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

module Phi.Widgets.X11.Systray ( systray
                               ) where

import Control.Concurrent
import Control.Monad
import Control.Monad.State
import Control.Monad.Trans

import Data.Bits
import Data.IORef
import Data.Maybe
import Data.Typeable
import qualified Data.Map as M

import Foreign.C.Types
import Foreign.Marshal
import Foreign.Ptr
import Foreign.Storable

import Graphics.Rendering.Cairo
import Graphics.Rendering.Cairo.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.Bindings.SystrayErrorHandler

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


data SystrayIconState = SystrayIconState !Window !Window deriving (Show, Eq)

instance Eq Phi where
  _ == _ = True

data SystrayState = SystrayState !Phi !Rectangle !Int ![SystrayIconState] deriving Eq

data Systray = Systray deriving (Show, Eq)

data SystrayMessage = AddIcon !Window !Window | RemoveIcon !Window | RenderIcon !Window !Window !Int !Int !Int !Int
                      deriving (Show, Typeable)


instance Widget Systray SystrayState (RenderCache SystrayState) where
  initWidget (Systray) phi dispvar screens = do
    phi' <- dupPhi phi
    forkIO $ systrayRunner phi' dispvar $ snd . head $ screens
    
    return $ SystrayState phi (fst . head $ screens) 0 []
  
  initCache _ = createRenderCache $ \(SystrayState phi systrayScreen reset icons) x y w h screen -> do
    when (screen == systrayScreen) $ do
      forM_ (zip [0..] icons) $ \(i, SystrayIconState midParent window) -> do
        let x' = x + i*(h+2)
        sendMessage phi $ RenderIcon midParent window x' y h h
    
    setOperator OperatorClear
    paint
  
  minSize _ (SystrayState _ systrayScreen _ icons) height screen = case True of 
    _ | screen == systrayScreen -> max 0 $ (length icons)*(height+2)-1
      | otherwise -> 0

  weight _ = 0
  
  render _ = renderCached

  
  handleMessage _ priv@(SystrayState phi screen reset icons) m = case (fromMessage m) of
    Just (AddIcon midParent window) -> SystrayState phi screen reset ((SystrayIconState midParent window):icons)
    Just (RemoveIcon window) -> SystrayState phi screen reset $ filter (\(SystrayIconState _ stateWindow) -> stateWindow /= window) icons
    _ -> case (fromMessage m) of
      Just (UpdateScreens screens) -> SystrayState phi (fst . head $ screens) reset icons
      _ -> case (fromMessage m) of
        Just ResetBackground -> SystrayState phi screen (reset+1) icons
        _ ->  priv


systrayRunner :: Phi -> Display -> Window -> IO ()
systrayRunner phi dispvar panelWindow = do
  let atoms = getAtoms dispvar
  initSuccess <- withDisplay dispvar $ flip initSystray atoms
  
  case initSuccess of
    Just xembedWindow -> flip evalStateT M.empty $ do
      sendMessage phi HoldShutdown
      
      forever $ do
        m <- receiveMessage phi
        case (fromMessage m) of
          Just event ->
            handleEvent event phi dispvar panelWindow xembedWindow
          _ ->
            case (fromMessage m) of
              Just (RenderIcon midParent window x y w h) -> do
                withDisplay dispvar $ \disp -> do
                  liftIO $ flip catch (\_ -> return ()) $ do
                    sync disp False
                    setSystrayErrorHandler
                    
                    (_, x', y', w', h', _, _) <- getGeometry disp midParent
                    (_, x'', y'', w'', h'', _, _) <- getGeometry disp window
                    let resize = (fromIntegral x) /= x' || (fromIntegral y) /= y' || (fromIntegral w) /= w' || (fromIntegral h) /= h'
                                 || 0 /= x'' || 0 /= y'' || (fromIntegral w) /= w'' || (fromIntegral h) /= h''
                    
                    when resize $ do
                      moveResizeWindow disp midParent (fromIntegral x) (fromIntegral y) (fromIntegral w) (fromIntegral h)
                      moveResizeWindow disp window 0 0 (fromIntegral w) (fromIntegral h)
                      sync disp False
                    
                    clearArea disp window 0 0 (fromIntegral w) (fromIntegral h) True
                      
                    sync disp False
                    xSetErrorHandler
                  
                  lastErrorWindow <- liftIO $ getLastErrorWindow
                  when (lastErrorWindow == window) $ do
                    removeIcon phi disp True window
              _ ->
                case (fromMessage m) of
                  Just Shutdown -> do
                    windows <- gets M.keys
                    withDisplay dispvar $ \disp -> do
                      mapM_ (removeIcon phi disp True) windows
                      liftIO $ do
                        destroyWindow disp xembedWindow
                        sync disp False
                      sendMessage phi ReleaseShutdown
                  _ ->
                    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


handleEvent :: Event -> Phi -> Display -> Window -> Window -> StateT (M.Map Window Window) IO ()
handleEvent message@ClientMessageEvent { ev_message_type = message_type, ev_data = messageData, ev_window = window } phi dispvar panelWindow 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 -> do
            when (iconID /= 0) $ withDisplay dispvar $ \disp -> addIcon phi disp (getAtoms dispvar) panelWindow $ fromIntegral iconID
          
            | opcode == sYSTEM_TRAY_BEGIN_MESSAGE || opcode == sYSTEM_TRAY_CANCEL_MESSAGE ->
            return ()
            
            | otherwise -> do
            liftIO $ putStrLn "Phi: unknown tray message"
            return ()
        
          
      _ ->
        return ()

handleEvent message@UnmapEvent { ev_window = window } phi dispvar panelWindow xembedWindow =
  withDisplay dispvar $ \disp -> removeIcon phi disp True window

handleEvent message@DestroyWindowEvent { ev_window = window } phi dispvar panelWindow xembedWindow =
  withDisplay dispvar $ \disp -> removeIcon phi disp False window

handleEvent message@AnyEvent { ev_window = window } phi dispvar panelWindow xembedWindow | ev_event_type message == reparentNotify = do
  parent <- liftIO $ alloca $ \rootPtr -> alloca $ \parentPtr -> alloca $ \childrenPtrPtr -> alloca $ \nChildrenPtr -> do
    status <- withDisplay dispvar $ \disp -> xQueryTree disp window rootPtr parentPtr childrenPtrPtr nChildrenPtr
    case status of
      0 ->
        return 0
      _ -> do
        childrenPtr <- peek childrenPtrPtr
        when (childrenPtr /= nullPtr) $
          xFree childrenPtr >> return ()
        peek parentPtr
  midParent <- gets $ M.lookup window
  when (midParent /= Just parent) $
    withDisplay dispvar $ \disp -> removeIcon phi disp False window
  return ()

handleEvent _ _ _ _ _ = return ()


addIcon :: Phi -> Xlib.Display -> Atoms -> Window -> Window -> StateT (M.Map Window Window) IO ()
addIcon phi disp atoms panelWindow window = do
  removeIcon phi disp False window
  
  liftIO $ selectInput disp window $ structureNotifyMask .|. propertyChangeMask
  
  midParent <- liftIO $ createSimpleWindow disp panelWindow (-16) (-16) 16 16 0 0 0
  
  liftIO $ do
    setWindowBackgroundPixmap disp midParent 1 -- ParentRelative
    
    sync disp False
    setSystrayErrorHandler
    
    reparentWindow disp window midParent 0 0
    
    mapRaised disp midParent
    mapWindow disp window
    
    allocaXEvent $ \event -> do
      putClientMessage event window (atom_XEMBED atoms) [fromIntegral currentTime, fromIntegral xEMBED_EMBEDDED_NOTIFY, 0, fromIntegral midParent, 0]
      sendEvent disp window False 0xFFFFFF event
    
    sync disp False
    xSetErrorHandler
  
  errorWindow <- liftIO $ getLastErrorWindow
  case True of
    _ | errorWindow /= window -> do
      sendMessage phi $ AddIcon midParent window
      sendMessage phi Repaint
      modify $ M.insert window midParent
      | otherwise ->
      liftIO $ destroyWindow disp midParent


removeIcon :: Phi -> Xlib.Display -> Bool -> Window -> StateT (M.Map Window Window) IO ()
removeIcon phi disp reparent window = do
  mmidParent <- gets $ M.lookup window
  case mmidParent of
    Just midParent -> do
      sendMessage phi $ RemoveIcon window
      sendMessage phi Repaint
      liftIO $ do
        selectInput disp window $ noEventMask
        when reparent $
          reparentWindow disp window (defaultRootWindow disp) 0 0
        destroyWindow disp midParent
        sync disp False
      modify $ M.delete window
    _ ->
      return ()


systray :: Systray
systray = Systray