awesome alert combining

Now an alert tracks files that have recently been added. As a large file
is added, it will have its own alert, that then combines with the tracker
when dones.

Also used for combining sanity checker alerts, as it could possibly want to
display a lot.

1 files changed, 63 insertions, 9 deletions

diff --git a/Assistant/Alert.hs b/Assistant/Alert.hs
index 0412dfe51..5877ba069 100644
--- a/Assistant/Alert.hs
+++ b/Assistant/Alert.hs
@@ -27,6 +27,15 @@ data AlertPriority = Filler | Low | Medium | High | Pinned
 {- An alert can be a simple message, or an arbitrary Yesod Widget. -}
 data AlertMessage = StringAlert String | WidgetAlert (Alert -> Widget)
 
+{- An alert can have an name, which is used to combine it with other similar
+ - alerts. -}
+data AlertName = AddFileAlert | DownloadFailedAlert | SanityCheckFixAlert
+	deriving (Eq)
+
+{- The first alert is the new alert, the second is an old alert.
+ - Should return a modified version of the old alert. -}
+type AlertCombiner = Maybe (Alert -> Alert -> Maybe Alert)
+
 data Alert = Alert
 	{ alertClass :: AlertClass
 	, alertHeader :: Maybe String
@@ -35,6 +44,8 @@ data Alert = Alert
 	, alertClosable :: Bool
 	, alertPriority :: AlertPriority
 	, alertIcon :: Maybe String
+	, alertCombiner :: AlertCombiner
+	, alertName :: Maybe AlertName
 	}
 
 type AlertPair = (AlertId, Alert)
@@ -123,17 +134,21 @@ isFiller alert = alertPriority alert == Filler
 
 {- Converts a given alert into filler, manipulating it in the AlertMap.
  -
- - Any old filler that looks the same as the reference alert is removed.
+ - Any old filler that looks the same as the reference alert is removed,
+ - or, if the input alert has an alertCombine that combines it with
+ - old filler, the old filler is replaced with the result, and the
+ - input alert is removed.
  -
  - Old filler alerts are pruned once maxAlerts is reached.
  -}
 convertToFiller :: AlertId -> Bool -> AlertMap -> AlertMap
 convertToFiller i success m = case M.lookup i m of
 	Nothing -> m
-	Just al -> 
+ 	Just al ->
 		let al' = makeAlertFiller success al
-		in pruneBloat $ M.filterWithKey (pruneSame al') $
-			M.insertWith' const i al' m
+		in case alertCombiner al' of
+			Nothing -> updatePrune al'
+			Just combiner -> updateCombine combiner al'
 	where
 		pruneSame ref k al = k == i || not (effectivelySameAlert ref al)
 		pruneBloat m'
@@ -144,6 +159,13 @@ convertToFiller i success m = case M.lookup i m of
 				pruneold l =
 			 		let (f, rest) = partition (\(_, al) -> isFiller al) l
 					in drop bloat f ++ rest
+		updatePrune al = pruneBloat $ M.filterWithKey (pruneSame al) $
+			M.insertWith' const i al m
+		updateCombine combiner al = 
+			let combined = M.mapMaybe (combiner al) m
+			in if M.null combined
+				then updatePrune al
+				else M.delete i $ M.union combined m
 
 baseActivityAlert :: Alert
 baseActivityAlert = Alert
@@ -154,6 +176,8 @@ baseActivityAlert = Alert
 	, alertClosable = False
 	, alertPriority = Medium
 	, alertIcon = Just "refresh"
+	, alertCombiner = Nothing
+	, alertName = Nothing
 	}
 
 activityAlert :: Maybe String -> String -> Alert
@@ -203,13 +227,43 @@ sanityCheckFixAlert :: String -> Alert
 sanityCheckFixAlert msg = Alert
 	{ alertClass = Warning
 	, alertHeader = Just "Fixed a problem"
-	, alertMessage = StringAlert $ unwords
-		[ "The daily sanity check found and fixed a problem:"
-		, msg
-		, "If these problems persist, consider filing a bug report."
-		]
+	, alertMessage = StringAlert $ unlines [ alerthead, msg, alertfoot ]
 	, alertBlockDisplay = True
 	, alertPriority = High
 	, alertClosable = True
 	, alertIcon = Just "exclamation-sign"
+	, alertName = Just SanityCheckFixAlert
+	, alertCombiner = messageCombiner combinemessage
+	}
+	where
+		alerthead = "The daily sanity check found and fixed a problem:"
+		alertfoot = "If these problems persist, consider filing a bug report."
+		combinemessage (StringAlert new) (StringAlert old) =
+			let newmsg = filter (/= alerthead) $
+				filter (/= alertfoot) $
+				lines old ++ lines new
+			in Just $ StringAlert $
+				unlines $ alerthead : newmsg ++ [alertfoot]
+		combinemessage _ _ = Nothing
+
+addFileAlert :: FilePath -> Alert
+addFileAlert file = (activityAlert (Just "Added") $ takeFileName file)
+	{ alertName = Just AddFileAlert
+	, alertCombiner = messageCombiner combinemessage
 	}
+	where
+		combinemessage (StringAlert new) (StringAlert old) =
+			Just $ StringAlert $
+				unlines $ take 10 $ new : lines old
+		combinemessage _ _ = Nothing
+
+messageCombiner :: (AlertMessage -> AlertMessage -> Maybe AlertMessage) -> AlertCombiner
+messageCombiner combinemessage = Just go
+	where
+		go new old
+			| alertClass new /= alertClass old = Nothing
+			| alertName new == alertName old =
+				case combinemessage (alertMessage new) (alertMessage old) of
+					Nothing -> Nothing
+					Just m -> Just $ old { alertMessage = m }
+			| otherwise = Nothing