    {-# LANGUAGE PatternGuards #-}
    -----------------------------------------------------------------------------
    -- |
    -- Module      :  XMonad.Actions.CopyWindow
    -- Copyright   :  (c) David Roundy <droundy@darcs.net>, Ivan Veselov <veselov@gmail.com>, Lanny Ripple <lan3ny@gmail.com>
    -- License     :  BSD3-style (see LICENSE)
    --
    -- Maintainer  :  ???
    -- Stability   :  unstable
    -- Portability :  unportable
    --
    -- Provides bindings to duplicate a window on multiple workspaces,
    -- providing dwm-like tagging functionality.
    --
    -----------------------------------------------------------------------------

    module XMonad.Actions.CopyWindow (
                                     -- * Usage
                                     -- $usage
                                     copy, copyToAll, copyWindow, runOrCopy
                                     , killAllOtherCopies, kill1
                                     -- * Highlight workspaces containing copies in logHook
                                     -- $logHook
                                     , wsContainingCopies
                                    ) where

    import XMonad
    import Control.Arrow ((&&&))
    import qualified Data.List as L

    import XMonad.Actions.WindowGo
    import qualified XMonad.StackSet as W

    -- $usage
    --
    -- You can use this module with the following in your @~\/.xmonad\/xmonad.hs@ file:
    --
    -- > import XMonad.Actions.CopyWindow
    --
    -- Then add something like this to your keybindings:
    --
    -- > -- mod-[1..9] @@ Switch to workspace N
    -- > -- mod-shift-[1..9] @@ Move client to workspace N
    -- > -- mod-control-shift-[1..9] @@ Copy client to workspace N
    -- > [((m .|. modm, k), windows $ f i)
    -- >     | (i, k) <- zip (workspaces x) [xK_1 ..]
    -- >     , (f, m) <- [(W.view, 0), (W.shift, shiftMask), (copy, shiftMask .|. controlMask)]]
    --
    -- To use the above key bindings you need also to import
    -- "XMonad.StackSet":
    --
    -- > import qualified XMonad.StackSet as W
    --
    -- You may also wish to redefine the binding to kill a window so it only
    -- removes it from the current workspace, if it's present elsewhere:
    --
    -- >  , ((modm .|. shiftMask, xK_c     ), kill1) -- @@ Close the focused window
    --
    -- Instead of copying a window from one workspace to another maybe you don't
    -- want to have to remember where you placed it.  For that consider:
    --
    -- >  , ((modm, xK_b    ), runOrCopy "firefox" (className =? "Firefox")) -- @@ run or copy firefox
    --
    -- Another possibility which this extension provides is 'making window
    -- always visible' (i.e. always on current workspace), similar to corresponding
    -- metacity functionality. This behaviour is emulated through copying given
    -- window to all the workspaces and then removing it when it's unneeded on
    -- all workspaces any more.
    --
    -- Here is the example of keybindings which provide these actions:
    --
    -- >  , ((modm, xK_v ), windows copyToAll) -- @@ Make focused window always visible
    -- >  , ((modm .|. shiftMask, xK_v ),  killAllOtherCopies) -- @@ Toggle window state back
    --
    -- For detailed instructions on editing your key bindings, see
    -- "XMonad.Doc.Extending#Editing_key_bindings".

    -- $logHook
    -- To distinguish workspaces containing copies of the focused window use
    -- something like:
    --
    -- > sampleLogHook h = do
    -- >    copies <- wsContainingCopies
    -- >    let check ws | ws `elem` copies = pad . xmobarColor "red" "black" $ ws
    -- >                 | otherwise = pad ws
    -- >    dynamicLogWithPP myPP {ppHidden = check, ppOutput = hPutStrLn h}
    -- >
    -- > main = do
    -- >    h <- spawnPipe "xmobar"
    -- >    xmonad defaultConfig { logHook = sampleLogHook h }

    -- | Copy the focused window to a workspace.
    copy :: (Eq s, Eq i, Eq a) => i -> W.StackSet i l a s sd -> W.StackSet i l a s sd
    copy n s | Just w <- W.peek s = copyWindow w n s
             | otherwise = s

    -- | Copy the focused window to all workspaces.
    copyToAll :: (Eq s, Eq i, Eq a) => W.StackSet i l a s sd -> W.StackSet i l a s sd
    copyToAll s = foldr copy s $ map W.tag (W.workspaces s)

    -- | Copy an arbitrary window to a workspace.
    copyWindow :: (Eq a, Eq i, Eq s) => a -> i -> W.StackSet i l a s sd -> W.StackSet i l a s sd
    copyWindow w n = copy'
        where copy' s = if n `W.tagMember` s
                        then W.view (W.currentTag s) $ insertUp' w $ W.view n s
                        else s
              insertUp' a s = W.modify (Just $ W.Stack a [] [])
                              (\(W.Stack t l r) -> if a `elem` t:l++r
                                                 then Just $ W.Stack t l r
                                                 else Just $ W.Stack a (L.delete a l) (L.delete a (t:r))) s

    -- | runOrCopy will run the provided shell command unless it can
    --  find a specified window in which case it will copy the window to
    --  the current workspace.  Similar to (i.e., stolen from) "XMonad.Actions.WindowGo".
    runOrCopy :: String -> Query Bool -> X ()
    runOrCopy = copyMaybe . spawn

    -- | Copy a window if it exists, run the first argument otherwise.
    copyMaybe :: X () -> Query Bool -> X ()
    copyMaybe f qry = ifWindow qry copyWin f
        where copyWin = ask >>= \w -> doF (\ws -> copyWindow w (W.currentTag ws) ws)

    -- | Remove the focused window from this workspace.  If it's present in no
    -- other workspace, then kill it instead. If we do kill it, we'll get a
    -- delete notify back from X.
    --
    -- There are two ways to delete a window. Either just kill it, or if it
    -- supports the delete protocol, send a delete event (e.g. firefox).
    kill1 :: X ()
    kill1 = do ss <- gets windowset
               whenJust (W.peek ss) $ \w -> if W.member w $ delete'' w ss
                                          then windows $ delete'' w
                                          else kill
        where delete'' w = W.modify Nothing (W.filter (/= w))

    -- | Kill all other copies of focused window (if they're present).
    -- 'All other' means here 'copies which are not on the current workspace'.
    killAllOtherCopies :: X ()
    killAllOtherCopies = do ss <- gets windowset
                            whenJust (W.peek ss) $ \w -> windows $
                                                       W.view (W.currentTag ss) .
                                                       delFromAllButCurrent w
        where
          delFromAllButCurrent w ss = foldr ($) ss $
                                      map (delWinFromWorkspace w . W.tag) $
                                      W.hidden ss ++ map W.workspace (W.visible ss)
          delWinFromWorkspace w wid = viewing wid $ W.modify Nothing (W.filter (/= w))

          viewing wis f ss = W.view (W.currentTag ss) $ f $ W.view wis ss

    -- | A list of hidden workspaces containing a copy of the focused window.
    wsContainingCopies :: X [WorkspaceId]
    wsContainingCopies = do
        ws <- gets windowset
        return $ copiesOfOn (W.peek ws) (taggedWindows $ W.hidden ws)

    -- | Get a list of tuples (tag, [Window]) for each workspace.
    taggedWindows :: [W.Workspace i l a] -> [(i, [a])]
    taggedWindows = map $ W.tag &&& W.integrate' . W.stack

    -- | Get tags with copies of the focused window (if present.)
    copiesOfOn :: (Eq a) => Maybe a -> [(i, [a])] -> [i]
    copiesOfOn foc tw = maybe [] hasCopyOf foc
      where hasCopyOf f = map fst $ filter ((f `elem` ) . snd) tw