module App.Validation.Email where

import Prelude

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

import GenericParser.RFC5322 as RFC5322
import GenericParser.SomeParsers as SomeParsers
import GenericParser.Parser as G

data EmailParsingError
  = CannotParse
  | CannotEntirelyParse
  | Size Int Int Int

data Error
  = ParsingError (G.Error EmailParsingError)

min_email_size :: Int
min_email_size = 5
max_email_size :: Int
max_email_size = 100

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

parse_full_email :: G.Parser EmailParsingError String
parse_full_email = do
  email_address <- RFC5322.address  G.<:> \_ -> CannotParse
  _ <- SomeParsers.eof              G.<:> \_ -> CannotEntirelyParse
  pos <- G.current_position
  if between min_email_size max_email_size pos
  then pure email_address
  else G.errorParser $ Just $ Size min_email_size max_email_size pos

parserEmail :: String -> V (Array Error) String
parserEmail str = parse parse_full_email str ParsingError

email :: String -> Either (Array Error) String
email s = toEither $ parserEmail s