module App.Validation.Label where

import Prelude

import Data.Either (Either(..))
import Data.Maybe (Maybe(..))
import Data.Validation.Semigroup (V, invalid, toEither)

import GenericParser.Parser as G
import GenericParser.SomeParsers as SomeParsers
import GenericParser.DomainParser.Common (DomainError) as DomainParser
import GenericParser.DomainParserRFC1035 (label) as RFC1035

data LabelParsingError
  = CannotParse (DomainParser.DomainError)
  | CannotEntirelyParse
  | Size Int Int Int

data Error
  = ParsingError (G.Error LabelParsingError)

min_label_size = 1 :: Int  -- arbitrary
max_label_size = 63 :: Int -- arbitrary

parse :: forall e v. G.Parser e v -> String -> ((G.Error e) -> Error) -> V (Array Error) v
parse (G.Parser p) str c = case p { string: str, position: 0 } of
  Left x  -> invalid $ [c x]
  Right x -> pure x.result

label_parser :: G.Parser LabelParsingError String
label_parser = do
  input <- G.current_input
  _ <- RFC1035.label G.<:> \e -> CannotParse e
  _ <- SomeParsers.eof    G.<:> \_ -> CannotEntirelyParse
  pos <- G.current_position
  if between min_label_size max_label_size pos
  then pure input.string
  else G.errorParser (Just $ Size min_label_size max_label_size pos)

label :: String -> Either (Array Error) String
label s = toEither $ parse label_parser s ParsingError