{-# LANGUAGE TypeFamilies, DeriveDataTypeable #-}

module Phi.Widgets.Systray ( systray
                           ) where

import Control.Concurrent
import Control.Monad

import Data.Maybe

import Foreign.C.Types

import Graphics.X11.Xlib hiding (Display)
import qualified Graphics.X11.Xlib as Xlib
import Graphics.X11.Xlib.Extras

import Phi.Bindings.Util

import Phi.Phi
import Phi.Types
import Phi.Widget
import Phi.X11.Atoms


data SystrayIconState = SystrayIconState deriving Show

data SystrayState = SystrayState Rectangle [SystrayIconState] deriving Show

data Systray = Systray deriving Show


instance WidgetClass Systray where
  type WidgetData Systray = SystrayState
  
  initWidget (Systray) phi dispvar = do
    forkIO $ systrayRunner phi dispvar
    
    return $ SystrayState (head . getScreens $ dispvar) []
  
  minSize _ (SystrayState systrayScreen icons) height screen = case True of 
    _ | screen == systrayScreen -> (length icons)*height
      | otherwise -> 0

  weight _ = 0
  
  render Systray (SystrayState systrayScreen icons) w h screen = case True of 
    _ | screen == systrayScreen -> do
      return ()
      | otherwise -> return ()


systrayRunner :: Phi -> Display -> IO ()
systrayRunner phi dispvar = do
  let atoms = getAtoms dispvar
  initSuccess <- withDisplay dispvar $ flip initSystray atoms
  
  case initSuccess of
    Just xembedWindow -> forever $ do
      m <- receiveMessage phi
      case (fromMessage m) of
        Just event ->
          handleEvent event phi dispvar xembedWindow
        _ ->
          return ()
    Nothing ->
      return ()


initSystray :: Xlib.Display -> Atoms -> IO (Maybe Window)
initSystray disp atoms = do
  currentSystrayWin <- xGetSelectionOwner disp $ atom_NET_SYSTEM_TRAY_SCREEN atoms
  
  if currentSystrayWin /= 0 then do
    pid <- liftM (fromMaybe "" . fmap (\pid -> " (pid" ++ show (fromIntegral pid :: CUShort) ++ ")") . join . fmap listToMaybe) $
           getWindowProperty16 disp (atom_NET_WM_PID atoms) currentSystrayWin
    
    putStrLn $ "Phi: another systray is running." ++ pid
    
    return Nothing
    else do
    xembedWin <- createSimpleWindow disp (defaultRootWindow disp) (-1) (-1) 1 1 0 0 0
    
    -- orient horizontally
    changeProperty32 disp xembedWin (atom_NET_SYSTEM_TRAY_ORIENTATION atoms) cARDINAL propModeReplace [0]
    
    -- set visual
    let rootwin = defaultRootWindow disp
        screen = defaultScreen disp
        visual = defaultVisual disp screen
        visualID = visualIDFromVisual visual
    changeProperty32 disp xembedWin (atom_NET_SYSTEM_TRAY_VISUAL atoms) vISUALID propModeReplace [fromIntegral visualID]
    
    xSetSelectionOwner disp (atom_NET_SYSTEM_TRAY_SCREEN atoms) xembedWin currentTime
    systrayWin <- xGetSelectionOwner disp $ atom_NET_SYSTEM_TRAY_SCREEN atoms
    if systrayWin /= xembedWin then do
      destroyWindow disp xembedWin
      putStrLn $ "Phi: can't initialize systray."
      return Nothing
      
      else do
      allocaXEvent $ \event -> do
        putClientMessage event rootwin (atomMANAGER atoms) [fromIntegral currentTime, fromIntegral (atom_NET_SYSTEM_TRAY_SCREEN atoms), fromIntegral xembedWin, 0, 0]
        sendEvent disp rootwin False structureNotifyMask event
      
      return $ Just xembedWin


sYSTEM_TRAY_REQUEST_DOCK :: CInt
sYSTEM_TRAY_REQUEST_DOCK = 0

sYSTEM_TRAY_BEGIN_MESSAGE :: CInt
sYSTEM_TRAY_BEGIN_MESSAGE = 1

sYSTEM_TRAY_CANCEL_MESSAGE :: CInt
sYSTEM_TRAY_CANCEL_MESSAGE = 2


handleEvent :: Event -> Phi -> Display -> Window -> IO ()
handleEvent ClientMessageEvent { ev_message_type = message_type, ev_data = messageData, ev_window = window } phi dispvar xembedWindow = do
  let atoms = getAtoms dispvar
  when (window == xembedWindow && message_type == atom_NET_SYSTEM_TRAY_OPCODE atoms) $ do
    case messageData of
      (_:opcode:iconID:_) -> do
        case True of
          _ | opcode == sYSTEM_TRAY_REQUEST_DOCK ->
            when (iconID /= 0) $ addIcon phi dispvar $ fromIntegral iconID
        
            | opcode == sYSTEM_TRAY_BEGIN_MESSAGE || opcode == sYSTEM_TRAY_CANCEL_MESSAGE ->
            return ()
            
            | otherwise -> do
            putStrLn "Phi: unknown tray message"
            return ()
        
          
      _ ->
        return ()

handleEvent _ _ _ _ = return ()


addIcon :: Phi -> Display -> Window -> IO ()
addIcon phi display window = do
  return ()


systray :: Widget
systray = Widget $ Systray