    -- Cryptonite.hs: shim for cryptonite
    -- Copyright © 2016  Clint Adams
    -- This software is released under the terms of the Expat license.
    -- (See the LICENSE file).

    {-# LANGUAGE FlexibleInstances #-}
    {-# LANGUAGE OverloadedStrings #-}
    {-# LANGUAGE PackageImports #-}
    {-# LANGUAGE UndecidableInstances #-}

    module Codec.Encryption.OpenPGP.Internal.Cryptonite (
        HOWrappedCCT(..)
    ) where

    import Control.Error.Util (note)
    import qualified "cryptonite" Crypto.Cipher.Types as CCT
    import qualified Crypto.Error as CE
    import Data.Bifunctor (bimap)
    import qualified Data.ByteString as B

    import Codec.Encryption.OpenPGP.Internal.HOBlockCipher

    newtype HOWrappedCCT a = HWCCT a

    instance CCT.BlockCipher cipher => HOBlockCipher (HOWrappedCCT cipher) where
        cipherInit = bimap show HWCCT . CE.eitherCryptoError . CCT.cipherInit
        cipherName (HWCCT c) = CCT.cipherName c
        cipherKeySize (HWCCT c) = CCT.cipherKeySize c
        blockSize (HWCCT c) = CCT.blockSize c
        cfbEncrypt (HWCCT c) iv bs = hammerIV iv >>= \i -> return (CCT.cfbEncrypt c i bs)
        cfbDecrypt (HWCCT c) iv bs = hammerIV iv >>= \i -> return (CCT.cfbDecrypt c i bs)

    hammerIV :: CCT.BlockCipher cipher => B.ByteString -> Either String (CCT.IV cipher)
    hammerIV = note "cryptonite bad IV" . CCT.makeIV