module Music.Time.Past where
import Control.Lens
import Control.Applicative
import Control.Comonad
import Data.Functor.Couple
import Data.Ord (comparing)
import Data.List (takeWhile, sort, sortBy, group)
import Data.List.Ordered
import Data.Maybe
import Data.Semigroup
import Control.Monad
import Music.Time.Behavior
import Music.Time.Reverse
import Music.Time.Segment
import Music.Time.Split
newtype Past a = Past { getPast :: (Min Time, a) }
deriving (Eq, Ord, Functor)
newtype Future a = Future { getFuture :: (Max Time, a) }
deriving (Eq, Ord, Functor)
instance HasDuration (Past a) where
_duration _ = 0
instance HasDuration (Future a) where
_duration _ = 0
instance HasPosition (Past a) where
_position (Past (extract -> t,_)) _ = t
instance HasPosition (Future a) where
_position (Future (extract -> t,_)) _ = t
past :: Past a -> Time -> Maybe a
past (Past (extract -> t, x)) t'
| t' <= t = Just x
| otherwise = Nothing
future :: Future a -> Time -> Maybe a
future (Future (extract -> t, x)) t'
| t' >= t = Just x
| otherwise = Nothing
indexPast :: [Past a] -> Time -> Maybe a
indexPast ps t = firstTrue $ fmap (\p -> past p t) $ sortBy (comparing _onset) ps
firstTrue :: [Maybe a] -> Maybe a
firstTrue = listToMaybe . join . fmap maybeToList
pastSeg :: Past (Segment a) -> Behavior (Maybe a)
pastSeg = undefined
futureSeg :: Future (Segment a) -> Behavior (Maybe a)
futureSeg = undefined