-- Copyright: 2009, 2010 Dino Morelli
-- License: BSD3 (see LICENSE)
-- Author: Dino Morelli <dino@ui3.info>

module Uacpid.Conf
   ( ConfMap
   , getConf
   , getConfDir
   , parseToMap
   )
   where

import Control.Monad
import Data.Map hiding ( map )
import Data.Maybe
import Prelude hiding ( lookup )
import System.Directory
import System.Environment
import System.FilePath
import Text.Regex ( matchRegex, mkRegex )

import Paths_uacpid


type ConfMap = Map String String


{- |
   Parse config file data into a simple (Map String String).

   For example, this:

   >  --- file start ---
   >  foo=one
   >  # a comment
   >
   >  bar
   >  baz-blorp=2
   >  --- file end ---

   becomes:

   >  fromList [("foo","one"),("bar",""),("baz-blorp","2")]

   Comments (prefixed with #) and blank lines in the config file 
   are discarded.
-}
parseToMap :: String -> ConfMap
parseToMap entireConf =
   fromList $ map (\[k, v] -> (k, v))
      $ catMaybes $ map (matchRegex re) $ lines entireConf
   where
      re = mkRegex "^([^#][^=]*)=?(.*)"


getHomeDir :: IO String
getHomeDir = getEnv "HOME"


getConfDir :: IO String
getConfDir = liftM (flip (</>) ".uacpid") getHomeDir


{- Create the user's home dir .uacpid directory and populate it
   with default and example files.
   This happens the first time uacpid is run for a given user
-}
initializeConfDir :: FilePath -> FilePath -> IO ()
initializeConfDir confDir confFilePath = do
   createDirectoryIfMissing True confDir

   defaultConfFilePath <- getDataFileName $
      "uacpid" </> "uacpid.conf"
   copyFile defaultConfFilePath confFilePath

   let eventsDir = confDir </> "events"
   createDirectory eventsDir

   let exampleAnything = "anything"
   exampleEventPath <- getDataFileName $
      "uacpid" </> "events" </> exampleAnything
   copyFile exampleEventPath $ eventsDir </> exampleAnything


getConf :: IO ConfMap
getConf = do
   -- Construct some paths using $HOME
   homeDir <- getHomeDir
   confDir <- getConfDir
   let confFilePath = confDir </> "uacpid.conf"

   flip unless
      (initializeConfDir confDir confFilePath)
      =<< doesDirectoryExist confDir

   -- Load the conf
   loadedConf <- liftM parseToMap $ readFile confFilePath

   -- Replace the log path with an absolute one using $HOME
   let realConf = insertWith (</>) "logPath" homeDir loadedConf

   -- While we're here doing first time things, make sure there's
   -- an events dir
   createDirectoryIfMissing True $ confDir </> "events"

   -- First time log directory creation
   let logDir = dropFileName $ fromJust $ lookup "logPath" realConf
   createDirectoryIfMissing True logDir

   return realConf