{-# LANGUAGE CPP #-}
{-# LANGUAGE Rank2Types #-}
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE EmptyDataDecls #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FunctionalDependencies #-}

#ifndef MIN_VERSION_base
#define MIN_VERSION_base(x,y,z) 1
#endif

-------------------------------------------------------------------------------
-- |
-- Module      :  Control.Lens.Tuple
-- Copyright   :  (C) 2012-16 Edward Kmett
-- License     :  BSD-style (see the file LICENSE)
-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
-- Stability   :  provisional
-- Portability :  Rank2Types
--
-------------------------------------------------------------------------------
module Control.Lens.Tuple
  (
  -- * Tuples
    Field1(..)
  , Field2(..)
  , Field3(..)
  , Field4(..)
  , Field5(..)
  , Field6(..)
  , Field7(..)
  , Field8(..)
  , Field9(..)
  -- * Strict variations
  , _1', _2', _3', _4', _5', _6', _7', _8', _9'
  ) where

import Control.Lens.Lens
import Data.Functor.Identity
import Data.Functor.Product
import Data.Profunctor (dimap)
import Data.Proxy (Proxy (Proxy))
import GHC.Generics (Generic (..), (:*:) (..), K1 (..), M1 (..), U1 (..))

#if !MIN_VERSION_base(4,8,0)
import Control.Applicative
#endif

-- $setup
-- >>> :set -XNoOverloadedStrings
-- >>> import Control.Lens

-- | Provides access to 1st field of a tuple.
class Field1 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 1st field of a tuple (and possibly change its type).
  --
  -- >>> (1,2)^._1
  -- 1
  --
  -- >>> _1 .~ "hello" $ (1,2)
  -- ("hello",2)
  --
  -- >>> (1,2) & _1 .~ "hello"
  -- ("hello",2)
  --
  -- >>> _1 putStrLn ("hello","world")
  -- hello
  -- ((),"world")
  --
  -- This can also be used on larger tuples as well:
  --
  -- >>> (1,2,3,4,5) & _1 +~ 41
  -- (42,2,3,4,5)
  --
  -- @
  -- '_1' :: 'Lens' (a,b) (a',b) a a'
  -- '_1' :: 'Lens' (a,b,c) (a',b,c) a a'
  -- '_1' :: 'Lens' (a,b,c,d) (a',b,c,d) a a'
  -- ...
  -- '_1' :: 'Lens' (a,b,c,d,e,f,g,h,i) (a',b,c,d,e,f,g,h,i) a a'
  -- @
  _1 :: Lens s t a b
  default _1 :: (Generic s, Generic t, GIxed N0 (Rep s) (Rep t) a b)
             => Lens s t a b
  _1 = ix proxyN0
  {-# INLINE _1 #-}

instance Field1 (Identity a) (Identity b) a b where
  _1 f (Identity a) = Identity <$> f a

instance Field1 (Product f g a) (Product f' g a) (f a) (f' a) where
  _1 f (Pair a b) = flip Pair b <$> f a

instance Field1 ((f :*: g) p) ((f' :*: g) p) (f p) (f' p) where
  _1 f (l :*: r) = (:*: r) <$> f l

-- | @
-- '_1' k ~(a,b) = (\\a' -> (a',b)) 'Data.Functor.<$>' k a
-- @
instance Field1 (a,b) (a',b) a a' where
  _1 k ~(a,b) = k a <&> \a' -> (a',b)
  {-# INLINE _1 #-}

instance Field1 (a,b,c) (a',b,c) a a' where
  _1 k ~(a,b,c) = k a <&> \a' -> (a',b,c)
  {-# INLINE _1 #-}

instance Field1 (a,b,c,d) (a',b,c,d) a a' where
  _1 k ~(a,b,c,d) = k a <&> \a' -> (a',b,c,d)
  {-# INLINE _1 #-}

instance Field1 (a,b,c,d,e) (a',b,c,d,e) a a' where
  _1 k ~(a,b,c,d,e) = k a <&> \a' -> (a',b,c,d,e)
  {-# INLINE _1 #-}

instance Field1 (a,b,c,d,e,f) (a',b,c,d,e,f) a a' where
  _1 k ~(a,b,c,d,e,f) = k a <&> \a' -> (a',b,c,d,e,f)
  {-# INLINE _1 #-}

instance Field1 (a,b,c,d,e,f,g) (a',b,c,d,e,f,g) a a' where
  _1 k ~(a,b,c,d,e,f,g) = k a <&> \a' -> (a',b,c,d,e,f,g)
  {-# INLINE _1 #-}

instance Field1 (a,b,c,d,e,f,g,h) (a',b,c,d,e,f,g,h) a a' where
  _1 k ~(a,b,c,d,e,f,g,h) = k a <&> \a' -> (a',b,c,d,e,f,g,h)
  {-# INLINE _1 #-}

instance Field1 (a,b,c,d,e,f,g,h,i) (a',b,c,d,e,f,g,h,i) a a' where
  _1 k ~(a,b,c,d,e,f,g,h,i) = k a <&> \a' -> (a',b,c,d,e,f,g,h,i)
  {-# INLINE _1 #-}

-- | Provides access to the 2nd field of a tuple.
class Field2 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 2nd field of a tuple.
  --
  -- >>> _2 .~ "hello" $ (1,(),3,4)
  -- (1,"hello",3,4)
  --
  -- >>> (1,2,3,4) & _2 *~ 3
  -- (1,6,3,4)
  --
  -- >>> _2 print (1,2)
  -- 2
  -- (1,())
  --
  -- @
  -- 'Control.Lens.Fold.anyOf' '_2' :: (s -> 'Bool') -> (a, s) -> 'Bool'
  -- 'Data.Traversable.traverse' '.' '_2' :: ('Control.Applicative.Applicative' f, 'Data.Traversable.Traversable' t) => (a -> f b) -> t (s, a) -> f (t (s, b))
  -- 'Control.Lens.Fold.foldMapOf' ('Data.Traversable.traverse' '.' '_2') :: ('Data.Traversable.Traversable' t, 'Data.Monoid.Monoid' m) => (s -> m) -> t (b, s) -> m
  -- @
  _2 :: Lens s t a b
  default _2 :: (Generic s, Generic t, GIxed N1 (Rep s) (Rep t) a b)
             => Lens s t a b
  _2 = ix proxyN1
  {-# INLINE _2 #-}

instance Field2 (Product f g a) (Product f g' a) (g a) (g' a) where
  _2 f (Pair a b) = Pair a <$> f b

instance Field2 ((f :*: g) p) ((f :*: g') p) (g p) (g' p) where
  _2 f (l :*: r) = (l :*:) <$> f r

-- | @
-- '_2' k ~(a,b) = (\\b' -> (a,b')) 'Data.Functor.<$>' k b
-- @
instance Field2 (a,b) (a,b') b b' where
  _2 k ~(a,b) = k b <&> \b' -> (a,b')
  {-# INLINE _2 #-}

instance Field2 (a,b,c) (a,b',c) b b' where
  _2 k ~(a,b,c) = k b <&> \b' -> (a,b',c)
  {-# INLINE _2 #-}

instance Field2 (a,b,c,d) (a,b',c,d) b b' where
  _2 k ~(a,b,c,d) = k b <&> \b' -> (a,b',c,d)
  {-# INLINE _2 #-}

instance Field2 (a,b,c,d,e) (a,b',c,d,e) b b' where
  _2 k ~(a,b,c,d,e) = k b <&> \b' -> (a,b',c,d,e)
  {-# INLINE _2 #-}

instance Field2 (a,b,c,d,e,f) (a,b',c,d,e,f) b b' where
  _2 k ~(a,b,c,d,e,f) = k b <&> \b' -> (a,b',c,d,e,f)
  {-# INLINE _2 #-}

instance Field2 (a,b,c,d,e,f,g) (a,b',c,d,e,f,g) b b' where
  _2 k ~(a,b,c,d,e,f,g) = k b <&> \b' -> (a,b',c,d,e,f,g)
  {-# INLINE _2 #-}

instance Field2 (a,b,c,d,e,f,g,h) (a,b',c,d,e,f,g,h) b b' where
  _2 k ~(a,b,c,d,e,f,g,h) = k b <&> \b' -> (a,b',c,d,e,f,g,h)
  {-# INLINE _2 #-}

instance Field2 (a,b,c,d,e,f,g,h,i) (a,b',c,d,e,f,g,h,i) b b' where
  _2 k ~(a,b,c,d,e,f,g,h,i) = k b <&> \b' -> (a,b',c,d,e,f,g,h,i)
  {-# INLINE _2 #-}

-- | Provides access to the 3rd field of a tuple.
class Field3 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 3rd field of a tuple.
  _3 :: Lens s t a b
  default _3 :: (Generic s, Generic t, GIxed N2 (Rep s) (Rep t) a b)
             => Lens s t a b
  _3 = ix proxyN2
  {-# INLINE _3 #-}

instance Field3 (a,b,c) (a,b,c') c c' where
  _3 k ~(a,b,c) = k c <&> \c' -> (a,b,c')
  {-# INLINE _3 #-}

instance Field3 (a,b,c,d) (a,b,c',d) c c' where
  _3 k ~(a,b,c,d) = k c <&> \c' -> (a,b,c',d)
  {-# INLINE _3 #-}

instance Field3 (a,b,c,d,e) (a,b,c',d,e) c c' where
  _3 k ~(a,b,c,d,e) = k c <&> \c' -> (a,b,c',d,e)
  {-# INLINE _3 #-}

instance Field3 (a,b,c,d,e,f) (a,b,c',d,e,f) c c' where
  _3 k ~(a,b,c,d,e,f) = k c <&> \c' -> (a,b,c',d,e,f)
  {-# INLINE _3 #-}

instance Field3 (a,b,c,d,e,f,g) (a,b,c',d,e,f,g) c c' where
  _3 k ~(a,b,c,d,e,f,g) = k c <&> \c' -> (a,b,c',d,e,f,g)
  {-# INLINE _3 #-}

instance Field3 (a,b,c,d,e,f,g,h) (a,b,c',d,e,f,g,h) c c' where
  _3 k ~(a,b,c,d,e,f,g,h) = k c <&> \c' -> (a,b,c',d,e,f,g,h)
  {-# INLINE _3 #-}

instance Field3 (a,b,c,d,e,f,g,h,i) (a,b,c',d,e,f,g,h,i) c c' where
  _3 k ~(a,b,c,d,e,f,g,h,i) = k c <&> \c' -> (a,b,c',d,e,f,g,h,i)
  {-# INLINE _3 #-}

-- | Provide access to the 4th field of a tuple.
class Field4 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 4th field of a tuple.
  _4 :: Lens s t a b
  default _4 :: (Generic s, Generic t, GIxed N3 (Rep s) (Rep t) a b)
             => Lens s t a b
  _4 = ix proxyN3
  {-# INLINE _4 #-}

instance Field4 (a,b,c,d) (a,b,c,d') d d' where
  _4 k ~(a,b,c,d) = k d <&> \d' -> (a,b,c,d')
  {-# INLINE _4 #-}

instance Field4 (a,b,c,d,e) (a,b,c,d',e) d d' where
  _4 k ~(a,b,c,d,e) = k d <&> \d' -> (a,b,c,d',e)
  {-# INLINE _4 #-}

instance Field4 (a,b,c,d,e,f) (a,b,c,d',e,f) d d' where
  _4 k ~(a,b,c,d,e,f) = k d <&> \d' -> (a,b,c,d',e,f)
  {-# INLINE _4 #-}

instance Field4 (a,b,c,d,e,f,g) (a,b,c,d',e,f,g) d d' where
  _4 k ~(a,b,c,d,e,f,g) = k d <&> \d' -> (a,b,c,d',e,f,g)
  {-# INLINE _4 #-}

instance Field4 (a,b,c,d,e,f,g,h) (a,b,c,d',e,f,g,h) d d' where
  _4 k ~(a,b,c,d,e,f,g,h) = k d <&> \d' -> (a,b,c,d',e,f,g,h)
  {-# INLINE _4 #-}

instance Field4 (a,b,c,d,e,f,g,h,i) (a,b,c,d',e,f,g,h,i) d d' where
  _4 k ~(a,b,c,d,e,f,g,h,i) = k d <&> \d' -> (a,b,c,d',e,f,g,h,i)
  {-# INLINE _4 #-}

-- | Provides access to the 5th field of a tuple.
class Field5 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 5th field of a tuple.
  _5 :: Lens s t a b
  default _5 :: (Generic s, Generic t, GIxed N4 (Rep s) (Rep t) a b)
             => Lens s t a b
  _5 = ix proxyN4
  {-# INLINE _5 #-}

instance Field5 (a,b,c,d,e) (a,b,c,d,e') e e' where
  _5 k ~(a,b,c,d,e) = k e <&> \e' -> (a,b,c,d,e')
  {-# INLINE _5 #-}

instance Field5 (a,b,c,d,e,f) (a,b,c,d,e',f) e e' where
  _5 k ~(a,b,c,d,e,f) = k e <&> \e' -> (a,b,c,d,e',f)
  {-# INLINE _5 #-}

instance Field5 (a,b,c,d,e,f,g) (a,b,c,d,e',f,g) e e' where
  _5 k ~(a,b,c,d,e,f,g) = k e <&> \e' -> (a,b,c,d,e',f,g)
  {-# INLINE _5 #-}

instance Field5 (a,b,c,d,e,f,g,h) (a,b,c,d,e',f,g,h) e e' where
  _5 k ~(a,b,c,d,e,f,g,h) = k e <&> \e' -> (a,b,c,d,e',f,g,h)
  {-# INLINE _5 #-}

instance Field5 (a,b,c,d,e,f,g,h,i) (a,b,c,d,e',f,g,h,i) e e' where
  _5 k ~(a,b,c,d,e,f,g,h,i) = k e <&> \e' -> (a,b,c,d,e',f,g,h,i)
  {-# INLINE _5 #-}

-- | Provides access to the 6th element of a tuple.
class Field6 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 6th field of a tuple.
  _6 :: Lens s t a b
  default _6 :: (Generic s, Generic t, GIxed N5 (Rep s) (Rep t) a b)
             => Lens s t a b
  _6 = ix proxyN5
  {-# INLINE _6 #-}

instance Field6 (a,b,c,d,e,f) (a,b,c,d,e,f') f f' where
  _6 k ~(a,b,c,d,e,f) = k f <&> \f' -> (a,b,c,d,e,f')
  {-# INLINE _6 #-}

instance Field6 (a,b,c,d,e,f,g) (a,b,c,d,e,f',g) f f' where
  _6 k ~(a,b,c,d,e,f,g) = k f <&> \f' -> (a,b,c,d,e,f',g)
  {-# INLINE _6 #-}

instance Field6 (a,b,c,d,e,f,g,h) (a,b,c,d,e,f',g,h) f f' where
  _6 k ~(a,b,c,d,e,f,g,h) = k f <&> \f' -> (a,b,c,d,e,f',g,h)
  {-# INLINE _6 #-}

instance Field6 (a,b,c,d,e,f,g,h,i) (a,b,c,d,e,f',g,h,i) f f' where
  _6 k ~(a,b,c,d,e,f,g,h,i) = k f <&> \f' -> (a,b,c,d,e,f',g,h,i)
  {-# INLINE _6 #-}

-- | Provide access to the 7th field of a tuple.
class Field7 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 7th field of a tuple.
  _7 :: Lens s t a b
  default _7 :: (Generic s, Generic t, GIxed N6 (Rep s) (Rep t) a b)
             => Lens s t a b
  _7 = ix proxyN6
  {-# INLINE _7 #-}

instance Field7 (a,b,c,d,e,f,g) (a,b,c,d,e,f,g') g g' where
  _7 k ~(a,b,c,d,e,f,g) = k g <&> \g' -> (a,b,c,d,e,f,g')
  {-# INLINE _7 #-}

instance Field7 (a,b,c,d,e,f,g,h) (a,b,c,d,e,f,g',h) g g' where
  _7 k ~(a,b,c,d,e,f,g,h) = k g <&> \g' -> (a,b,c,d,e,f,g',h)
  {-# INLINE _7 #-}

instance Field7 (a,b,c,d,e,f,g,h,i) (a,b,c,d,e,f,g',h,i) g g' where
  _7 k ~(a,b,c,d,e,f,g,h,i) = k g <&> \g' -> (a,b,c,d,e,f,g',h,i)
  {-# INLINE _7 #-}

-- | Provide access to the 8th field of a tuple.
class Field8 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 8th field of a tuple.
  _8 :: Lens s t a b
  default _8 :: (Generic s, Generic t, GIxed N7 (Rep s) (Rep t) a b)
             => Lens s t a b
  _8 = ix proxyN7
  {-# INLINE _8 #-}

instance Field8 (a,b,c,d,e,f,g,h) (a,b,c,d,e,f,g,h') h h' where
  _8 k ~(a,b,c,d,e,f,g,h) = k h <&> \h' -> (a,b,c,d,e,f,g,h')
  {-# INLINE _8 #-}

instance Field8 (a,b,c,d,e,f,g,h,i) (a,b,c,d,e,f,g,h',i) h h' where
  _8 k ~(a,b,c,d,e,f,g,h,i) = k h <&> \h' -> (a,b,c,d,e,f,g,h',i)
  {-# INLINE _8 #-}

-- | Provides access to the 9th field of a tuple.
class Field9 s t a b | s -> a, t -> b, s b -> t, t a -> s where
  -- | Access the 9th field of a tuple.
  _9 :: Lens s t a b
  default _9 :: (Generic s, Generic t, GIxed N8 (Rep s) (Rep t) a b)
             => Lens s t a b
  _9 = ix proxyN8
  {-# INLINE _9 #-}

instance Field9 (a,b,c,d,e,f,g,h,i) (a,b,c,d,e,f,g,h,i') i i' where
  _9 k ~(a,b,c,d,e,f,g,h,i) = k i <&> \i' -> (a,b,c,d,e,f,g,h,i')
  {-# INLINE _9 #-}

-- Strict versions of the _1 .. _9 operations

-- | Strict version of '_1'
_1' :: Field1 s t a b => Lens s t a b
_1' = \f !x -> _1 f x
{-# INLINE _1' #-}

-- | Strict version of '_2'
_2' :: Field2 s t a b => Lens s t a b
_2' = \f !x -> _2 f x
{-# INLINE _2' #-}

-- | Strict version of '_3'
_3' :: Field3 s t a b => Lens s t a b
_3' = \f !x -> _3 f x
{-# INLINE _3' #-}

-- | Strict version of '_4'
_4' :: Field4 s t a b => Lens s t a b
_4' = \f !x -> _4 f x
{-# INLINE _4' #-}

-- | Strict version of '_5'
_5' :: Field5 s t a b => Lens s t a b
_5' = \f !x -> _5 f x
{-# INLINE _5' #-}

-- | Strict version of '_6'
_6' :: Field6 s t a b => Lens s t a b
_6' = \f !x -> _6 f x
{-# INLINE _6' #-}

-- | Strict version of '_7'
_7' :: Field7 s t a b => Lens s t a b
_7' = \f !x -> _7 f x
{-# INLINE _7' #-}

-- | Strict version of '_8'
_8' :: Field8 s t a b => Lens s t a b
_8' = \f !x -> _8 f x
{-# INLINE _8' #-}

-- | Strict version of '_9'
_9' :: Field9 s t a b => Lens s t a b
_9' = \f !x -> _9 f x
{-# INLINE _9' #-}


ix :: (Generic s, Generic t, GIxed n (Rep s) (Rep t) a b) => f n -> Lens s t a b
ix n f = fmap to . gix n f . from
{-# INLINE ix #-}

type family GSize (f :: * -> *)
type instance GSize U1 = Z
type instance GSize (K1 i c) = S Z
type instance GSize (M1 i c f) = GSize f
type instance GSize (a :*: b) = Add (GSize a) (GSize b)

class GIxed n s t a b | n s -> a, n t -> b, n s b -> t, n t a -> s where
  gix :: f n -> Lens (s x) (t x) a b

instance GIxed N0 (K1 i a) (K1 i b) a b where
  gix _ = dimap unK1 (fmap K1)
  {-# INLINE gix #-}

instance GIxed n s t a b => GIxed n (M1 i c s) (M1 i c t) a b where
  gix n = dimap unM1 (fmap M1) . gix n
  {-# INLINE gix #-}

instance (p ~ GT (GSize s) n,
          p ~ GT (GSize t) n,
          GIxed' p n s s' t t' a b)
      => GIxed n (s :*: s') (t :*: t') a b where
  gix = gix' (Proxy :: Proxy p)
  {-# INLINE gix #-}

#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 706
-- $gixed-fundeps
-- >>> :set -XDeriveGeneric -XFlexibleInstances -XMultiParamTypeClasses
-- >>> import GHC.Generics (Generic)
-- >>> data Product a b = a :* b deriving Generic
-- >>> instance Field1 (Product a b) (Product a' b) a a'
-- >>> instance Field2 (Product a b) (Product a b') b b'
#endif

class (p ~ GT (GSize s) n,
       p ~ GT (GSize t) n)
   => GIxed' p n s s' t t' a b | p n s s' -> a
                               , p n t t' -> b
                               , p n s s' b -> t t'
                               , p n t t' a -> s s' where
  gix' :: f p -> g n -> Lens ((s :*: s') x) ((t :*: t') x) a b

instance (GT (GSize s) n ~ T,
          GT (GSize t) n ~ T,
          GIxed n s t a b)
      => GIxed' T n s s' t s' a b where
  gix' _ n f (s :*: s') = (:*: s') <$> gix n f s
  {-# INLINE gix' #-}

instance (GT (GSize s) n ~ F,
          n' ~ Subtract (GSize s) n,
          GIxed n' s' t' a b)
      => GIxed' F n s s' s t' a b where
  gix' _ _  f (s :*: s') = (s :*:) <$> gix (Proxy :: Proxy n') f s'
  {-# INLINE gix' #-}

data Z
data S a

data T
data F

type family Add x y
type instance Add Z y = y
type instance Add (S x) y = S (Add x y)

type family Subtract x y
type instance Subtract Z x = x
type instance Subtract (S x) (S y) = Subtract x y

type family GT x y
type instance GT Z x = F
type instance GT (S x) Z = T
type instance GT (S x) (S y) = GT x y

type N0 = Z
type N1 = S N0
type N2 = S N1
type N3 = S N2
type N4 = S N3
type N5 = S N4
type N6 = S N5
type N7 = S N6
type N8 = S N7

proxyN0 :: Proxy N0
proxyN0 = Proxy
{-# INLINE proxyN0 #-}

proxyN1 :: Proxy N1
proxyN1 = Proxy
{-# INLINE proxyN1 #-}

proxyN2 :: Proxy N2
proxyN2 = Proxy
{-# INLINE proxyN2 #-}

proxyN3 :: Proxy N3
proxyN3 = Proxy
{-# INLINE proxyN3 #-}

proxyN4 :: Proxy N4
proxyN4 = Proxy
{-# INLINE proxyN4 #-}

proxyN5 :: Proxy N5
proxyN5 = Proxy
{-# INLINE proxyN5 #-}

proxyN6 :: Proxy N6
proxyN6 = Proxy
{-# INLINE proxyN6 #-}

proxyN7 :: Proxy N7
proxyN7 = Proxy
{-# INLINE proxyN7 #-}

proxyN8 :: Proxy N8
proxyN8 = Proxy
{-# INLINE proxyN8 #-}