module Data.Apart.Shape (Shape (..)) where

import Data.Bifoldable (Bifoldable (..))
import Data.Bifunctor (Bifunctor (..))
import Data.Bitraversable (Bitraversable (..))
import Data.Semigroup (Semigroup (..))

-- | Type that can tell you about aggregate state of your structure.
data Shape t raw value
	= Ready (t value) -- ^ Segment of values in memory
	| Converted raw -- ^ Segment of values somewhere else

instance (Show (t value), Show value, Show raw) => Show (Shape t raw value) where
	show (Ready values)  = show values
	show (Converted raw) = "{" <> show raw <> "}"

instance Functor t => Functor (Shape t raw) where
	fmap f (Ready values)  = Ready $ f <$> values
	fmap f (Converted raw) = Converted raw

instance Foldable t => Foldable (Shape t raw) where
	foldr f acc (Ready values)  = foldr f acc values
	foldr f acc (Converted raw) = acc

instance Traversable t => Traversable (Shape t raw) where
	traverse f (Ready values)  = Ready <$> traverse f values
	traverse _ (Converted raw) = pure $ Converted raw

instance Functor t => Bifunctor (Shape t) where
	bimap _ f (Ready values)  = Ready $ f <$> values
	bimap g _ (Converted raw) = Converted $ g raw

instance Foldable t => Bifoldable (Shape t) where
	bifoldr _ f acc (Ready values)  = foldr f acc values
	bifoldr g _ acc (Converted raw) = g raw acc

instance Traversable t => Bitraversable (Shape t) where
	bitraverse _ f (Ready values)  = Ready <$> traverse f values
	bitraverse g _ (Converted raw) = Converted <$> g raw