-- Module      : Data.TConfig

-- Copyright   : (c) Anthony Simpson 2009

-- License     : BSD3

--

-- Maintainer  : DiscipleRayne@gmail.com

-- Stability   : relatively stable

-- Portability : portable

---------------------------------------------------

{-|

  A small and simple text file configuration

  library written in Haskell. It is similar

  to the INI file format, but lacks a few of

  it's features, such as sections. It is

  suitable for simple games that need to

  keep track of certain information between

  plays.

-}

module Data.TConfig

    (

     getValue

   , repConfig

   , readConfig

   , writeConfig

   , remKey

   , addKey

   , Conf ()

   ) where

import Data.Char

import qualified Data.Map as M

import Control.Monad

type Key   = String

type Value = String

type Conf  = M.Map Key Value

-- |Adds a key and value to the end of the configuration.

addKey :: Key -> Value -> Conf -> Conf

addKey = M.insert

-- |Utility function.

-- Removes a key and its value from the configuration.

remKey :: Key -> Conf -> Conf

remKey = M.delete

-- |Utility function. Searches a configuration for a

-- key, and returns its value.

getValue :: Key -> Conf -> Maybe Value

getValue = M.lookup

-- |Utility function. Replaces the value

-- associated with a key in a configuration.

repConfig :: Key -> Value -> Conf -> Conf

repConfig k rv conf = let f _ = Just rv

                      in M.alter f k conf

-- |Reads a file and parses to a Map String String.

readConfig :: FilePath -> IO Conf

readConfig path = liftM (M.fromList . map ((\(a, b) -> (filter (not . isSpace) a, dropWhile isSpace $ tail b)) . break (== '=')) . filter (not . null) . lines) $ readFile path

-- |Parses a parsed configuration back to a file.

writeConfig :: FilePath -> Conf -> IO ()

writeConfig path = writeFile path . unlines . map (\(a, b) -> a ++ " = " ++ b) . M.toList