propellor/Utility/Scheduled.hs

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{- scheduled activities
-
- Copyright 2013 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Scheduled (
Schedule(..),
Recurrance(..),
ScheduledTime(..),
NextTime(..),
WeekDay,
MonthDay,
YearDay,
nextTime,
startTime,
fromSchedule,
fromScheduledTime,
toScheduledTime,
fromRecurrance,
toRecurrance,
toSchedule,
parseSchedule,
prop_schedule_roundtrips
) where
import Utility.Data
import Utility.QuickCheck
import Utility.PartialPrelude
import Utility.Misc
import Control.Applicative
import Data.List
import Data.Time.Clock
import Data.Time.LocalTime
import Data.Time.Calendar
import Data.Time.Calendar.WeekDate
import Data.Time.Calendar.OrdinalDate
import Data.Tuple.Utils
import Data.Char
{- Some sort of scheduled event. -}
data Schedule = Schedule Recurrance ScheduledTime
deriving (Eq, Read, Show, Ord)
data Recurrance
= Daily
| Weekly (Maybe WeekDay)
| Monthly (Maybe MonthDay)
| Yearly (Maybe YearDay)
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| Divisible Int Recurrance
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-- ^ Days, Weeks, or Months of the year evenly divisible by a number.
-- (Divisible Year is years evenly divisible by a number.)
deriving (Eq, Read, Show, Ord)
type WeekDay = Int
type MonthDay = Int
type YearDay = Int
data ScheduledTime
= AnyTime
| SpecificTime Hour Minute
deriving (Eq, Read, Show, Ord)
type Hour = Int
type Minute = Int
{- Next time a Schedule should take effect. The NextTimeWindow is used
- when a Schedule is allowed to start at some point within the window. -}
data NextTime
= NextTimeExactly LocalTime
| NextTimeWindow LocalTime LocalTime
deriving (Eq, Read, Show)
startTime :: NextTime -> LocalTime
startTime (NextTimeExactly t) = t
startTime (NextTimeWindow t _) = t
nextTime :: Schedule -> Maybe LocalTime -> IO (Maybe NextTime)
nextTime schedule lasttime = do
now <- getCurrentTime
tz <- getTimeZone now
return $ calcNextTime schedule lasttime $ utcToLocalTime tz now
{- Calculate the next time that fits a Schedule, based on the
- last time it occurred, and the current time. -}
calcNextTime :: Schedule -> Maybe LocalTime -> LocalTime -> Maybe NextTime
calcNextTime (Schedule recurrance scheduledtime) lasttime currenttime
| scheduledtime == AnyTime = do
next <- findfromtoday True
return $ case next of
NextTimeWindow _ _ -> next
NextTimeExactly t -> window (localDay t) (localDay t)
| otherwise = NextTimeExactly . startTime <$> findfromtoday False
where
findfromtoday anytime = findfrom recurrance afterday today
where
today = localDay currenttime
afterday = sameaslastday || toolatetoday
toolatetoday = not anytime && localTimeOfDay currenttime >= nexttime
sameaslastday = lastday == Just today
lastday = localDay <$> lasttime
nexttime = case scheduledtime of
AnyTime -> TimeOfDay 0 0 0
SpecificTime h m -> TimeOfDay h m 0
exactly d = NextTimeExactly $ LocalTime d nexttime
window startd endd = NextTimeWindow
(LocalTime startd nexttime)
(LocalTime endd (TimeOfDay 23 59 0))
findfrom r afterday candidate = case r of
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Daily
| afterday -> Just $ exactly $ addDays 1 candidate
| otherwise -> Just $ exactly candidate
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Weekly Nothing
| afterday -> skip 1
| otherwise -> case (wday <$> lastday, wday candidate) of
(Nothing, _) -> Just $ window candidate (addDays 6 candidate)
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(Just old, curr)
| old == curr -> Just $ window candidate (addDays 6 candidate)
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| otherwise -> skip 1
Monthly Nothing
| afterday -> skip 1
| maybe True (\old -> mnum candidate > mnum old && mday candidate >= (mday old `mod` minmday)) lastday ->
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-- Window only covers current month,
-- in case there is a Divisible requirement.
Just $ window candidate (endOfMonth candidate)
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| otherwise -> skip 1
Yearly Nothing
| afterday -> skip 1
| maybe True (\old -> ynum candidate > ynum old && yday candidate >= (yday old `mod` minyday)) lastday ->
Just $ window candidate (endOfYear candidate)
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| otherwise -> skip 1
Weekly (Just w)
| w < 0 || w > maxwday -> Nothing
| w == wday candidate -> if afterday
then Just $ exactly $ addDays 7 candidate
else Just $ exactly candidate
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| otherwise -> Just $ exactly $
addDays (fromIntegral $ (w - wday candidate) `mod` 7) candidate
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Monthly (Just m)
| m < 0 || m > maxmday -> Nothing
-- TODO can be done more efficiently than recursing
| m == mday candidate -> if afterday
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then skip 1
else Just $ exactly candidate
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| otherwise -> skip 1
Yearly (Just y)
| y < 0 || y > maxyday -> Nothing
| y == yday candidate -> if afterday
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then skip 365
else Just $ exactly candidate
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| otherwise -> skip 1
Divisible n r'@Daily -> handlediv n r' yday (Just maxyday)
Divisible n r'@(Weekly _) -> handlediv n r' wnum (Just maxwnum)
Divisible n r'@(Monthly _) -> handlediv n r' mnum (Just maxmnum)
Divisible n r'@(Yearly _) -> handlediv n r' ynum Nothing
Divisible _ r'@(Divisible _ _) -> findfrom r' afterday candidate
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where
skip n = findfrom r False (addDays n candidate)
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handlediv n r' getval mmax
| n > 0 && maybe True (n <=) mmax =
findfromwhere r' (divisible n . getval) afterday candidate
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| otherwise = Nothing
findfromwhere r p afterday candidate
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| maybe True (p . getday) next = next
| otherwise = maybe Nothing (findfromwhere r p True . getday) next
where
next = findfrom r afterday candidate
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getday = localDay . startTime
divisible n v = v `rem` n == 0
endOfMonth :: Day -> Day
endOfMonth day =
let (y,m,_d) = toGregorian day
in fromGregorian y m (gregorianMonthLength y m)
endOfYear :: Day -> Day
endOfYear day =
let (y,_m,_d) = toGregorian day
in endOfMonth (fromGregorian y maxmnum 1)
-- extracting various quantities from a Day
wday :: Day -> Int
wday = thd3 . toWeekDate
wnum :: Day -> Int
wnum = snd3 . toWeekDate
mday :: Day -> Int
mday = thd3 . toGregorian
mnum :: Day -> Int
mnum = snd3 . toGregorian
yday :: Day -> Int
yday = snd . toOrdinalDate
ynum :: Day -> Int
ynum = fromIntegral . fst . toOrdinalDate
{- Calendar max and mins. -}
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
maxwday = 7
fromRecurrance :: Recurrance -> String
fromRecurrance (Divisible n r) =
fromRecurrance' (++ "s divisible by " ++ show n) r
fromRecurrance r = fromRecurrance' ("every " ++) r
fromRecurrance' :: (String -> String) -> Recurrance -> String
fromRecurrance' a Daily = a "day"
fromRecurrance' a (Weekly n) = onday n (a "week")
fromRecurrance' a (Monthly n) = onday n (a "month")
fromRecurrance' a (Yearly n) = onday n (a "year")
fromRecurrance' a (Divisible _n r) = fromRecurrance' a r -- not used
onday :: Maybe Int -> String -> String
onday (Just n) s = "on day " ++ show n ++ " of " ++ s
onday Nothing s = s
toRecurrance :: String -> Maybe Recurrance
toRecurrance s = case words s of
("every":"day":[]) -> Just Daily
("on":"day":sd:"of":"every":something:[]) -> withday sd something
("every":something:[]) -> noday something
("days":"divisible":"by":sn:[]) ->
Divisible <$> getdivisor sn <*> pure Daily
("on":"day":sd:"of":something:"divisible":"by":sn:[]) ->
Divisible
<$> getdivisor sn
<*> withday sd something
("every":something:"divisible":"by":sn:[]) ->
Divisible
<$> getdivisor sn
<*> noday something
(something:"divisible":"by":sn:[]) ->
Divisible
<$> getdivisor sn
<*> noday something
_ -> Nothing
where
constructor "week" = Just Weekly
constructor "month" = Just Monthly
constructor "year" = Just Yearly
constructor u
| "s" `isSuffixOf` u = constructor $ reverse $ drop 1 $ reverse u
| otherwise = Nothing
withday sd u = do
c <- constructor u
d <- readish sd
Just $ c (Just d)
noday u = do
c <- constructor u
Just $ c Nothing
getdivisor sn = do
n <- readish sn
if n > 0
then Just n
else Nothing
fromScheduledTime :: ScheduledTime -> String
fromScheduledTime AnyTime = "any time"
fromScheduledTime (SpecificTime h m) =
show h' ++ (if m > 0 then ":" ++ pad 2 (show m) else "") ++ " " ++ ampm
where
pad n s = take (n - length s) (repeat '0') ++ s
(h', ampm)
| h == 0 = (12, "AM")
| h < 12 = (h, "AM")
| h == 12 = (h, "PM")
| otherwise = (h - 12, "PM")
toScheduledTime :: String -> Maybe ScheduledTime
toScheduledTime "any time" = Just AnyTime
toScheduledTime v = case words v of
(s:ampm:[])
| map toUpper ampm == "AM" ->
go s h0
| map toUpper ampm == "PM" ->
go s (\h -> (h0 h) + 12)
| otherwise -> Nothing
(s:[]) -> go s id
_ -> Nothing
where
h0 h
| h == 12 = 0
| otherwise = h
go :: String -> (Int -> Int) -> Maybe ScheduledTime
go s adjust =
let (h, m) = separate (== ':') s
in SpecificTime
<$> (adjust <$> readish h)
<*> if null m then Just 0 else readish m
fromSchedule :: Schedule -> String
fromSchedule (Schedule recurrance scheduledtime) = unwords
[ fromRecurrance recurrance
, "at"
, fromScheduledTime scheduledtime
]
toSchedule :: String -> Maybe Schedule
toSchedule = eitherToMaybe . parseSchedule
parseSchedule :: String -> Either String Schedule
parseSchedule s = do
r <- maybe (Left $ "bad recurrance: " ++ recurrance) Right
(toRecurrance recurrance)
t <- maybe (Left $ "bad time of day: " ++ scheduledtime) Right
(toScheduledTime scheduledtime)
Right $ Schedule r t
where
(rws, tws) = separate (== "at") (words s)
recurrance = unwords rws
scheduledtime = unwords tws
instance Arbitrary Schedule where
arbitrary = Schedule <$> arbitrary <*> arbitrary
instance Arbitrary ScheduledTime where
arbitrary = oneof
[ pure AnyTime
, SpecificTime
<$> choose (0, 23)
<*> choose (1, 59)
]
instance Arbitrary Recurrance where
arbitrary = oneof
[ pure Daily
, Weekly <$> arbday
, Monthly <$> arbday
, Yearly <$> arbday
, Divisible
<$> positive arbitrary
<*> oneof -- no nested Divisibles
[ pure Daily
, Weekly <$> arbday
, Monthly <$> arbday
, Yearly <$> arbday
]
]
where
arbday = oneof
[ Just <$> nonNegative arbitrary
, pure Nothing
]
prop_schedule_roundtrips :: Schedule -> Bool
prop_schedule_roundtrips s = toSchedule (fromSchedule s) == Just s