{-# LANGUAGE DeriveDataTypeable, MultiParamTypeClasses, ScopedTypeVariables #-}
module CmdLine where

import CmdLib
import Storage.Hashed.Hash
import Core( hdecode )
import qualified Data.ByteString.Char8 as BSC

newtype Path = Path String deriving (Show, Typeable, Data, Read)
newtype HashF = HashF String deriving (Show, Typeable, Data, Read)

data Flag = Repo Path | Root HashF | From Path | To Path
          deriving (Typeable, Data, Show, Read)

instance FlagType Flag where
  describe (Repo _) = "path to the backup repository"
  describe (Root _) = "root hash of the backup to select"
  readFlag _ = fallback <+< Path <+< HashF

-- XXX These are a hack, since hashed-storage fails to provide the
-- instances. Should be harmless otherwise.
instance Typeable Hash
instance Data Hash

data Setup = Setup { repo :: FilePath
                   , root :: Maybe Hash }
           deriving (Typeable, Data)

instance Combine Setup Flag where
  combine (Repo (Path p)) f = f { repo = p }
  combine (Root (HashF p)) f = f { root = Just $ hdecode $ BSC.pack p }
  combine _ x = x
  initial = Setup { root = Nothing }