{-# LANGUAGE DataKinds             #-}
{-# LANGUAGE FlexibleContexts      #-}
{-# LANGUAGE GADTs                 #-}
{-# LANGUAGE ScopedTypeVariables   #-}
{-# LANGUAGE TypeOperators         #-}
{-# LANGUAGE RankNTypes            #-}
{-# LANGUAGE PolyKinds             #-}
{-# LANGUAGE TypeFamilies          #-}
{-# LANGUAGE ConstraintKinds       #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE UndecidableInstances  #-}
{-# LANGUAGE AllowAmbiguousTypes   #-}
{-# LANGUAGE BangPatterns          #-}
{-# LANGUAGE TypeApplications      #-}
{-# OPTIONS_GHC -fwarn-incomplete-patterns #-}
{-|
Module      : Control.MapReduce.Engines.Vector
Description : map-reduce-folds builders
Copyright   : (c) Adam Conner-Sax 2019
License     : BSD-3-Clause
Maintainer  : adam_conner_sax@yahoo.com
Stability   : experimental

map-reduce engine (fold builder) using @Vector@ as its intermediate type.
-}
module Control.MapReduce.Engines.Vector
  (
    -- * Engines
    vectorEngine
  , vectorEngineM

  -- * groupBy functions
  , groupByHashableKey
  , groupByOrderedKey

  -- * re-exports
  , toList
  )
where

import qualified Control.MapReduce.Core        as MRC
import qualified Control.MapReduce.Engines     as MRE

import qualified Control.Foldl                 as FL
import           Control.Monad                  ( (<=<) )
import qualified Data.Foldable                 as F
import           Data.Hashable                  ( Hashable )
import qualified Data.HashMap.Strict           as HMS
import qualified Data.Map.Strict               as MS
import qualified Data.Sequence                 as Seq
import qualified Data.Vector                   as V
import           Data.Vector                    ( Vector
                                                , toList
                                                )
import           Control.Arrow                  ( second )

-- | case analysis of @Unpack@ for @Vector@ based mapReduce
unpackVector :: MRC.Unpack x y -> Vector x -> Vector y
unpackVector :: forall x y. Unpack x y -> Vector x -> Vector y
unpackVector (MRC.Filter x -> Bool
t) = forall a. (a -> Bool) -> Vector a -> Vector a
V.filter x -> Bool
t
unpackVector (MRC.Unpack x -> g y
f) = forall a b. (a -> Vector b) -> Vector a -> Vector b
V.concatMap (forall a. [a] -> Vector a
V.fromList forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (t :: * -> *) a. Foldable t => t a -> [a]
F.toList forall b c a. (b -> c) -> (a -> b) -> a -> c
. x -> g y
f)
{-# INLINABLE unpackVector #-}

-- | case analysis of @Unpack@ for @Vector@ based mapReduce
unpackVectorM :: Monad m => MRC.UnpackM m x y -> Vector x -> m (Vector y)
unpackVectorM :: forall (m :: * -> *) x y.
Monad m =>
UnpackM m x y -> Vector x -> m (Vector y)
unpackVectorM (MRC.FilterM x -> m Bool
t) = forall (m :: * -> *) a.
Monad m =>
(a -> m Bool) -> Vector a -> m (Vector a)
V.filterM x -> m Bool
t
unpackVectorM (MRC.UnpackM x -> m (g y)
f) =
  forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (forall a b. (a -> Vector b) -> Vector a -> Vector b
V.concatMap forall a. a -> a
id) forall b c a. (b -> c) -> (a -> b) -> a -> c
. 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] -> Vector a
V.fromList forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (t :: * -> *) a. Foldable t => t a -> [a]
F.toList) forall b c a. (b -> c) -> (a -> b) -> a -> c
. x -> m (g y)
f)
{-# INLINABLE unpackVectorM #-}


-- | group the mapped and assigned values by key using a @Data.HashMap.Strict@
groupByHashableKey
  :: forall k c . (Hashable k, Eq k) => Vector (k, c) -> Vector (k, Seq.Seq c)
groupByHashableKey :: forall k c.
(Hashable k, Eq k) =>
Vector (k, c) -> Vector (k, Seq c)
groupByHashableKey Vector (k, c)
v =
  let hm :: HashMap k (Seq c)
hm = forall k v.
(Eq k, Hashable k) =>
(v -> v -> v) -> [(k, v)] -> HashMap k v
HMS.fromListWith forall a. Semigroup a => a -> a -> a
(<>) forall a b. (a -> b) -> a -> b
$ forall a. Vector a -> [a]
V.toList forall a b. (a -> b) -> a -> b
$ forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (forall (a :: * -> * -> *) b c d.
Arrow a =>
a b c -> a (d, b) (d, c)
second forall a. a -> Seq a
Seq.singleton) Vector (k, c)
v
  in  forall a. [a] -> Vector a
V.fromList forall a b. (a -> b) -> a -> b
$ forall k v. HashMap k v -> [(k, v)]
HMS.toList HashMap k (Seq c)
hm -- HML.foldrWithKey (\k lc v -> V.snoc v (k,lc)) V.empty hm 
{-# INLINABLE groupByHashableKey #-}

-- | group the mapped and assigned values by key using a @Data.Map.Strict@
groupByOrderedKey
  :: forall k c . Ord k => Vector (k, c) -> Vector (k, Seq.Seq c)
groupByOrderedKey :: forall k c. Ord k => Vector (k, c) -> Vector (k, Seq c)
groupByOrderedKey Vector (k, c)
v =
  let hm :: Map k (Seq c)
hm = forall k a. Ord k => (a -> a -> a) -> [(k, a)] -> Map k a
MS.fromListWith forall a. Semigroup a => a -> a -> a
(<>) forall a b. (a -> b) -> a -> b
$ forall a. Vector a -> [a]
V.toList forall a b. (a -> b) -> a -> b
$ forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (forall (a :: * -> * -> *) b c d.
Arrow a =>
a b c -> a (d, b) (d, c)
second forall a. a -> Seq a
Seq.singleton) Vector (k, c)
v
  in  forall a. [a] -> Vector a
V.fromList forall a b. (a -> b) -> a -> b
$ forall k a. Map k a -> [(k, a)]
MS.toList Map k (Seq c)
hm --MS.foldrWithKey (\k lc s -> VS.cons (k,lc) s) VS.empty hm
{-# INLINABLE groupByOrderedKey #-}

-- | map-reduce-fold builder, using @Vector@, returning a @Vector@ result
vectorEngine
  :: (Foldable g, Functor g)
  => (Vector (k, c) -> Vector (k, g c))
  -> MRE.MapReduceFold y k c Vector x d
vectorEngine :: forall (g :: * -> *) k c y x d.
(Foldable g, Functor g) =>
(Vector (k, c) -> Vector (k, g c))
-> MapReduceFold y k c Vector x d
vectorEngine Vector (k, c) -> Vector (k, g c)
groupByKey Unpack x y
u (MRC.Assign y -> (k, c)
a) Reduce k c d
r = forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap
  ( forall a b. (a -> b) -> Vector a -> Vector b
V.map (forall a b c. (a -> b -> c) -> (a, b) -> c
uncurry (forall (h :: * -> *) k x d.
(Foldable h, Functor h) =>
Reduce k x d -> k -> h x -> d
MRE.reduceFunction Reduce k c d
r))
  forall b c a. (b -> c) -> (a -> b) -> a -> c
. Vector (k, c) -> Vector (k, g c)
groupByKey
  forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a b. (a -> b) -> Vector a -> Vector b
V.map y -> (k, c)
a
  forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall x y. Unpack x y -> Vector x -> Vector y
unpackVector Unpack x y
u
  )
  forall (v :: * -> *) a. Vector v a => Fold a (v a)
FL.vector
{-# INLINABLE vectorEngine #-}

-- | effectful map-reduce-fold builder, using @Vector@, returning an effectful @Vector@ result
vectorEngineM
  :: (Monad m, Traversable g)
  => (Vector (k, c) -> Vector (k, g c))
  -> MRE.MapReduceFoldM m y k c Vector x d
vectorEngineM :: forall (m :: * -> *) (g :: * -> *) k c y x d.
(Monad m, Traversable g) =>
(Vector (k, c) -> Vector (k, g c))
-> MapReduceFoldM m y k c Vector x d
vectorEngineM Vector (k, c) -> Vector (k, g c)
groupByKey UnpackM m x y
u (MRC.AssignM y -> m (k, c)
a) ReduceM m k c d
r = forall (m :: * -> *) a b x.
Monad m =>
(a -> m b) -> FoldM m x a -> FoldM m x b
MRC.postMapM
  ( (forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
traverse (forall a b c. (a -> b -> c) -> (a, b) -> c
uncurry (forall (h :: * -> *) (m :: * -> *) k x d.
(Traversable h, Monad m) =>
ReduceM m k x d -> k -> h x -> m d
MRE.reduceFunctionM ReduceM m k c d
r)) forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<<)
  forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap Vector (k, c) -> Vector (k, g c)
groupByKey
  forall b c a. (b -> c) -> (a -> b) -> a -> c
. (forall (m :: * -> *) a b.
Monad m =>
(a -> m b) -> Vector a -> m (Vector b)
V.mapM y -> m (k, c)
a forall (m :: * -> *) b c a.
Monad m =>
(b -> m c) -> (a -> m b) -> a -> m c
<=< forall (m :: * -> *) x y.
Monad m =>
UnpackM m x y -> Vector x -> m (Vector y)
unpackVectorM UnpackM m x y
u)
  )
  (forall (m :: * -> *) a b. Monad m => Fold a b -> FoldM m a b
FL.generalize forall (v :: * -> *) a. Vector v a => Fold a (v a)
FL.vector)
{-# INLINABLE vectorEngineM #-}
-- NB: If we are willing to constrain to PrimMonad m, then we can use vectorM here which can do in-place updates, etc.