{-# LANGUAGE CPP #-}

#ifndef MIN_VERSION_semigroups
#define MIN_VERSION_semigroups(x,y,z) 0
#endif

-----------------------------------------------------------------------------
-- |
-- Copyright   :  (C) 2011-2015 Edward Kmett
-- License     :  BSD-style (see the file LICENSE)
--
-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
-- Stability   :  provisional
-- Portability :  portable
--
----------------------------------------------------------------------------
module Data.Semigroup.Foldable.Class
  ( Foldable1(..)
  , Bifoldable1(..)
  ) where

import Control.Applicative
import Control.Applicative.Backwards
import Control.Applicative.Lift
import Control.Monad.Trans.Identity
import Data.Bifoldable
import Data.Bifunctor.Biff
import Data.Bifunctor.Clown
import Data.Bifunctor.Flip
import Data.Bifunctor.Join
import Data.Bifunctor.Product as Bifunctor
import Data.Bifunctor.Joker
import Data.Bifunctor.Tannen
import Data.Bifunctor.Wrapped
import Data.Foldable
import Data.Functor.Compose

#ifdef MIN_VERSION_comonad
import Data.Functor.Coproduct
#endif

import Data.Functor.Identity
import Data.Functor.Product as Functor
import Data.Functor.Reverse
import Data.Functor.Sum
import Data.List.NonEmpty (NonEmpty(..))
import Data.Tagged
import Data.Traversable.Instances ()

#ifdef MIN_VERSION_containers
import Data.Tree
#endif

import Data.Semigroup hiding (Product, Sum)
import Prelude hiding (foldr)

class Foldable t => Foldable1 t where
  fold1 :: Semigroup m => t m -> m
  foldMap1 :: Semigroup m => (a -> m) -> t a -> m

  foldMap1 f = maybe (error "foldMap1") id . getOption . foldMap (Option . Just . f)
  fold1 = foldMap1 id

class Bifoldable t => Bifoldable1 t where
  bifold1 :: Semigroup m => t m m -> m
  bifold1 = bifoldMap1 id id
  {-# INLINE bifold1 #-}

  bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> t a b -> m
  bifoldMap1 f g = maybe (error "bifoldMap1") id . getOption . bifoldMap (Option . Just . f) (Option . Just . g)
  {-# INLINE bifoldMap1 #-}

#if MIN_VERSION_semigroups(0,16,2)
instance Bifoldable1 Arg where
  bifoldMap1 f g (Arg a b) = f a <> g b
#endif

instance Bifoldable1 Either where
  bifoldMap1 f _ (Left a) = f a
  bifoldMap1 _ g (Right b) = g b
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 (,) where
  bifoldMap1 f g (a, b) = f a <> g b
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 ((,,) x) where
  bifoldMap1 f g (_,a,b) = f a <> g b
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 ((,,,) x y) where
  bifoldMap1 f g (_,_,a,b) = f a <> g b
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 ((,,,,) x y z) where
  bifoldMap1 f g (_,_,_,a,b) = f a <> g b
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 Const where
  bifoldMap1 f _ (Const a) = f a
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 Tagged where
  bifoldMap1 _ g (Tagged b) = g b
  {-# INLINE bifoldMap1 #-}

instance (Bifoldable1 p, Foldable1 f, Foldable1 g) => Bifoldable1 (Biff p f g) where
  bifoldMap1 f g = bifoldMap1 (foldMap1 f) (foldMap1 g) . runBiff
  {-# INLINE bifoldMap1 #-}

instance Foldable1 f => Bifoldable1 (Clown f) where
  bifoldMap1 f _ = foldMap1 f . runClown
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 p => Bifoldable1 (Flip p) where
  bifoldMap1 f g = bifoldMap1 g f . runFlip
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 p => Foldable1 (Join p) where
  foldMap1 f (Join a) = bifoldMap1 f f a
  {-# INLINE foldMap1 #-}

instance Foldable1 g => Bifoldable1 (Joker g) where
  bifoldMap1 _ g = foldMap1 g . runJoker
  {-# INLINE bifoldMap1 #-}

instance (Bifoldable1 f, Bifoldable1 g) => Bifoldable1 (Bifunctor.Product f g) where
  bifoldMap1 f g (Bifunctor.Pair x y) = bifoldMap1 f g x <> bifoldMap1 f g y
  {-# INLINE bifoldMap1 #-}

instance (Foldable1 f, Bifoldable1 p) => Bifoldable1 (Tannen f p) where
  bifoldMap1 f g = foldMap1 (bifoldMap1 f g) . runTannen
  {-# INLINE bifoldMap1 #-}

instance Bifoldable1 p => Bifoldable1 (WrappedBifunctor p) where
  bifoldMap1 f g = bifoldMap1 f g . unwrapBifunctor
  {-# INLINE bifoldMap1 #-}

#ifdef MIN_VERSION_containers
instance Foldable1 Tree where
  foldMap1 f (Node a []) = f a
  foldMap1 f (Node a (x:xs)) = f a <> foldMap1 (foldMap1 f) (x :| xs)
#endif

instance Foldable1 Identity where
  foldMap1 f = f . runIdentity

instance Foldable1 m => Foldable1 (IdentityT m) where
  foldMap1 f = foldMap1 f . runIdentityT

instance Foldable1 f => Foldable1 (Backwards f) where
  foldMap1 f = foldMap1 f . forwards

instance (Foldable1 f, Foldable1 g) => Foldable1 (Compose f g) where
  foldMap1 f = foldMap1 (foldMap1 f) . getCompose

instance Foldable1 f => Foldable1 (Lift f) where
  foldMap1 f (Pure x)  = f x
  foldMap1 f (Other y) = foldMap1 f y

instance (Foldable1 f, Foldable1 g) => Foldable1 (Functor.Product f g) where
  foldMap1 f (Functor.Pair a b) = foldMap1 f a <> foldMap1 f b

instance Foldable1 f => Foldable1 (Reverse f) where
  foldMap1 f = getDual . foldMap1 (Dual . f) . getReverse

instance (Foldable1 f, Foldable1 g) => Foldable1 (Sum f g) where
  foldMap1 f (InL x) = foldMap1 f x
  foldMap1 f (InR y) = foldMap1 f y

#ifdef MIN_VERSION_comonad
instance (Foldable1 f, Foldable1 g) => Foldable1 (Coproduct f g) where
  foldMap1 f = coproduct (foldMap1 f) (foldMap1 f)
#endif

instance Foldable1 NonEmpty where
  foldMap1 f (a :| []) = f a
  foldMap1 f (a :| b : bs) = f a <> foldMap1 f (b :| bs)

instance Foldable1 ((,) a) where
  foldMap1 f (_, x) = f x

instance Foldable1 g => Foldable1 (Joker g a) where
  foldMap1 g = foldMap1 g . runJoker
  {-# INLINE foldMap1 #-}
