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>

1 files changed, 272 insertions, 0 deletions

diff --git a/users/grfn/xanthous/src/Xanthous/Data/EntityMap.hs b/users/grfn/xanthous/src/Xanthous/Data/EntityMap.hs
new file mode 100644
index 0000000000..d24defa841
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Data/EntityMap.hs
@@ -0,0 +1,272 @@
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE DeriveTraversable  #-}
+{-# LANGUAGE TupleSections      #-}
+{-# LANGUAGE TemplateHaskell    #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE DeriveFunctor      #-}
+--------------------------------------------------------------------------------
+module Xanthous.Data.EntityMap
+  ( EntityMap
+  , _EntityMap
+  , EntityID
+  , emptyEntityMap
+  , insertAt
+  , insertAtReturningID
+  , fromEIDsAndPositioned
+  , toEIDsAndPositioned
+  , atPosition
+  , atPositionWithIDs
+  , positions
+  , lookup
+  , lookupWithPosition
+  -- , positionedEntities
+  , neighbors
+  , Deduplicate(..)
+
+  -- * debug
+  , byID
+  , byPosition
+  , lastID
+
+  ) where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude hiding (lookup)
+import Xanthous.Data
+  ( Position
+  , Positioned(..)
+  , positioned
+  , Neighbors(..)
+  , neighborPositions
+  )
+import Xanthous.Data.VectorBag
+import Xanthous.Orphans ()
+import Xanthous.Util (EqEqProp(..))
+--------------------------------------------------------------------------------
+import Data.Monoid (Endo(..))
+import Test.QuickCheck (Arbitrary(..), CoArbitrary, Function)
+import Test.QuickCheck.Checkers (EqProp)
+import Test.QuickCheck.Instances.UnorderedContainers ()
+import Test.QuickCheck.Instances.Vector ()
+import Text.Show (showString, showParen)
+import Data.Aeson
+--------------------------------------------------------------------------------
+
+type EntityID = Word32
+type NonNullSet a = NonNull (Set a)
+
+data EntityMap a where
+  EntityMap ::
+    { _byPosition :: Map Position (NonNullSet EntityID)
+    , _byID       :: HashMap EntityID (Positioned a)
+    , _lastID     :: EntityID
+    } -> EntityMap a
+  deriving stock (Functor, Foldable, Traversable, Generic)
+  deriving anyclass (NFData, CoArbitrary, Function)
+deriving via (EqEqProp (EntityMap a)) instance (Eq a, Ord a) => EqProp (EntityMap a)
+makeLenses ''EntityMap
+
+instance ToJSON a => ToJSON (EntityMap a) where
+  toJSON = toJSON . toEIDsAndPositioned
+
+
+instance FromJSON a => FromJSON (EntityMap a) where
+  parseJSON = fmap (fromEIDsAndPositioned @[_]) . parseJSON
+
+byIDInvariantError :: forall a. a
+byIDInvariantError = error $ "Invariant violation: All EntityIDs in byPosition "
+  <> "must point to entityIDs in byID"
+
+instance (Ord a, Eq a) => Eq (EntityMap a) where
+  -- em₁ == em₂ = em₁ ^. _EntityMap == em₂ ^. _EntityMap
+  (==) = (==) `on` view (_EntityMap . to sort)
+
+deriving stock instance (Ord a) => Ord (EntityMap a)
+
+instance Show a => Show (EntityMap a) where
+  showsPrec pr em
+    = showParen (pr > 10)
+    $ showString
+    . ("fromEIDsAndPositioned " <>)
+    . show
+    . toEIDsAndPositioned
+    $ em
+
+instance Arbitrary a => Arbitrary (EntityMap a) where
+  arbitrary = review _EntityMap <$> arbitrary
+  shrink em = review _EntityMap <$> shrink (em ^. _EntityMap)
+
+type instance Index (EntityMap a) = EntityID
+type instance IxValue (EntityMap a) = (Positioned a)
+instance Ixed (EntityMap a) where ix eid = at eid . traverse
+
+instance At (EntityMap a) where
+  at eid = lens (view $ byID . at eid) setter
+    where
+      setter :: EntityMap a -> Maybe (Positioned a) -> EntityMap a
+      setter m Nothing = fromMaybe m $ do
+        Positioned pos _ <- m ^. byID . at eid
+        pure $ m
+          & removeEIDAtPos pos
+          & byID . at eid .~ Nothing
+      setter m (Just pe@(Positioned pos _)) = m
+        & (case lookupWithPosition eid m of
+             Nothing -> id
+             Just (Positioned origPos _) -> removeEIDAtPos origPos
+          )
+        & byID . at eid ?~ pe
+        & byPosition . at pos %~ \case
+            Nothing -> Just $ opoint eid
+            Just es -> Just $ ninsertSet eid es
+      removeEIDAtPos pos =
+        byPosition . at pos %~ (>>= fromNullable . ndeleteSet eid)
+
+instance Semigroup (EntityMap a) where
+  em₁ <> em₂ = alaf Endo foldMap (uncurry insertAt) (em₂ ^. _EntityMap) em₁
+
+instance Monoid (EntityMap a) where
+  mempty = emptyEntityMap
+
+instance FunctorWithIndex EntityID EntityMap
+
+instance FoldableWithIndex EntityID EntityMap
+
+instance TraversableWithIndex EntityID EntityMap where
+  itraversed = byID . itraversed . rmap sequenceA . distrib
+  itraverse = itraverseOf itraversed
+
+type instance Element (EntityMap a) = a
+instance MonoFoldable (EntityMap a)
+
+emptyEntityMap :: EntityMap a
+emptyEntityMap = EntityMap mempty mempty 0
+
+newtype Deduplicate a = Deduplicate (EntityMap a)
+  deriving stock (Show, Traversable, Generic)
+  deriving newtype (Eq, Functor, Foldable, EqProp, Arbitrary)
+
+instance Semigroup (Deduplicate a) where
+  (Deduplicate em₁) <> (Deduplicate em₂) =
+    let _byID = em₁ ^. byID <> em₂ ^. byID
+        _byPosition = mempty &~ do
+          ifor_ _byID $ \eid (Positioned pos _) ->
+            at pos %= \case
+              Just eids -> Just $ ninsertSet eid eids
+              Nothing -> Just $ opoint eid
+        _lastID = fromMaybe 1 $ maximumOf (ifolded . asIndex) _byID
+    in Deduplicate EntityMap{..}
+
+
+--------------------------------------------------------------------------------
+
+_EntityMap :: Iso' (EntityMap a) [(Position, a)]
+_EntityMap = iso hither yon
+  where
+    hither :: EntityMap a -> [(Position, a)]
+    hither em = do
+       (pos, eids) <- em ^. byPosition . _Wrapped
+       eid <- toList eids
+       ent <- em ^.. byID . at eid . folded . positioned
+       pure (pos, ent)
+    yon :: [(Position, a)] -> EntityMap a
+    yon poses = alaf Endo foldMap (uncurry insertAt) poses emptyEntityMap
+
+
+insertAtReturningID :: forall a. Position -> a -> EntityMap a -> (EntityID, EntityMap a)
+insertAtReturningID pos e em =
+  let (eid, em') = em & lastID <+~ 1
+  in em'
+     & byID . at eid ?~ Positioned pos e
+     & byPosition . at pos %~ \case
+       Nothing -> Just $ opoint eid
+       Just es -> Just $ ninsertSet eid es
+     & (eid, )
+
+insertAt :: forall a. Position -> a -> EntityMap a -> EntityMap a
+insertAt pos e = snd . insertAtReturningID pos e
+
+atPosition :: forall a. (Ord a, Show a) => Position -> Lens' (EntityMap a) (VectorBag a)
+atPosition pos = lens getter setter
+  where
+    getter em =
+      let eids :: VectorBag EntityID
+          eids = maybe mempty (VectorBag . toVector . toNullable)
+                 $ em ^. byPosition . at pos
+      in getEIDAssume em <$> eids
+    setter em Empty = em & byPosition . at pos .~ Nothing
+    setter em (sort -> entities) =
+      let origEIDs = maybe Empty toNullable $ em ^. byPosition . at pos
+          origEntitiesWithIDs =
+            sortOn snd $ toList origEIDs <&> \eid -> (eid, getEIDAssume em eid)
+          go alles₁@((eid, e₁) :< es₁) -- orig
+             (e₂ :< es₂)               -- new
+            | e₁ == e₂
+              -- same, do nothing
+            = let (eids, lastEID, byID') = go es₁ es₂
+              in (insertSet eid eids, lastEID, byID')
+            | otherwise
+              -- e₂ is new, generate a new ID for it
+            = let (eids, lastEID, byID') = go alles₁ es₂
+                  eid' = succ lastEID
+              in (insertSet eid' eids, eid', byID' & at eid' ?~ Positioned pos e₂)
+          go Empty Empty = (mempty, em ^. lastID, em ^. byID)
+          go orig Empty =
+            let byID' = foldr deleteMap (em ^. byID) $ map fst orig
+            in (mempty, em ^. lastID, byID')
+          go Empty (new :< news) =
+            let (eids, lastEID, byID') = go Empty news
+                eid' = succ lastEID
+            in (insertSet eid' eids, eid', byID' & at eid' ?~ Positioned pos new)
+          go _ _ = error "unreachable"
+          (eidsAtPosition, newLastID, newByID) = go origEntitiesWithIDs entities
+      in em & byPosition . at pos .~ fromNullable eidsAtPosition
+            & byID .~ newByID
+            & lastID .~ newLastID
+
+getEIDAssume :: EntityMap a -> EntityID -> a
+getEIDAssume em eid = fromMaybe byIDInvariantError
+  $ em ^? byID . ix eid . positioned
+
+atPositionWithIDs :: Position -> EntityMap a -> Vector (EntityID, Positioned a)
+atPositionWithIDs pos em =
+  let eids = maybe mempty (toVector . toNullable)
+             $ em ^. byPosition . at pos
+  in (id &&& Positioned pos . getEIDAssume em) <$> eids
+
+fromEIDsAndPositioned
+  :: forall mono a. (MonoFoldable mono, Element mono ~ (EntityID, Positioned a))
+  => mono
+  -> EntityMap a
+fromEIDsAndPositioned eps = newLastID $ alaf Endo foldMap insert' eps mempty
+  where
+    insert' (eid, pe@(Positioned pos _))
+      = (byID . at eid ?~ pe)
+      . (byPosition . at pos %~ \case
+            Just eids -> Just $ ninsertSet eid eids
+            Nothing   -> Just $ opoint eid
+        )
+    newLastID em = em & lastID
+      .~ fromMaybe 1
+         (maximumOf (ifolded . asIndex) (em ^. byID))
+
+toEIDsAndPositioned :: EntityMap a -> [(EntityID, Positioned a)]
+toEIDsAndPositioned = itoListOf $ byID . ifolded
+
+positions :: EntityMap a -> [Position]
+positions = toListOf $ byPosition . to keys . folded
+
+lookupWithPosition :: EntityID -> EntityMap a -> Maybe (Positioned a)
+lookupWithPosition eid = view $ byID . at eid
+
+lookup :: EntityID -> EntityMap a -> Maybe a
+lookup eid = fmap (view positioned) . lookupWithPosition eid
+
+-- unlawful :(
+-- positionedEntities :: IndexedTraversal EntityID (EntityMap a) (EntityMap b) (Positioned a) (Positioned b)
+-- positionedEntities = byID . itraversed
+
+neighbors :: (Ord a, Show a) => Position -> EntityMap a -> Neighbors (VectorBag a)
+neighbors pos em = (\p -> view (atPosition p) em) <$> neighborPositions pos
+
+--------------------------------------------------------------------------------
+makeWrapped ''Deduplicate