module Codec.CBOR.UUID (encode, decode) where

import qualified Codec.Serialise as Ser
import qualified Codec.CBOR.Encoding as Ser (Encoding, encodeTag)
import qualified Codec.CBOR.Decoding as Ser (Decoder, decodeTag)
import qualified Data.ByteString.Lazy as BL
import qualified Data.UUID.Types as UUID

-- | Encoded according to [draft-bormann-cbor-tags-oid-06](https://tools.ietf.org/html/draft-bormann-cbor-tags-oid-06).
--
-- 19 bytes consisting of @0xd8@, @0x25@, @0x50@, and the 16 raw bytes of the
-- UUID in network order. For example, the UUID @8b0d1a20-dcc5-11d9-bda9-0002a5d5c51b@ is
-- encoded as @"\\xd8\\x25\\x50\\x8b\\x0d\\x1a\\x20\\xdc\\xc5\\x11\\xd9\\xbd\\xa9\\x00\\x02\\xa5\\xd5\\xc5\\x1b"@.
encode :: UUID.UUID -> Ser.Encoding
encode = \u ->
  Ser.encodeTag 0x25 <>
  Ser.encode (BL.toStrict (UUID.toByteString u))
{-# INLINABLE encode #-}

-- | Decode according to [draft-bormann-cbor-tags-oid-06](https://tools.ietf.org/html/draft-bormann-cbor-tags-oid-06).
--
-- 19 bytes consisting of @0xd8@, @0x25@, @0x50@, and the 16 raw bytes of the
-- UUID in network order. For example, the UUID @8b0d1a20-dcc5-11d9-bda9-0002a5d5c51b@ is expected to be
-- encoded as @"\\xd8\\x25\\x50\\x8b\\x0d\\x1a\\x20\\xdc\\xc5\\x11\\xd9\\xbd\\xa9\\x00\\x02\\xa5\\xd5\\xc5\\x1b"@.
decode :: Ser.Decoder s UUID.UUID
decode = do
  tag <- Ser.decodeTag
  case tag of
    0x25 -> do
      bs <- Ser.decode
      case UUID.fromByteString (BL.fromStrict bs) of
        Nothing -> fail "UUID"
        Just x -> pure x
    _ -> fail "UUID"
{-# INLINABLE decode #-}