module TodoListItem where

data TodoListItem = TodoListItem
        { name :: String
        , done :: Bool
        }
        deriving (Eq)

instance Show TodoListItem where
        show (TodoListItem name done) =
                s done ++ " " ++ name ++ "\n"
            where
                s True = "x"
                s False = "o"
        showList = foldr ((.) . shows) id

instance Read TodoListItem where
        readsPrec _ input = do
                let (item, rest) = break (== '\n') input
                let (d, n) = splitAt 2 item
                let
                        done = case d of
                                "x " -> True
                                "o " -> False
                                _ -> error "Invalid status"
                        name = case n of
                                "" -> error "empty name"
                                something -> filter (/= '\r') something
                [(TodoListItem name done, rest)]