integrate double ratchet into agent (#268)

* separate skipped messages from ratchet

* return diff for skipped messages instead of the whole state (tests fail)

* fix ratchet tests

* JSON encoding/decoding for ratchet state

* schema for ratchets

* split MonadUnliftIO instance for ExceptT to a separate file

* update StrEncoding instance for Str

* ratchet store methods

* updateRatchet store method

* move E2E ratchet params to Ratchet module

* x3dh key agreement for double ratchet

* test/fix x3dh, use x3dh for ratchets initialization

* store/get x3dh keys, save ratchet of fixed X448 type

* double-ratchet encryption integration (tests fail)

* fix double ratchet

* fix padding and message length

* remove unused code for "activations"

* remove comment

* add version checks for forward/backward compatibility

* split loading ratchet and skipped message keys

* remove unused encoding instances for Algorithm types

* update ratchet initialization params

src/Simplex/Messaging/Encoding/String.hs

@@ -5,10 +5,18 @@ module Simplex.Messaging.Encoding.String
   ( StrEncoding (..),
     Str (..),
     strP_,
+    strToJSON,
+    strToJEncoding,
+    strParseJSON,
+    base64urlP,
   )
 where
 
 import Control.Applicative (optional)
+import Data.Aeson (FromJSON (..), ToJSON (..))
+import qualified Data.Aeson as J
+import qualified Data.Aeson.Encoding as JE
+import qualified Data.Aeson.Types as JT
 import Data.Attoparsec.ByteString.Char8 (Parser)
 import qualified Data.Attoparsec.ByteString.Char8 as A
 import qualified Data.ByteString.Base64.URL as U
@@ -16,6 +24,7 @@ import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Char (isAlphaNum)
 import qualified Data.List.NonEmpty as L
+import Data.Text.Encoding (decodeLatin1, encodeUtf8)
 import Data.Word (Word16)
 import Simplex.Messaging.Parsers (parseAll)
 import Simplex.Messaging.Util ((<$?>))
@@ -34,6 +43,7 @@ class StrEncoding a where
 -- base64url encoding/decoding of ByteStrings - the parser only allows non-empty strings
 instance StrEncoding ByteString where
   strEncode = U.encode
+  strDecode = U.decode
   strP = base64urlP
 
 base64urlP :: Parser ByteString
@@ -43,11 +53,19 @@ base64urlP = do
   either fail pure $ U.decode (str <> pad)
 
 newtype Str = Str {unStr :: ByteString}
+  deriving (Eq, Show)
 
 instance StrEncoding Str where
   strEncode = unStr
   strP = Str <$> A.takeTill (== ' ') <* optional A.space
 
+instance ToJSON Str where
+  toJSON (Str s) = strToJSON s
+  toEncoding (Str s) = strToJEncoding s
+
+instance FromJSON Str where
+  parseJSON = fmap Str . strParseJSON "Str"
+
 instance StrEncoding a => StrEncoding (Maybe a) where
   strEncode = maybe "" strEncode
   strP = optional strP
@@ -88,3 +106,12 @@ instance (StrEncoding a, StrEncoding b, StrEncoding c, StrEncoding d, StrEncodin
 
 strP_ :: StrEncoding a => Parser a
 strP_ = strP <* A.space
+
+strToJSON :: StrEncoding a => a -> J.Value
+strToJSON = J.String . decodeLatin1 . strEncode
+
+strToJEncoding :: StrEncoding a => a -> J.Encoding
+strToJEncoding = JE.text . decodeLatin1 . strEncode
+
+strParseJSON :: StrEncoding a => String -> J.Value -> JT.Parser a
+strParseJSON name = J.withText name $ either fail pure . parseAll strP . encodeUtf8