vanadium/xmonad: use event handling to set master pane count

nix/configurations/vanadium/home/xmonad/xmonad.hs

@@ -16,7 +16,6 @@ import XMonad.Hooks.OnPropertyChange
 import XMonad.Hooks.RefocusLast
 import XMonad.Hooks.StatusBar
 import XMonad.Layout.FocusTracking
-import XMonad.Layout.IfMax
 import XMonad.Layout.Magnifier hiding (Toggle)
 import qualified XMonad.Layout.Magnifier as Mag
 import XMonad.Layout.NoBorders
@@ -24,6 +23,7 @@ import XMonad.Layout.Reflect
 import XMonad.Layout.Reflect.Message
 import XMonad.Layout.Renamed
 import XMonad.Layout.ResizableTile
+import XMonad.Layout.SetMasterNTall
 import XMonad.Layout.Spacing
 import XMonad.Layout.ToggleLayouts
 import qualified XMonad.StackSet as W
@@ -71,23 +71,16 @@ main =
 myLayout =
     avoidStruts
   $ smartBorders
-  $ toggleLayouts (mag tallr) full
+  $ toggleLayouts (magnifierOff tallr) full
   where
-    mag = magnifierOff
-
     full = focusTracking Full
 
-    mkTallrN n =
-      smartSpacingWithEdge 5
-      $ reflectMsg . reflectHoriz
-      $ ResizableTall n (1/10) (3/7) []
-
     tallr =
       renamed [ Replace "Tall" ]
-      $ ifMax 3 (mkTallrN 1)
-      $ ifMax 5 (mkTallrN 2)
-      $ ifMax 7 (mkTallrN 3)
-      $ mkTallrN 4
+      $ smartSpacingWithEdge 5
+      $ reflectMsg . reflectHoriz
+      $ SetMasterNTall
+      $ ResizableTall 1 (1/10) (3/7) []
 
 isSioyek :: Query Bool
 isSioyek = className =? "sioyek"
@@ -202,14 +195,33 @@ myEventHandleHook =
   -- Imagine Spotify playing in the background, a track change would focus that workspace.
   -- We prevent this by checking if the window is in the current workspace
   onTitleChange
-    $ (windowIsInCurrentWorkspace -->)
-    $ composeAll
-    [ isSpotify  --> doShiftAndGreedyView multimediaWS
-    , isYouTube  --> doShiftAndGreedyView multimediaWS
-    , isDiscord  --> doShiftAndGreedyView chatWS
-    , isWhatsApp --> doShiftAndGreedyView chatWS
-    , isElement  --> doShiftAndGreedyView chatWS
-    ]
+    ( windowIsInCurrentWorkspace --> composeAll
+        [ isSpotify  --> doShiftAndGreedyView multimediaWS
+        , isYouTube  --> doShiftAndGreedyView multimediaWS
+        , isDiscord  --> doShiftAndGreedyView chatWS
+        , isWhatsApp --> doShiftAndGreedyView chatWS
+        , isElement  --> doShiftAndGreedyView chatWS
+        ]
+    )
+  <> setMasterNEventHandleHook
+
+setMasterNEventHandleHook :: Event -> X All
+setMasterNEventHandleHook ev =
+  let adjustMasterCount :: X ()
+      adjustMasterCount = do
+          count <- gets $ length . W.integrate' . W.stack . W.workspace . W.current . windowset
+          if count <= 3 then sendMessage (SetMasterN 1)
+          else if count <= 5 then sendMessage (SetMasterN 2)
+          else if count <= 7 then sendMessage (SetMasterN 3)
+          else pure ()
+  in  do
+    case ev of
+      MapRequestEvent{} -> adjustMasterCount
+      ConfigureEvent{} -> adjustMasterCount
+      DestroyWindowEvent {} -> adjustMasterCount
+      _ -> pure ()
+
+    pure (All True)
 
 doShiftAndGreedyView :: WorkspaceId -> Query (Endo WindowSet)
 doShiftAndGreedyView n = doF . go =<< ask