{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE TypeFamilies #-}

module Cursor.Map.KeyValue
  ( KeyValueCursor (..),
    makeKeyValueCursorKey,
    makeKeyValueCursorValue,
    rebuildKeyValueCursor,
    keyValueCursorSelection,
    mapKeyValueCursor,
    keyValueCursorSelectKey,
    keyValueCursorSelectValue,
    keyValueCursorToggleSelected,
    KeyValueToggle (..),
    traverseKeyValueCursor,
    keyValueCursorTraverseKeyCase,
    keyValueCursorTraverseValueCase,
    foldKeyValueCursor,
  )
where

import Control.DeepSeq
import Data.Validity
import GHC.Generics (Generic)

data KeyValueCursor kc vc k v
  = KeyValueCursorKey kc v
  | KeyValueCursorValue k vc
  deriving (Show, Eq, Generic)

instance
  (Validity kc, Validity vc, Validity k, Validity v) =>
  Validity (KeyValueCursor kc vc k v)

instance (NFData kc, NFData vc, NFData k, NFData v) => NFData (KeyValueCursor kc vc k v)

makeKeyValueCursorKey :: kc -> v -> KeyValueCursor kc vc k v
makeKeyValueCursorKey = KeyValueCursorKey

makeKeyValueCursorValue :: k -> vc -> KeyValueCursor kc vc k v
makeKeyValueCursorValue = KeyValueCursorValue

rebuildKeyValueCursor :: (kc -> k) -> (vc -> v) -> KeyValueCursor kc vc k v -> (k, v)
rebuildKeyValueCursor f _ (KeyValueCursorKey kc v) = (f kc, v)
rebuildKeyValueCursor _ g (KeyValueCursorValue k vc) = (k, g vc)

keyValueCursorSelection :: KeyValueCursor kc vc k v -> KeyValueToggle
keyValueCursorSelection (KeyValueCursorKey _ _) = KeySelected
keyValueCursorSelection (KeyValueCursorValue _ _) = ValueSelected

mapKeyValueCursor ::
  (kc -> lc) ->
  (vc -> wc) ->
  (k -> l) ->
  (v -> w) ->
  KeyValueCursor kc vc k v ->
  KeyValueCursor lc wc l w
mapKeyValueCursor a b c d kvc =
  case kvc of
    KeyValueCursorKey kc v -> KeyValueCursorKey (a kc) (d v)
    KeyValueCursorValue k vc -> KeyValueCursorValue (c k) (b vc)

keyValueCursorSelectKey ::
  (k -> kc) -> (vc -> v) -> KeyValueCursor kc vc k v -> KeyValueCursor kc vc k v
keyValueCursorSelectKey g h kvc =
  case kvc of
    KeyValueCursorValue k vc -> KeyValueCursorKey (g k) (h vc)
    _ -> kvc

keyValueCursorSelectValue ::
  (kc -> k) -> (v -> vc) -> KeyValueCursor kc vc k v -> KeyValueCursor kc vc k v
keyValueCursorSelectValue f i kvc =
  case kvc of
    KeyValueCursorKey kc v -> KeyValueCursorValue (f kc) (i v)
    _ -> kvc

keyValueCursorToggleSelected ::
  (kc -> k) ->
  (k -> kc) ->
  (vc -> v) ->
  (v -> vc) ->
  KeyValueCursor kc vc k v ->
  KeyValueCursor kc vc k v
keyValueCursorToggleSelected f g h i kvc =
  case kvc of
    KeyValueCursorKey kc v -> KeyValueCursorValue (f kc) (i v)
    KeyValueCursorValue k vc -> KeyValueCursorKey (g k) (h vc)

data KeyValueToggle
  = KeySelected
  | ValueSelected
  deriving (Show, Eq, Generic)

instance Validity KeyValueToggle

traverseKeyValueCursor :: (kc -> v -> f c) -> (k -> vc -> f c) -> KeyValueCursor kc vc k v -> f c
traverseKeyValueCursor = foldKeyValueCursor

keyValueCursorTraverseKeyCase ::
  Applicative f =>
  (kc -> v -> f (kc', v')) ->
  KeyValueCursor kc vc k v ->
  f (KeyValueCursor kc' vc k v')
keyValueCursorTraverseKeyCase func =
  \case
    KeyValueCursorKey kc v -> uncurry KeyValueCursorKey <$> func kc v
    KeyValueCursorValue k vc -> pure (KeyValueCursorValue k vc)

keyValueCursorTraverseValueCase ::
  Applicative f =>
  (k -> vc -> f (k', vc')) ->
  KeyValueCursor kc vc k v ->
  f (KeyValueCursor kc vc' k' v)
keyValueCursorTraverseValueCase func =
  \case
    KeyValueCursorKey kc v -> pure (KeyValueCursorKey kc v)
    KeyValueCursorValue k vc -> uncurry KeyValueCursorValue <$> func k vc

foldKeyValueCursor :: (kc -> v -> c) -> (k -> vc -> c) -> KeyValueCursor kc vc k v -> c
foldKeyValueCursor keyFunc valFunc kvc =
  case kvc of
    KeyValueCursorKey kc v -> keyFunc kc v
    KeyValueCursorValue k vc -> valFunc k vc