com.github.eikek.calev.akka.internal.UpcomingEventProvider.scala Maven / Gradle / Ivy

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package com.github.eikek.calev.akka.internal

import java.time.{Clock, Duration => JavaDuration, ZonedDateTime}

import scala.concurrent.duration._

import com.github.eikek.calev.CalEvent

private[akka] class UpcomingEventProvider(
    clock: Clock,
    minInterval: Option[FiniteDuration] = None
) {
  private def now = clock.instant().atZone(clock.getZone)

  def apply(
      calEvent: CalEvent,
      delay: FiniteDuration = Duration.Zero
  ): Option[(ZonedDateTime, FiniteDuration)] = {
    val refInstant: ZonedDateTime = now.minusNanos(delay.toNanos)
    calEvent
      .nextElapse(refInstant)
      .map { instant =>
        (instant, JavaDuration.between(refInstant, instant).toMillis.millis)
      }
      .flatMap {
        case (_, duration)
            if minInterval.exists(min => duration.toMillis < min.toMillis) =>
          apply(calEvent, minInterval.get)
        case (dt, duration) =>
          Some((dt, duration))
      }
  }

}