// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.container.di

import com.yahoo.container.di.componentgraph.core.ComponentGraphTest.{SimpleComponent, SimpleComponent2}
import com.yahoo.container.di.componentgraph.Provider
import com.yahoo.container.di.componentgraph.core.{ComponentGraph, ComponentNode, Node}
import org.junit.{After, Before, Ignore, Test}
import org.junit.Assert._
import org.hamcrest.CoreMatchers._
import com.yahoo.config.test.TestConfig
import com.yahoo.component.AbstractComponent
import ContainerTest._

import scala.collection.JavaConversions
import com.yahoo.config.di.IntConfig

import scala.concurrent.{Await, Future, future}
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.Try
import com.yahoo.container.di.config.RestApiContext
import com.yahoo.container.bundle.MockBundle
import com.yahoo.container.di.componentgraph.core.ComponentNode.ComponentConstructorException

import scala.language.postfixOps

/**
 * @author tonytv
 * @author gjoranv
 */
class ContainerTest {
  var dirConfigSource: DirConfigSource = _

  @Before def setup()  {
    dirConfigSource = new DirConfigSource("ContainerTest-")
  }

  @After def cleanup() {
    dirConfigSource.cleanup()
  }

  @Test
  def components_can_be_created_from_config() {
    writeBootstrapConfigs()
    dirConfigSource.writeConfig("test", """stringVal "myString" """)

    val container = newContainer(dirConfigSource)

    val component = createComponentTakingConfig(container.runOnce())
    assertThat(component.config.stringVal(), is("myString"))

    container.shutdownConfigurer()
  }

  @Test
  def components_are_reconfigured_after_config_update_without_bootstrap_configs() {
    writeBootstrapConfigs()
    dirConfigSource.writeConfig("test", """stringVal "original" """)

    val container = newContainer(dirConfigSource)

    val componentGraph = container.runOnce()
    val component = createComponentTakingConfig(componentGraph)

    assertThat(component.config.stringVal(), is("original"))

    // Reconfigure
    dirConfigSource.writeConfig("test", """stringVal "reconfigured" """)
    container.reloadConfig(2)

    val newComponentGraph = container.runOnce(componentGraph)
    val component2 = createComponentTakingConfig(newComponentGraph)
    assertThat(component2.config.stringVal(), is("reconfigured"))

    container.shutdownConfigurer()
  }

  @Test
  def graph_is_updated_after_bootstrap_update() {
    dirConfigSource.writeConfig("test", """stringVal "original" """)
    writeBootstrapConfigs("id1")

    val container = newContainer(dirConfigSource)

    val graph = container.runOnce()
    val component = createComponentTakingConfig(graph)
    assertThat(component.getId.toString, is("id1"))

    writeBootstrapConfigsWithMultipleComponents(Array(
      ("id1", classOf[ComponentTakingConfig]),
      ("id2", classOf[ComponentTakingConfig])))

    container.reloadConfig(2)
    val newGraph = container.runOnce(graph)

    assertThat(ComponentGraph.getNode(newGraph, "id1"), notNullValue(classOf[Node]))
    assertThat(ComponentGraph.getNode(newGraph, "id2"), notNullValue(classOf[Node]))

    container.shutdownConfigurer()
  }

  //@Test TODO
  def deconstructor_is_given_guice_components() {
  }

  @Test
  def osgi_component_is_deconstructed_when_not_reused() {
    writeBootstrapConfigs("id1", classOf[DestructableComponent])

    val container = newContainer(dirConfigSource)

    val oldGraph = container.runOnce()
    val componentToDestruct = oldGraph.getInstance(classOf[DestructableComponent])

    writeBootstrapConfigs("id2", classOf[DestructableComponent])
    container.reloadConfig(2)
    container.runOnce(oldGraph)
    assertTrue(componentToDestruct.deconstructed)
  }

  @Ignore  // because logAndDie is impossible(?) to verify programmatically
  @Test
  def manually_verify_what_happens_when_first_graph_contains_component_that_throws_exception_in_ctor() {
    writeBootstrapConfigs("thrower", classOf[ComponentThrowingExceptionInConstructor])
    val container = newContainer(dirConfigSource)
    var currentGraph: ComponentGraph = null
    try {
      currentGraph = container.runOnce()
      fail("Expected to log and die.")
    } catch {
      case _: Throwable => fail("Expected to log and die")
    }
  }

  @Test
  def previous_graph_is_retained_when_new_graph_contains_component_that_throws_exception_in_ctor() {
    val simpleComponentEntry = ComponentEntry("simpleComponent", classOf[SimpleComponent])

    writeBootstrapConfigs(Array(simpleComponentEntry))
    val container = newContainer(dirConfigSource)
    var currentGraph = container.runOnce()

    val simpleComponent = currentGraph.getInstance(classOf[SimpleComponent])

    writeBootstrapConfigs("thrower", classOf[ComponentThrowingExceptionInConstructor])
    container.reloadConfig(2)
    try {
      currentGraph = container.runOnce(currentGraph)
      fail("Expected exception")
    } catch {
      case _: ComponentConstructorException => // Expected, do nothing
      case _: Throwable => fail("Expected ComponentConstructorException")
    }
    assertEquals(1, currentGraph.generation)

    // Also verify that next reconfig is successful
    val componentTakingConfigEntry = ComponentEntry("componentTakingConfig", classOf[ComponentTakingConfig])
    dirConfigSource.writeConfig("test", """stringVal "myString" """)
    writeBootstrapConfigs(Array(simpleComponentEntry, componentTakingConfigEntry))
    container.reloadConfig(3)
    currentGraph = container.runOnce(currentGraph)

    assertEquals(3, currentGraph.generation)
    assertSame(simpleComponent, currentGraph.getInstance(classOf[SimpleComponent]))
    assertNotNull(currentGraph.getInstance(classOf[ComponentTakingConfig]))
  }

  @Test
  def previous_graph_is_retained_when_new_graph_throws_exception_for_missing_config() {
    val simpleComponentEntry = ComponentEntry("simpleComponent", classOf[SimpleComponent])

    writeBootstrapConfigs(Array(simpleComponentEntry))
    val container = newContainer(dirConfigSource)
    var currentGraph = container.runOnce()

    val simpleComponent = currentGraph.getInstance(classOf[SimpleComponent])

    writeBootstrapConfigs("thrower", classOf[ComponentThrowingExceptionForMissingConfig])
    dirConfigSource.writeConfig("test", """stringVal "myString" """)
    container.reloadConfig(2)
    try {
      currentGraph = container.runOnce(currentGraph)
      fail("Expected exception")
    } catch {
      case _: IllegalArgumentException => // Expected, do nothing
      case _: Throwable => fail("Expected IllegalArgumentException")
    }
    assertEquals(1, currentGraph.generation)
  }

  @Test
  def runOnce_hangs_waiting_for_valid_config_after_invalid_config() {
    dirConfigSource.writeConfig("test", """stringVal "original" """)
    writeBootstrapConfigs("myId", classOf[ComponentTakingConfig])

    val container = newContainer(dirConfigSource)
    var currentGraph = container.runOnce()

    writeBootstrapConfigs("thrower", classOf[ComponentThrowingExceptionForMissingConfig])
    container.reloadConfig(2)

    try {
      currentGraph = container.runOnce(currentGraph)
      fail("expected exception")
    } catch {
      case e: Exception =>
    }

    val newGraph = Future {
      currentGraph = container.runOnce(currentGraph)
      currentGraph
    }

    Try {
      Await.ready(newGraph, 1 second)
    } foreach { x => fail("Expected waiting for new config.") }


    writeBootstrapConfigs("myId2", classOf[ComponentTakingConfig])
    container.reloadConfig(3)

    assertNotNull(Await.result(newGraph, 5 minutes))
  }


  @Test
  def bundle_info_is_set_on_rest_api_context() {
    val clazz = classOf[RestApiContext]

    writeBootstrapConfigs("restApiContext", clazz)
    dirConfigSource.writeConfig("jersey-bundles", """bundles[0].spec "mock-entry-to-enforce-a-MockBundle" """)
    dirConfigSource.writeConfig("jersey-injection", """inject[0]" """)

    val container = newContainer(dirConfigSource)
    val componentGraph = container.runOnce()

    val restApiContext = componentGraph.getInstance(clazz)
    assertNotNull(restApiContext)

    assertThat(restApiContext.getBundles.size, is(1))
    assertThat(restApiContext.getBundles.get(0).symbolicName, is(MockBundle.SymbolicName))
    assertThat(restApiContext.getBundles.get(0).version, is(MockBundle.BundleVersion))

    container.shutdownConfigurer()
   }

  @Test
  def restApiContext_has_all_components_injected() {
    new JerseyInjectionTest {
      assertFalse(restApiContext.getInjectableComponents.isEmpty)
      assertThat(restApiContext.getInjectableComponents.size(), is(2))

      container.shutdownConfigurer()
    }
  }

  // TODO: reuse injectedComponent as a named component when we support that
  trait JerseyInjectionTest {
    val restApiClass = classOf[RestApiContext]
    val injectedClass = classOf[SimpleComponent]
    val injectedComponentId = "injectedComponent"
    val anotherComponentClass = classOf[SimpleComponent2]
    val anotherComponentId = "anotherComponent"

    val componentsConfig: String =
      ComponentEntry(injectedComponentId, injectedClass).asConfig(0) + "\n" +
        ComponentEntry(anotherComponentId, anotherComponentClass).asConfig(1) + "\n" +
        ComponentEntry("restApiContext", restApiClass).asConfig(2) + "\n" +
        s"components[2].inject[0].id $injectedComponentId\n" +
        s"components[2].inject[1].id $anotherComponentId\n"

    val injectionConfig = s"""inject[1]
                             |inject[0].instance $injectedComponentId
                             |inject[0].forClass "${injectedClass.getName}"
                            """.stripMargin

    dirConfigSource.writeConfig("components", componentsConfig)
    dirConfigSource.writeConfig("bundles", "")
    dirConfigSource.writeConfig("jersey-bundles", """bundles[0].spec "mock-entry-to-enforce-a-MockBundle" """)
    dirConfigSource.writeConfig("jersey-injection", injectionConfig)

    val container = newContainer(dirConfigSource)
    val componentGraph = container.runOnce()

    val restApiContext = componentGraph.getInstance(restApiClass)
  }

  case class ComponentEntry(componentId: String,  classId: Class[_]) {
    def asConfig(position: Int): String = {
      <config>
      |components[{position}].id "{componentId}"
      |components[{position}].classId "{classId.getName}"
      |components[{position}].configId "{dirConfigSource.configId}"
      </config>.text.stripMargin.trim
    }
  }

  def writeBootstrapConfigs(componentEntries: Array[ComponentEntry]) {
    dirConfigSource.writeConfig("bundles", "")
    dirConfigSource.writeConfig("components", """
      components[%s]
      %s
    """.format(componentEntries.length,
      componentEntries.zipWithIndex.map{ case (entry, index) => entry.asConfig(index) }.mkString("\n")))
  }

  def writeBootstrapConfigs(componentId: String = classOf[ComponentTakingConfig].getName,
                            classId: Class[_] = classOf[ComponentTakingConfig]) {

    writeBootstrapConfigs(Array(ComponentEntry(componentId, classId)))
  }

  def writeBootstrapConfigsWithMultipleComponents(idAndClass: Array[(String, Class[_])]) {
    writeBootstrapConfigs(idAndClass.map{case(id, classId) => ComponentEntry(id, classId)})
  }


  @Test
  def providers_are_destructed() {
    writeBootstrapConfigs("id1", classOf[DestructableProvider])

    val deconstructor = new ComponentDeconstructor {
      def deconstruct(component: AnyRef) {
        component match  {
          case c : AbstractComponent => c.deconstruct()
          case p : Provider[_] => p.deconstruct()
        }
      }
    }

    val container = newContainer(dirConfigSource, deconstructor)

    val oldGraph = container.runOnce()
    val destructableEntity = oldGraph.getInstance(classOf[DestructableEntity])

    writeBootstrapConfigs("id2", classOf[DestructableProvider])
    container.reloadConfig(2)
    container.runOnce(oldGraph)

    assertTrue(destructableEntity.deconstructed)
  }
}


object ContainerTest {
  class DestructableEntity {
    var deconstructed = false
  }

  class DestructableProvider extends Provider[DestructableEntity] {
    val instance = new DestructableEntity

    def get() = instance

    def deconstruct() {
      require(! instance.deconstructed)
      instance.deconstructed = true
    }
  }

  class ComponentTakingConfig(val config: TestConfig) extends AbstractComponent {
    require(config != null)
  }

  class ComponentThrowingExceptionInConstructor() {
    throw new RuntimeException("This component fails upon construction.")
  }

  class ComponentThrowingExceptionForMissingConfig(intConfig: IntConfig) extends AbstractComponent {
    fail("This component should never be created. Only used for tests where 'int' config is missing.")
  }

  class DestructableComponent extends AbstractComponent {
    var deconstructed = false
    override def deconstruct() {
      deconstructed = true
    }
  }

  class TestDeconstructor extends ComponentDeconstructor {
    def deconstruct(component: AnyRef) {
      component match {
        case vespaComponent: DestructableComponent => vespaComponent.deconstruct()
        case _ =>
      }
    }
  }

  private def newContainer(dirConfigSource: DirConfigSource,
                           deconstructor: ComponentDeconstructor = new TestDeconstructor()):
  Container = {
    new Container(new CloudSubscriberFactory(dirConfigSource.configSource), dirConfigSource.configId, deconstructor)
  }

  def createComponentTakingConfig(componentGraph: ComponentGraph): ComponentTakingConfig = {
    componentGraph.getInstance(classOf[ComponentTakingConfig])
  }

  def convertMap[K, V](map: java.util.Map[K, V]): Map[K, V] = JavaConversions.mapAsScalaMap(map).toMap
}