/*
 * =========================================================================================
 * Copyright © 2013-2014 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.system

import java.lang.management.ManagementFactory
import akka.actor._
import akka.event.Logging
import kamon.Kamon
import kamon.metric.Metrics
import kamon.metrics._
import scala.collection.JavaConverters._
import scala.concurrent.duration._

object SystemMetrics extends ExtensionId[SystemMetricsExtension] with ExtensionIdProvider {
  override def lookup(): ExtensionId[_ <: Extension] = SystemMetrics
  override def createExtension(system: ExtendedActorSystem): SystemMetricsExtension = new SystemMetricsExtension(system)
}

class SystemMetricsExtension(private val system: ExtendedActorSystem) extends Kamon.Extension {
  import kamon.system.SystemMetricsExtension._

  val log = Logging(system, classOf[SystemMetricsExtension])
  log.info(s"Starting the Kamon(SystemMetrics) extension")

  val config = system.settings.config.getConfig("kamon.system-metrics")
  val dispatcher = system.dispatchers.lookup(config.getString("dispatcher"))
  val sigarFolder = system.settings.config.getString("kamon.sigar.folder")
  val systemMetricsExtension = Kamon(Metrics)(system)

  //System Metrics
  system.actorOf(SystemMetricsCollector.props(1 second), "system-metrics-collector")

  //JVM Metrics
  systemMetricsExtension.register(HeapMetrics(Heap), HeapMetrics.Factory)
  systemMetricsExtension.register(NonHeapMetrics(NonHeap), NonHeapMetrics.Factory)
  systemMetricsExtension.register(ClassLoadingMetrics(Classes), ClassLoadingMetrics.Factory)
  systemMetricsExtension.register(ThreadMetrics(Threads), ThreadMetrics.Factory)

  garbageCollectors.map { gc ⇒
    val gcName = sanitize(gc.getName)
    val recorder = systemMetricsExtension.register(GCMetrics(gcName), GCMetrics.Factory(gc))
    system.actorOf(GcMetricsCollector.props(1 second, recorder, GcMetricExtractor(gc)), s"$gcName-collector")
  }
}

object SystemMetricsExtension {
  val CPU = "cpu"
  val ProcessCPU = "process-cpu"
  val Network = "network"
  val Memory = "memory"
  val Heap = "heap"
  val NonHeap = "non-heap"
  val Classes = "classes"
  val Threads = "thread"
  val ContextSwitches = "context-switches"
  val Disk = "disk"
  val LoadAverage = "load-average"

  def toKB(value: Long): Long = value / 1024
  def toMB(value: Long): Long = value / 1024 / 1024
  def toLong(value: Double): Long = math round (value * 100L)
  def sanitize(str: String): String = str.replaceAll("""[^\w]""", "-")

  val garbageCollectors = ManagementFactory.getGarbageCollectorMXBeans.asScala.filter(_.isValid)
}