WIP add bluetooth indicator to xmobar

bin/xmobar.hs

@@ -1,3 +1,4 @@
+import Xmobar.Plugins.Bluetooth
 import Xmobar.Plugins.IntelBacklight
 import Xmobar.Plugins.Screensaver
 
@@ -26,6 +27,7 @@ myTemplate = formatTemplate left right
             , "%alsa:default:Master%"
             , "%battery%"
             , "%intelbacklight%"
+            , "%bluetooth%"
             , "%screensaver%"
             , "%locks%"
             , "%date%"
@@ -121,6 +123,8 @@ config confDir = defaultConfig
 
       , Run $ Screensaver ("<fn=1>\xf254</fn>", T.fgColor, T.backdropFgColor)
 
+      , Run $ Bluetooth ("BT", T.fgColor, T.backdropFgColor)
+
       , Run UnsafeStdinReader
       ]
   }

lib/Xmobar/Plugins/Bluetooth.hs

@@ -0,0 +1,49 @@
+{-# LANGUAGE LambdaCase        #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Xmobar.Plugins.Bluetooth where
+
+import Control.Concurrent
+import Control.Monad
+
+import Data.List  (find)
+import Data.Maybe (mapMaybe)
+
+import DBus
+import DBus.Client
+
+import Xmobar
+
+newtype Bluetooth = Bluetooth (String, String, String) deriving (Read, Show)
+
+rule :: MatchRule
+rule = matchAny
+  { matchPath = Just "/org/bluez/hci0"
+  , matchInterface = Just "org.freedesktop.DBus.Properties"
+  , matchMember = Just "PropertiesChanged"
+  }
+
+instance Exec Bluetooth where
+  alias (Bluetooth _) = "bluetooth"
+  start (Bluetooth (text, colorOn, colorOff)) cb = do
+    client <- connectSystem
+    _ <- addMatch client rule $ cb . fmtState . stateFromSignal
+    -- TODO initialize here
+    -- cb . formatBrightness =<< callGetBrightness
+    forever (threadDelay 5000)
+    where
+      -- TODO this is total utter garbage...but it works...
+      stateFromSignal sig = join
+          $ fmap (fromVariant :: (Variant -> Maybe Bool))
+          $ join
+          $ fmap (fromVariant :: (Variant -> Maybe Variant))
+          $ fmap snd
+          $ find (\(k, _) -> (fromVariant k :: Maybe String) == Just "Powered")
+          $ concatMap dictionaryItems
+          $ mapMaybe fromVariant
+          $ filter (\v -> variantType v == TypeDictionary TypeString TypeVariant)
+          $ signalBody sig
+      fmtState = \case
+        Just s -> wrapColor text $ if s then colorOn else colorOff
+        Nothing -> "N/A"
+      wrapColor s c = "<fc=" ++ c ++ ">" ++ s ++ "</fc>"

my-xmonad.cabal

@@ -14,8 +14,9 @@ library
                    , DBus.IntelBacklight
                    , DBus.Internal
                    , DBus.Screensaver
-                   , Xmobar.Plugins.Screensaver
+                   , Xmobar.Plugins.Bluetooth
                    , Xmobar.Plugins.IntelBacklight
+                   , Xmobar.Plugins.Screensaver
     build-depends: base
                  , X11 >= 1.9.1
                  , colour >= 2.3.5