plugins {
  id 'com.github.johnrengelman.shadow' version '2.0.2'
}

description = 'OpenCensus Agent'

def agentPackage = 'io.opencensus.contrib.agent'
def agentMainClass = "${agentPackage}.AgentMain"

// The package containing the classes that need to be loaded by the bootstrap classloader because
// they are used from classes loaded by the bootstrap classloader.
def agentBootstrapPackage = "${agentPackage}.bootstrap"
def agentBootstrapPackageDir = agentBootstrapPackage.replace('.', '/') + '/'
def agentBootstrapClasses = agentBootstrapPackageDir + '**'

// The package to which we relocate all third party packages. This avoids any conflicts of the
// agent's classes with the app's classes, which are loaded by the same classloader (the system
// classloader).
def agentRepackaged = "${agentPackage}.deps"

dependencies {
  compileOnly libraries.auto_service
  compileOnly libraries.findbugs_annotations
  compileOnly libraries.grpc_context
  compileOnly project(':opencensus-api')
  compile libraries.byte_buddy
  compile libraries.config
  compile libraries.guava

  signature 'org.codehaus.mojo.signature:java17:1.0@signature'
}

jar {
  manifest {
    // Set the required manifest attributes for the Java agent, cf.
    // https://docs.oracle.com/javase/8/docs/api/java/lang/instrument/package-summary.html.
    attributes 'Premain-Class': agentMainClass
    attributes 'Can-Retransform-Classes': true
  }
}

// Create bootstrap.jar containing the classes that need to be loaded by the bootstrap
// classloader.
task bootstrapJar(type: Jar) {
  // Output to 'bootstrap.jar'.
  baseName = 'bootstrap'
  version = null

  from sourceSets.main.output
  include agentBootstrapClasses
}

shadowJar.dependsOn bootstrapJar

// Bundle the agent's classes and dependencies into a single, self-contained JAR file.
shadowJar {
  // Output to opencensus-contrib-agent-VERSION.jar.
  classifier = null

  // Include only the following dependencies (excluding transitive dependencies).
  dependencies {
    include(dependency(libraries.byte_buddy))
    include(dependency(libraries.config))
    include(dependency(libraries.guava))
  }

  // Exclude cruft which still snuck in.
  exclude 'META-INF/maven/**'
  exclude agentBootstrapClasses

  // Relocate third party packages to avoid any conflicts of the agent's classes with the app's
  // classes, which are loaded by the same classloader (the system classloader).
  // Byte Buddy:
  relocate 'net.bytebuddy', agentRepackaged + '.bytebuddy'
  // Config:
  relocate 'com.typesafe.config', agentRepackaged + '.config'
  // Guava:
  relocate 'com.google.common', agentRepackaged + '.guava'
  relocate 'com.google.thirdparty.publicsuffix', agentRepackaged + '.publicsuffix'

  doLast {
    def agentPackageDir = agentPackage.replace('.', '/') + '/'
    def agentBootstrapJar = agentPackageDir + 'bootstrap.jar'

    // Bundle bootstrap.jar.
    ant.jar(update: 'true', destfile: shadowJar.archivePath) {
      mappedresources {
        fileset(file: bootstrapJar.archivePath)
        globmapper(from: '*', to: agentBootstrapJar)
      }
    }

    // Assert that there's nothing obviously wrong with the JAR's contents.
    new java.util.zip.ZipFile(shadowJar.archivePath).withCloseable {
      // Must have bundled the bootstrap.jar.
      assert it.entries().any { it.name == agentBootstrapJar }

      it.entries().each { entry ->
        // Must not contain anything outside of ${agentPackage}, ...
        assert entry.name.startsWith(agentPackageDir) ||
               // ... except for the expected entries.
               [ agentPackageDir,
                 'META-INF/MANIFEST.MF',
                 'META-INF/services/io.opencensus.contrib.agent.instrumentation.Instrumenter',
                 'reference.conf',
               ].any { entry.isDirectory() ? it.startsWith(entry.name) : it == entry.name }
        // Also, should not have the bootstrap classes.
        assert !entry.name.startsWith(agentBootstrapPackageDir)
      }
    }
  }
}

jar.finalizedBy shadowJar

// TODO(stschmidt): Proguard-shrink the agent JAR.

// Integration tests. The setup was initially based on
// https://www.petrikainulainen.net/programming/gradle/getting-started-with-gradle-integration-testing/.
// We run the same suite of integration tests on different Java versions with the agent enabled.
// The JAVA_HOMES environment variable lists the home directories of the Java installations used
// for integration testing.

// The default JAR has been replaced with a self-contained JAR by the shadowJar task. Therefore,
// remove all declared dependencies from the generated Maven POM for said JAR.
uploadArchives {
  repositories {
    mavenDeployer {
      pom.whenConfigured {
        dependencies = []
      }
    }
  }
}

sourceSets {
  integrationTest {
    java {
      compileClasspath += main.output + test.output
      runtimeClasspath += main.output + test.output
      srcDir file('src/integration-test/java')
    }
    resources.srcDir file('src/integration-test/resources')
  }
}

configurations {
  integrationTestCompile.extendsFrom testCompile
  integrationTestRuntime.extendsFrom testRuntime
}

dependencies {
  integrationTestCompile project(':opencensus-api')
  integrationTestCompile project(':opencensus-testing')
  integrationTestRuntime libraries.grpc_context
  integrationTestRuntime project(':opencensus-impl-lite')
}

// Disable findbugs for integration tests, too.
findbugsIntegrationTest.enabled = false

def javaExecutables = (System.getenv('JAVA_HOMES') ?: '')
    .tokenize(File.pathSeparator)
    .plus(System.getProperty('java.home'))
    .collect { org.apache.tools.ant.taskdefs.condition.Os.isFamily(
                   org.apache.tools.ant.taskdefs.condition.Os.FAMILY_WINDOWS)
                   ? "${it}/bin/java.exe"
                   : "${it}/bin/java" }
    .collect { new File(it).getCanonicalPath() }
    .unique()

assert javaExecutables.size > 0 :
       'No Java executables found for running integration tests'

task integrationTest

javaExecutables.eachWithIndex { javaExecutable, index ->
  def perVersionIntegrationTest = task("integrationTest_${index}", type: Test) {
    testLogging {
      // Let Gradle output the stdout and stderr from tests, too. This is useful for investigating
      // test failures on Travis, where we can't view Gradle's test reports.
      showStandardStreams = true

      // Include the exception message and full stacktrace for failed tests.
      exceptionFormat 'full'
    }

    dependsOn shadowJar

    testClassesDirs = sourceSets.integrationTest.output.classesDirs
    classpath = sourceSets.integrationTest.runtimeClasspath

    executable = javaExecutable

    // The JaCoCo agent must be specified first so that it can instrument our agent.
    // This is a work around for the issue that the JaCoCo agent is added last, cf.
    // https://discuss.gradle.org/t/jacoco-gradle-adds-the-agent-last-to-jvm-args/7124.
    doFirst {
      jvmArgs jacoco.asJvmArg  // JaCoCo agent first.
      jvmArgs "-javaagent:${shadowJar.archivePath}"  // Our agent second.
      jacoco.enabled = false  // Don't add the JaCoCo agent again.
    }

    doFirst { logger.lifecycle("Running integration tests using ${javaExecutable}.") }
  }

  integrationTest.dependsOn perVersionIntegrationTest
}

check.dependsOn integrationTest
integrationTest.mustRunAfter test

// Merge JaCoCo's execution data from all tests into the main test's execution data file.
task jacocoMerge(type: JacocoMerge) {
  tasks.withType(Test).each { testTask ->
    dependsOn testTask
    executionData testTask.jacoco.destinationFile
  }
  doLast {
    destinationFile.renameTo test.jacoco.destinationFile
  }
}

jacocoTestReport.dependsOn jacocoMerge

// JMH benchmarks

dependencies {
  jmh libraries.grpc_context
}

// Make the agent JAR available using a fixed file name so that we don't have to modify the JMH
// benchmarks whenever the version changes.
task agentJar(type: Copy) {
  dependsOn shadowJar

  from shadowJar.archivePath
  into libsDir
  rename { 'agent.jar' }
}

jmhJar.dependsOn agentJar
jmhJar.dependsOn integrationTest