[WIP] - Window change hooks

1 files changed, 45 insertions, 0 deletions

diff --git a/src/Rahm/Desktop/Hooks/WindowChange.hs b/src/Rahm/Desktop/Hooks/WindowChange.hs
new file mode 100644
index 0000000..0038f47
--- /dev/null
+++ b/src/Rahm/Desktop/Hooks/WindowChange.hs
@@ -0,0 +1,45 @@
+module Rahm.Desktop.Hooks.WindowChange where
+
+import XMonad
+import Control.Monad
+import qualified XMonad.Util.ExtensibleState as XS
+import Data.Default
+import Rahm.Desktop.Workspaces
+
+import qualified XMonad.StackSet as W
+
+data Location = Location WorkspaceId (Maybe Window)
+  deriving (Read, Show, Eq)
+
+newtype LastLocation = LastLocation (Maybe Location)
+  deriving (Read, Show)
+
+instance Default LastLocation where
+  def = LastLocation Nothing
+
+instance ExtensionClass LastLocation where
+  initialValue = def
+  extensionType = PersistentExtension
+
+-- Creates a log hook from the function provided.
+--
+-- The first argument to the function is the old window, the second argument in
+-- the new window.
+withLocationChangeHook :: (Location -> Location -> X ()) -> XConfig l -> XConfig l
+withLocationChangeHook fn config =
+  config {
+    logHook = do
+      logHook config
+
+      currentLocation <-
+        Location <$> getCurrentWorkspace <*> withWindowSet (return . W.peek)
+
+      LastLocation last <- XS.get
+
+      whenJust last $ \lastLocation ->
+        when (lastLocation /= currentLocation) $
+          fn lastLocation currentLocation
+
+      XS.put $ LastLocation $ Just currentLocation
+      return ()
+  }