module Ssb.Identity where

import           Protolude               hiding ( Identity )
import           Control.Monad.Fail
import           Data.Aeson              hiding ( encode )
import qualified Data.ByteString.Base64        as Base64
import qualified Crypto.Saltine.Core.Sign      as Nacl
import qualified Crypto.Saltine.Class          as Nacl

import           Data.Serialize                 ( Serialize )
import           Data.Either.Combinators        ( mapLeft )
import qualified Data.ByteString               as S
import qualified Data.Text                     as T

newtype PrivateKey = PrivateKey ByteString
  deriving (Eq,Generic,Ord,Show)

extractPrivateKey :: PrivateKey -> ByteString
extractPrivateKey (PrivateKey a) = a

instance Serialize PrivateKey

formatPrivateKey :: PrivateKey -> Text
formatPrivateKey (PrivateKey buf) = "@" <> pubKey <> ".ed25519"
  where pubKey = decodeUtf8 $ Base64.encode buf

parsePrivateKey :: Text -> Either Text PrivateKey
parsePrivateKey arg = decode $ T.dropEnd constLen $ T.drop 1 arg
 where
  constLen = T.length ".ed25519"
  decode   = fmap PrivateKey . mapLeft toS . Base64.decode . encodeUtf8

instance FromJSON PrivateKey where
  parseJSON = withText "PrivateKey" $ \v -> case parsePrivateKey v of
    Left  err -> fail $ toS err
    Right a   -> return a

instance ToJSON PrivateKey where
  toJSON arg = String $ formatPrivateKey arg

newtype PublicKey = PublicKey ByteString
  deriving (Eq,Generic,Ord,Show)

extractPublicKey :: PublicKey -> ByteString
extractPublicKey (PublicKey a) = a

instance Serialize PublicKey

formatPublicKey :: PublicKey -> Text
formatPublicKey (PublicKey buf) = "@" <> pubKey <> ".ed25519"
  where pubKey = decodeUtf8 $ Base64.encode buf

parsePublicKey :: Text -> Either Text PublicKey
parsePublicKey arg = decode $ T.dropEnd constLen $ T.drop 1 arg
 where
  constLen = T.length ".ed25519"
  decode   = fmap PublicKey . mapLeft toS . Base64.decode . encodeUtf8

instance FromJSON PublicKey where
  parseJSON = withText "PublicKey" $ \v -> case parsePublicKey v of
    Left  err -> fail $ toS err
    Right a   -> return a

instance ToJSON PublicKey where
  toJSON arg = String $ formatPublicKey arg

-- | Identity represents a user or agent on the scuttlebutt network.  Each of
-- these entities own their own append-only message feed.
data Identity = Identity
  { privateKey :: Maybe PrivateKey
  , publicKey :: PublicKey
  } deriving (Eq,Generic,Show)

instance FromJSON Identity

instance ToJSON Identity

newIdentity :: IO Identity
newIdentity = do
  (secret, public) <- Nacl.newKeypair
  return Identity { privateKey = Just $ PrivateKey $ Nacl.encode secret
                  , publicKey  = PublicKey $ Nacl.encode public
                  }