package akka.cluster

import java.security.MessageDigest
import java.util.concurrent.TimeUnit

import org.openjdk.jmh.annotations.{Benchmark, BenchmarkMode, Fork, Measurement, Mode, OutputTimeUnit, Param, State, Warmup, Scope => JmhScope}

@Fork(2)
@State(JmhScope.Benchmark)
@BenchmarkMode(Array(Mode.Throughput))
@Warmup(iterations = 5)
@Measurement(iterations = 10)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
class NodeHash {

  @Param(Array("j", "m", "h"))
  var value = ""

  def hashCurrent(name: String): String = {
    val digester = MessageDigest.getInstance("MD5")
    digester.update(name.getBytes("UTF-8"))
    digester.digest.map { h =>
      "%02x".format(0xFF & h)
    }.mkString
  }

  def hashProposed(name: String): String = {
    val digester = MessageDigest.getInstance("MD5")
    digester.update(name.getBytes("UTF-8"))
    val digest = digester.digest
    val ch = new Array[Char](digest.length * 2)
    var i = 0
    while (i < digest.length) {
      val h = digest(i)
      ch(i * 2) = Character.forDigit((h >> 4) & 0xF, 16)
      ch(i * 2 + 1) = Character.forDigit(h & 0xF, 16)
      i += 1
    }
    String.valueOf(ch)
  }

  @Benchmark
  def current: String = hashCurrent(value)

  @Benchmark
  def proposed: String = hashProposed(value)

}