{-# LANGUAGE FlexibleContexts #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Xmobar.Main
-- Copyright   :  (c) Andrea Rossato
-- License     :  BSD-style (see LICENSE)
--
-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
-- Stability   :  unstable
-- Portability :  unportable
--
-- The main module of Xmobar, a text based status bar
--
-----------------------------------------------------------------------------

module Main ( -- * Main Stuff
              -- $main
              main
            , readConfig
            , readDefaultConfig
            ) where

import Xmobar
import Parsers
import Config
import XUtil

import Data.List (intercalate)

import Paths_xmobar (version)
import Data.Version (showVersion)
import Graphics.X11.Xlib
import System.Console.GetOpt
import System.Exit
import System.Environment
import System.Posix.Files
import Control.Monad (unless)

-- $main

-- | The main entry point
main :: IO ()
main = do
  initThreads
  d   <- openDisplay ""
  args     <- getArgs
  (o,file) <- getOpts args
  (c,defaultings) <- case file of
                       [cfgfile] -> readConfig cfgfile
                       _         -> readDefaultConfig

  unless (null defaultings) $ putStrLn $ "Fields missing from config defaulted: "
                                            ++ intercalate "," defaultings

  conf  <- doOpts c o
  fs    <- initFont d (font conf)
  cls   <- mapM (parseTemplate conf) (splitTemplate conf)
  vars  <- mapM (mapM startCommand) cls
  (r,w) <- createWin d fs conf
  startLoop (XConf d r w fs conf) vars

-- | Splits the template in its parts
splitTemplate :: Config -> [String]
splitTemplate conf =
  case break (==l) t of
    (le,_:re) -> case break (==r) re of
                   (ce,_:ri) -> [le, ce, ri]
                   _         -> def
    _         -> def
  where [l, r] = if length (alignSep conf) == 2
                 then alignSep conf
                 else alignSep defaultConfig
        t = template conf
        def = [t, "", ""]


-- | Reads the configuration files or quits with an error
readConfig :: FilePath -> IO (Config,[String])
readConfig f = do
  file <- io $ fileExist f
  s    <- io $ if file then readFileSafe f else error $ f ++ ": file not found!\n" ++ usage
  either (\err -> error $ f ++ ": configuration file contains errors at:\n" ++ show err)
         return $ parseConfig s

-- | Read default configuration file or load the default config
readDefaultConfig :: IO (Config,[String])
readDefaultConfig = do
  home <- io $ getEnv "HOME"
  let path = home ++ "/.xmobarrc"
  f <- io $ fileExist path
  if f then readConfig path else return (defaultConfig,[])

data Opts = Help
          | Version
          | Font     String
          | BgColor  String
          | FgColor  String
          | T
          | B
          | AlignSep String
          | Commands String
          | SepChar  String
          | Template String
          | OnScr    String
       deriving Show

options :: [OptDescr Opts]
options =
    [ Option ['h','?' ] ["help"     ] (NoArg  Help                ) "This help"
    , Option ['V'     ] ["version"  ] (NoArg  Version             ) "Show version information"
    , Option ['f'     ] ["font"     ] (ReqArg Font     "font name") "The font name"
    , Option ['B'     ] ["bgcolor"  ] (ReqArg BgColor  "bg color" ) "The background color. Default black"
    , Option ['F'     ] ["fgcolor"  ] (ReqArg FgColor  "fg color" ) "The foreground color. Default grey"
    , Option ['o'     ] ["top"      ] (NoArg  T                   ) "Place xmobar at the top of the screen"
    , Option ['b'     ] ["bottom"   ] (NoArg  B                   ) "Place xmobar at the bottom of the screen"
    , Option ['a'     ] ["alignsep" ] (ReqArg AlignSep "alignsep" ) "Separators for left, center and right text\nalignment. Default: '}{'"
    , Option ['s'     ] ["sepchar"  ] (ReqArg SepChar  "char"     ) "The character used to separate commands in\nthe output template. Default '%'"
    , Option ['t'     ] ["template" ] (ReqArg Template "template" ) "The output template"
    , Option ['c'     ] ["commands" ] (ReqArg Commands "commands" ) "The list of commands to be executed"
    , Option ['x'     ] ["screen"   ] (ReqArg OnScr    "screen"   ) "On which X screen number to start"
    ]

getOpts :: [String] -> IO ([Opts], [String])
getOpts argv =
    case getOpt Permute options argv of
      (o,n,[])   -> return (o,n)
      (_,_,errs) -> error (concat errs ++ usage)

usage :: String
usage = (usageInfo header options) ++ footer
    where header = "Usage: xmobar [OPTION...] [FILE]\nOptions:"
          footer = "\nMail bug reports and suggestions to " ++ mail ++ "\n"

info :: String
info = "xmobar " ++ showVersion version
        ++ "\n (C) 2007 - 2010 Andrea Rossato "
        ++ "\n (C) 2010 - 2011 Jose A Ortega Ruiz\n "
        ++ mail ++ "\n" ++ license

mail :: String
mail = "<xmobar@projects.haskell.org>"

license :: String
license = "\nThis program is distributed in the hope that it will be useful,\n" ++
          "but WITHOUT ANY WARRANTY; without even the implied warranty of\n" ++
          "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" ++
          "See the License for more details."

doOpts :: Config -> [Opts] -> IO Config
doOpts conf []     = return conf
doOpts conf (o:oo) =
    case o of
      Help       -> putStr   usage >> exitWith ExitSuccess
      Version    -> putStrLn info  >> exitWith ExitSuccess
      Font     s -> doOpts (conf {font     = s     }) oo
      BgColor  s -> doOpts (conf {bgColor  = s     }) oo
      FgColor  s -> doOpts (conf {fgColor  = s     }) oo
      T          -> doOpts (conf {position = Top   }) oo
      B          -> doOpts (conf {position = Bottom}) oo
      AlignSep s -> doOpts (conf {alignSep = s     }) oo
      SepChar  s -> doOpts (conf {sepChar  = s     }) oo
      Template s -> doOpts (conf {template = s     }) oo
      OnScr    n -> doOpts (conf {position = OnScreen (read n) $ position conf}) oo
      Commands s -> case readCom s of
                      Right x -> doOpts (conf { commands = x }) oo
                      Left e  -> putStr (e ++ usage) >> exitWith (ExitFailure 1)
    where readCom str =
              case readStr str of
	        [x] -> Right x
	        _   -> Left "xmobar: cannot read list of commands specified with the -c option\n"
          readStr str =
              [x | (x,t) <- reads str, ("","") <- lex t]