refactor: introduce ADT for battery state

1 files changed, 30 insertions, 8 deletions

diff --git a/app/Sensor.hs b/app/Sensor.hs
index a9acf15..8c984f8 100644
--- a/app/Sensor.hs
+++ b/app/Sensor.hs
@@ -195,7 +195,13 @@ mem = diagram 3 memStat
 
 data BatStat = BatStat deriving (Show)
 
-instance (S.MonadSensor m) => S.Aggregate m BatStat (Float, Bool) where
+data BatState
+  = NotCharging
+  | Charging
+  | Discharging
+  deriving (Generic, Eq, NFData)
+
+instance (S.MonadSensor m) => S.Aggregate m BatStat (Float, BatState) where
   aggregate _ = forever do S.yield =<< parse <* sleep
     where
       parse = liftIO do
@@ -204,9 +210,14 @@ instance (S.MonadSensor m) => S.Aggregate m BatStat (Float, Bool) where
           =<< listDirectory "/sys/class/power_supply"
       combine abs =
         ( product (map fst abs),
-          or (map Prelude.snd abs)
+          if any ((==) Discharging) (map Prelude.snd abs)
+            then Discharging
+            else
+              if any ((==) Charging) (map Prelude.snd abs)
+                then Charging
+                else NotCharging
         )
-      parse1 :: FilePath -> IO (Float, Bool)
+      parse1 :: FilePath -> IO (Float, BatState)
       parse1 fp =
         liftM2
           (,)
@@ -219,13 +230,24 @@ instance (S.MonadSensor m) => S.Aggregate m BatStat (Float, Bool) where
                   <*> (readFile (fp </> "energy_full") (pure . read))
               ]
           )
-          (choice False [readFile (fp </> "status") (pure . (==) "charging" . map toLower)])
+          (choice NotCharging [readFile (fp </> "status") (pure . parseBatState . map toLower)])
+      parseBatState :: String -> BatState
+      parseBatState string =
+        case string of
+          "not charging" ->
+            NotCharging
+          "charging" ->
+            Charging
+          "discharging" ->
+            Discharging
+          _ ->
+            error ("invalid bat state: " ++ string)
 
 bat :: (S.MonadSensor m) => S.Sensor m () P.Doc
 bat =
-  S.sensor BatStat >>= \(value, charging) ->
-    if charging
-      then
+  S.sensor BatStat >>= \(value, batState) ->
+    case batState of
+      Charging ->
         if
           | value >= 0.9 -> pure (P.pretty "\xf0085")
           | value >= 0.8 -> pure (P.pretty "\xf008b")
@@ -237,7 +259,7 @@ bat =
           | value >= 0.2 -> pure (P.pretty "\xf0087")
           | value >= 0.1 -> pure (P.pretty "\xf0086")
           | otherwise -> pure (P.pretty "\xf089c")
-      else
+      _ ->
         if
           | value >= 0.95 -> pure (P.pretty "\xf0079")
           | value >= 0.9 -> pure (P.pretty "\xf0082")