{-# LANGUAGE AllowAmbiguousTypes #-}

{- | 'traverse' for generic data types.

TODO This is harder to conceptualize than generic 'foldMap'. No nice clean
explanation yet.

This function can provide generic support for simple parser-esque types.
-}

module Generic.Data.Function.Traverse
  ( GenericTraverse(..)
  , genericTraverseNonSum , GTraverseNonSum
  , GenericTraverseSum(..), PfxTagCfg(..)
  , genericTraverseSum,     GTraverseSum
  , eqShowPfxTagCfg
  ) where

import GHC.Generics

import Generic.Data.Function.Traverse.NonSum
import Generic.Data.Function.Traverse.Sum
import Generic.Data.Function.Traverse.Constructor

import Data.Text qualified as Text

-- | Generic 'traverse' over a term of non-sum data type @f a@,
--   where @f@ is set by the @tag@ you pass.
genericTraverseNonSum
    :: forall {k} (tag :: k) a
    .  ( Generic a
       , Functor (GenericTraverseF tag)
       , GTraverseNonSum tag (Rep a)
    ) => GenericTraverseF tag a
genericTraverseNonSum :: forall {k} (tag :: k) a.
(Generic a, Functor (GenericTraverseF tag),
 GTraverseNonSum tag (Rep a)) =>
GenericTraverseF tag a
genericTraverseNonSum = Rep a Any -> a
forall a x. Generic a => Rep a x -> a
forall x. Rep a x -> a
to (Rep a Any -> a)
-> GenericTraverseF tag (Rep a Any) -> GenericTraverseF tag a
forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (tag :: k) (gf :: Type -> Type) p.
GTraverseNonSum tag gf =>
GenericTraverseF tag (gf p)
forall {k} {k1} (tag :: k) (gf :: k1 -> Type) (p :: k1).
GTraverseNonSum tag gf =>
GenericTraverseF tag (gf p)
gTraverseNonSum @tag

-- | Generic 'traverse' over a term of sum data type @f a@,
--   where @f@ is set by the @tag@ you pass.
--
-- You must provide a configuration for how to handle constructors.
genericTraverseSum
    :: forall {k} (tag :: k) a pt
    .  ( Generic a
       , Functor (GenericTraverseF tag)
       , GTraverseSum tag (Rep a)
       , GenericTraverseC tag pt
    ) => PfxTagCfg pt -> GenericTraverseF tag a
genericTraverseSum :: forall {k} (tag :: k) a pt.
(Generic a, Functor (GenericTraverseF tag),
 GTraverseSum tag (Rep a), GenericTraverseC tag pt) =>
PfxTagCfg pt -> GenericTraverseF tag a
genericTraverseSum PfxTagCfg pt
ptc = Rep a Any -> a
forall a x. Generic a => Rep a x -> a
forall x. Rep a x -> a
to (Rep a Any -> a)
-> GenericTraverseF tag (Rep a Any) -> GenericTraverseF tag a
forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall (tag :: k) (gf :: Type -> Type) pt p.
(GTraverseSum tag gf, GenericTraverseC tag pt) =>
PfxTagCfg pt -> GenericTraverseF tag (gf p)
forall {k} {k1} (tag :: k) (gf :: k1 -> Type) pt (p :: k1).
(GTraverseSum tag gf, GenericTraverseC tag pt) =>
PfxTagCfg pt -> GenericTraverseF tag (gf p)
gTraverseSum @tag PfxTagCfg pt
ptc

-- | Construct a prefix tag config using existing 'Eq' and 'Show' instances.
--
-- The user only needs to provide the constructor name parser.
eqShowPfxTagCfg :: (Eq a, Show a) => (String -> a) -> PfxTagCfg a
eqShowPfxTagCfg :: forall a. (Eq a, Show a) => (String -> a) -> PfxTagCfg a
eqShowPfxTagCfg String -> a
f = PfxTagCfg
    { pfxTagCfgFromCstr :: String -> a
pfxTagCfgFromCstr = String -> a
f
    , pfxTagCfgEq :: a -> a -> Bool
pfxTagCfgEq = a -> a -> Bool
forall a. Eq a => a -> a -> Bool
(==)
    , pfxTagCfgShow :: a -> Text
pfxTagCfgShow = String -> Text
Text.pack (String -> Text) -> (a -> String) -> a -> Text
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> String
forall a. Show a => a -> String
show
    }