Crontab in Scala

crontab.scala

// libraryDependencies += "com.github.alonsodomin.cron4s" %% "cron4s-core"            % "0.8.0"

import java.time.*
import cron4s.*
import cron4s.lib.javatime.*
import scala.concurrent.ExecutionContext.Implicits.global
import scala.annotation.tailrec
import scala.concurrent.Future

final case class Job(name: String) {
  println(s"Job($name)")
}

def cron[A](job: => A, cronString: String): Unit = {
  val cron = Cron.unsafeParse(cronString)
  @tailrec
  def go(): Unit = {
    val now = ZonedDateTime.now(ZoneId.systemDefault())
    cron.next(now) match
      case Some(nextTime) =>
        val durationUntilNextExecution = Duration.between(now, nextTime)
        val s                          = durationUntilNextExecution.getSeconds() * 1000L
        val n                          = durationUntilNextExecution.getNano() / 1000000L
        val mill                       = s + n
        println(s"The next command will be launched in $mill milliseconds")
        Thread.sleep(mill)
        Future { job }
        go()
      case _ => ()
  }
  Future { go() }
}

// run 
cron(Job("Tom"), "*/3 * * * * ?")