From 20a68552c1e35467cb9dc70be0c3d2fe0734066e Mon Sep 17 00:00:00 2001
From: Leon Kowarschick <5300871+elkowar@users.noreply.github.com>
Date: Mon, 6 Jul 2020 13:45:59 +0200
Subject: [PATCH] Fix window swallowing problems in xmonad

---
 files/.xmonad/lib/Config.hs           |  4 +--
 files/.xmonad/lib/WindowSwallowing.hs | 48 +++++++++++++++++++--------
 2 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/files/.xmonad/lib/Config.hs b/files/.xmonad/lib/Config.hs
index 3680931..48356d6 100644
--- a/files/.xmonad/lib/Config.hs
+++ b/files/.xmonad/lib/Config.hs
@@ -23,9 +23,9 @@ import qualified XMonad.Util.ExtensibleState as XS
 import qualified Rofi
 import qualified DescribedSubmap
 import qualified TiledDragging
---import qualified WindowSwallowing
+import qualified WindowSwallowing
 
-import XMonad.Hooks.WindowSwallowing as WindowSwallowing
+--import XMonad.Hooks.WindowSwallowing as WindowSwallowing
 
 
 import Data.Foldable                  ( for_ )
diff --git a/files/.xmonad/lib/WindowSwallowing.hs b/files/.xmonad/lib/WindowSwallowing.hs
index 7035fca..31b98af 100644
--- a/files/.xmonad/lib/WindowSwallowing.hs
+++ b/files/.xmonad/lib/WindowSwallowing.hs
@@ -44,11 +44,14 @@ where
 import           XMonad
 import qualified XMonad.StackSet               as W
 import qualified XMonad.Util.ExtensibleState   as XS
-import           XMonad.Util.Run                ( runProcessWithInput )
+import           XMonad.Util.Run                ( runProcessWithInput
+                                                , safeSpawn
+                                                )
 import           XMonad.Util.WindowProperties
 import           Data.Semigroup                 ( All(..) )
 import qualified Data.Map.Strict               as M
 import           Data.List                      ( isInfixOf )
+import           Data.Maybe                     ( fromMaybe )
 import           Control.Monad                  ( when )
 
 -- $usage
@@ -58,7 +61,7 @@ import           Control.Monad                  ( when )
 --
 -- and using 'swallowEventHook' somewhere in your 'handleEventHook', for example:
 --
--- > myHandleEventHook = swallowEventHook [className =? "Alacritty", className =? "Termite"] [return True]
+-- > myHandleEventHook = swallowEventHook (className =? "Alacritty" <||> className =? "Termite") (return True)
 --
 -- For more information on editing your handleEventHook and key bindings,
 -- see "XMonad.Doc.Extending".
@@ -117,6 +120,7 @@ swallowEventHook parentQueries childQueries event = do
       XS.modify . setStackBeforeWindowClosing . currentStack $ ws
       XS.modify . setFloatingBeforeWindowClosing . W.floating $ ws
 
+
     -- This is called right after any window closes.
     DestroyWindowEvent { ev_event = eventId, ev_window = childWindow } ->
       -- Because DestroyWindowEvent is emitted a lot more often then you think,
@@ -130,17 +134,33 @@ swallowEventHook parentQueries childQueries event = do
         case (maybeSwallowedParent, maybeOldStack) of
           (Just parent, Just oldStack) -> do
             -- If there actually is a corresponding swallowed parent window for this window,
-            -- we will restore and place it where the closed window was.
-            -- For this, we look at the stack-state that was stored /before/ the window was closed,
-            -- and replace the focused window with the now restored parent.
-            -- we do this to make sure the parent is restored in the exact position the child was at.
-            windows
-              (\ws ->
-                updateCurrentStack
-                    (const $ Just $ oldStack { W.focus = parent })
-                  $ moveFloatingState childWindow parent
-                  $ ws { W.floating = oldFloating }
-              )
+            -- we will try to restore it.
+            -- because there are some cases where the stack-state is not stored correctly in the ConfigureEvent hook,
+            -- we have to first check if the stack-state is valid.
+            -- if it is, we can restore the parent exactly where the child window was before being closed
+            -- if the stored stack-state is invalid however, we still restore the window
+            -- by just inserting it as the focused window in the stack.
+            stackStoredCorrectly <- do
+              curStack <- withWindowSet (return . currentStack)
+              let oldLen = length (W.integrate oldStack)
+              let curLen = length (W.integrate' curStack)
+              return (oldLen - 1 == curLen && childWindow == W.focus oldStack)
+
+            if stackStoredCorrectly
+              then windows
+                (\ws ->
+                  updateCurrentStack
+                      (const $ Just $ oldStack { W.focus = parent })
+                    $ moveFloatingState childWindow parent
+                    $ ws { W.floating = oldFloating }
+                )
+              else windows
+                (W.modify
+                  (Just $ W.Stack parent [] [])
+                  (\s -> Just
+                    $ s { W.focus = parent, W.down = W.focus s : W.down s }
+                  )
+                )
             -- after restoring, we remove the information about the swallowing from the state.
             XS.modify $ removeSwallowed childWindow
             XS.modify $ setStackBeforeWindowClosing Nothing
@@ -149,7 +169,6 @@ swallowEventHook parentQueries childQueries event = do
     _ -> return ()
   return $ All True
 
-
 -- | run a pure transformation on the Stack of the currently focused workspace.
 updateCurrentStack
   :: (Maybe (W.Stack a) -> Maybe (W.Stack a))
@@ -223,3 +242,4 @@ instance ExtensionClass SwallowingState where
 fi :: (Integral a, Num b) => a -> b
 fi = fromIntegral
 
+