1 files changed, 95 insertions, 0 deletions
diff --git a/src/main.hs b/src/main.hs
new file mode 100644
index 0000000..bd2bc73
--- /dev/null
+++ b/src/main.hs
@@ -0,0 +1,95 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE LambdaCase #-}
+
+import qualified Data.Aeson
+import Data.Aeson.Encode.Pretty
+import qualified Data.ByteString.Lazy.Char8
+import Data.MIME.Extended
+import qualified Options.Applicative
+import qualified System.Exit
+import System.IO (hPutStrLn,stderr)
+
+
+
+data Options = Options
+    { optionDecode :: Bool
+    , optionInputFile :: String
+    , optionOutputFile :: String
+    }
+
+
+optionsParser :: Options.Applicative.Parser Options
+optionsParser =
+    Options
+        <$> Options.Applicative.switch
+            ( Options.Applicative.long "decode"
+            <> Options.Applicative.short 'd'
+            <> Options.Applicative.help "Decode JSON to IMF"
+            )
+        <*> Options.Applicative.strOption
+            ( Options.Applicative.long "input"
+            <> Options.Applicative.short 'i'
+            <> Options.Applicative.help "File to read."
+            <> Options.Applicative.value "-"
+            <> Options.Applicative.metavar "PATH"
+            )
+        <*> Options.Applicative.strOption
+            ( Options.Applicative.long "output"
+            <> Options.Applicative.short 'o'
+            <> Options.Applicative.help "File to write."
+            <> Options.Applicative.value "-"
+            <> Options.Applicative.metavar "PATH"
+            )
+
+
+newtype MIMENoTweak = MIMENoTweak MIME
+
+instance RenderMessage MIMENoTweak where
+    buildBody h (MIMENoTweak b) = buildBody h b
+
+
+main :: IO ()
+main = do
+    options <-
+      Options.Applicative.execParser $
+        Options.Applicative.info optionsParser Options.Applicative.briefDesc
+
+    let input =
+          case optionInputFile options of
+            "-" ->
+              Data.ByteString.Lazy.Char8.getContents
+            path ->
+              Data.ByteString.Lazy.Char8.readFile path
+        output =
+          case optionOutputFile options of
+            "-" ->
+              Data.ByteString.Lazy.Char8.putStrLn
+            path ->
+              Data.ByteString.Lazy.Char8.writeFile path
+
+    s <- input
+
+    if optionDecode options then
+      case Data.Aeson.decode s :: Maybe MIMEMessage of
+        Just (Message h b) ->
+          output $ renderMessage (Message h (MIMENoTweak b))
+
+        Nothing -> do
+          hPutStrLn stderr "error: failed to decode MIME message"
+          System.Exit.exitFailure
+
+    else
+      case parse (message mime) s of
+        Right mail ->
+          output $ encodePretty' conf mail
+
+        Left err -> do
+          hPutStrLn stderr $ "error: " <> err
+          System.Exit.exitFailure
+
+  where
+    conf =
+      defConfig
+        { confCompare = keyOrder ["headers","body"] `mappend` compare
+        , confIndent = Spaces 2
+        }