    {-# LANGUAGE DeriveDataTypeable, PatternGuards, FlexibleInstances, MultiParamTypeClasses, CPP #-}
    -----------------------------------------------------------------------------
    -- |
    -- Module       : XMonad.Hooks.ManageDocks
    -- Copyright    : (c) Joachim Breitner <mail@joachim-breitner.de>
    -- License      : BSD
    --
    -- Maintainer   : Joachim Breitner <mail@joachim-breitner.de>
    -- Stability    : unstable
    -- Portability  : unportable
    --
    -- This module provides tools to automatically manage 'dock' type programs,
    -- such as gnome-panel, kicker, dzen, and xmobar.

    module XMonad.Hooks.ManageDocks (
        -- * Usage
        -- $usage
        manageDocks, checkDock, AvoidStruts, avoidStruts, avoidStrutsOn,
        docksEventHook,
        ToggleStruts(..),
        SetStruts(..),
        module XMonad.Util.Types,

    #ifdef TESTING
        r2c,
        c2r,
        RectC(..),
    #endif

        -- for XMonad.Actions.FloatSnap
        calcGap
        ) where

    -----------------------------------------------------------------------------
    import XMonad
    import Foreign.C.Types (CLong)
    import XMonad.Layout.LayoutModifier
    import XMonad.Util.Types
    import XMonad.Util.WindowProperties (getProp32s)
    import XMonad.Util.XUtils (fi)
    import Data.Monoid (All(..), mempty)

    import qualified Data.Set as S

    -- $usage
    -- To use this module, add the following import to @~\/.xmonad\/xmonad.hs@:
    --
    -- > import XMonad.Hooks.ManageDocks
    --
    -- The first component is a 'ManageHook' which recognizes these
    -- windows and de-manages them, so that xmonad does not try to tile
    -- them.  To enable it:
    --
    -- > manageHook = ... <+> manageDocks
    --
    -- The second component is a layout modifier that prevents windows
    -- from overlapping these dock windows.  It is intended to replace
    -- xmonad's so-called \"gap\" support.  First, you must add it to your
    -- list of layouts:
    --
    -- > layoutHook = avoidStruts (tall ||| mirror tall ||| ...)
    -- >                   where  tall = Tall 1 (3/100) (1/2)
    --
    -- The third component is an event hook that causes new docks to appear
    -- immediately, instead of waiting for the next focus change.
    --
    -- > handleEventHook = ... <+> docksEventHook
    --
    -- 'AvoidStruts' also supports toggling the dock gaps; add a keybinding
    -- similar to:
    --
    -- > ,((modm, xK_b     ), sendMessage ToggleStruts)
    --
    -- If you have multiple docks, you can toggle their gaps individually.
    -- For example, to toggle only the top gap:
    --
    -- > ,((modm .|. controlMask, xK_t), sendMessage $ ToggleStrut U)
    --
    -- Similarly, you can use 'D', 'L', and 'R' to individually toggle
    -- gaps on the bottom, left, or right.
    --
    -- If you want certain docks to be avoided but others to be covered by
    -- default, you can manually specify the sides of the screen on which
    -- docks should be avoided, using 'avoidStrutsOn'.  For example:
    --
    -- > layoutHook = avoidStrutsOn [U,L] (tall ||| mirror tall ||| ...)
    --
    -- /Important note/: if you are switching from manual gaps
    -- (defaultGaps in your config) to avoidStruts (recommended, since
    -- manual gaps will probably be phased out soon), be sure to switch
    -- off all your gaps (with mod-b) /before/ reloading your config with
    -- avoidStruts!  Toggling struts with a 'ToggleStruts' message will
    -- not work unless your gaps are set to zero.
    --
    -- For detailed instructions on editing your key bindings, see
    -- "XMonad.Doc.Extending#Editing_key_bindings".
    --

    -- | Detects if the given window is of type DOCK and if so, reveals
    --   it, but does not manage it.
    manageDocks :: ManageHook
    manageDocks = checkDock --> (doIgnore <+> clearGapCache)
        where clearGapCache = do
                liftX (broadcastMessage ClearGapCache)
                mempty

    -- | Checks if a window is a DOCK or DESKTOP window
    checkDock :: Query Bool
    checkDock = ask >>= \w -> liftX $ do
        dock <- getAtom "_NET_WM_WINDOW_TYPE_DOCK"
        desk <- getAtom "_NET_WM_WINDOW_TYPE_DESKTOP"
        mbr <- getProp32s "_NET_WM_WINDOW_TYPE" w
        case mbr of
            Just rs -> return $ any (`elem` [dock,desk]) (map fromIntegral rs)
            _       -> return False

    -- | Whenever a new dock appears, refresh the layout immediately to avoid the
    -- new dock.
    docksEventHook :: Event -> X All
    docksEventHook (MapNotifyEvent {ev_window = w}) = do
        whenX ((not `fmap` (isClient w)) <&&> runQuery checkDock w) $ do
            broadcastMessage ClearGapCache
            refresh
        return (All True)
    docksEventHook _ = return (All True)

    -- | Gets the STRUT config, if present, in xmonad gap order
    getStrut :: Window -> X [Strut]
    getStrut w = do
        msp <- getProp32s "_NET_WM_STRUT_PARTIAL" w
        case msp of
            Just sp -> return $ parseStrutPartial sp
            Nothing -> fmap (maybe [] parseStrut) $ getProp32s "_NET_WM_STRUT" w
     where
        parseStrut xs@[_, _, _, _] = parseStrutPartial . take 12 $ xs ++ cycle [minBound, maxBound]
        parseStrut _ = []

        parseStrutPartial [l, r, t, b, ly1, ly2, ry1, ry2, tx1, tx2, bx1, bx2]
         = filter (\(_, n, _, _) -> n /= 0)
            [(L, l, ly1, ly2), (R, r, ry1, ry2), (U, t, tx1, tx2), (D, b, bx1, bx2)]
        parseStrutPartial _ = []

    -- | Goes through the list of windows and find the gap so that all
    --   STRUT settings are satisfied.
    calcGap :: S.Set Direction2D -> X (Rectangle -> Rectangle)
    calcGap ss = withDisplay $ \dpy -> do
        rootw <- asks theRoot
        -- We don't keep track of dock like windows, so we find all of them here
        (_,_,wins) <- io $ queryTree dpy rootw
        struts <- (filter careAbout . concat) `fmap` mapM getStrut wins

        -- we grab the window attributes of the root window rather than checking
        -- the width of the screen because xlib caches this info and it tends to
        -- be incorrect after RAndR
        wa <- io $ getWindowAttributes dpy rootw
        let screen = r2c $ Rectangle (fi $ wa_x wa) (fi $ wa_y wa) (fi $ wa_width wa) (fi $ wa_height wa)
        return $ \r -> c2r $ foldr (reduce screen) (r2c r) struts
      where careAbout (s,_,_,_) = s `S.member` ss

    -- | Adjust layout automagically: don't cover up any docks, status
    --   bars, etc.
    avoidStruts :: LayoutClass l a => l a -> ModifiedLayout AvoidStruts l a
    avoidStruts = avoidStrutsOn [U,D,L,R]

    -- | Adjust layout automagically: don't cover up docks, status bars,
    --   etc. on the indicated sides of the screen.  Valid sides are U
    --   (top), D (bottom), R (right), or L (left).
    avoidStrutsOn :: LayoutClass l a =>
                     [Direction2D]
                  -> l a
                  -> ModifiedLayout AvoidStruts l a
    avoidStrutsOn ss = ModifiedLayout $ AvoidStruts (S.fromList ss) Nothing

    data AvoidStruts a = AvoidStruts {
        avoidStrutsDirection :: S.Set Direction2D,
        avoidStrutsRectCache :: Maybe (S.Set Direction2D, Rectangle, Rectangle )
    }  deriving ( Read, Show )

    -- | Message type which can be sent to an 'AvoidStruts' layout
    --   modifier to alter its behavior.
    data ToggleStruts = ToggleStruts
                      | ToggleStrut Direction2D
      deriving (Read,Show,Typeable)

    instance Message ToggleStruts

    -- | message sent to ensure that caching the gaps won't give a wrong result
    -- because a new dock has been added
    data ClearGapCache = ClearGapCache
      deriving (Read,Show,Typeable)
    instance Message ClearGapCache

    -- | SetStruts is a message constructor used to set or unset specific struts,
    -- regardless of whether or not the struts were originally set. Here are some
    -- example bindings:
    --
    -- Show all gaps:
    --
    -- >   ,((modm .|. shiftMask  ,xK_b),sendMessage $ SetStruts [minBound .. maxBound] [])
    --
    -- Hide all gaps:
    --
    -- >   ,((modm .|. controlMask,xK_b),sendMessage $ SetStruts [] [minBound .. maxBound])
    --
    -- Show only upper and left gaps:
    --
    -- >   ,((modm .|. controlMask .|. shiftMask,xK_b),sendMessage $ SetStruts [U,L] [minBound .. maxBound])
    --
    -- Hide the bottom keeping whatever the other values were:
    --
    -- >   ,((modm .|. controlMask .|. shiftMask,xK_g),sendMessage $ SetStruts [] [D])
    data SetStruts = SetStruts { addedStruts   :: [Direction2D]
                               , removedStruts :: [Direction2D] -- ^ These are removed from the currently set struts before 'addedStruts' are added.
                               }
      deriving (Read,Show,Typeable)

    instance Message SetStruts

    instance LayoutModifier AvoidStruts a where
        modifyLayoutWithUpdate as@(AvoidStruts ss cache) w r = do
            nr <- case cache of
                Just (ss', r', nr) | ss' == ss, r' == r -> return nr
                _ -> do
                    nr <- fmap ($ r) (calcGap ss)
                    setWorkarea nr
                    return nr
            arranged <- runLayout w nr
            let newCache = Just (ss, r, nr)
            return (arranged, if newCache == cache
                        then Nothing
                        else Just as{ avoidStrutsRectCache = newCache } )

        pureMess as@(AvoidStruts { avoidStrutsDirection = ss }) m
            | Just ToggleStruts    <- fromMessage m = Just $ as { avoidStrutsDirection = toggleAll ss }
            | Just (ToggleStrut s) <- fromMessage m = Just $ as { avoidStrutsDirection = toggleOne s ss }
            | Just (SetStruts n k) <- fromMessage m
            , let newSS = S.fromList n `S.union` (ss S.\\ S.fromList k)
            , newSS /= ss = Just $ as { avoidStrutsDirection = newSS }
            | Just ClearGapCache <- fromMessage m = Just $ as { avoidStrutsRectCache = Nothing }
            | otherwise = Nothing
          where toggleAll x | S.null x = S.fromList [minBound .. maxBound]
                            | otherwise = S.empty
                toggleOne x xs | x `S.member` xs = S.delete x xs
                               | otherwise   = x `S.insert` xs

    setWorkarea :: Rectangle -> X ()
    setWorkarea (Rectangle x y w h) = withDisplay $ \dpy -> do
        a <- getAtom "_NET_WORKAREA"
        c <- getAtom "CARDINAL"
        r <- asks theRoot
        io $ changeProperty32 dpy r a c propModeReplace [fi x, fi y, fi w, fi h]

    -- | (Direction, height\/width, initial pixel, final pixel).

    type Strut = (Direction2D, CLong, CLong, CLong)

    -- | (Initial x pixel, initial y pixel,
    --    final x pixel, final y pixel).

    newtype RectC = RectC (CLong, CLong, CLong, CLong) deriving (Eq,Show)

    -- | Invertible conversion.

    r2c :: Rectangle -> RectC
    r2c (Rectangle x y w h) = RectC (fi x, fi y, fi x + fi w - 1, fi y + fi h - 1)

    -- | Invertible conversion.

    c2r :: RectC -> Rectangle
    c2r (RectC (x1, y1, x2, y2)) = Rectangle (fi x1) (fi y1) (fi $ x2 - x1 + 1) (fi $ y2 - y1 + 1)

    reduce :: RectC -> Strut -> RectC -> RectC
    reduce (RectC (sx0, sy0, sx1, sy1)) (s, n, l, h) (RectC (x0, y0, x1, y1)) =
     RectC $ case s of
        L | p (y0, y1) && qh x1     -> (mx x0 sx0, y0       , x1       , y1       )
        R | p (y0, y1) && qv sx1 x0 -> (x0       , y0       , mn x1 sx1, y1       )
        U | p (x0, x1) && qh y1     -> (x0       , mx y0 sy0, x1       , y1       )
        D | p (x0, x1) && qv sy1 y0 -> (x0       , y0       , x1       , mn y1 sy1)
        _                           -> (x0       , y0       , x1       , y1       )
     where
        mx a b = max a (b + n)
        mn a b = min a (b - n)
        p r = r `overlaps` (l, h)
        -- Filter out struts that cover the entire rectangle:
        qh d1 = n <= d1
        qv sd1 d0 = sd1 - n >= d0

    -- | Do the two ranges overlap?
    --
    -- Precondition for every input range @(x, y)@: @x '<=' y@.
    --
    -- A range @(x, y)@ is assumed to include every pixel from @x@ to @y@.

    overlaps :: Ord a => (a, a) -> (a, a) -> Bool
    (a, b) `overlaps` (x, y) =
      inRange (a, b) x || inRange (a, b) y || inRange (x, y) a
      where
      inRange (i, j) k = i <= k && k <= j