#include "thyme.h"
module Data.Thyme.Calendar.WeekdayOfMonth
( Year, Month, DayOfWeek
, module Data.Thyme.Calendar.WeekdayOfMonth
) where
import Prelude
import Control.Applicative
import Control.Arrow
import Control.DeepSeq
import Control.Lens
import Control.Monad
import Data.AffineSpace
import Data.Data
import Data.Thyme.Calendar
import Data.Thyme.Calendar.Internal
import GHC.Generics (Generic)
import System.Random
import Test.QuickCheck
data WeekdayOfMonth = WeekdayOfMonth
{ womYear :: !Year
, womMonth :: !Month
, womNth :: !Int
, womDayOfWeek :: !DayOfWeek
} deriving (INSTANCES_USUAL, Show)
instance NFData WeekdayOfMonth
instance Bounded WeekdayOfMonth where
minBound = minBound ^. weekdayOfMonth
maxBound = maxBound ^. weekdayOfMonth
instance Random WeekdayOfMonth where
randomR = randomIsoR weekdayOfMonth
random = first (^. weekdayOfMonth) . random
instance Arbitrary WeekdayOfMonth where
arbitrary = view weekdayOfMonth <$> arbitrary
shrink wom = view weekdayOfMonth <$> shrink (weekdayOfMonth # wom)
instance CoArbitrary WeekdayOfMonth where
coarbitrary (WeekdayOfMonth y m n d)
= coarbitrary y . coarbitrary m
. coarbitrary n . coarbitrary d
weekdayOfMonth :: Iso' Day WeekdayOfMonth
weekdayOfMonth = iso toWeekday fromWeekday where
toWeekday :: Day -> WeekdayOfMonth
toWeekday day@(view ordinalDate -> ord) = WeekdayOfMonth y m n wd where
YearMonthDay y m d = ord ^. yearMonthDay
WeekDate _ _ wd = toWeekOrdinal ord day
n = 1 + div (d 1) 7
fromWeekday :: WeekdayOfMonth -> Day
fromWeekday (WeekdayOfMonth y m n wd) = refDay .+^ s * offset where
refOrd = yearMonthDay # YearMonthDay y m
(if n < 0 then monthLength (isLeapYear y) m else 1)
refDay = ordinalDate # refOrd
WeekDate _ _ wd1 = toWeekOrdinal refOrd refDay
s = signum n
wo = s * (wd wd1)
offset = (abs n 1) * 7 + if wo < 0 then wo + 7 else wo
weekdayOfMonthValid :: WeekdayOfMonth -> Maybe Day
weekdayOfMonthValid (WeekdayOfMonth y m n wd) = (refDay .+^ s * offset)
<$ guard (n /= 0 && 1 <= wd && wd <= 7 && offset < len) where
len = monthLength (isLeapYear y) m
refOrd = yearMonthDay # YearMonthDay y m (if n < 0 then len else 1)
refDay = ordinalDate # refOrd
WeekDate _ _ wd1 = toWeekOrdinal refOrd refDay
s = signum n
wo = s * (wd wd1)
offset = (abs n 1) * 7 + if wo < 0 then wo + 7 else wo
LENS(WeekdayOfMonth,womYear,Year)
LENS(WeekdayOfMonth,womMonth,Month)
LENS(WeekdayOfMonth,womNth,Int)
LENS(WeekdayOfMonth,womDayOfWeek,DayOfWeek)