phi/lib/Phi/Widgets/Taskbar.hs

{-# LANGUAGE MultiParamTypeClasses, DeriveDataTypeable, TypeSynonymInstances, FlexibleInstances #-}

module Phi.Widgets.Taskbar ( IconStyle
                           , idIconStyle
                           , desaturateIconStyle
                           , TaskStyle(..)
                           , DesktopStyle(..)
                           , TaskbarConfig(..)
                           , defaultTaskbarConfig
                           , Taskbar
                           , taskbar
                           ) where

import Control.Arrow
import Control.Concurrent
import Control.Monad
import Control.Monad.State.Strict
import Control.Monad.Trans

import Data.Array.MArray
import Data.Bits
import Data.Char
import Data.Function
import Data.IORef
import Data.List
import Data.Maybe
import Data.Typeable
import Data.Unique
import Data.Word
import qualified Data.Accessor.Basic as A
import qualified Data.Accessor.Container as AC
import qualified Data.Map as M

import Foreign.C.Types

import Graphics.Rendering.Cairo
import Graphics.Rendering.Pango.Cairo
import Graphics.Rendering.Pango.Enums (PangoRectangle(..))
import Graphics.Rendering.Pango.Layout
import Graphics.Rendering.Pango.Font

import Graphics.XHB
import Graphics.XHB.Gen.Xproto

import Codec.Binary.UTF8.String

import Phi.Phi
import Phi.Types
import Phi.Border
import Phi.Widget
import Phi.X11.Atoms
import Phi.X11.Util


newtype IconStyle = IconStyle { withIconStyle :: Surface -> Render () }
instance Eq IconStyle where
  _ == _ = True

idIconStyle :: IconStyle
idIconStyle = IconStyle $ flip withPatternForSurface setSource

desaturateIconStyle :: Double -> IconStyle
desaturateIconStyle v = IconStyle $ \icon -> do
  w <- imageSurfaceGetWidth icon
  h <- imageSurfaceGetHeight icon
  
  renderWithSimilarSurface ContentColorAlpha w h $ \surface -> do
    renderWith surface $ do
      setOperator OperatorAdd
      withPatternForSurface icon setSource
      paint
      
      setSourceRGB 0 0 0
      paint
      
      setOperator OperatorHslSaturation
      setSourceRGBA 0 0 0 (1-v)
      paint
      
      setOperator OperatorDestIn
      withPatternForSurface icon setSource
      paint
    
    withPatternForSurface surface setSource


downscaled :: Double -> Surface -> Render ()
downscaled s surface = do
  case True of
    _ | s < 0.5 -> do
      w <- imageSurfaceGetWidth surface
      h <- imageSurfaceGetHeight surface
      
      renderWithSimilarSurface ContentColorAlpha (ceiling (fromIntegral w*s)) (ceiling (fromIntegral h*s)) $ \surface' -> do
        renderWith surface' $ do
          scale 0.5 0.5
          downscaled (2*s) surface
          paint
        withPatternForSurface surface' setSource
      
      | otherwise -> do
      scale s s
      withPatternForSurface surface setSource


data TaskStyle = TaskStyle { taskFont      :: !String
                           , taskColor     :: !Color
                           , taskBorder    :: !BorderConfig
                           , taskIconStyle :: !IconStyle
                           } deriving Eq

data DesktopStyle = DesktopStyle { desktopFont       :: !String
                                 , desktopLabelWidth :: !Int
                                 , desktopLabelGap   :: !Int
                                 , desktopColor      :: !Color
                                 , desktopBorder     :: !BorderConfig
                                 }

data TaskbarConfig = TaskbarConfig { taskMaxSize      :: !Int
                                   , normalTaskStyle  :: !TaskStyle
                                   , activeTaskStyle  :: !TaskStyle
                                   , desktopStyle     :: !(Maybe (DesktopStyle, DesktopStyle))
                                   }

defaultStyle :: TaskStyle
defaultStyle = TaskStyle { taskFont = "Sans 8"
                         , taskColor = (0, 0, 0, 1)
                         , taskBorder = defaultBorderConfig { backgroundColor = (0.75, 0.75, 0.75, 1) }
                         , taskIconStyle = idIconStyle
                         }

defaultTaskbarConfig :: TaskbarConfig
defaultTaskbarConfig = TaskbarConfig { taskMaxSize = 200
                                     , normalTaskStyle = defaultStyle
                                     , activeTaskStyle = defaultStyle {taskBorder = defaultBorderConfig { borderColor = (1, 1, 1, 1) }}
                                     , desktopStyle = Nothing
                                     }

data Taskbar = Taskbar TaskbarConfig

data TaskbarState = TaskbarState { taskbarScreens           :: ![RECTANGLE]
                                 , taskbarActiveWindow      :: !WINDOW
                                 , taskbarDesktopCount      :: !Int
                                 , taskbarCurrentDesktop    :: !Int
                                 , taskbarDesktopNames      :: ![String]
                                 , taskbarWindows           :: ![WINDOW]
                                 , taskbarWindowStates      :: !(M.Map WINDOW WindowState)
                                 } deriving Eq

data Icon = Icon !Unique !Int !Surface
instance Eq Icon where (Icon a _ _) == (Icon b _ _) = a == b
instance Show Icon where show (Icon _ size _) = "Icon { size = " ++ (show size) ++ " }"

createIcon :: Int -> Surface -> IO Icon
createIcon size surface = do
  id <- newUnique
  return $ Icon id size surface


data WindowState = WindowState { windowTitle    :: !String
                               , windowDesktop  :: !Int
                               , windowVisible  :: !Bool
                               , windowIcons    :: ![Icon]
                               , windowGeometry :: !RECTANGLE
                               } deriving (Eq, Show)

data WindowCache = WindowCache { createScaledIconCached :: !(IOCache ([Icon], Int) (Maybe Icon))
                               , renderWindowCached     :: !(IOCache (String, Maybe Icon, TaskStyle, Int, Int) Surface)
                               }

createScaledIconCached' = A.fromSetGet (\a cache -> cache {createScaledIconCached = a}) createScaledIconCached
renderWindowCached' = A.fromSetGet (\a cache -> cache {renderWindowCached = a}) renderWindowCached


newtype DesktopCache = DesktopCache (IOCache () ())

emptyWindowCache :: WindowCache
emptyWindowCache = WindowCache { createScaledIconCached = createIOCache createScaledIcon
                               , renderWindowCached     = createIOCache doRenderWindow
                               }

data TaskbarCache = TaskbarCache { desktopCaches :: !(M.Map Int DesktopCache)
                                 , windowCaches  :: !(M.Map WINDOW WindowCache)
                                 }

-- substitute for the liftT function in Data.Accessor.MonadState that uses the strict StateT variant
liftT :: (Monad m) => A.T r s -> StateT s m a -> StateT r m a
liftT f m = do
  s0 <- gets $ A.get f
  (a,s1) <- lift $ runStateT m s0
  modify $ A.set f s1
  return a

liftIOStateT :: (MonadIO m) => StateT s IO a -> StateT s m a
liftIOStateT m = do 
  s0 <- get
  (a,s1) <- liftIO $ runStateT m s0
  put s1
  return a

cached :: (MonadIO m, Eq a) => A.T s (IOCache a b) -> a -> StateT s m b
cached t = liftT t . liftIOStateT . runIOCache

data TaskbarMessage = WindowListUpdate ![WINDOW] !(M.Map WINDOW WindowState)
                    | DesktopCountUpdate !Int
                    | CurrentDesktopUpdate !Int
                    | DesktopNamesUpdate ![String]
                    | ActiveWindowUpdate !WINDOW
                    deriving (Typeable, Show)

instance Widget Taskbar TaskbarState (M.Map WINDOW WindowCache) where
  initWidget (Taskbar _) phi dispvar screens = do
    phi' <- dupPhi phi
    forkIO $ taskbarRunner phi' dispvar
    
    return $ TaskbarState (map fst screens) (fromXid xidNone) 0 (-1) [] [] M.empty
  
  initCache _ = M.empty
    
  minSize _ _ _ _ = 0
  weight _ = 1
  
  render (Taskbar config) TaskbarState { taskbarScreens = screens
                                       , taskbarActiveWindow = activeWindow
                                       , taskbarDesktopCount = desktopCount
                                       , taskbarCurrentDesktop = currentDesktop
                                       , taskbarDesktopNames = desktopNames
                                       , taskbarWindows = windows
                                       , taskbarWindowStates = windowStates
                                       } _ _ w h screen = do
    let windowScreen w = maximumBy (compare `on` unionArea (windowGeometry w)) screens
        screenWindows  = filter ((== Just screen) . fmap windowScreen . flip M.lookup windowStates) windows
        desktopNumbers = take desktopCount $ zip [0..] (desktopNames ++ repeat "")
        desktops       = map (\desktop -> (desktop, filter (fromMaybe False . fmap (windowOnDesktop . fst $ desktop) . flip M.lookup windowStates) screenWindows)) desktopNumbers
        
        windowCount    = sum $ map (length . snd) $ desktops
        
        dstyle d       = fmap (if d == currentDesktop then snd else fst) $ desktopStyle config
        dlabelwidth d  = fromMaybe 0 $ fmap desktopLabelWidth $ dstyle d
        gap d ds       = if null (snd $ desktops !! d) then 0 else desktopLabelGap ds
        dleftwidth d   = fromMaybe 0 $ fmap (\ds@DesktopStyle {desktopBorder = border}
                                             -> (borderLeft $ margin border) + (borderWidth border) + (borderLeft $ padding border)
                                                + dlabelwidth d + gap d ds) $ dstyle d
        dwidth d       = fromMaybe 0 $ fmap (\ds@DesktopStyle {desktopBorder = border}
                                             -> (borderH $ margin border) + 2*(borderWidth border) + (borderH $ padding border)
                                                + dlabelwidth d + gap d ds) $ dstyle d
        
        desktopsWidth  = sum $ map (dwidth . fst) desktopNumbers
        windowWidth    = if windowCount == 0 then 0 else min (taskMaxSize config) ((w - desktopsWidth) `div` windowCount)
    
    surface <- liftIO $ createImageSurface FormatARGB32 w h
    cache <- liftM (M.filterWithKey $ \w _ -> elem w windows) get
    cache' <- renderWith surface $ flip execStateT cache $ do
      lift $ do
        setOperator OperatorClear
        paint
        
        setOperator OperatorOver
      
      flip (flip foldM_ 0) desktops $ \nwindows (desktop, desktopWindows) -> do
        let dstyle' = dstyle (fst desktop)
            dx = dleftwidth (fst desktop) + (sum $ map dwidth $ take (fst desktop) [0..]) + nwindows*windowWidth
        
        case dstyle' of
          Just ds -> do
            let (r, g, b, a) = desktopColor ds
            lift $ do
              save
              drawBorder (desktopBorder ds) (dx - dleftwidth (fst desktop)) 0 (dwidth (fst desktop) + windowWidth * length desktopWindows) h
              clip
              
              setSourceRGBA r g b a
              renderText (desktopFont ds) (fromIntegral (dx - dlabelwidth (fst desktop) - gap (fst desktop) ds)) 0 (dlabelwidth (fst desktop)) h $ snd desktop
              
              restore
            
            forM_ (zip [0..] desktopWindows) $ \(i, window) -> do
              let style = (if window == activeWindow then activeTaskStyle else normalTaskStyle) config
                  h' = h - (borderV $ margin $ desktopBorder ds) - 2*(borderWidth $ desktopBorder ds) - (borderV $ padding $ desktopBorder ds)
                  mstate = M.lookup window windowStates
                  x = dx + i*windowWidth
                  y = (borderTop $ margin $ desktopBorder ds) + (borderWidth $ desktopBorder ds) + (borderTop $ padding $ desktopBorder ds)
              
              case mstate of
                Just state -> do
                  windowSurface <- liftT (AC.mapDefault emptyWindowCache window) . liftIOStateT $ renderWindow state style windowWidth h'
                  lift $ do
                    save
                    translate (fromIntegral $ x - 5) (fromIntegral $ y - 5)
                    withPatternForSurface windowSurface setSource
                    paint
                    restore
            
                Nothing -> return ()
        
          _ -> return ()
      
        return $ nwindows + length desktopWindows
    put cache'
    
    return [(True, SurfaceSlice 0 surface)]
      
  
  handleMessage _ priv m = case (fromMessage m) of
    Just (WindowListUpdate windows windowStates) -> priv { taskbarWindows = windows
                                                         , taskbarWindowStates = windowStates
                                                         }
    Just (DesktopCountUpdate count) -> priv {taskbarDesktopCount = count}
    Just (CurrentDesktopUpdate current) -> priv {taskbarCurrentDesktop = current}
    Just (DesktopNamesUpdate names) -> priv {taskbarDesktopNames = names}
    Just (ActiveWindowUpdate window) -> priv {taskbarActiveWindow = window}
    _ -> case (fromMessage m) of
      Just (UpdateScreens screens) -> priv {taskbarScreens = map fst screens}
      _ -> priv


renderText :: String -> Int -> Int -> Int -> Int -> String -> Render ()
renderText font x y w h text = do
  layout <- createLayout ""
  (_, PangoRectangle _ _ textWidth textHeight) <- liftIO $ do
    layoutSetMarkup layout $ "<span font='" ++ font ++ "'>" ++ (escapeMarkup text) ++ "</span>"
    layoutSetWidth layout $ Just $ fromIntegral w
    layoutSetEllipsize layout EllipsizeEnd
    
    layoutGetExtents layout
  
  
  moveTo ((fromIntegral x) + ((fromIntegral w) - textWidth)/2) ((fromIntegral y) + ((fromIntegral h) - textHeight)/2)
  showLayout layout

renderWindow :: WindowState -> TaskStyle -> Int -> Int -> StateT WindowCache IO Surface
renderWindow state style w h = do
  let h' = h - (borderV $ margin $ taskBorder style)
  
  scaledIcon <- cached createScaledIconCached' (windowIcons state, h')
  cached renderWindowCached' (windowTitle state, scaledIcon, style, w, h)

doRenderWindow :: (String, Maybe Icon, TaskStyle, Int, Int) -> IO Surface
doRenderWindow (title, scaledIcon, style, w, h) = do
  let (r, g, b, a) = taskColor style
      leftBorder = (borderLeft $ margin $ taskBorder style) + (borderWidth $ taskBorder style) + (borderLeft $ padding $ taskBorder style)
      rightBorder = (borderRight $ margin $ taskBorder style) + (borderWidth $ taskBorder style) + (borderRight $ padding $ taskBorder style)
      h' = h - (borderV $ margin $ taskBorder style)
  
  surface <- createImageSurface FormatARGB32 (w+10) (h+10)
  renderWith surface $ do
    translate 5 5
    
    save
    drawBorder (taskBorder style) 0 0 w h
    clip
    
    setSourceRGBA r g b a
    renderText (taskFont style) (fromIntegral (leftBorder + h' + 3)) 0 (w - leftBorder - h' - 3 - rightBorder) h title
    
    restore
    
    case scaledIcon of
      Just (Icon _ _ icon) -> do
        save
        translate (fromIntegral leftBorder) (fromIntegral . borderTop . margin . taskBorder $ style)
        withIconStyle (taskIconStyle style) icon
        paint
        restore
    
      _ -> return ()
  
  return surface
                

createScaledIcon :: ([Icon], Int) -> IO (Maybe Icon)
createScaledIcon (icons, h) = do
  case bestIcon of
    Just (Icon _ _ icon) -> do
      scaledIcon <- createSimilarSurface icon ContentColorAlpha h h
      renderWith scaledIcon $ do
        imageW <- imageSurfaceGetWidth icon
        imageH <- imageSurfaceGetHeight icon
        
        let scalef = (fromIntegral h)/(fromIntegral $ max imageW imageH)
        
        case () of
          _ | imageH < imageW -> translate 0 (fromIntegral (imageW-imageH)*scalef/2)
            | otherwise -> translate (fromIntegral (imageH-imageW)*scalef/2) 0
        
        downscaled scalef icon
        paint
      fmap Just $ createIcon h scaledIcon
          
    _ -> return Nothing
  
  where
    bestIcon = listToMaybe $ sortBy compareIcons icons
    compareIcons = flip (compare `on` (\(Icon _ size _) -> size))


windowOnDesktop :: Int -> WindowState -> Bool
windowOnDesktop desktop state = (windowVisible state) && (desktop == windowDesktop state)


taskbarRunner :: Phi -> Display -> IO ()
taskbarRunner phi dispvar = do
  (windows, states) <- liftIO $ withDisplay dispvar $ \disp -> do
    (windows, states) <- getWindowStates disp (getAtoms dispvar) M.empty
    desktopCount <- getDesktopCount disp (getAtoms dispvar) 
    current <- getCurrentDesktop disp (getAtoms dispvar) 
    names <- getDesktopNames disp (getAtoms dispvar)
    activeWindow <- getActiveWindow disp (getAtoms dispvar) 
    sendMessage phi $ WindowListUpdate windows states
    sendMessage phi $ DesktopCountUpdate desktopCount
    sendMessage phi $ CurrentDesktopUpdate current
    sendMessage phi $ DesktopNamesUpdate names
    sendMessage phi $ ActiveWindowUpdate activeWindow
    return (windows, states)
  sendMessage phi Repaint
  
  flip evalStateT (windows, states) $ forever $ do
    m <- receiveMessage phi
    case (fromMessage m) of
      Just (XEvent event) ->
        handleEvent phi dispvar event
      _ ->
        return ()


handleEvent :: Phi -> Display -> SomeEvent -> StateT ([WINDOW], M.Map WINDOW WindowState) IO ()
handleEvent phi dispvar event =
  case (fromEvent event) of
    Just e -> handlePropertyNotifyEvent phi dispvar e
    Nothing -> case (fromEvent event) of
      Just e -> handleConfigureNotifyEvent phi dispvar e
      Nothing -> return ()

handlePropertyNotifyEvent :: Phi -> Display -> PropertyNotifyEvent -> StateT ([WINDOW], M.Map WINDOW WindowState) IO ()
handlePropertyNotifyEvent phi dispvar MkPropertyNotifyEvent {atom_PropertyNotifyEvent = atom, window_PropertyNotifyEvent = window} = do
  let atoms = getAtoms dispvar
  
  when (elem atom $ map ($ atoms) [ atom_NET_ACTIVE_WINDOW
                                  , atom_NET_NUMBER_OF_DESKTOPS
                                  , atom_NET_CURRENT_DESKTOP
                                  , atom_NET_DESKTOP_NAMES
                                  , atom_NET_CLIENT_LIST
                                  , atom_NET_WM_ICON
                                  , atomWM_NAME
                                  , atom_NET_WM_NAME
                                  , atom_NET_WM_DESKTOP
                                  , atom_NET_WM_STATE
                                  ]) $ withDisplay dispvar $ \conn -> do
    let rootwin = getRoot conn
    if (window == rootwin)
      then do
      when (atom == atom_NET_ACTIVE_WINDOW atoms) $ do
        activeWindow <- liftIO $ getActiveWindow conn atoms
        sendMessage phi $ ActiveWindowUpdate activeWindow
        sendMessage phi Repaint
      when (atom == atom_NET_NUMBER_OF_DESKTOPS atoms) $ do
        desktopCount <- liftIO $ getDesktopCount conn atoms
        sendMessage phi $ DesktopCountUpdate desktopCount
        sendMessage phi Repaint
      when (atom == atom_NET_CURRENT_DESKTOP atoms) $ do
        current <- liftIO $ getCurrentDesktop conn atoms
        sendMessage phi $ CurrentDesktopUpdate current
        sendMessage phi Repaint
      when (atom == atom_NET_DESKTOP_NAMES atoms) $ do
        names <- liftIO $ getDesktopNames conn atoms
        sendMessage phi $ DesktopNamesUpdate names
        sendMessage phi Repaint
      when (atom == atom_NET_CLIENT_LIST atoms) $ do
        (windows, windowStates) <- get
        (windows', windowStates') <- liftIO $ getWindowStates conn atoms windowStates
        
        when (windows /= windows') $ do
          sendMessage phi $ WindowListUpdate windows' windowStates'
          sendMessage phi Repaint
          put (windows', windowStates')
    
      else do
      (windows, windowStates) <- get
      when (elem window windows) $ do
        case () of
          _ | (atom == atom_NET_WM_ICON atoms) -> do
            icons <- liftIO $ getWindowIcons conn atoms window
            let windowStates' = M.update (\state -> Just state {windowIcons = icons}) window windowStates
            sendMessage phi $ WindowListUpdate windows windowStates'
            sendMessage phi Repaint
            put (windows, windowStates')
        
            | otherwise -> do
            (name, desktop, visible) <- liftIO $ getWindowInfo conn atoms window
            let mwindowState = M.lookup window windowStates
            case mwindowState of
              Just windowState -> do
                let windowState' = windowState {windowTitle = name, windowDesktop = desktop, windowVisible = visible}
            
                when (windowState /= windowState') $ do
                  let windowStates' = M.insert window windowState' windowStates
                  sendMessage phi $ WindowListUpdate windows windowStates'
                  sendMessage phi Repaint
                  put (windows, windowStates')
              Nothing ->
                return ()


handleConfigureNotifyEvent :: Phi -> Display -> ConfigureNotifyEvent -> StateT ([WINDOW], M.Map WINDOW WindowState) IO ()
handleConfigureNotifyEvent phi dispvar MkConfigureNotifyEvent {window_ConfigureNotifyEvent = window} = do
  (windows, windowStates) <- get
  when (elem window windows) $ withDisplay dispvar $ \conn -> do
    let geom = fmap windowGeometry . M.lookup window $ windowStates
    geom' <- liftIO $ getWindowGeometry conn window
    when (geom /= (Just geom')) $ do
      let windowStates' = M.update (\state -> Just state {windowGeometry = geom'}) window windowStates
      sendMessage phi $ WindowListUpdate windows windowStates'
      sendMessage phi Repaint
      put (windows, windowStates')


getDesktopCount :: Connection -> Atoms -> IO Int
getDesktopCount conn atoms =
  liftM (fromIntegral . fromMaybe 0 . join . fmap listToMaybe) $ getProperty32 conn (getRoot conn) (atom_NET_NUMBER_OF_DESKTOPS atoms)

getCurrentDesktop :: Connection -> Atoms -> IO Int
getCurrentDesktop conn atoms =
  liftM (fromIntegral . fromMaybe (-1) . join . fmap listToMaybe) $ getProperty32 conn (getRoot conn) (atom_NET_CURRENT_DESKTOP atoms)

getDesktopNames :: Connection -> Atoms -> IO [String]
getDesktopNames conn atoms =
  liftM (map (decode . map fromIntegral) . break' . fromMaybe []) $ getProperty8 conn (getRoot conn) (atom_NET_DESKTOP_NAMES atoms)
  where
    break' l = case dropWhile (== 0) l of
      [] -> []
      l' -> w : break' l''
        where (w, l'') = break (== 0) l'

getActiveWindow :: Connection -> Atoms -> IO WINDOW
getActiveWindow conn atoms =
  liftM (fromXid . toXid . fromMaybe 0 . join . fmap listToMaybe) $ getProperty32 conn (getRoot conn) (atom_NET_ACTIVE_WINDOW atoms)

getWindowStates :: Connection -> Atoms -> M.Map WINDOW WindowState -> IO ([WINDOW], M.Map WINDOW WindowState)
getWindowStates conn atoms windowStates = do
  windows <- getWindowList conn atoms
  
  let windowStates' = map (\w -> (w, M.lookup w windowStates)) windows
  
  newWindowStates <- mapM getWindowState' windowStates'
  
  return (windows, M.fromList newWindowStates)
    where
      getWindowState' (window, Just windowState) = return (window, windowState) 
      getWindowState' (window, Nothing) = do
        changeWindowAttributes conn window $ toValueParam [(CWEventMask, toMask [EventMaskPropertyChange, EventMaskStructureNotify])]
        windowState <- getWindowState conn atoms window
        return (window, windowState)

getWindowState :: Connection -> Atoms -> WINDOW -> IO WindowState
getWindowState conn atoms window = do
  (name, workspace, visible) <- getWindowInfo conn atoms window
  icons <- getWindowIcons conn atoms window
  geom <- getWindowGeometry conn window
  
  return $ WindowState { windowTitle = name 
                       , windowDesktop = workspace 
                       , windowVisible = visible 
                       , windowIcons = icons
                       , windowGeometry = geom
                       }

getWindowInfo :: Connection -> Atoms -> WINDOW -> IO (String, Int, Bool)
getWindowInfo conn atoms window = do
  netwmname <- liftM (fmap (decode . map fromIntegral)) $ getProperty8 conn window (atom_NET_WM_NAME atoms)
  wmname <- case netwmname of
    Just name -> return name
    Nothing -> liftM (map unsignedChr . fromMaybe []) $ getProperty8 conn window (atom_NET_WM_NAME atoms)
  
  workspace <- liftM (fromIntegral . fromMaybe 0xFFFFFFFF . join . fmap listToMaybe) $ getProperty32 conn window (atom_NET_WM_DESKTOP atoms)
  visible <- showWindow conn atoms window
  
  return (wmname, workspace, visible)
    where
      unsignedChr = chr . fromIntegral

getWindowIcons :: Connection -> Atoms -> WINDOW -> IO [Icon]
getWindowIcons conn atoms window = getProperty32 conn window (atom_NET_WM_ICON atoms) >>= readIcons . fromMaybe []


readIcons :: [Word32] -> IO [Icon]
readIcons (width:height:iconData) = do
  if ((fromIntegral $ length iconData) < (width*height)) then return [] else do
    let (thisIcon, rest) = splitAt (fromIntegral (width*height)) iconData
    surface <- createImageSurface FormatARGB32 (fromIntegral width) (fromIntegral height)
    surfaceData <- imageSurfaceGetPixels surface :: IO (SurfaceData Int Word32)
    forM_ (zip thisIcon [0..]) $ \(e, i) -> writeArray surfaceData i $ premultiply $ fromIntegral e
    
    surfaceMarkDirty surface
    
    liftM2 (:) (createIcon (fromIntegral $ max width height) surface) (readIcons rest)

readIcons _ = return []

premultiply :: Word32 -> Word32
premultiply c = a .|. r .|. g .|. b
  where
    amask = 0xFF000000
    rmask = 0x00FF0000
    gmask = 0x0000FF00
    bmask = 0x000000FF
    
    a = c .&. amask
    pm mask = (((c .&. mask) * (a `shiftR` 24)) `div` 0xFF) .&. mask
    
    r = pm rmask
    g = pm gmask
    b = pm bmask


getWindowGeometry :: Connection -> WINDOW -> IO RECTANGLE
getWindowGeometry conn window =
  getGeometry conn (fromXid . toXid $ window) >>= getReply >>= return . ((const $ MkRECTANGLE 0 0 0 0) ||| (\(MkGetGeometryReply _ _ x y width height _) -> MkRECTANGLE x y width height))

showWindow :: Connection -> Atoms -> WINDOW -> IO Bool
showWindow conn atoms window = do
  states <- liftM (map (fromXid . toXid) . fromMaybe []) $ getProperty32 conn window (atom_NET_WM_STATE atoms)
  transientFor <- liftM (map fromIntegral . fromMaybe []) $ getProperty32 conn window (atomWM_TRANSIENT_FOR atoms)
  windowType <- liftM (fromMaybe (atom_NET_WM_WINDOW_TYPE_NORMAL atoms) . fmap (fromXid . toXid) . join . fmap listToMaybe) $
                getProperty32 conn window (atom_NET_WM_STATE atoms)
  
  return $ not $ or [ elem (atom_NET_WM_STATE_SKIP_TASKBAR atoms) states 
                    , transientFor /= [] && transientFor /= [0]
                    , elem windowType $ map ($ atoms) [ atom_NET_WM_WINDOW_TYPE_DOCK 
                                                      , atom_NET_WM_WINDOW_TYPE_DESKTOP 
                                                      , atom_NET_WM_WINDOW_TYPE_TOOLBAR 
                                                      , atom_NET_WM_WINDOW_TYPE_MENU 
                                                      , atom_NET_WM_WINDOW_TYPE_SPLASH
                                                      ]
                    ]


getWindowList :: Connection -> Atoms -> IO [WINDOW]
getWindowList conn atoms = liftM (map (fromXid . toXid) . join . maybeToList) $ getProperty32 conn (getRoot conn) (atom_NET_CLIENT_LIST atoms)

taskbar :: TaskbarConfig -> Taskbar
taskbar = Taskbar