/xanthous/src/Xanthous/Entities/Draw/Util.hs
new file mode 100644
index 0000000000..aa6c5fa4fc
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Draw/Util.hs
@@ -0,0 +1,31 @@
+module Xanthous.Entities.Draw.Util where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+--------------------------------------------------------------------------------
+import Brick.Widgets.Border.Style
+import Brick.Types (Edges(..))
+--------------------------------------------------------------------------------
+
+borderFromEdges :: BorderStyle -> Edges Bool -> Char
+borderFromEdges bstyle edges = ($ bstyle) $ case edges of
+  Edges False False  False False -> const '☐'
+
+  Edges True  False  False False -> bsVertical
+  Edges False True   False False -> bsVertical
+  Edges False False  True  False -> bsHorizontal
+  Edges False False  False True  -> bsHorizontal
+
+  Edges True  True   False False -> bsVertical
+  Edges True  False  True  False -> bsCornerBR
+  Edges True  False  False True  -> bsCornerBL
+
+  Edges False True   True  False -> bsCornerTR
+  Edges False True   False True  -> bsCornerTL
+  Edges False False  True  True  -> bsHorizontal
+
+  Edges False True   True  True  -> bsIntersectT
+  Edges True  False  True  True  -> bsIntersectB
+  Edges True  True   False True  -> bsIntersectL
+  Edges True  True   True  False -> bsIntersectR
+
+  Edges True  True   True  True  -> bsIntersectFull
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Entities.hs b/users/grfn/xanthous/src/Xanthous/Entities/Entities.hs
new file mode 100644
index 0000000000..a0c037a1b4
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Entities.hs
@@ -0,0 +1,63 @@
+{-# LANGUAGE StandaloneDeriving #-}
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+--------------------------------------------------------------------------------
+module Xanthous.Entities.Entities () where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude
+--------------------------------------------------------------------------------
+import           Test.QuickCheck
+import qualified Test.QuickCheck.Gen as Gen
+import           Data.Aeson
+--------------------------------------------------------------------------------
+import           Xanthous.Entities.Character
+import           Xanthous.Entities.Item
+import           Xanthous.Entities.Creature
+import           Xanthous.Entities.Environment
+import           Xanthous.Entities.Marker
+import           Xanthous.Game.State
+import           Xanthous.Util.QuickCheck
+import           Data.Aeson.Generic.DerivingVia
+--------------------------------------------------------------------------------
+
+instance Arbitrary SomeEntity where
+  arbitrary = Gen.oneof
+    [ SomeEntity <$> arbitrary @Character
+    , SomeEntity <$> arbitrary @Item
+    , SomeEntity <$> arbitrary @Creature
+    , SomeEntity <$> arbitrary @Wall
+    , SomeEntity <$> arbitrary @Door
+    , SomeEntity <$> arbitrary @GroundMessage
+    , SomeEntity <$> arbitrary @Staircase
+    , SomeEntity <$> arbitrary @Marker
+    ]
+
+instance FromJSON SomeEntity where
+  parseJSON = withObject "Entity" $ \obj -> do
+    (entityType :: Text) <- obj .: "type"
+    case entityType of
+      "Character" -> SomeEntity @Character <$> obj .: "data"
+      "Item" -> SomeEntity @Item <$> obj .: "data"
+      "Creature" -> SomeEntity @Creature <$> obj .: "data"
+      "Wall" -> SomeEntity @Wall <$> obj .: "data"
+      "Door" -> SomeEntity @Door <$> obj .: "data"
+      "GroundMessage" -> SomeEntity @GroundMessage <$> obj .: "data"
+      "Staircase" -> SomeEntity @Staircase <$> obj .: "data"
+      "Marker" -> SomeEntity @Marker <$> obj .: "data"
+      _ -> fail . unpack $ "Invalid entity type \"" <> entityType <> "\""
+
+deriving via WithOptions '[ FieldLabelModifier '[Drop 1] ] GameLevel
+  instance FromJSON GameLevel
+deriving via WithOptions '[ FieldLabelModifier '[Drop 1] ] GameState
+  instance FromJSON GameState
+
+instance Entity SomeEntity where
+  entityAttributes (SomeEntity ent) = entityAttributes ent
+  description (SomeEntity ent) = description ent
+  entityChar (SomeEntity ent) = entityChar ent
+  entityCollision (SomeEntity ent) = entityCollision ent
+
+instance Function SomeEntity where
+  function = functionJSON
+
+instance CoArbitrary SomeEntity where
+  coarbitrary = coarbitrary . encode
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Entities.hs-boot b/users/grfn/xanthous/src/Xanthous/Entities/Entities.hs-boot
new file mode 100644
index 0000000000..519a862c6a
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Entities.hs-boot
@@ -0,0 +1,14 @@
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+module Xanthous.Entities.Entities where
+
+import Test.QuickCheck
+import Data.Aeson
+import Xanthous.Game.State (SomeEntity, GameState, Entity)
+
+instance Arbitrary SomeEntity
+instance Function SomeEntity
+instance CoArbitrary SomeEntity
+instance FromJSON SomeEntity
+instance Entity SomeEntity
+
+instance FromJSON GameState
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Environment.hs b/users/grfn/xanthous/src/Xanthous/Entities/Environment.hs
new file mode 100644
index 0000000000..b45a91eabe
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Environment.hs
@@ -0,0 +1,160 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Xanthous.Entities.Environment
+  (
+    -- * Walls
+    Wall(..)
+
+    -- * Doors
+  , Door(..)
+  , open
+  , closed
+  , locked
+  , unlockedDoor
+
+    -- * Messages
+  , GroundMessage(..)
+
+    -- * Stairs
+  , Staircase(..)
+  ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+--------------------------------------------------------------------------------
+import Test.QuickCheck
+import Brick (str)
+import Brick.Widgets.Border.Style (unicode)
+import Brick.Types (Edges(..))
+import Data.Aeson
+import Data.Aeson.Generic.DerivingVia
+--------------------------------------------------------------------------------
+import Xanthous.Entities.Draw.Util
+import Xanthous.Data
+import Xanthous.Data.Entities
+import Xanthous.Game.State
+import Xanthous.Util.QuickCheck
+--------------------------------------------------------------------------------
+
+data Wall = Wall
+  deriving stock (Show, Eq, Ord, Generic, Enum)
+  deriving anyclass (NFData, CoArbitrary, Function)
+
+instance ToJSON Wall where
+  toJSON = const $ String "Wall"
+
+instance FromJSON Wall where
+  parseJSON = withText "Wall" $ \case
+    "Wall" -> pure Wall
+    _      -> fail "Invalid Wall: expected Wall"
+
+instance Brain Wall where step = brainVia Brainless
+
+instance Entity Wall where
+  entityAttributes _ = defaultEntityAttributes
+    & blocksVision .~ True
+    & blocksObject .~ True
+  description _ = "a wall"
+  entityChar _ = "┼"
+
+instance Arbitrary Wall where
+  arbitrary = pure Wall
+
+wallEdges :: (MonoFoldable mono, Element mono ~ SomeEntity)
+          => Neighbors mono -> Edges Bool
+wallEdges neighs = any (entityIs @Wall) <$> edges neighs
+
+instance Draw Wall where
+  drawWithNeighbors neighs _wall =
+    str . pure . borderFromEdges unicode $ wallEdges neighs
+
+data Door = Door
+  { _open   :: Bool
+  , _locked :: Bool
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function, ToJSON, FromJSON)
+  deriving Arbitrary via GenericArbitrary Door
+makeLenses ''Door
+
+instance Draw Door where
+  drawWithNeighbors neighs door
+    = str . pure . ($ door ^. open) $ case wallEdges neighs of
+        Edges True  False  False False -> vertDoor
+        Edges False True   False False -> vertDoor
+        Edges True  True   False False -> vertDoor
+        Edges False False  True  False -> horizDoor
+        Edges False False  False True  -> horizDoor
+        Edges False False  True  True  -> horizDoor
+        _                              -> allsidesDoor
+    where
+      horizDoor True = '␣'
+      horizDoor False = 'ᚔ'
+      vertDoor True = '['
+      vertDoor False = 'ǂ'
+      allsidesDoor True = '+'
+      allsidesDoor False = '▥'
+
+instance Brain Door where step = brainVia Brainless
+
+instance Entity Door where
+  entityAttributes door = defaultEntityAttributes
+    & blocksVision .~ not (door ^. open)
+  description door | door ^. open = "an open door"
+                   | otherwise    = "a closed door"
+  entityChar _ = "d"
+  entityCollision door | door ^. open = Nothing
+                       | otherwise = Just Stop
+
+closed :: Lens' Door Bool
+closed = open . involuted not
+
+-- | A closed, unlocked door
+unlockedDoor :: Door
+unlockedDoor = Door
+  { _open = False
+  , _locked = False
+  }
+
+--------------------------------------------------------------------------------
+
+newtype GroundMessage = GroundMessage Text
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary GroundMessage
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ 'TagSingleConstructors 'True
+                        , 'SumEnc 'ObjWithSingleField
+                        ]
+           GroundMessage
+  deriving Draw
+       via DrawStyledCharacter ('Just 'Yellow) 'Nothing "≈"
+           GroundMessage
+instance Brain GroundMessage where step = brainVia Brainless
+
+instance Entity GroundMessage where
+  description = const "a message on the ground. Press r. to read it."
+  entityChar = const "≈"
+  entityCollision = const Nothing
+
+--------------------------------------------------------------------------------
+
+data Staircase = UpStaircase | DownStaircase
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary Staircase
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ 'TagSingleConstructors 'True
+                        , 'SumEnc 'ObjWithSingleField
+                        ]
+           Staircase
+instance Brain Staircase where step = brainVia Brainless
+
+instance Draw Staircase where
+  draw UpStaircase = str "<"
+  draw DownStaircase = str ">"
+
+instance Entity Staircase where
+  description UpStaircase = "a staircase leading upwards"
+  description DownStaircase = "a staircase leading downwards"
+  entityChar UpStaircase = "<"
+  entityChar DownStaircase = ">"
+  entityCollision = const Nothing
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Item.hs b/users/grfn/xanthous/src/Xanthous/Entities/Item.hs
new file mode 100644
index 0000000000..b50a5eab80
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Item.hs
@@ -0,0 +1,49 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE StandaloneDeriving #-}
+--------------------------------------------------------------------------------
+module Xanthous.Entities.Item
+  ( Item(..)
+  , itemType
+  , newWithType
+  , isEdible
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude
+import           Test.QuickCheck
+import           Data.Aeson (ToJSON, FromJSON)
+import           Data.Aeson.Generic.DerivingVia
+--------------------------------------------------------------------------------
+import           Xanthous.Entities.RawTypes hiding (Item, description, isEdible)
+import qualified Xanthous.Entities.RawTypes as Raw
+import           Xanthous.Game.State
+--------------------------------------------------------------------------------
+
+data Item = Item
+  { _itemType :: ItemType
+  }
+  deriving stock (Eq, Show, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Draw via DrawRawChar "_itemType" 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
+
+isEdible :: Item -> Bool
+isEdible = Raw.isEdible . view itemType
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Marker.hs b/users/grfn/xanthous/src/Xanthous/Entities/Marker.hs
new file mode 100644
index 0000000000..14d02872ed
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Marker.hs
@@ -0,0 +1,41 @@
+--------------------------------------------------------------------------------
+module Xanthous.Entities.Marker ( Marker(..) ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+--------------------------------------------------------------------------------
+import           Data.Aeson
+import           Test.QuickCheck
+import qualified Graphics.Vty.Attributes as Vty
+import qualified Graphics.Vty.Image as Vty
+import           Brick.Widgets.Core (raw)
+--------------------------------------------------------------------------------
+import           Xanthous.Game.State
+import           Xanthous.Data.Entities (EntityAttributes(..))
+--------------------------------------------------------------------------------
+
+-- | Mark on the map - for use in debugging / development only.
+newtype Marker = Marker Text
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving (Semigroup, Monoid, ToJSON, FromJSON, Arbitrary) via Text
+
+instance Brain Marker where step = brainVia Brainless
+
+instance Entity Marker where
+  entityAttributes = const EntityAttributes
+    { _blocksVision = False
+    , _blocksObject = False
+    , _collision = Stop
+    }
+  description (Marker m) = "[M] " <> m
+  entityChar = const $ "X" & style .~ markerStyle
+  entityCollision = const Nothing
+
+instance Draw Marker where
+  draw = const . raw $ Vty.char markerStyle 'X'
+  drawPriority = const maxBound
+
+markerStyle :: Vty.Attr
+markerStyle = Vty.defAttr
+  `Vty.withForeColor` Vty.red
+  `Vty.withBackColor` Vty.black
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/RawTypes.hs b/users/grfn/xanthous/src/Xanthous/Entities/RawTypes.hs
new file mode 100644
index 0000000000..30039662f0
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/RawTypes.hs
@@ -0,0 +1,133 @@
+{-# LANGUAGE TemplateHaskell       #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+--------------------------------------------------------------------------------
+module Xanthous.Entities.RawTypes
+  (
+    EntityRaw(..)
+  , _Creature
+  , _Item
+
+    -- * Creatures
+  , CreatureType(..)
+  , hostile
+
+    -- * Items
+  , ItemType(..)
+    -- ** Item sub-types
+    -- *** Edible
+  , EdibleItem(..)
+  , isEdible
+    -- *** Wieldable
+  , WieldableItem(..)
+  , isWieldable
+
+    -- * Lens classes
+  , HasAttackMessage(..)
+  , HasChar(..)
+  , HasDamage(..)
+  , HasDescription(..)
+  , HasEatMessage(..)
+  , HasEdible(..)
+  , HasFriendly(..)
+  , HasHitpointsHealed(..)
+  , HasLongDescription(..)
+  , HasMaxHitpoints(..)
+  , HasName(..)
+  , HasSpeed(..)
+  , HasWieldable(..)
+  ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+import Test.QuickCheck
+import Data.Aeson.Generic.DerivingVia
+import Data.Aeson (ToJSON, FromJSON)
+--------------------------------------------------------------------------------
+import Xanthous.Messages (Message(..))
+import Xanthous.Data (TicksPerTile, Hitpoints)
+import Xanthous.Data.EntityChar
+import Xanthous.Util.QuickCheck
+--------------------------------------------------------------------------------
+
+data CreatureType = CreatureType
+  { _name         :: !Text
+  , _description  :: !Text
+  , _char         :: !EntityChar
+  , _maxHitpoints :: !Hitpoints
+  , _friendly     :: !Bool
+  , _speed        :: !TicksPerTile
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary CreatureType
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       CreatureType
+makeFieldsNoPrefix ''CreatureType
+
+hostile :: Lens' CreatureType Bool
+hostile = friendly . involuted not
+
+--------------------------------------------------------------------------------
+
+data EdibleItem = EdibleItem
+  { _hitpointsHealed :: Int
+  , _eatMessage :: Maybe Message
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary EdibleItem
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       EdibleItem
+makeFieldsNoPrefix ''EdibleItem
+
+data WieldableItem = WieldableItem
+  { _damage :: !Hitpoints
+  , _attackMessage :: !(Maybe Message)
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary WieldableItem
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       WieldableItem
+makeFieldsNoPrefix ''WieldableItem
+
+--------------------------------------------------------------------------------
+
+data ItemType = ItemType
+  { _name            :: Text
+  , _description     :: Text
+  , _longDescription :: Text
+  , _char            :: EntityChar
+  , _edible          :: Maybe EdibleItem
+  , _wieldable       :: Maybe WieldableItem
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+  deriving Arbitrary via GenericArbitrary ItemType
+  deriving (ToJSON, FromJSON)
+       via WithOptions '[ FieldLabelModifier '[Drop 1] ]
+                       ItemType
+makeFieldsNoPrefix ''ItemType
+
+-- | Can this item be eaten?
+isEdible :: ItemType -> Bool
+isEdible = has $ edible . _Just
+
+-- | Can this item be used as a weapon?
+isWieldable :: ItemType -> Bool
+isWieldable = has $ wieldable . _Just
+
+--------------------------------------------------------------------------------
+
+data EntityRaw
+  = Creature CreatureType
+  | Item ItemType
+  deriving stock (Show, Eq, Generic)
+  deriving anyclass (NFData)
+  deriving Arbitrary via GenericArbitrary EntityRaw
+  deriving (FromJSON)
+       via WithOptions '[ SumEnc ObjWithSingleField ]
+                       EntityRaw
+makePrisms ''EntityRaw
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Raws.hs b/users/grfn/xanthous/src/Xanthous/Entities/Raws.hs
new file mode 100644
index 0000000000..d4cae7ccc2
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Raws.hs
@@ -0,0 +1,59 @@
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Entities.Raws
+  ( raws
+  , raw
+  , RawType(..)
+  , rawsWithType
+  , entityFromRaw
+  ) where
+--------------------------------------------------------------------------------
+import           Data.FileEmbed
+import qualified Data.Yaml as Yaml
+import           Xanthous.Prelude
+import           System.FilePath.Posix
+--------------------------------------------------------------------------------
+import           Xanthous.Entities.RawTypes
+import           Xanthous.Game.State
+import qualified Xanthous.Entities.Creature as Creature
+import qualified Xanthous.Entities.Item as Item
+import           Xanthous.AI.Gormlak ()
+--------------------------------------------------------------------------------
+rawRaws :: [(FilePath, ByteString)]
+rawRaws = $(embedDir "src/Xanthous/Entities/Raws")
+
+raws :: HashMap Text EntityRaw
+raws
+  = mapFromList
+  . map (bimap
+         (pack . takeBaseName)
+         (either (error . Yaml.prettyPrintParseException) id
+          . Yaml.decodeEither'))
+  $ rawRaws
+
+raw :: Text -> Maybe EntityRaw
+raw n = raws ^. at n
+
+class RawType (a :: Type) where
+  _RawType :: Prism' EntityRaw a
+
+instance RawType CreatureType where
+  _RawType = prism' Creature $ \case
+    Creature c -> Just c
+    _ -> Nothing
+
+instance RawType ItemType where
+  _RawType = prism' Item $ \case
+    Item i -> Just i
+    _ -> Nothing
+
+rawsWithType :: forall a. RawType a => HashMap Text a
+rawsWithType = mapFromList . itoListOf (ifolded . _RawType) $ raws
+
+--------------------------------------------------------------------------------
+
+entityFromRaw :: EntityRaw -> SomeEntity
+entityFromRaw (Creature creatureType)
+  = SomeEntity $ Creature.newWithType creatureType
+entityFromRaw (Item itemType)
+  = SomeEntity $ Item.newWithType itemType
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Raws/gormlak.yaml b/users/grfn/xanthous/src/Xanthous/Entities/Raws/gormlak.yaml
new file mode 100644
index 0000000000..2eac895190
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Raws/gormlak.yaml
@@ -0,0 +1,13 @@
+Creature:
+  name: gormlak
+  description: a gormlak
+  longDescription: |
+    A chittering imp-like creature with bright yellow horns. It adores shiny objects
+    and gathers in swarms.
+  char:
+    char: g
+    style:
+      foreground: red
+  maxHitpoints: 5
+  speed: 125
+  friendly: false
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Raws/noodles.yaml b/users/grfn/xanthous/src/Xanthous/Entities/Raws/noodles.yaml
new file mode 100644
index 0000000000..c3f19dce91
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Raws/noodles.yaml
@@ -0,0 +1,12 @@
+Item:
+  name: noodles
+  description: "a big bowl o' noodles"
+  longDescription: You know exactly what kind of noodles
+  char:
+    char: 'n'
+    style:
+      foreground: yellow
+  edible:
+    hitpointsHealed: 2
+    eatMessage:
+      - You slurp up the noodles. Yumm!
diff --git a/users/grfn/xanthous/src/Xanthous/Entities/Raws/stick.yaml b/users/grfn/xanthous/src/Xanthous/Entities/Raws/stick.yaml
new file mode 100644
index 0000000000..bc7fde4d8b
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Entities/Raws/stick.yaml
@@ -0,0 +1,14 @@
+Item:
+  name: stick
+  description: a wooden stick
+  longDescription: A sturdy branch broken off from some sort of tree
+  char:
+    char: ∤
+    style:
+      foreground: yellow
+  wieldable:
+    damage: 2
+    attackMessage:
+      - You bonk the {{creature.creatureType.name}} over the head with your stick.
+      - You bash the {{creature.creatureType.name}} on the noggin with your stick.
+      - You whack the {{creature.creatureType.name}} with your stick.