{-# 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.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)

-- | Type class used to perform requests to the Neo4j based on graphs.
--
class GraphQuery a where
  -- | Type of entity describing node for request.
  type NodeReq a :: *
  -- | Type of entity describing relationship for request.
  type RelReq  a :: *
  -- | Type of node entity which will be extracted from result.
  type NodeRes a :: *
  -- | Type of relationship entity which will be extracted from result.
  type RelRes  a :: *

  -- | Convert requestable entities to text in the query.
  requestEntities :: (Requestable (NodeName, NodeReq a),
                      Requestable ((NodeName, NodeName), RelReq a))
                  => [(NodeName, NodeReq a)]
                  -> [((NodeName, NodeName), RelReq a)]
                  -> (Text, [Text])

  -- | Abstract function to form query for request.
  --
  formQuery :: (Requestable (NodeName, NodeReq a),
                Requestable ((NodeName, NodeName), RelReq a),
                Returnable (NodeName, NodeReq a),
                Returnable ((NodeName, NodeName), RelReq a))
            => [Text]                                -- ^ Custom conditions that will be added to @WHERE@ block.
            -> Graph NodeName (NodeReq a) (RelReq a) -- ^ Request graph template.
            -> Text                                  -- ^ Cypher query as text.
  formQuery [NodeName]
customConds Graph NodeName (NodeReq a) (RelReq a)
graph = [text|$completeRequest
                                      $conditionsQ
                                      WITH DISTINCT $distinctVars
                                      RETURN $completeReturn|]
    where
      vertices' :: [(NodeName, NodeReq a)]
vertices'        = forall k a. Map k a -> [(k, a)]
toList (Graph NodeName (NodeReq a) (RelReq a)
graph forall s a. s -> Getting a s a -> a
^. forall n a1 b a2.
Lens (Graph n a1 b) (Graph n a2 b) (Map n a1) (Map n a2)
vertices)
      relations' :: [((NodeName, NodeName), RelReq a)]
relations'       = forall k a. Map k a -> [(k, a)]
toList (Graph NodeName (NodeReq a) (RelReq a)
graph forall s a. s -> Getting a s a -> a
^. forall n a b1 b2.
Lens (Graph n a b1) (Graph n a b2) (Map (n, n) b1) (Map (n, n) b2)
relations)
      distinctVars :: NodeName
distinctVars     = NodeName -> [NodeName] -> NodeName
intercalate NodeName
", " forall a b. (a -> b) -> a -> b
$ forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap forall a b. (a, b) -> a
fst [(NodeName, NodeReq a)]
vertices' forall a. [a] -> [a] -> [a]
++ forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap ((NodeName, NodeName) -> NodeName
relationName forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b. (a, b) -> a
fst) [((NodeName, NodeName), RelReq a)]
relations'

      (NodeName
completeRequest, [NodeName]
reqConds) = forall a.
(GraphQuery a, Requestable (NodeName, NodeReq a),
 Requestable ((NodeName, NodeName), RelReq a)) =>
[(NodeName, NodeReq a)]
-> [((NodeName, NodeName), RelReq a)] -> (NodeName, [NodeName])
requestEntities @a [(NodeName, NodeReq a)]
vertices' [((NodeName, NodeName), RelReq a)]
relations'

      conditions :: [NodeName]
conditions       = [NodeName]
reqConds forall a. [a] -> [a] -> [a]
++ [NodeName]
customConds
      conditionsQ :: NodeName
conditionsQ      = if forall (t :: * -> *) a. Foldable t => t a -> Bool
Prelude.null [NodeName]
conditions then NodeName
"" else NodeName
" WHERE " forall a. Semigroup a => a -> a -> a
<> NodeName -> [NodeName] -> NodeName
intercalate NodeName
" AND " [NodeName]
conditions

      returnVertices :: [NodeName]
returnVertices   = forall a. Returnable a => a -> NodeName
return' forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. (a -> Bool) -> [a] -> [a]
filter forall a. Returnable a => a -> Bool
isReturned' [(NodeName, NodeReq a)]
vertices'
      returnRelations :: [NodeName]
returnRelations  = forall a. Returnable a => a -> NodeName
return' forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall a. (a -> Bool) -> [a] -> [a]
filter forall a. Returnable a => a -> Bool
isReturned' [((NodeName, NodeName), RelReq a)]
relations'

      completeReturn :: NodeName
completeReturn   = NodeName -> [NodeName] -> NodeName
intercalate NodeName
", " forall a b. (a -> b) -> a -> b
$ forall a. (a -> Bool) -> [a] -> [a]
Prelude.filter (Bool -> Bool
not forall b c a. (b -> c) -> (a -> b) -> a -> c
. NodeName -> Bool
T.null) forall a b. (a -> b) -> a -> b
$ [NodeName]
returnVertices forall a. [a] -> [a] -> [a]
++ [NodeName]
returnRelations

  -- | Abstract function which exctracts graph from records if nodes and relations can be extracted.
  --
  extractGraphs :: (Extractable (NodeRes a), Extractable (RelRes a), MonadIO m)
                => [NodeName]
                -> [(NodeName, NodeName)]
                -> [Record]
                -> BoltActionT m [Graph NodeName (NodeRes a) (RelRes a)]
  extractGraphs [NodeName]
verticesN [(NodeName, NodeName)]
relationsN [Record]
records = forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (\BoltId
i -> do
        [(NodeName, NodeRes a)]
vertices'  <- forall a b. [a] -> [b] -> [(a, b)]
zip [NodeName]
verticesN  forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
traverse (forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (forall a. [a] -> BoltId -> a
!! BoltId
i) forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b c. (a -> b -> c) -> b -> a -> c
flip forall a (m :: * -> *).
(Extractable a, MonadIO m) =>
NodeName -> [Record] -> BoltActionT m [a]
extract [Record]
records               ) [NodeName]
verticesN
        [((NodeName, NodeName), RelRes a)]
relations' <- forall a b. [a] -> [b] -> [(a, b)]
zip [(NodeName, NodeName)]
relationsN forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
traverse (forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (forall a. [a] -> BoltId -> a
!! BoltId
i) forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b c. (a -> b -> c) -> b -> a -> c
flip forall a (m :: * -> *).
(Extractable a, MonadIO m) =>
NodeName -> [Record] -> BoltActionT m [a]
extract [Record]
records forall b c a. (b -> c) -> (a -> b) -> a -> c
. (NodeName, NodeName) -> NodeName
relationName) [(NodeName, NodeName)]
relationsN
        forall (f :: * -> *) a. Applicative f => a -> f a
pure forall a b. (a -> b) -> a -> b
$ forall n a b. Map n a -> Map (n, n) b -> Graph n a b
Graph (forall k a. Ord k => [(k, a)] -> Map k a
fromList [(NodeName, NodeRes a)]
vertices') (forall k a. Ord k => [(k, a)] -> Map k a
fromList [((NodeName, NodeName), RelRes a)]
relations'))
      [BoltId
0 .. forall (t :: * -> *) a. Foldable t => t a -> BoltId
length [Record]
records forall a. Num a => a -> a -> a
- BoltId
1]

  -- | For given query graph, perform query and extract results graph.
  --
  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 [NodeName]
conds Graph NodeName (NodeReq a) (RelReq a)
graph = do
      [Record]
response <- forall (m :: * -> *).
(MonadIO m, HasCallStack) =>
NodeName -> BoltActionT m [Record]
query forall a b. (a -> b) -> a -> b
$ forall a.
(GraphQuery a, Requestable (NodeName, NodeReq a),
 Requestable ((NodeName, NodeName), RelReq a),
 Returnable (NodeName, NodeReq a),
 Returnable ((NodeName, NodeName), RelReq a)) =>
[NodeName] -> Graph NodeName (NodeReq a) (RelReq a) -> NodeName
formQuery @a [NodeName]
conds Graph NodeName (NodeReq a) (RelReq a)
graph
      forall a (m :: * -> *).
(GraphQuery a, Extractable (NodeRes a), Extractable (RelRes a),
 MonadIO m) =>
[NodeName]
-> [(NodeName, NodeName)]
-> [Record]
-> BoltActionT m [Graph NodeName (NodeRes a) (RelRes a)]
extractGraphs @a [NodeName]
presentedVertices [(NodeName, NodeName)]
presentedRelations [Record]
response
    where
      presentedVertices :: [NodeName]
presentedVertices  = forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap forall a b. (a, b) -> a
fst forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. (a -> Bool) -> [a] -> [a]
filter forall a. Returnable a => a -> Bool
isReturned' forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall k a. Map k a -> [(k, a)]
toList forall a b. (a -> b) -> a -> b
$ Graph NodeName (NodeReq a) (RelReq a)
graph forall s a. s -> Getting a s a -> a
^. forall n a1 b a2.
Lens (Graph n a1 b) (Graph n a2 b) (Map n a1) (Map n a2)
vertices
      presentedRelations :: [(NodeName, NodeName)]
presentedRelations = forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap forall a b. (a, b) -> a
fst forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. (a -> Bool) -> [a] -> [a]
filter forall a. Returnable a => a -> Bool
isReturned' forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall k a. Map k a -> [(k, a)]
toList forall a b. (a -> b) -> a -> b
$ Graph NodeName (NodeReq a) (RelReq a)
graph forall s a. s -> Getting a s a -> a
^. forall n a b1 b2.
Lens (Graph n a b1) (Graph n a b2) (Map (n, n) b1) (Map (n, n) b2)
relations

---------------------------------------------------------------------------------------
-- GET --
---------------------------------------------------------------------------------------

-- | Get request with graph result.
--
data GetRequest = GetRequest

instance GraphQuery GetRequest where
  type NodeReq GetRequest = NodeGetter
  type RelReq  GetRequest = RelGetter
  type NodeRes GetRequest = NodeResult
  type RelRes  GetRequest = RelResult
  requestEntities :: (Requestable (NodeName, NodeReq GetRequest),
 Requestable ((NodeName, NodeName), RelReq GetRequest)) =>
[(NodeName, NodeReq GetRequest)]
-> [((NodeName, NodeName), RelReq GetRequest)]
-> (NodeName, [NodeName])
requestEntities         = [(NodeName, NodeGetter)]
-> [((NodeName, NodeName), RelGetter)] -> (NodeName, [NodeName])
requestGetters

---------------------------------------------------------------------------------------
-- PUT --
---------------------------------------------------------------------------------------

-- | Put request in Bolt format with 'BoltId's of uploaded entities as result.
--
data PutRequest = PutRequest

instance GraphQuery PutRequest where
  type NodeReq PutRequest = PutNode
  type RelReq  PutRequest = PutRelationship
  type NodeRes PutRequest = BoltId
  type RelRes  PutRequest = BoltId
  requestEntities :: (Requestable (NodeName, NodeReq PutRequest),
 Requestable ((NodeName, NodeName), RelReq PutRequest)) =>
[(NodeName, NodeReq PutRequest)]
-> [((NodeName, NodeName), RelReq PutRequest)]
-> (NodeName, [NodeName])
requestEntities          = [(NodeName, PutNode)]
-> [((NodeName, NodeName), PutRelationship)]
-> (NodeName, [NodeName])
requestPut

-- | Helper function to merge graphs of results, i.e.
-- if you requested graph @A -> B -> C@
-- and in the database there were two @B@ entities connected to the same entity @A@
-- and four @C@ entities connected to the same two entities @B@,
-- Cypher query will return four graphs which satisfy this path,
-- despite the fact that @A@ was present only once in the database
-- and @B@ was present only two times in the database.
--
-- This function will merge these four graphs in one
-- and return nodes by node names with suffixes equal to their 'BoltId's.
--
-- For example, if there were four graphs:
--
-- @
--   nodes: [A (boltId = 0), B (boltId = 1), C (boltId = 3)], relations: [A -> B, B -> C];
--   nodes: [A (boltId = 0), B (boltId = 1), C (boltId = 4)], relations: [A -> B, B -> C];
--   nodes: [A (boltId = 0), B (boltId = 2), C (boltId = 5)], relations: [A -> B, B -> C];
--   nodes: [A (boltId = 0), B (boltId = 2), C (boltId = 6)], relations: [A -> B, B -> C].
-- @
-- this function will merge them into new graph:
--
-- @
--   nodes: [A0 (boltId = 0), B1 (boltId = 1), B2 (boltId = 2),
--           C3 (boltId = 3), C4 (boltId = 4), C5 (boltId = 5), C6 (boltId = 6)],
--   relations: [A0 -> B1, A0 -> B2, B1 -> C3, B1 -> C4, B2 -> C5, B2 -> C6].
-- @
--
mergeGraphs :: GetBoltId a => [Graph NodeName a b] -> Graph NodeName a b
mergeGraphs :: forall a b.
GetBoltId a =>
[Graph NodeName a b] -> Graph NodeName a b
mergeGraphs [Graph NodeName a b]
graphs = forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl' forall a b.
GetBoltId a =>
Graph NodeName a b -> Graph NodeName a b -> Graph NodeName a b
mergeGraph forall n a b. Ord n => Graph n a b
emptyGraph (forall a b. GetBoltId a => Graph NodeName a b -> Graph NodeName a b
updateGraph forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> [Graph NodeName a b]
graphs)
  where
    updateGraph :: GetBoltId a => Graph NodeName a b -> Graph NodeName a b
    updateGraph :: forall a b. GetBoltId a => Graph NodeName a b -> Graph NodeName a b
updateGraph Graph NodeName a b
graph = forall n a b. Map n a -> Map (n, n) b -> Graph n a b
Graph Map NodeName a
newVertices Map (NodeName, NodeName) b
newRelations
      where
        namesMap :: Map NodeName NodeName
namesMap     = (\NodeName
name        a
node     ->  NodeName
name forall a. Semigroup a => a -> a -> a
<> (String -> NodeName
pack forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. Show a => a -> String
show forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. GetBoltId a => a -> BoltId
getBoltId forall a b. (a -> b) -> a -> b
$ a
node)  ) forall k a b. (k -> a -> b) -> Map k a -> Map k b
`mapWithKey` (Graph NodeName a b
graph forall s a. s -> Getting a s a -> a
^. forall n a1 b a2.
Lens (Graph n a1 b) (Graph n a2 b) (Map n a1) (Map n a2)
vertices)
        newVertices :: Map NodeName a
newVertices  = (\NodeName
name                 ->  Map NodeName NodeName
namesMap forall k a. Ord k => Map k a -> k -> a
! NodeName
name                           ) forall k2 k1 a. Ord k2 => (k1 -> k2) -> Map k1 a -> Map k2 a
`mapKeys`    (Graph NodeName a b
graph forall s a. s -> Getting a s a -> a
^. forall n a1 b a2.
Lens (Graph n a1 b) (Graph n a2 b) (Map n a1) (Map n a2)
vertices)
        newRelations :: Map (NodeName, NodeName) b
newRelations = (\(NodeName
startName, NodeName
endName) -> (Map NodeName NodeName
namesMap forall k a. Ord k => Map k a -> k -> a
! NodeName
startName, Map NodeName NodeName
namesMap forall k a. Ord k => Map k a -> k -> a
! NodeName
endName) ) forall k2 k1 a. Ord k2 => (k1 -> k2) -> Map k1 a -> Map k2 a
`mapKeys`    (Graph NodeName a b
graph forall s a. s -> Getting a s a -> a
^. forall n a b1 b2.
Lens (Graph n a b1) (Graph n a b2) (Map (n, n) b1) (Map (n, n) b2)
relations)

    mergeGraph :: GetBoltId a => Graph NodeName a b -> Graph NodeName a b -> Graph NodeName a b
    mergeGraph :: forall a b.
GetBoltId a =>
Graph NodeName a b -> Graph NodeName a b -> Graph NodeName a b
mergeGraph Graph NodeName a b
graphToMerge Graph NodeName a b
initialGraph = forall s t a b. ASetter s t a b -> (a -> b) -> s -> t
over forall n a b1 b2.
Lens (Graph n a b1) (Graph n a b2) (Map (n, n) b1) (Map (n, n) b2)
relations (forall k a. Ord k => Map k a -> Map k a -> Map k a
union (Graph NodeName a b
graphToMerge forall s a. s -> Getting a s a -> a
^. forall n a b1 b2.
Lens (Graph n a b1) (Graph n a b2) (Map (n, n) b1) (Map (n, n) b2)
relations)) forall a b. (a -> b) -> a -> b
$
                                           forall s t a b. ASetter s t a b -> (a -> b) -> s -> t
over forall n a1 b a2.
Lens (Graph n a1 b) (Graph n a2 b) (Map n a1) (Map n a2)
vertices  (forall k a. Ord k => Map k a -> Map k a -> Map k a
union (Graph NodeName a b
graphToMerge forall s a. s -> Getting a s a -> a
^. forall n a1 b a2.
Lens (Graph n a1 b) (Graph n a2 b) (Map n a1) (Map n a2)
vertices))
                                           Graph NodeName a b
initialGraph