-- | ASN1 utils for TLS
module Network.TLS.Util.ASN1 (
    decodeASN1Object,
    encodeASN1Object,
) where

import Data.ASN1.BinaryEncoding (DER (..))
import Data.ASN1.Encoding (decodeASN1', encodeASN1')
import Data.ASN1.Types (ASN1Object, fromASN1, toASN1)
import Network.TLS.Imports

-- | Attempt to decode a bytestring representing
-- an DER ASN.1 serialized object into the object.
decodeASN1Object
    :: ASN1Object a
    => String
    -> ByteString
    -> Either String a
decodeASN1Object name bs =
    case decodeASN1' DER bs of
        Left e -> Left (name ++ ": cannot decode ASN1: " ++ show e)
        Right asn1 -> case fromASN1 asn1 of
            Left e -> Left (name ++ ": cannot parse ASN1: " ++ show e)
            Right (d, _) -> Right d

-- | Encode an ASN.1 Object to the DER serialized bytestring
encodeASN1Object
    :: ASN1Object a
    => a
    -> ByteString
encodeASN1Object obj = encodeASN1' DER $ toASN1 obj []