+import Data.Aeson.Types
+import Data.Default.Class
+
+-- Variant of Aeson's `.:?` that interprets a String as a
+-- single-element list, so it is possible to have either
+-- "ip":["1.2.3.4"]
+-- or
+-- "ip":"1.2.3.4"
+-- with the same result.
+(.:/) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
+obj .:/ key = case H.lookup key obj of
+ Nothing -> pure Nothing
+ Just v -> case v of
+ String s -> parseJSON $ Array (V.singleton v)
+ _ -> parseJSON v
+
+data IntRRService = IntRRService { isvName :: String
+ , isvProto :: String
+ , isvPrio :: Int
+ , isvWeight :: Int
+ , isvPort :: Int
+ , isvHost :: String
+ } deriving (Show, Eq)
+
+instance FromJSON IntRRService where
+ parseJSON (Array a) =
+ if length a == 6 then IntRRService
+ <$> parseJSON (a ! 0)
+ <*> parseJSON (a ! 1)
+ <*> parseJSON (a ! 2)
+ <*> parseJSON (a ! 3)
+ <*> parseJSON (a ! 4)
+ <*> parseJSON (a ! 5)
+ else empty
+ parseJSON _ = empty
+
+makeMx :: Object -> Parser (Maybe [String])
+makeMx o =
+ case H.lookup "service" o of
+ Nothing -> pure Nothing
+ Just (Array a) -> do
+ isvl <- parseJSON (Array a)
+ return $ Just $ map mxStr $ filter mxMatch isvl
+ where
+ mxMatch isv = isvName isv == "smtp"
+ && isvProto isv == "tcp"
+ && isvPort isv == 25
+ mxStr isv = (show (isvPrio isv)) ++ "\t" ++ (isvHost isv)
+ Just _ -> empty
+
+makeSubmap :: Object -> Parser (Maybe (Map String NmcDom))
+makeSubmap o = ((.).(.)) merge merge <$> takeTls o <*> takeSrv o <*> takeMap o
+
+takeMap :: Object -> Parser (Maybe (Map String NmcDom))
+takeMap o = o .:? "map" -- FIXME split over dots here
+
+takeSrv :: Object -> Parser (Maybe (Map String NmcDom))
+takeSrv o =
+ case H.lookup "service" o of
+ Nothing -> pure Nothing
+ Just (Array a) -> do
+ isvl <- parseJSON (Array a)
+ return $ foldr addSrv (Just M.empty) isvl
+ where
+ addSrv isv acc = subm `merge` acc
+ where
+ subm = Just (M.singleton ("_" ++ isvProto isv) sub2)
+ sub2 = def { domSubmap =
+ Just (M.singleton ("_" ++ isvName isv) sub3) }
+ sub3 = def { domSrv = Just [ NmcRRSrv (isvPrio isv)
+ (isvWeight isv)
+ (isvPort isv)
+ (isvHost isv) ] }
+ Just _ -> empty
+
+-- takeTls is almost, but not quite, entirely unlike takeSrv
+takeTls :: Object -> Parser (Maybe (Map String NmcDom))
+takeTls o =
+ case H.lookup "tls" o of
+ Nothing -> pure Nothing
+ Just (Object t) ->
+ (parseJSON (Object t) :: Parser (Map String (Map String [NmcRRTlsa])))
+ >>= tmap2dmap
+ where
+ tmap2dmap :: Map String (Map String [NmcRRTlsa])
+ -> Parser (Maybe (Map String NmcDom))
+ -- FIXME return parse error on invalid proto or port
+ tmap2dmap m1 = return $ foldrWithKey addprotoelem (Just M.empty) m1
+ addprotoelem k1 m2 acc = protoelem k1 m2 `merge` acc
+ protoelem k1 m2 = Just (M.singleton ("_" ++ k1) (pmap2dmap m2))
+ pmap2dmap m2 = foldrWithKey addportelem def m2
+ addportelem k2 v acc = portelem k2 v `merge` acc
+ portelem k2 v =
+ def { domSubmap = Just (M.singleton ("_" ++ k2)
+ def { domTlsa = Just v }) }
+ Just _ -> empty
+
+class Mergeable a where
+ merge :: a -> a -> a -- bias towads second arg
+
+instance (Ord k, Mergeable a) => Mergeable (Map k a) where
+ merge mx my = unionWith merge my mx
+
+-- Alas, the following is not possible in Haskell :-(
+-- instance Mergeable String where
+-- merge _ b = b
+
+instance Mergeable Value where
+ merge _ b = b