{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE UndecidableInstances, PatternSynonyms #-}
{-# OPTIONS_GHC -Wno-orphans #-}
--------------------------------------------------------------------------------
module Xanthous.Orphans
  ( ppTemplate
  ) where
--------------------------------------------------------------------------------
import           Xanthous.Prelude hiding (elements, (.=))
--------------------------------------------------------------------------------
import           Data.Aeson
import           Data.Aeson.Types (typeMismatch)
import           Data.List.NonEmpty (NonEmpty(..))
import qualified Data.List.NonEmpty as NonEmpty
import           Data.Text.Arbitrary ()
import           Graphics.Vty.Attributes
import           Brick.Widgets.Edit
import           Data.Text.Zipper.Generic (GenericTextZipper)
import           Brick.Widgets.Core (getName)
import           System.Random (StdGen)
import           Test.QuickCheck
import           Text.Megaparsec (errorBundlePretty)
import           Text.Megaparsec.Pos
import           Text.Mustache
import           Text.Mustache.Type ( showKey )
import           Control.Monad.State
--------------------------------------------------------------------------------
import           Xanthous.Util.JSON

instance forall s a.
  ( Cons s s a a
  , IsSequence s
  , Element s ~ a
  ) => Cons (NonNull s) (NonNull s) a a where
  _Cons = prism hither yon
    where
      hither :: (a, NonNull s) -> NonNull s
      hither (a, ns) =
        let s = toNullable ns
        in impureNonNull $ a <| s

      yon :: NonNull s -> Either (NonNull s) (a, NonNull s)
      yon ns = case nuncons ns of
        (_, Nothing) -> Left ns
        (x, Just xs) -> Right (x, xs)

instance forall a. Cons (NonEmpty a) (NonEmpty a) a a where
  _Cons = prism hither yon
    where
      hither :: (a, NonEmpty a) -> NonEmpty a
      hither (a, x :| xs) = a :| (x : xs)

      yon :: NonEmpty a -> Either (NonEmpty a) (a, NonEmpty a)
      yon ns@(x :| xs) = case xs of
        (y : ys) -> Right (x, y :| ys)
        [] -> Left ns


instance Arbitrary PName where
  arbitrary = PName . pack <$> listOf1 (elements ['a'..'z'])

instance Arbitrary Key where
  arbitrary = Key <$> listOf1 arbSafeText
    where arbSafeText = pack <$> listOf1 (elements ['a'..'z'])
  shrink (Key []) = error "unreachable"
  shrink k@(Key [_]) = pure k
  shrink (Key (p:ps)) = Key . (p :) <$> shrink ps

instance Arbitrary Pos where
  arbitrary = mkPos . succ . abs <$> arbitrary
  shrink (unPos -> 1) = []
  shrink (unPos -> x) = mkPos <$> [x..1]

instance Arbitrary Node where
  arbitrary = sized node
    where
      node n | n > 0 = oneof $ leaves ++ branches (n `div` 2)
      node _ = oneof leaves
      branches n =
        [ Section <$> arbitrary <*> subnodes n
        , InvertedSection <$> arbitrary <*> subnodes n
        ]
      subnodes = fmap concatTextBlocks . listOf . node
      leaves =
        [ TextBlock . pack <$> listOf1 (elements ['a'..'z'])
        , EscapedVar <$> arbitrary
        , UnescapedVar <$> arbitrary
        -- TODO fix pretty-printing of mustache partials
        -- , Partial <$> arbitrary <*> arbitrary
        ]
  shrink = genericShrink

concatTextBlocks :: [Node] -> [Node]
concatTextBlocks [] = []
concatTextBlocks [x] = [x]
concatTextBlocks (TextBlock txt₁ : TextBlock txt₂ : xs)
  = concatTextBlocks $ TextBlock (txt₁ <> txt₂) : concatTextBlocks xs
concatTextBlocks (x : xs) = x : concatTextBlocks xs

instance Arbitrary Template where
  arbitrary = do
    template <- concatTextBlocks <$> arbitrary
    -- templateName <- arbitrary
    -- rest <- arbitrary
    let templateName = "template"
        rest = mempty
    pure $ Template
      { templateActual = templateName
      , templateCache = rest & at templateName ?~ template
      }
  shrink (Template actual cache) =
    let Just tpl = cache ^. at actual
    in do
      cache' <- shrink cache
      tpl' <- shrink tpl
      actual' <- shrink actual
      pure $ Template
        { templateActual = actual'
        , templateCache = cache' & at actual' ?~ tpl'
        }

instance CoArbitrary Template where
  coarbitrary = coarbitrary . ppTemplate

instance Function Template where
  function = functionMap ppTemplate parseTemplatePartial
    where
      parseTemplatePartial txt
        = compileMustacheText "template" txt ^?! _Right

instance Arbitrary a => Arbitrary (NonEmpty a) where
  arbitrary = do
    x <- arbitrary
    xs <- arbitrary
    pure $ x :| xs

instance CoArbitrary a => CoArbitrary (NonEmpty a) where
  coarbitrary = coarbitrary . toList

instance Function a => Function (NonEmpty a) where
  function = functionMap toList NonEmpty.fromList

ppNode :: Map PName [Node] -> Node -> Text
ppNode _ (TextBlock txt) = txt
ppNode _ (EscapedVar k) = "{{" <> showKey k <> "}}"
ppNode ctx (Section k body) =
  let sk = showKey k
  in "{{#" <> sk <> "}}" <> foldMap (ppNode ctx) body <> "{{/" <> sk <> "}}"
ppNode _ (UnescapedVar k) = "{{{" <> showKey k <> "}}}"
ppNode ctx (InvertedSection k body) =
  let sk = showKey k
  in "{{^" <> sk <> "}}" <> foldMap (ppNode ctx) body <> "{{/" <> sk <> "}}"
ppNode _ (Partial n _) = "{{> " <> unPName n <> "}}"

ppTemplate :: Template -> Text
ppTemplate (Template actual cache) =
  case cache ^. at actual of
    Nothing -> error "Template not found?"
    Just nodes -> foldMap (ppNode cache) nodes

instance ToJSON Template where
  toJSON = String . ppTemplate

instance FromJSON Template where
  parseJSON
    = withText "Template"
    $ either (fail . errorBundlePretty) pure
    . compileMustacheText "template"

instance CoArbitrary Text where
  coarbitrary = coarbitrary . unpack

instance Function Text where
  function = functionMap unpack pack

deriving anyclass instance NFData Node
deriving anyclass instance NFData Template

instance FromJSON Color where
  parseJSON (String "black")         = pure black
  parseJSON (String "red")           = pure red
  parseJSON (String "green")         = pure green
  parseJSON (String "yellow")        = pure yellow
  parseJSON (String "blue")          = pure blue
  parseJSON (String "magenta")       = pure magenta
  parseJSON (String "cyan")          = pure cyan
  parseJSON (String "white")         = pure white
  parseJSON (String "brightBlack")   = pure brightBlack
  parseJSON (String "brightRed")     = pure brightRed
  parseJSON (String "brightGreen")   = pure brightGreen
  parseJSON (String "brightYellow")  = pure brightYellow
  parseJSON (String "brightBlue")    = pure brightBlue
  parseJSON (String "brightMagenta") = pure brightMagenta
  parseJSON (String "brightCyan")    = pure brightCyan
  parseJSON (String "brightWhite")   = pure brightWhite
  parseJSON n@(Number _)             = Color240 <$> parseJSON n
  parseJSON x                        = typeMismatch "Color" x

instance ToJSON Color where
  toJSON color
    | color == black         = "black"
    | color == red           = "red"
    | color == green         = "green"
    | color == yellow        = "yellow"
    | color == blue          = "blue"
    | color == magenta       = "magenta"
    | color == cyan          = "cyan"
    | color == white         = "white"
    | color == brightBlack   = "brightBlack"
    | color == brightRed     = "brightRed"
    | color == brightGreen   = "brightGreen"
    | color == brightYellow  = "brightYellow"
    | color == brightBlue    = "brightBlue"
    | color == brightMagenta = "brightMagenta"
    | color == brightCyan    = "brightCyan"
    | color == brightWhite   = "brightWhite"
    | Color240 num <- color  = toJSON num
    | otherwise             = error $ "unimplemented: " <> show color

instance (Eq a, Show a, Read a, FromJSON a) => FromJSON (MaybeDefault a) where
  parseJSON Null                   = pure Default
  parseJSON (String "keepCurrent") = pure KeepCurrent
  parseJSON x                      = SetTo <$> parseJSON x

instance ToJSON a => ToJSON (MaybeDefault a) where
  toJSON Default     = Null
  toJSON KeepCurrent = String "keepCurrent"
  toJSON (SetTo x)   = toJSON x

--------------------------------------------------------------------------------

instance Arbitrary Color where
  arbitrary = oneof [ Color240 <$> choose (0, 239)
                    , ISOColor <$> choose (0, 15)
                    ]

deriving anyclass instance CoArbitrary Color
deriving anyclass instance Function Color

instance (Eq a, Show a, Read a, Arbitrary a) => Arbitrary (MaybeDefault a) where
  arbitrary = oneof [ pure Default
                    , pure KeepCurrent
                    , SetTo <$> arbitrary
                    ]

instance CoArbitrary a => CoArbitrary (MaybeDefault a) where
  coarbitrary Default = variant @Int 1
  coarbitrary KeepCurrent = variant @Int 2
  coarbitrary (SetTo x) = variant @Int 3 . coarbitrary x

instance (Eq a, Show a, Read a, Function a) => Function (MaybeDefault a) where
  function = functionShow

instance Arbitrary Attr where
  arbitrary = do
    attrStyle <- arbitrary
    attrForeColor <- arbitrary
    attrBackColor <- arbitrary
    attrURL <- arbitrary
    pure Attr {..}

deriving anyclass instance CoArbitrary Attr
deriving anyclass instance Function Attr

instance ToJSON Attr where
  toJSON Attr{..} = object
    [ "style" .= maybeDefaultToJSONWith styleToJSON attrStyle
    , "foreground" .= attrForeColor
    , "background" .= attrBackColor
    , "url" .= attrURL
    ]
    where
      maybeDefaultToJSONWith _ Default = Null
      maybeDefaultToJSONWith _ KeepCurrent = String "keepCurrent"
      maybeDefaultToJSONWith tj (SetTo x) = tj x
      styleToJSON style
        | style == standout     = "standout"
        | style == underline    = "underline"
        | style == reverseVideo = "reverseVideo"
        | style == blink        = "blink"
        | style == dim          = "dim"
        | style == bold         = "bold"
        | style == italic       = "italic"
        | otherwise            = toJSON style

instance FromJSON Attr where
  parseJSON = withObject "Attr" $ \obj -> do
    attrStyle <- parseStyle =<< obj .:? "style" .!= Default
    attrForeColor <- obj .:? "foreground" .!= Default
    attrBackColor <- obj .:? "background" .!= Default
    attrURL <- obj .:? "url" .!= Default
    pure Attr{..}

    where
      parseStyle (SetTo (String "standout"))     = pure (SetTo standout)
      parseStyle (SetTo (String "underline"))    = pure (SetTo underline)
      parseStyle (SetTo (String "reverseVideo")) = pure (SetTo reverseVideo)
      parseStyle (SetTo (String "blink"))        = pure (SetTo blink)
      parseStyle (SetTo (String "dim"))          = pure (SetTo dim)
      parseStyle (SetTo (String "bold"))         = pure (SetTo bold)
      parseStyle (SetTo (String "italic"))       = pure (SetTo italic)
      parseStyle (SetTo n@(Number _))            = SetTo <$> parseJSON n
      parseStyle (SetTo v)                       = typeMismatch "Style" v
      parseStyle Default                         = pure Default
      parseStyle KeepCurrent                     = pure KeepCurrent

--------------------------------------------------------------------------------

instance NFData a => NFData (NonNull a) where
  rnf xs = xs `seq` toNullable xs `deepseq` ()

instance forall t name. (NFData t, Monoid t, NFData name)
                 => NFData (Editor t name) where
  rnf ed = getName @_ @name ed `deepseq` getEditContents ed `deepseq` ()

instance NFData StdGen where
  -- StdGen's fields are bang-patterned so this is actually correct!
  rnf sg = sg `seq` ()

deriving via (ReadShowJSON StdGen) instance ToJSON StdGen
deriving via (ReadShowJSON StdGen) instance FromJSON StdGen

instance Function StdGen where
  function = functionShow

--------------------------------------------------------------------------------

instance CoArbitrary a => CoArbitrary (NonNull a) where
  coarbitrary = coarbitrary . toNullable

instance (MonoFoldable a, Function a) => Function (NonNull a) where
  function = functionMap toNullable $ fromMaybe (error "null") . fromNullable

instance (Arbitrary t, Arbitrary n, GenericTextZipper t)
       => Arbitrary (Editor t n) where
  arbitrary = editor <$> arbitrary <*> arbitrary <*> arbitrary

instance forall t n. (CoArbitrary t, CoArbitrary n, Monoid t)
              => CoArbitrary (Editor t n) where
  coarbitrary ed = coarbitrary (getName @_ @n ed, getEditContents ed)

instance CoArbitrary StdGen where
  coarbitrary = coarbitrary . show

--------------------------------------------------------------------------------

deriving newtype instance (Arbitrary s, CoArbitrary (m (a, s)))
            => CoArbitrary (StateT s m a)