module Data.Language.TypeScript
  ( Statement(..)
  , Type(..)
  , Name(..)
  , TypeDeclaration(..)
  , Primitive(..)
  , Object(..)
  , Union(..)
  ) where
{-# OPTIONS_GHC -Wall #-}

import Data.Text (Text)
import Data.Text.Prettyprint.Doc
import Data.Map (Map)
import qualified Data.Map as Map
import Data.List

deriving stock instance Show Name
newtype Name = Name Text

deriving stock instance Show Statement
data Statement = StatementTypeDeclaration TypeDeclaration

instance Pretty Name where
  pretty (Name nm) = pretty nm

data TypeDeclaration = TypeDeclaration Name Type
deriving stock instance Show TypeDeclaration
instance Pretty TypeDeclaration where
  pretty = error "TODO"

data Primitive = TsText | TsInteger
deriving stock instance Show Primitive
instance Pretty Primitive where
  pretty = \case
    TsText -> "string"
    TsInteger -> "number"

newtype Object = Object (Map Text Type)
deriving stock instance Show Object
instance Pretty Object where
  pretty (Object m) = vsep $ ["{", nest 2 (vsep docs), "}"]
    where
    docs = decl <$> Map.toList m
    decl :: (Text, Type) -> Doc ann
    decl (txt, tp) = pretty txt <> ":" <+> pretty tp <> ";"

newtype Union = Union ([] Type)

deriving stock instance Show Union
instance Pretty Union where
  pretty (Union tps) = sepBy "|" $ pretty <$> tps

sepBy :: Doc a -> [Doc a] -> Doc a
sepBy x = sep . intersperse x

data Type = Primitive Primitive | TypeObject Object | TypeUnion Union | Array Type | TypeNamed Name
deriving stock instance Show Type
instance Pretty Type where
  pretty = \case
    Primitive p  -> pretty p
    TypeObject o -> pretty o
    TypeUnion u  -> pretty u
    Array a      -> pretty a
    TypeNamed n  -> pretty n