{-# LANGUAGE AllowAmbiguousTypes #-}
{-# LANGUAGE ConstrainedClassMethods #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeFamilyDependencies #-}
module Database.Bolt.Extras.Graph.Internal.GraphQuery
(
GraphQuery (..)
, GetRequest (..)
, PutRequest (..)
, mergeGraphs
) where
import Control.Lens (over, (^.))
import Control.Monad.IO.Class (MonadIO)
import Data.List (foldl')
import Data.Map.Strict (fromList,
mapKeys,
mapWithKey,
toList,
union, (!))
import Data.Monoid ((<>))
import Data.Text as T (Text, intercalate,
null,
pack)
import Database.Bolt (BoltActionT,
Record,
query)
import Database.Bolt.Extras (BoltId, GetBoltId (..))
import Database.Bolt.Extras.Graph.Internal.AbstractGraph (Graph (..),
NodeName,
emptyGraph,
relationName,
relations,
vertices)
import Database.Bolt.Extras.Graph.Internal.Class (Extractable (..),
Requestable (..),
Returnable (..))
import Database.Bolt.Extras.Graph.Internal.Get (NodeGetter,
NodeResult,
RelGetter,
RelResult,
requestGetters)
import Database.Bolt.Extras.Graph.Internal.Put (PutNode, PutRelationship,
requestPut)
import NeatInterpolation (text)
class GraphQuery a where
type NodeReq a :: *
type RelReq a :: *
type NodeRes a :: *
type RelRes a :: *
requestEntities :: (Requestable (NodeName, NodeReq a),
Requestable ((NodeName, NodeName), RelReq a))
=> [(NodeName, NodeReq a)]
-> [((NodeName, NodeName), RelReq a)]
-> (Text, [Text])
formQuery :: (Requestable (NodeName, NodeReq a),
Requestable ((NodeName, NodeName), RelReq a),
Returnable (NodeName, NodeReq a),
Returnable ((NodeName, NodeName), RelReq a))
=> [Text]
-> Graph NodeName (NodeReq a) (RelReq a)
-> Text
formQuery customConds graph = [text|$completeRequest
$conditionsQ
WITH DISTINCT $distinctVars
RETURN $completeReturn|]
where
vertices' = toList (graph ^. vertices)
relations' = toList (graph ^. relations)
distinctVars = intercalate ", " $ fmap fst vertices' ++ fmap (relationName . fst) relations'
(completeRequest, reqConds) = requestEntities @a vertices' relations'
conditions = reqConds ++ customConds
conditionsQ = if Prelude.null conditions then "" else " WHERE " <> intercalate " AND " conditions
returnVertices = return' <$> filter isReturned' vertices'
returnRelations = return' <$> filter isReturned' relations'
completeReturn = intercalate ", " $ Prelude.filter (not . T.null) $ returnVertices ++ returnRelations
extractGraphs :: (Extractable (NodeRes a), Extractable (RelRes a), MonadIO m)
=> [NodeName]
-> [(NodeName, NodeName)]
-> [Record]
-> BoltActionT m [Graph NodeName (NodeRes a) (RelRes a)]
extractGraphs verticesN relationsN records = mapM (\i -> do
vertices' <- zip verticesN <$> traverse (fmap (!! i) . flip extract records ) verticesN
relations' <- zip relationsN <$> traverse (fmap (!! i) . flip extract records . relationName) relationsN
pure $ Graph (fromList vertices') (fromList relations'))
[0 .. length records - 1]
makeRequest :: (Requestable (NodeName, NodeReq a),
Requestable ((NodeName, NodeName), RelReq a),
Returnable (NodeName, NodeReq a),
Returnable ((NodeName, NodeName), RelReq a),
Extractable (NodeRes a),
Extractable (RelRes a),
MonadIO m)
=> [Text]
-> Graph NodeName (NodeReq a) (RelReq a)
-> BoltActionT m [Graph NodeName (NodeRes a) (RelRes a)]
makeRequest conds graph = do
response <- query $ formQuery @a conds graph
extractGraphs @a presentedVertices presentedRelations response
where
presentedVertices = fmap fst . filter isReturned' . toList $ graph ^. vertices
presentedRelations = fmap fst . filter isReturned' . toList $ graph ^. relations
data GetRequest = GetRequest
instance GraphQuery GetRequest where
type NodeReq GetRequest = NodeGetter
type RelReq GetRequest = RelGetter
type NodeRes GetRequest = NodeResult
type RelRes GetRequest = RelResult
requestEntities = requestGetters
data PutRequest = PutRequest
instance GraphQuery PutRequest where
type NodeReq PutRequest = PutNode
type RelReq PutRequest = PutRelationship
type NodeRes PutRequest = BoltId
type RelRes PutRequest = BoltId
requestEntities = requestPut
mergeGraphs :: GetBoltId a => [Graph NodeName a b] -> Graph NodeName a b
mergeGraphs graphs = foldl' mergeGraph emptyGraph (updateGraph <$> graphs)
where
updateGraph :: GetBoltId a => Graph NodeName a b -> Graph NodeName a b
updateGraph graph = Graph newVertices newRelations
where
namesMap = (\name node -> name <> (pack . show . getBoltId $ node) ) `mapWithKey` (graph ^. vertices)
newVertices = (\name -> namesMap ! name ) `mapKeys` (graph ^. vertices)
newRelations = (\(startName, endName) -> (namesMap ! startName, namesMap ! endName) ) `mapKeys` (graph ^. relations)
mergeGraph :: GetBoltId a => Graph NodeName a b -> Graph NodeName a b -> Graph NodeName a b
mergeGraph graphToMerge initialGraph = over relations (union (graphToMerge ^. relations)) $
over vertices (union (graphToMerge ^. vertices))
initialGraph