module Utils.Schedule.Week.TimeSlot
  ( TimeSlot, firstSlot, lastSlot, slotStep, slotsToDisplay, isInTimeSlot
  , timeSlotToUTCTime
  , formatTimeSlotW
  ) where

import Import

import Handler.Utils.DateTime (formatTimeRangeW)


-- TODO: very temporary slot representation, WORK IN PROGRESS
-- TODO: include UTCTime stamps for begin and end (end timestamp excluded)
type TimeSlot = Int

firstSlot, lastSlot, slotStep :: TimeSlot
firstSlot = 8
lastSlot = 18
slotStep = 2

slotsToDisplay :: [TimeSlot]
slotsToDisplay = [firstSlot,firstSlot+slotStep..lastSlot]


-- | Check whether a given time of day lies within a given time slot
isInTimeSlot :: TimeOfDay -> TimeSlot -> Bool
isInTimeSlot time slot = TimeOfDay slot 0 0 <= time && time < TimeOfDay (slot+slotStep) 0 0

-- | Convert a TimeSlot to UTCTime for a given TimeZone
timeSlotToUTCTime :: TimeZone -> Day -> TimeSlot -> UTCTime
timeSlotToUTCTime tz day slot = UTCTime{..} where
  utctDay     = slotDayOffset `addDays` day
  utctDayTime = timeOfDayToTime slotTimeOfDay
  (slotDayOffset, slotTimeOfDay) = localToUTCTimeOfDay tz $ TimeOfDay slot 0 0

-- TODO: refactor in progress
-- | Format a given TimeSlot t as time range from t until the next TimeSlot
formatTimeSlotW :: TimeSlot -> Widget
formatTimeSlotW slot = formatTimeRangeW SelFormatTime (TimeOfDay slot 0 0) $ Just $ TimeOfDay (slot+slotStep) 0 0