{-# LANGUAGE CPP #-}
import           Control.Monad
import           Data.Maybe
import           Network
import           System.Console.GetOpt
import           System.Environment
import           System.Exit
import           System.Posix.Types
import           System.Posix.User

data CmdOpt
    = OptPortNum   PortNumber
    | OptLSDir     FilePath
    | OptUserName  String
    | OptGroupName String
    | OptHelp
    deriving (Eq, Show)


defaultPort :: PortNumber
defaultPort = fromIntegral 8080

defaultUserName :: String
defaultUserName = "daemon"

defaultGroupName :: String
defaultGroupName = "daemon"


options :: [OptDescr CmdOpt]
options = [ Option ['p'] ["port"]
                   (ReqArg (OptPortNum . fromIntegral . read) "NUM")
                   ("Port number to listen. (default: " ++ show defaultPort ++ ")")

          , Option ['d'] ["localstatedir"]
                   (ReqArg OptLSDir "DIR")
                   ("Path to the database directory. (default: " ++ LOCALSTATEDIR ++ ")")

          , Option ['u'] ["user"]
                   (ReqArg OptUserName "USER")
                   ("Which user to setuid. (default: " ++ defaultUserName ++ ")")

          , Option ['g'] ["group"]
                   (ReqArg OptGroupName "GROUP")
                   ("Which user to setgid. (default: " ++ defaultGroupName ++ ")")

          , Option ['h'] ["help"]
                   (NoArg OptHelp)
                   "Print this message."
          ]


printUsage :: IO ()
printUsage = do putStrLn "Usage:"
                putStrLn "  rakka [OPTIONS...]"
                putStrLn ""
                putStr $ usageInfo "Options:" options


main :: IO ()
main = do (opts, nonOpts, errors) <- return . getOpt Permute options =<< getArgs

          when (not $ null errors)
                   $ do mapM_ putStr errors
                        exitWith $ ExitFailure 1

          when (any (\ x -> x == OptHelp) opts)
                   $ do printUsage
                        exitWith ExitSuccess

          when (not $ null nonOpts)
                   $ do printUsage
                        exitWith $ ExitFailure 1

          portNum <- getPortNum opts
          uid     <- getUserID opts

          print portNum
          print uid


getPortNum :: [CmdOpt] -> IO PortNumber
getPortNum opts
    = do let xs = mapMaybe (\ x -> case x of
                                     OptPortNum n -> Just n
                                     _            -> Nothing) opts
         case xs of
           []     -> return defaultPort
           (x:[]) -> return x
           _      -> error "too many --port options."


getUserID :: [CmdOpt] -> IO UserID
getUserID opts
    = do let xs   = mapMaybe (\ x -> case x of
                                       OptUserName n -> Just n
                                       _             -> Nothing) opts
             name = case xs of
                      []     -> defaultUserName
                      (x:[]) -> x
                      _      -> error "too many --user options."

         userEnt <- getUserEntryForName name
         return $ userID userEnt