{-# LANGUAGE CPP #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Plugins.Mail
-- Copyright   :  (c) Spencer Janssen
-- License     :  BSD-style (see LICENSE)
--
-- Maintainer  :  Spencer Janssen <sjanssen@cse.unl.edu>
-- Stability   :  unstable
-- Portability :  unportable
--
-- A plugin for checking mail.
--
-----------------------------------------------------------------------------

module Xmobar.Plugins.Mail(Mail(..),MailX(..)) where

import Xmobar.Run.Exec
#ifdef INOTIFY

import Xmobar.System.Utils (expandHome, changeLoop)

import Control.Monad
import Control.Concurrent.STM

import System.Directory
import System.FilePath
import System.INotify
import System.Console.GetOpt

import Data.List (isPrefixOf)
import Data.Set (Set)
import qualified Data.Set as S

#if MIN_VERSION_hinotify(0,3,10)
import qualified Data.ByteString.Char8 as BS (ByteString, pack, unpack)
unpack :: BS.ByteString -> String
unpack = BS.unpack
pack :: String -> BS.ByteString
pack = BS.pack
#else
unpack :: String -> String
unpack = id
pack :: String -> String
pack = id
#endif
#else
import System.IO
#endif

data MOptions = MOptions
               { oDir :: FilePath
               , oPrefix :: String
               , oSuffix :: String
               }

defaults :: MOptions
defaults = MOptions {oDir = "", oPrefix = "", oSuffix = ""}

options :: [OptDescr (MOptions -> MOptions)]
options =
  [ Option "d" ["dir"] (ReqArg (\x o -> o { oDir = x }) "") ""
  , Option "p" ["prefix"] (ReqArg (\x o -> o { oPrefix = x }) "") ""
  , Option "s" ["suffix"] (ReqArg (\x o -> o { oSuffix = x }) "") ""
  ]

parseOptions :: [String] -> IO MOptions
parseOptions args =
  case getOpt Permute options args of
    (o, _, []) -> return $ foldr id defaults o
    (_, _, errs) -> ioError . userError $ concat errs


-- | A list of mail box names and paths to maildirs.
data Mail = Mail [(String, FilePath)] String
    deriving (Read, Show)

-- | A list of mail box names, paths to maildirs and display colors.
data MailX = MailX [(String, FilePath, String)] [String] String
    deriving (Read, Show)

instance Exec Mail where
  alias (Mail _ a) = a
  start (Mail ms a) = start (MailX (map (\(n,p) -> (n,p,"")) ms) [] a)

instance Exec MailX where
    alias (MailX _ _ a) = a
#ifndef INOTIFY
    start _ _ =
        hPutStrLn stderr $ "Warning: xmobar is not compiled with -fwith_inotify,"
                        ++ " but the Mail plugin requires it."
#else
    start (MailX ms args _) cb = do
        vs <- mapM (const $ newTVarIO S.empty) ms
        opts <- parseOptions args
        let prefix = oPrefix opts
            suffix = oSuffix opts
            dir = oDir opts
            ps = map (\(_,p,_) -> if null dir then p else dir </> p) ms
            rs = map (</> "new") ps
            ev = [Move, MoveIn, MoveOut, Create, Delete]

        ds <- mapM expandHome rs
        i <- initINotify
        zipWithM_ (\d v -> addWatch i ev d (handle v)) (map pack ds) vs

        forM_ (zip ds vs) $ \(d, v) -> do
            s <- fmap (S.fromList . filter (not . isPrefixOf "."))
                    $ getDirectoryContents d
            atomically $ modifyTVar v (S.union s)

        changeLoop (mapM (fmap S.size . readTVar) vs) $ \ns ->
            let showmbx m n c = if c == ""
                                then m ++ show n
                                else "<fc=" ++ c ++ ">" ++ m ++ show n ++ "</fc>"
                cnts = [showmbx m n c | ((m,_,c), n) <- zip ms ns , n /= 0 ]
            in cb $ if null cnts then "" else prefix ++ unwords cnts ++ suffix

handle :: TVar (Set String) -> Event -> IO ()
handle v e = atomically $ modifyTVar v $ case e of
    Created  {} -> create
    MovedIn  {} -> create
    Deleted  {} -> delete
    MovedOut {} -> delete
    _           -> id
 where
    delete = S.delete ((unpack . filePath) e)
    create = S.insert ((unpack . filePath) e)
#endif