2 files changed, 70 insertions, 0 deletions
diff --git a/src/Rahm/Desktop/History.hs b/src/Rahm/Desktop/History.hs
new file mode 100644
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+++ b/src/Rahm/Desktop/History.hs
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+module Rahm.Desktop.History where
+
+import Data.IntMap (IntMap)
+import qualified Data.IntMap as IntMap
+import Data.Default
+
+import Rahm.Desktop.Hooks.WindowChange
+
+data History = History {
+    currentIndex :: Int
+  , history :: IntMap Location
+  }
+
+instance Default History where
+  def = History 0 IntMap.empty
+
+addToHistory :: Location -> History -> History
+addToHistory loc (History currentIndex hist) =
+  let hist' = if currentIndex > 100
+                then IntMap.delete (currentIndex - 100) hist
+                else hist
+    in History (currentIndex + 1 ) (IntMap.insert currentIndex loc hist)
+
+historyHook :: Location -> Location -> X ()
+historyHook = undefined
diff --git a/src/Rahm/Desktop/Hooks/WindowChange.hs b/src/Rahm/Desktop/Hooks/WindowChange.hs
new file mode 100644
index 0000000..0038f47
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+++ b/src/Rahm/Desktop/Hooks/WindowChange.hs
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+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 ()
+  }