blackout_schedule.clj

(defn build-schedule []
  (let [start-date (t/zoned-date-time "2022-11-01T00:00:00+02:00[Europe/Kiev]")
        days (range 1 30)
        interval (t/new-duration 6 :hours)
        duration (t/new-duration 2 :hours)
        for-day (fn [day]
                    (let [day-offset (* 2 (nth [0 2 1] (mod day 3)))
                          offset-duration (t/+ (t/new-duration (- day 1) :days)
                                               (t/new-duration day-offset :hours))
                          first-blackout (t/>> start-date offset-duration)]

                      (take 4 (iterate #(t/>> % interval) first-blackout))))
        dates (mapcat for-day days)]

      (map-indexed
        (fn [index date]
            {
              :from (->  date t/instant i/to-epoch-milli)
              :to (-> (t/>> date duration) t/instant i/to-epoch-milli)
              :description "Відключення"
              :uid (str "me.shevtsov.leonid.blackout-schedule.Nov." index)})
        dates)))

schedule_fragment.ics

BEGIN:VCALENDAR
PRODID:-//Leonid Shevtsov//Blackout-Schedule 0.0.1//EN
VERSION:2.0
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTSTAMP:20221104T222050Z
DTSTART:20221101T040000
DTEND:20221101T060000
SUMMARY:Відключення
UID:me.shevtsov.leonid.blackout-schedule.Nov.0
END:VEVENT
END:VCALENDAR