package kamon.util

import java.time.{Duration, Instant}

import kamon.util
import org.scalatest.{Matchers, WordSpec}

class ClockSpec extends WordSpec with Matchers {
  "the Clock" should {
    "generate nanosecond precision Instants" in {
      newClock().instant().getNano() % MicrosInSecond shouldNot be(0)
    }

    "turn Instants into micros" in {
      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.000000000Z")) shouldBe 1513586399000000L
      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.000000010Z")) shouldBe 1513586399000000L
      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.987654321Z")) shouldBe 1513586399987654L
      Clock.toEpochMicros(Instant.parse("2017-12-18T08:39:59.987000000Z")) shouldBe 1513586399987000L
    }

    "calculate nanos between two Instants" in {
      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987654321Z"), Instant.parse("2017-12-18T08:39:59.987654322Z")) shouldBe 1
      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987654322Z"), Instant.parse("2017-12-18T08:39:59.987654321Z")) shouldBe -1
      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987Z"), Instant.parse("2017-12-18T08:39:59.988Z")) shouldBe 1000000
      Clock.nanosBetween(Instant.parse("2017-12-18T08:39:59.987654Z"), Instant.parse("2017-12-18T08:39:59.987Z")) shouldBe -654000
    }

    "calculate ticks aligned to rounded boundaries" in {
      Clock.nextTick(Instant.parse("2017-12-18T08:39:59.999Z"), Duration.ofSeconds(10)).toString shouldBe "2017-12-18T08:40:00Z"
      Clock.nextTick(Instant.parse("2017-12-18T08:40:00.000Z"), Duration.ofSeconds(10)).toString shouldBe "2017-12-18T08:40:10Z"
      Clock.nextTick(Instant.parse("2017-12-18T08:39:14.906Z"), Duration.ofSeconds(10)).toString shouldBe "2017-12-18T08:39:20Z"
    }
  }

  val MicrosInSecond = 1000000

  def newClock(): Clock =
    new util.Clock.Default()
}