{-# LINE 2 "./Graphics/UI/Gtk/General/General.chs" #-}
-- -*-haskell-*-
-- GIMP Toolkit (GTK) General
--
-- Author : Axel Simon, Manuel M. T. Chakravarty
--
-- Created: 8 December 1998
--
-- Copyright (C) 2000..2005 Axel Simon, Manuel M. T. Chakravarty
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public
-- License as published by the Free Software Foundation; either
-- version 2.1 of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- Lesser General Public License for more details.
--
-- |
-- Maintainer : gtk2hs-users@lists.sourceforge.net
-- Stability : provisional
-- Portability : portable (depends on GHC)
--
-- library initialization, main event loop, and events
--
module Graphics.UI.Gtk.General.General (
-- getDefaultLanguage,
  -- * Initialisation
  initGUI,

  -- ** Support for OS threads
  unsafeInitGUIForThreadedRTS,
  postGUISync,
  postGUIAsync,
  threadsEnter,
  threadsLeave,

  -- * Main event loop
  mainGUI,
  mainQuit,

  -- ** Less commonly used event loop functions
  eventsPending,
  mainLevel,
  mainIteration,
  mainIterationDo,
  mainDoEvent,

  -- ** Call when mainloop is left






  -- * Grab widgets
  grabAdd,
  grabGetCurrent,
  grabRemove,

  -- * Timeout and idle callbacks
  Priority,
  priorityLow,
  priorityDefaultIdle,
  priorityHighIdle,
  priorityDefault,
  priorityHigh,
  timeoutAdd,
  timeoutAddFull,
  timeoutRemove,
  idleAdd,
  idleRemove,
  inputAdd,
  inputRemove,
  IOCondition(..),
  HandlerId,
  FD
  ) where

import Control.Applicative
import Prelude
import System.Environment (getProgName, getArgs)
import Control.Monad (liftM, when)
import Control.Concurrent (rtsSupportsBoundThreads, newEmptyMVar,
                           putMVar, takeMVar)

import System.Glib.FFI
import System.Glib.UTFString
import qualified System.Glib.MainLoop as ML
import System.Glib.MainLoop ( Priority, priorityLow, priorityDefaultIdle,
  priorityHighIdle, priorityDefault, priorityHigh, timeoutRemove, idleRemove,
  inputRemove, IOCondition(..), HandlerId )
import Graphics.UI.Gtk.Abstract.Object (makeNewObject)
import Graphics.UI.Gtk.Gdk.EventM (EventM)
import Control.Monad.Reader (ask)
import Control.Monad.Trans (liftIO)
import Graphics.UI.Gtk.Types
{-# LINE 100 "./Graphics/UI/Gtk/General/General.chs" #-}


{-# LINE 102 "./Graphics/UI/Gtk/General/General.chs" #-}

{-
-- | Retreive the current language.
-- * This function returns a String which's pointer can be used later on for
-- comarisions.
--
--getDefaultLanguage :: GlibString string => IO string
--getDefaultLanguage = do
-- strPtr <- {#call unsafe get_default_language#}
-- str <- peekUTFString strPtr
-- destruct strPtr
-- return str
-}

unsafeInitGUIForThreadedRTS = initGUI

-- We compile this module using -#includ"gtk/wingtk.h" to bypass the win32 abi
-- check however we do not compile users programs with this header so if
-- initGUI was ever inlined in a users program, then that program would not
-- bypass the abi check and would fail on startup. So to stop that we must
-- prevent initGUI from being inlined.
{-# NOINLINE initGUI #-}
-- | Initialize the GUI.
--
-- This must be called before any other function in the Gtk2Hs library.
--
-- This function initializes the GUI toolkit and parses all Gtk
-- specific arguments. The remaining arguments are returned. If the
-- initialization of the toolkit fails for whatever reason, an exception
-- is thrown.
--
-- * Throws: @error \"Cannot initialize GUI.\"@
--
--
-- * If you want to use Gtk2Hs and in a multi-threaded application then it is your obligation
-- to ensure that all calls to Gtk+ happen in a single OS thread.
-- If you want to make calls to Gtk2Hs functions from a Haskell thread other
-- than the one that calls this functions and 'mainGUI' then you will have to
-- \'post\' your GUI actions to the main GUI thread. You can do this using
-- 'postGUISync' or 'postGUIAsync'. See also 'threadsEnter'.
--
initGUI :: IO [String]
initGUI = do
  initialise
  when rtsSupportsBoundThreads initialiseGThreads
  -- note: initizliseGThreads calls 'threadsEnter'
  prog <- getProgName
  args <- getArgs
  let allArgs = (prog:args)
  withMany withUTFString (map stringToGlib allArgs) $ \addrs ->
    withArrayLen addrs $ \argc argv ->
    with argv $ \argvp ->
    with argc $ \argcp -> do
      res <- gtk_init_check (castPtr argcp) (castPtr argvp)
      if (toBool res) then do
        argc'   <- peek argcp
        argv'   <- peek argvp
        _:addrs'  <- peekArray argc' argv'  -- drop the program name
        mapM ((glibToString <$>) . peekUTFString) addrs'
        else error "Cannot initialize GUI."

-- g_thread_init aborts the whole program if it's called more than once so
-- we've got to keep track of whether or not we've called it already. Sigh.
--
foreign import ccall "hsgthread.h gtk2hs_threads_initialise"
  initialiseGThreads :: IO ()

foreign import ccall "hsgthread.h gtk2hs_initialise"
  initialise :: IO ()

-- | Post an action to be run in the main GUI thread.
--
-- The current thread blocks until the action completes and the result is
-- returned.
--
postGUISync :: IO a -> IO a
postGUISync action = do
  resultVar <- newEmptyMVar
  idleAdd (action >>= putMVar resultVar >> return False) priorityDefault
  takeMVar resultVar

-- | Post an action to be run in the main GUI thread.
--
-- The current thread continues and does not wait for the result of the
-- action.
--
postGUIAsync :: IO () -> IO ()
postGUIAsync action = do
  idleAdd (action >> return False) priorityDefault
  return ()

-- | Acquire the global Gtk lock.
--
-- * During normal operation, this lock is held by the thread from which all
-- interaction with Gtk is performed. When calling 'mainGUI', the thread will
-- release this global lock before it waits for user interaction. During this
-- time it is, in principle, possible to use a different OS thread (any other
-- Haskell thread that is bound to the Gtk OS thread will be blocked anyway)
-- to interact with Gtk by explicitly acquiring the lock, calling Gtk functions
-- and releasing the lock. However, the Gtk functions that are called from this
-- different thread may not trigger any calls to the OS since this will
-- lead to a crash on Windows (the Win32 API can only be used from a single
-- thread). Since it is very hard to tell which function only interacts on
-- Gtk data structures and which function call actual OS functions, it
-- is best not to use this feature at all. A better way to perform updates
-- in the background is to spawn a Haskell thread and to perform the update
-- to Gtk widgets using 'postGUIAsync' or 'postGUISync'. These will execute
-- their arguments from the main loop, that is, from the OS thread of Gtk,
-- thereby ensuring that any Gtk and OS function can be called.
--
threadsEnter :: IO ()
threadsEnter =
  threadsEnter'_ >>= \res ->
  return ()
{-# LINE 213 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Release the global Gtk lock.
--
-- * The use of this function is not recommended. See 'threadsEnter'.
--
threadsLeave :: IO ()
threadsLeave =
  threadsLeave'_ >>= \res ->
  return ()
{-# LINE 219 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Inquire the number of events pending on the event queue
--
eventsPending :: IO Int
eventsPending = liftM fromIntegral gtk_events_pending
{-# LINE 224 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Run the Gtk+ main event loop.
--
mainGUI :: IO ()
mainGUI = gtk_main
{-# LINE 229 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Inquire the main loop level.
--
-- * Callbacks that take more time to process can call 'mainIteration' to keep
-- the GUI responsive. Each time the main loop is restarted this way, the main
-- loop counter is increased. This function returns this counter.
--
mainLevel :: IO Int
mainLevel = liftM (toEnum.fromEnum) gtk_main_level
{-# LINE 238 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Exit the main event loop.
--
mainQuit :: IO ()
mainQuit = gtk_main_quit
{-# LINE 243 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Process an event, block if necessary.
--
-- * Returns @True@ if 'mainQuit' was called while processing the event.
--
mainIteration :: IO Bool
mainIteration = liftM toBool gtk_main_iteration
{-# LINE 250 "./Graphics/UI/Gtk/General/General.chs" #-}

-- | Process a single event.
--
-- * Called with @True@, this function behaves as 'mainIteration' in that it
-- waits until an event is available for processing. It will return
-- immediately, if passed @False@.
--
-- * Returns @True@ if the 'mainQuit' was called while processing the event.
--
mainIterationDo :: Bool -> IO Bool
mainIterationDo blocking =
  liftM toBool $ gtk_main_iteration_do (fromBool blocking)

-- | Processes a single GDK event. This is public only to allow filtering of events between GDK and
-- GTK+. You will not usually need to call this function directly.
--
-- While you should not call this function directly, you might want to know how exactly events are
-- handled. So here is what this function does with the event:
--
-- 1. Compress enter\/leave notify events. If the event passed build an enter\/leave pair together with
-- the next event (peeked from GDK) both events are thrown away. This is to avoid a backlog of
-- (de-)highlighting widgets crossed by the pointer.
--
-- 2. Find the widget which got the event. If the widget can't be determined the event is thrown away
-- unless it belongs to a INCR transaction. In that case it is passed to
-- 'selectionIncrEvent'.
--
-- 3. Then the event is passed on a stack so you can query the currently handled event with
-- 'getCurrentEvent'.
--
-- 4. The event is sent to a widget. If a grab is active all events for widgets that are not in the
-- contained in the grab widget are sent to the latter with a few exceptions:
--
-- * Deletion and destruction events are still sent to the event widget for obvious reasons.
--
-- * Events which directly relate to the visual representation of the event widget.
--
-- * Leave events are delivered to the event widget if there was an enter event delivered to it
-- before without the paired leave event.
--
-- * Drag events are not redirected because it is unclear what the semantics of that would be.
--
-- Another point of interest might be that all key events are first passed through the key snooper
-- functions if there are any. Read the description of 'keySnooperInstall' if you need this
-- feature.
--
-- 5. After finishing the delivery the event is popped from the event stack.
mainDoEvent :: EventM t ()
mainDoEvent = do
  ptr <- ask
  liftIO $ gtk_main_do_event (castPtr ptr)
{-# LINE 344 "./Graphics/UI/Gtk/General/General.chs" #-}
-- | add a grab widget
--
grabAdd :: WidgetClass wd => wd -> IO ()
grabAdd = (\(Widget arg1) -> withForeignPtr arg1 $ \argPtr1 ->gtk_grab_add argPtr1) . toWidget

-- | inquire current grab widget
--
grabGetCurrent :: IO (Maybe Widget)
grabGetCurrent = do
  wPtr <- gtk_grab_get_current
{-# LINE 354 "./Graphics/UI/Gtk/General/General.chs" #-}
  if (wPtr==nullPtr) then return Nothing else
    liftM Just $ makeNewObject mkWidget (return wPtr)

-- | remove a grab widget
--
grabRemove :: WidgetClass w => w -> IO ()
grabRemove = (\(Widget arg1) -> withForeignPtr arg1 $ \argPtr1 ->gtk_grab_remove argPtr1) . toWidget

-- | Sets a function to be called at regular intervals, with the default
-- priority 'priorityDefault'. The function is called repeatedly until it
-- returns @False@, after which point the timeout function will not be called
-- again. The first call to the function will be at the end of the first interval.
--
-- Note that timeout functions may be delayed, due to the processing of other
-- event sources. Thus they should not be relied on for precise timing. After
-- each call to the timeout function, the time of the next timeout is
-- recalculated based on the current time and the given interval (it does not
-- try to 'catch up' time lost in delays).
--
-- This function differs from 'ML.timeoutAdd' in that the action will
-- be executed within the global Gtk+ lock. It is therefore possible to
-- call Gtk+ functions from the action.
--
timeoutAdd :: IO Bool -> Int -> IO HandlerId
timeoutAdd fun msec = timeoutAddFull fun priorityDefault msec

-- | Sets a function to be called at regular intervals, with the given
-- priority. The function is called repeatedly until it returns @False@, after
-- which point the timeout function will not be called again. The first call
-- to the function will be at the end of the first interval.
--
-- Note that timeout functions may be delayed, due to the processing of other
-- event sources. Thus they should not be relied on for precise timing. After
-- each call to the timeout function, the time of the next timeout is
-- recalculated based on the current time and the given interval (it does not
-- try to 'catch up' time lost in delays).
--
-- This function differs from 'ML.timeoutAddFull' in that the action will
-- be executed within the global Gtk+ lock. It is therefore possible to
-- call Gtk+ functions from the action.
--
timeoutAddFull :: IO Bool -> Priority -> Int -> IO HandlerId
timeoutAddFull fun pri msec =
  ML.timeoutAddFull (threadsEnter >> fun >>= \r -> threadsLeave >> return r)
                    pri msec

-- | Add a callback that is called whenever the system is idle.
--
-- * A priority can be specified via an integer. This should usually be
-- 'priorityDefaultIdle'.
--
-- * If the function returns @False@ it will be removed.
--
-- This function differs from 'ML.idleAdd' in that the action will
-- be executed within the global Gtk+ lock. It is therefore possible to
-- call Gtk+ functions from the action.
--
idleAdd :: IO Bool -> Priority -> IO HandlerId
idleAdd fun pri =
  ML.idleAdd (threadsEnter >> fun >>= \r -> threadsLeave >> return r) pri

type FD = Int

-- | Adds the file descriptor into the main event loop with the given priority.
--
-- This function differs from 'ML.inputAdd' in that the action will
-- be executed within the global Gtk+ lock. It is therefore possible to
-- call Gtk+ functions from the action.
--
inputAdd ::
    FD -- ^ a file descriptor
 -> [IOCondition] -- ^ the condition to watch for
 -> Priority -- ^ the priority of the event source
 -> IO Bool -- ^ the function to call when the condition is satisfied.
                  -- The function should return False if the event source
                  -- should be removed.
 -> IO HandlerId -- ^ the event source id
inputAdd fd conds pri fun =
  ML.inputAdd fd conds pri (threadsEnter >> fun >>= \r -> threadsLeave >> return r)

foreign import ccall unsafe "gtk_init_check"
  gtk_init_check :: ((Ptr CInt) -> ((Ptr (Ptr (Ptr CChar))) -> (IO CInt)))

foreign import ccall safe "gdk_threads_enter"
  threadsEnter'_ :: (IO ())

foreign import ccall unsafe "gdk_threads_leave"
  threadsLeave'_ :: (IO ())

foreign import ccall safe "gtk_events_pending"
  gtk_events_pending :: (IO CInt)

foreign import ccall safe "gtk_main"
  gtk_main :: (IO ())

foreign import ccall unsafe "gtk_main_level"
  gtk_main_level :: (IO CUInt)

foreign import ccall safe "gtk_main_quit"
  gtk_main_quit :: (IO ())

foreign import ccall safe "gtk_main_iteration"
  gtk_main_iteration :: (IO CInt)

foreign import ccall safe "gtk_main_iteration_do"
  gtk_main_iteration_do :: (CInt -> (IO CInt))

foreign import ccall safe "gtk_main_do_event"
  gtk_main_do_event :: ((Ptr ()) -> (IO ()))

foreign import ccall safe "gtk_grab_add"
  gtk_grab_add :: ((Ptr Widget) -> (IO ()))

foreign import ccall safe "gtk_grab_get_current"
  gtk_grab_get_current :: (IO (Ptr Widget))

foreign import ccall safe "gtk_grab_remove"
  gtk_grab_remove :: ((Ptr Widget) -> (IO ()))