properly render untweaked MIME messages

3 files changed, 35 insertions, 8 deletions

diff --git a/mailaids.cabal b/mailaids.cabal
index f883db2..8eecdc1 100644
--- a/mailaids.cabal
+++ b/mailaids.cabal
@@ -26,3 +26,4 @@ executable mailaid
   other-modules:
     Data.ByteString.Extended
     Data.MIME.Extended
+    Data.MIME.Untweaked
diff --git a/src/Data/MIME/Untweaked.hs b/src/Data/MIME/Untweaked.hs
new file mode 100644
index 0000000..56acd43
--- /dev/null
+++ b/src/Data/MIME/Untweaked.hs
@@ -0,0 +1,31 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Data.MIME.Untweaked where
+
+import Data.Foldable (fold)
+import Data.List.NonEmpty (intersperse)
+import Data.MIME
+import qualified Data.ByteString.Builder as Builder
+
+
+
+newtype Untweaked = Untweaked MIME
+
+
+toUntweaked :: Message ctx MIME -> Message ctx Untweaked
+toUntweaked (Message h b) = Message h (Untweaked b)
+
+
+instance RenderMessage Untweaked where
+  buildBody _h (Untweaked z) = Just $ case z of
+    Part partbody -> Builder.byteString partbody
+    Encapsulated msg -> buildMessage . toUntweaked $ msg
+    Multipart _sub b xs ->
+      let
+        boundary = "--" <> Builder.byteString (unBoundary b)
+      in
+        boundary <> "\r\n"
+        <> fold (intersperse ("\r\n" <> boundary <> "\r\n") (fmap (buildMessage . toUntweaked) xs))
+        <> "\r\n" <> boundary <> "--\r\n"
+    FailedParse _ bs -> Builder.byteString bs
+
+
diff --git a/src/main.hs b/src/main.hs
index bd2bc73..6c4b061 100644
--- a/src/main.hs
+++ b/src/main.hs
@@ -5,6 +5,7 @@ import qualified Data.Aeson
 import Data.Aeson.Encode.Pretty
 import qualified Data.ByteString.Lazy.Char8
 import Data.MIME.Extended
+import Data.MIME.Untweaked (toUntweaked)
 import qualified Options.Applicative
 import qualified System.Exit
 import System.IO (hPutStrLn,stderr)
@@ -42,12 +43,6 @@ optionsParser =
             )
 
 
-newtype MIMENoTweak = MIMENoTweak MIME
-
-instance RenderMessage MIMENoTweak where
-    buildBody h (MIMENoTweak b) = buildBody h b
-
-
 main :: IO ()
 main = do
     options <-
@@ -71,8 +66,8 @@ main = do
 
     if optionDecode options then
       case Data.Aeson.decode s :: Maybe MIMEMessage of
-        Just (Message h b) ->
-          output $ renderMessage (Message h (MIMENoTweak b))
+        Just m ->
+          output $ renderMessage (toUntweaked m)
 
         Nothing -> do
           hPutStrLn stderr "error: failed to decode MIME message"