{-# LANGUAGE OverloadedStrings, FlexibleContexts #-}
-- |
-- Module: Data.Greskell.Extra
-- Description: Extra utility functions implemented by Greskell
-- Maintainer: Toshio Ito <debug.ito@gmail.com>
--
-- Extra utility functions implemented by Greskell.
--
-- @since 0.2.3.0
module Data.Greskell.Extra
  ( -- * Property readers
    -- $readers
    lookupAs,
    lookupAs',
    lookupListAs,
    lookupListAs',
    pMapToFail,
    -- * Property writers
    writeKeyValues,
    (<=:>),
    (<=?>),
    writePropertyKeyValues,
    writePMapProperties,
    -- * Control idioms
    gWhenEmptyInput
  ) where

import Data.Aeson (ToJSON)
import Control.Category ((<<<))
import Data.Foldable (Foldable)
import Data.Greskell.Binder (Binder, newBind)
import Data.Greskell.Graph
  ( Property(..), Element, KeyValue(..), (=:), Key
  )
import qualified Data.Greskell.Graph as Graph
import Data.Greskell.GTraversal
  ( Walk, WalkType, SideEffect, Transform,
    ToGTraversal(..), Split, Lift, liftWalk,
    gProperty, gCoalesce, gUnfold, gFold
  )
import Data.Greskell.PMap
  ( PMap, pMapToList,
    lookupAs,
    lookupAs',
    lookupListAs,
    lookupListAs',
    pMapToFail
  )
import Data.Monoid (mconcat)
import Data.Text (Text)

-- $setup
--
-- >>> :set -XOverloadedStrings
-- >>> import Control.Category ((>>>))
-- >>> import Data.Function ((&))
-- >>> import Data.Greskell.Binder (runBinder)
-- >>> import Data.Greskell.Greskell (toGremlin)
-- >>> import Data.Greskell.Graph (AVertex)
-- >>> import Data.Greskell.GTraversal (GTraversal, source, sV', gHas2, (&.), gAddV)
-- >>> import Data.List (sortBy)
-- >>> import Data.Ord (comparing)
-- >>> import qualified Data.HashMap.Strict as HashMap

-- $readers
--
-- Re-export property readers.
--
-- @since 1.0.0.0

-- | Make a series of @.property@ steps to write the given key-value
-- pairs as properties.
--
-- @since 0.2.3.0
--
-- >>> let binder = (writePropertyKeyValues [("age", (21 :: Int))] :: Binder (Walk SideEffect AVertex AVertex))
-- >>> let (walk, binding) = runBinder binder
-- >>> toGremlin walk
-- "__.property(\"age\",__v0).identity()"
-- >>> sortBy (comparing fst) $ HashMap.toList binding
-- [("__v0",Number 21.0)]
writePropertyKeyValues :: (ToJSON v, Element e) => [(Text, v)] -> Binder (Walk SideEffect e e)
writePropertyKeyValues :: [(Text, v)] -> Binder (Walk SideEffect e e)
writePropertyKeyValues [(Text, v)]
pairs = ([KeyValue e] -> Walk SideEffect e e)
-> Binder [KeyValue e] -> Binder (Walk SideEffect e e)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap [KeyValue e] -> Walk SideEffect e e
forall e. Element e => [KeyValue e] -> Walk SideEffect e e
writeKeyValues (Binder [KeyValue e] -> Binder (Walk SideEffect e e))
-> Binder [KeyValue e] -> Binder (Walk SideEffect e e)
forall a b. (a -> b) -> a -> b
$ ((Text, v) -> Binder (KeyValue e))
-> [(Text, v)] -> Binder [KeyValue e]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (Text, v) -> Binder (KeyValue e)
forall b a. ToJSON b => (Text, b) -> Binder (KeyValue a)
toKeyValue [(Text, v)]
pairs
  where
    toKeyValue :: (Text, b) -> Binder (KeyValue a)
toKeyValue (Text
key, b
value) = Text -> Key a b
forall a b. Text -> Key a b
Graph.key Text
key Key a b -> b -> Binder (KeyValue a)
forall b a. ToJSON b => Key a b -> b -> Binder (KeyValue a)
<=:> b
value

-- | Make a series of @.property@ steps to write the given key-value
-- pairs as properties. Use '<=:>' and '<=?>' to make a 'KeyValue'
-- within 'Binder'.
--
-- >>> let keyAge = ("age" :: Key AVertex Int)
-- >>> let keyName = ("name" :: Key AVertex Text)
-- >>> let (walk, binding) = runBinder $ writeKeyValues <$> sequence [keyAge <=:> 21, keyName <=:> "Josh"]
-- >>> toGremlin walk
-- "__.property(\"age\",__v0).property(\"name\",__v1).identity()"
-- >>> sortBy (comparing fst) $ HashMap.toList binding
-- [("__v0",Number 21.0),("__v1",String "Josh")]
--
-- @since 1.0.0.0
writeKeyValues :: Element e => [KeyValue e] -> Walk SideEffect e e
writeKeyValues :: [KeyValue e] -> Walk SideEffect e e
writeKeyValues [KeyValue e]
pairs = [Walk SideEffect e e] -> Walk SideEffect e e
forall a. Monoid a => [a] -> a
mconcat ([Walk SideEffect e e] -> Walk SideEffect e e)
-> [Walk SideEffect e e] -> Walk SideEffect e e
forall a b. (a -> b) -> a -> b
$ KeyValue e -> [Walk SideEffect e e]
forall a. Element a => KeyValue a -> [Walk SideEffect a a]
toPropStep (KeyValue e -> [Walk SideEffect e e])
-> [KeyValue e] -> [Walk SideEffect e e]
forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<< [KeyValue e]
pairs
  where
    toPropStep :: KeyValue a -> [Walk SideEffect a a]
toPropStep (KeyValue Key a b
k Greskell b
v) = [Key a b -> Greskell b -> Walk SideEffect a a
forall e v.
Element e =>
Key e v -> Greskell v -> Walk SideEffect e e
gProperty Key a b
k Greskell b
v]
    toPropStep (KeyNoValue Key a b
_) = []

-- | Make a series of @.property@ steps to write all properties in the
-- given 'PMap'.
--
-- @since 1.0.0.0
writePMapProperties :: (Foldable c, ToJSON v, Element e)
                    => PMap c v -> Binder (Walk SideEffect e e)
writePMapProperties :: PMap c v -> Binder (Walk SideEffect e e)
writePMapProperties = [(Text, v)] -> Binder (Walk SideEffect e e)
forall v e.
(ToJSON v, Element e) =>
[(Text, v)] -> Binder (Walk SideEffect e e)
writePropertyKeyValues ([(Text, v)] -> Binder (Walk SideEffect e e))
-> (PMap c v -> [(Text, v)])
-> PMap c v
-> Binder (Walk SideEffect e e)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. PMap c v -> [(Text, v)]
forall (c :: * -> *) v. Foldable c => PMap c v -> [(Text, v)]
pMapToList

-- | Like '=:', but this one takes a real value, binds it into a
-- 'Greskell' value and returns 'KeyValue'.
--
-- @since 1.0.0.0
(<=:>) :: ToJSON b => Key a b -> b -> Binder (KeyValue a)
<=:> :: Key a b -> b -> Binder (KeyValue a)
(<=:>) Key a b
k b
v = Key a b -> Greskell b -> KeyValue a
forall a b. Key a b -> Greskell b -> KeyValue a
(=:) Key a b
k (Greskell b -> KeyValue a)
-> Binder (Greskell b) -> Binder (KeyValue a)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> b -> Binder (Greskell b)
forall v. ToJSON v => v -> Binder (Greskell v)
newBind b
v

-- | Like '<=:>', but this one is for an optional property. If the
-- value is 'Just', it's equivalent to '<=:>'. If the value is
-- 'Nothing', it returns 'KeyNoValue'.
--
-- >>> let keyNName = ("nickname" :: Key AVertex (Maybe Text))
-- >>> let keyCompany = ("company" :: Key AVertex (Maybe Text))
-- >>> let (walk, binding) = runBinder $ writeKeyValues <$> sequence [keyNName <=?> Nothing, keyCompany <=?> Just "foobar.com"]
-- >>> toGremlin walk
-- "__.property(\"company\",__v0).identity()"
-- >>> sortBy (comparing fst) $ HashMap.toList binding
-- [("__v0",String "foobar.com")]
--
-- @since 1.0.0.0
(<=?>) :: ToJSON b => Key a (Maybe b) -> Maybe b -> Binder (KeyValue a)
<=?> :: Key a (Maybe b) -> Maybe b -> Binder (KeyValue a)
(<=?>) Key a (Maybe b)
k v :: Maybe b
v@(Just b
_) = Key a (Maybe b)
k Key a (Maybe b) -> Maybe b -> Binder (KeyValue a)
forall b a. ToJSON b => Key a b -> b -> Binder (KeyValue a)
<=:> Maybe b
v
(<=?>) Key a (Maybe b)
k Maybe b
Nothing = KeyValue a -> Binder (KeyValue a)
forall (m :: * -> *) a. Monad m => a -> m a
return (KeyValue a -> Binder (KeyValue a))
-> KeyValue a -> Binder (KeyValue a)
forall a b. (a -> b) -> a -> b
$ Key a (Maybe b) -> KeyValue a
forall a b. Key a b -> KeyValue a
KeyNoValue Key a (Maybe b)
k

-- | The result 'Walk' emits the input elements as-is when there is at
-- least one input element. If there is no input element, it runs the
-- body traversal once and outputs its result.
--
-- You can use this function to implement \"upsert\" a vertex
-- (i.e. add a vertex if not exist).
--
-- >>> let getMarko = (source "g" & sV' [] &. gHas2 "name" "marko" :: GTraversal Transform () AVertex)
-- >>> let upsertMarko = (liftWalk getMarko &. gWhenEmptyInput (gAddV "person" >>> gProperty "name" "marko") :: GTraversal SideEffect () AVertex)
--
-- See also: https://stackoverflow.com/questions/46027444/
--
-- @since 1.1.0.0
gWhenEmptyInput :: (ToGTraversal g, Split cc c, Lift Transform cc, Lift Transform c, WalkType c, WalkType cc)
                => g cc [s] s -- ^ the body traversal
                -> Walk c s s -- ^ the result walk
gWhenEmptyInput :: g cc [s] s -> Walk c s s
gWhenEmptyInput g cc [s] s
body = [GTraversal cc [s] s] -> Walk c [s] s
forall (g :: * -> * -> * -> *) cc c s e.
(ToGTraversal g, Split cc c, Lift Transform c, WalkType c,
 WalkType cc) =>
[g cc s e] -> Walk c s e
gCoalesce
                       [ GTraversal Transform [s] s -> GTraversal cc [s] s
forall (g :: * -> * -> * -> *) from to s e.
(ToGTraversal g, WalkType from, WalkType to, Lift from to) =>
g from s e -> g to s e
liftWalk (GTraversal Transform [s] s -> GTraversal cc [s] s)
-> GTraversal Transform [s] s -> GTraversal cc [s] s
forall a b. (a -> b) -> a -> b
$ Walk Transform [s] s -> GTraversal Transform [s] s
forall (g :: * -> * -> * -> *) c s e.
(ToGTraversal g, WalkType c) =>
g c s e -> GTraversal c s e
toGTraversal Walk Transform [s] s
forall a. AsIterator a => Walk Transform a (IteratorItem a)
gUnfold,
                         g cc [s] s -> GTraversal cc [s] s
forall (g :: * -> * -> * -> *) c s e.
(ToGTraversal g, WalkType c) =>
g c s e -> GTraversal c s e
toGTraversal g cc [s] s
body
                       ] Walk c [s] s -> Walk c s [s] -> Walk c s s
forall k (cat :: k -> k -> *) (b :: k) (c :: k) (a :: k).
Category cat =>
cat b c -> cat a b -> cat a c
<<< Walk Transform s [s] -> Walk c s [s]
forall (g :: * -> * -> * -> *) from to s e.
(ToGTraversal g, WalkType from, WalkType to, Lift from to) =>
g from s e -> g to s e
liftWalk Walk Transform s [s]
forall a. Walk Transform a [a]
gFold