/* =========================================================================================
 * Copyright © 2013-2017 the kamon project <http://kamon.io/>
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the
 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions
 * and limitations under the License.
 * =========================================================================================
 */

package kamon.metric

import kamon.jsr166.LongAdder
import org.slf4j.LoggerFactory

trait Counter {
  def unit: MeasurementUnit

  def increment(): Unit
  def increment(times: Long): Unit
}

class LongAdderCounter(name: String, tags: Map[String, String], val unit: MeasurementUnit) extends Counter {
  import LongAdderCounter.logger

  private val adder = new LongAdder()

  def increment(): Unit =
    adder.increment()

  def increment(times: Long): Unit = {
    if (times >= 0) adder.add(times)
    else logger.warn(s"Ignored attempt to decrement counter [$name]")
  }

  def snapshot(resetState: Boolean = true): MetricValue =
    if(resetState)
      MetricValue(name, tags, unit, adder.sumAndReset())
    else
      MetricValue(name, tags, unit, adder.sum())
}

object LongAdderCounter {
  private val logger = LoggerFactory.getLogger(classOf[LongAdderCounter])
}