java-8-time.clj

;; Today at 2:05pm: (either future or past)
(.toInstant
  (LocalDateTime/of (LocalDate/now) (LocalTime/of 14 05))
  (ZoneOffset/UTC))

(defn ms-until+next
  "Returns a vector of milliseconds:
   1. The ms until the H:M of today. Negative if in the past.
   2. The ms until the next H:M
   - Equal if in the future."
  [^LocalTime local-time]
  (let [then (.toInstant
               (LocalDateTime/of (LocalDate/now) local-time)
               (ZoneOffset/UTC))
        now-ms (System/currentTimeMillis)
        ms-until (- (inst-ms then) now-ms)]
    [ms-until (if (neg? ms-until)
                (- (inst-ms (.plus then 1 (ChronoUnit/DAYS))) now-ms)
                ms-until)]))
#_(ms-until+next (LocalTime/of 14 3))


;; Days since epoch:
(.toEpochDay (.toLocalDate
                 (.atOffset (Instant/ofEpochMilli some-ms)
                            (ZoneOffset/UTC))))

;; Get the hour of right now:
(.getHour (LocalTime/now (ZoneOffset/UTC)))

;; d is a Date instance, get next Monday (or today):
(.with
  (LocalDate/of (+ 1900 (.getYear d))
                (inc (.getMonth d))
                (.getDate d))
  (TemporalAdjusters/previousOrSame DayOfWeek/MONDAY))

(defn secs->string
  "Converts a seconds to a string using:
   - w - week (if move then 45 days)
   - d - days
   - h - hours
   - m - minutes
   - s - seconds"
  ^String [secs]
  (let [d (Duration/of secs ChronoUnit/SECONDS)
        days (.toDays d)
        d (if (zero? days) d (.minusDays d days))
        [weeks days] (if (< 45 days) [(quot days 7) (rem days 7)] [0 days])
        hours (.toHours d)
        d (if (zero? hours) d (.minusHours d hours))
        mins (.toMinutes d)
        d (if (zero? mins) d (.minusMinutes d mins))
        secs (.getSeconds d)]
    (str/join " "
              (sequence
                (comp

                  (map (fn [n s]
                         (when-not (zero? n)
                           (str n s))))
                  (remove nil?))
                [weeks days hours mins secs]
                [\w \d \h \m \s]))))