/**
 * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
 */

package akka

import sbt._
import sbt.Keys._

/**
 * Sigar java agent injection build settings.
 */
object SigarLoader {

  import Dependencies.Compile.Provided.sigarLoader

  /** Enable Sigar java agent injection during tests. */
  lazy val sigarTestEnabled = sys.props.get("akka.test.sigar").getOrElse("false").toBoolean

  lazy val sigarArtifact = TaskKey[File]("sigar-artifact", "Location of Sigar java agent jar.")

  lazy val sigarOptions = TaskKey[String]("sigar-options", "JVM command line options for Sigar java agent.")

  lazy val sigarFolder = SettingKey[File]("sigar-folder", "Location of native library extracted by Sigar java agent.")

  /** Sigar agent command line option property. */
  val sigarFolderProperty = "kamon.sigar.folder"

  def provideSigarOptions = (sigarArtifact, sigarFolder) map { (artifact, folder) =>
    "-javaagent:" + artifact + "=" + sigarFolderProperty + "=" + folder
  }

  def locateSigarArtifact = update map { report =>
    val artifactList = report.matching(
      moduleFilter(organization = sigarLoader.organization, name = sigarLoader.name)
    )
    require(artifactList.size == 1, "Expecting single artifact, while found: " + artifactList)
    artifactList(0)
  }

  // TODO remove Sigar form test:test* classpath, it is provided by Sigar agent.
  lazy val sigarSettings = {
    Seq(
      //
      // Prepare Sigar agent options.
      sigarArtifact <<= locateSigarArtifact,
      sigarFolder := target.value / "native",
      sigarOptions <<= provideSigarOptions,
      //
      fork in Test := true
    ) ++ (
        // Invoke Sigar agent at JVM init time, to extract and load native Sigar library.
        if (sigarTestEnabled) Seq(
          javaOptions in Test += sigarOptions.value
        )
        else Seq()
      )
  }

}