Improve handling on monthly/yearly scheduling.

Code was still buggy, it turns out (though the recursion checker caught
it). In the case of (Schedule (Monthly Nothing) AnyTime), where the last
run was on yyyy-12-31, it looped forever.

Also, the handling of (Schedule (Yearly Nothing) AnyTime) was wacky where
the last run was yyyy-12-31. It would suggest a window starting on the 3rd
for the next run (because 31 mod 28 is 3).

I think that originally I was wanted to avoid running on 01-01 if it had
just run on 12-31. But the code didn't accomplish this, and it's not
necessary anyway. This is supposed to calculate the next window meeting the
schedule, and for (Schedule (Monthly Nothing), the window starts at 01-01
and runs through 01-31. If that causes two back-to-back runs, well the next
one will not be until 02-01 at the earliest.

Also, back-to-back runs can be avoided, if desired, by using Divisible 2.

1 files changed, 7 insertions, 10 deletions

diff --git a/Utility/Scheduled.hs b/Utility/Scheduled.hs
index 1b25cb4c7..4dfa4d04c 100644
--- a/Utility/Scheduled.hs
+++ b/Utility/Scheduled.hs
@@ -14,6 +14,7 @@ module Utility.Scheduled (
 	MonthDay,
 	YearDay,
 	nextTime,
+	calcNextTime,
 	startTime,
 	fromSchedule,
 	fromScheduledTime,
@@ -22,7 +23,7 @@ module Utility.Scheduled (
 	toRecurrance,
 	toSchedule,
 	parseSchedule,
-	prop_schedule_roundtrips
+	prop_schedule_roundtrips,
 ) where
 
 import Utility.Data
@@ -127,14 +128,14 @@ calcNextTime schedule@(Schedule recurrance scheduledtime) lasttime currenttime
 					| otherwise -> skip 1
 		Monthly Nothing
 			| afterday -> skip 1
-			| maybe True (\old -> mday candidate > mday old && mday candidate >= (mday old `mod` minmday)) lastday ->
-				-- Window only covers current month,
-				-- in case there is a Divisible requirement.
+			-- any day in the month following lasttime
+			| maybe True (\old -> (mnum candidate > mnum old || ynum candidate > ynum old)) lastday ->
 				Just $ window candidate (endOfMonth candidate)
 			| otherwise -> skip 1
 		Yearly Nothing
 			| afterday -> skip 1
-			| maybe True (\old -> ynum candidate > ynum old && yday candidate >= (yday old `mod` minyday)) lastday ->
+			-- any day in the year following lasttime
+			| maybe True (\old -> ynum candidate > ynum old) lastday ->
 				Just $ window candidate (endOfYear candidate)
 			| otherwise -> skip 1
 		Weekly (Just w)
@@ -200,17 +201,13 @@ yday = snd . toOrdinalDate
 ynum :: Day -> Int
 ynum = fromIntegral . fst . toOrdinalDate
 
-{- Calendar max and mins. -}
+{- Calendar max values. -}
 maxyday :: Int
 maxyday = 366 -- with leap days
-minyday :: Int
-minyday = 365
 maxwnum :: Int
 maxwnum = 53 -- some years have more than 52
 maxmday :: Int
 maxmday = 31
-minmday :: Int
-minmday = 28
 maxmnum :: Int
 maxmnum = 12
 maxwday :: Int