module Data.SMTP.Parser.Seal (
  --parseRcptSeal, parseRcptSealParam, SealAttribute,
  headersToSeal) where

import Data.SMTP.Types.Seal
import Data.SMTP.Types.Resource
import qualified Data.ByteString.Base64 as B64
import qualified Data.ByteString.Char8 as C8
import Data.ByteString (ByteString)

headersToSeal :: [Header] -> Maybe Seal
headersToSeal hh = let
  mycp = decode2maybe =<< getH hh cpHeaderName
  mynonce = decode2maybe =<< getH hh nonceHeaderName
  mycode = decode2maybe =<< getH hh sealHeaderName
  in do
    cp' <- mycp
    code' <- mycode
    Just $ Seal cp' code' mynonce
  where
    getH :: [Header] -> String -> Maybe ByteString
    getH hh' h = C8.pack <$> getHeaderValue hh' h
    either2maybef :: (a -> Either b c) -> a -> Maybe c
    either2maybef f v = either2maybe $ f v
    either2maybe :: Either a b -> Maybe b
    either2maybe (Left _) = Nothing
    either2maybe (Right v) = Just v
    decode2maybe = either2maybef B64.decode