From 4b31294bb1aece30ef461175f311c462b6df55b5 Mon Sep 17 00:00:00 2001
From: Yecine Megdiche <yecine.megdiche@gmail.com>
Date: Sun, 2 Apr 2023 15:30:25 +0200
Subject: [PATCH] X.H.StickyWindows: WIP

---
 XMonad/Util/StickyWindows.hs | 84 ++++++++++++++++++++++++++++++++++++
 xmonad-contrib.cabal         |  1 +
 2 files changed, 85 insertions(+)
 create mode 100644 XMonad/Util/StickyWindows.hs

diff --git a/XMonad/Util/StickyWindows.hs b/XMonad/Util/StickyWindows.hs
new file mode 100644
index 0000000000..476dd4ac75
--- /dev/null
+++ b/XMonad/Util/StickyWindows.hs
@@ -0,0 +1,84 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonad.Util.StickyWindows
+-- Description :  TODO
+-- Copyright   :  (c) Yecine Megdiche <yecine.megdiche@gmail.com>
+-- License     :  BSD3-style (see LICENSE)
+--
+-- Maintainer  :  Yecine Megdiche <yecine.megdiche@gmail.com>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- TODO
+--
+-----------------------------------------------------------------------------
+module XMonad.Util.StickyWindows (
+  sticky,
+  stick,
+  unstick
+  ) where
+
+import qualified Data.Map                      as M
+import qualified Data.Set                      as S
+import           XMonad
+import           XMonad.Prelude
+import qualified XMonad.StackSet               as W
+import qualified XMonad.Util.ExtensibleState   as XS
+
+data StickyState = SS
+  { lastWs   :: WorkspaceId
+  , stickies :: M.Map ScreenId (S.Set Window)
+  }
+  deriving (Show, Read)
+
+instance ExtensionClass StickyState where
+  initialValue  = SS mempty M.empty
+  extensionType = PersistentExtension
+
+modifySticky
+  :: (S.Set Window -> S.Set Window) -> ScreenId -> StickyState -> StickyState
+modifySticky f sid (SS ws ss) =
+  SS ws $ M.alter (Just . f . fromMaybe S.empty) sid ss
+
+modifyStickyM :: (S.Set Window -> S.Set Window) -> ScreenId -> X ()
+modifyStickyM f sid = XS.modify (modifySticky f sid)
+
+stick' :: Window -> ScreenId -> X ()
+stick' = modifyStickyM . S.insert
+
+unstick' :: Window -> ScreenId -> X ()
+unstick' = modifyStickyM . S.delete
+
+unstick :: Window -> X ()
+unstick w = unstick' w =<< currentScreen
+
+stick :: Window -> X ()
+stick w = stick' w =<< currentScreen
+
+currentScreen :: X ScreenId
+currentScreen = gets $ W.screen . W.current . windowset
+
+sticky :: XConfig l -> XConfig l
+sticky xconf = xconf
+  { logHook         = logHook xconf >> stickyLogHook
+  , handleEventHook = handleEventHook xconf <> stickyEventHook
+  }
+
+stickyLogHook :: X ()
+stickyLogHook = do
+  ws <- gets $ W.current . windowset
+  let sid   = W.screen ws
+      wsTag = W.tag . W.workspace $ ws
+  lastWS_ <- XS.gets lastWs
+  unless (wsTag == lastWS_)
+    $   XS.gets (M.lookup sid . stickies)
+    >>= maybe mempty (moveWindows wsTag)
+    >>  XS.modify (\(SS _ ws') -> SS wsTag ws')
+
+moveWindows :: WorkspaceId -> S.Set Window -> X ()
+moveWindows wsTag = traverse_ (\w -> windows $ W.focusDown . W.shiftWin wsTag w )
+
+stickyEventHook :: Event -> X All
+stickyEventHook DestroyWindowEvent { ev_window = w } =
+  XS.modify (\(SS ws ss) -> SS ws (M.map (S.delete w) ss)) $> All True
+stickyEventHook _ = return (All True)
diff --git a/xmonad-contrib.cabal b/xmonad-contrib.cabal
index eb1d007035..c44ce15f31 100644
--- a/xmonad-contrib.cabal
+++ b/xmonad-contrib.cabal
@@ -400,6 +400,7 @@ library
                         XMonad.Util.SpawnNamedPipe
                         XMonad.Util.SpawnOnce
                         XMonad.Util.Stack
+                        XMonad.Util.StickyWindows
                         XMonad.Util.StringProp
                         XMonad.Util.Themes
                         XMonad.Util.Timer