package io.vertx.ext.dropwizard.impl;

import java.util.concurrent.TimeUnit;

Author:
Julien Viet/**
 * @author <a href="mailto:julien@julienviet.com">Julien Viet</a>
 */
public class InstantThroughput {

  static final long ONE_SEC = TimeUnit.SECONDS.toNanos(1);
  static final long TWO_SECS = TimeUnit.SECONDS.toNanos(2);

  private volatile long prevCount = -1;
  private volatile long timestamp = 0;
  private volatile long count = 0;

  void check() {
    long now = System.nanoTime();
    if (now - timestamp > ONE_SEC) {
      if (now - timestamp < TWO_SECS) {
        prevCount = count;
      } else {
        if (prevCount > 0) {
          prevCount = 0;
        }
      }
      timestamp = now;
      count = 0;
    }
  }

  public void mark() {
//    System.out.println("mark");
    check();
    count++;
  }

  public long count() {
//    System.out.println("count");
    check();
    return prevCount != -1 ? prevCount : count;
  }
}