/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you 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.
 */

import org.elasticsearch.gradle.test.RestIntegTestTask
import org.elasticsearch.gradle.Version

apply plugin: 'elasticsearch.standalone-test'

// This is a top level task which we will add dependencies to below.
// It is a single task that can be used to backcompat tests against all versions.
task bwcTest {
  description = 'Runs backwards compatibility tests.'
  group = 'verification'
}

for (Version version : bwcVersions.wireCompatible) {
  /*
   * The goal here is to:
   * <ul>
   *  <li>start three nodes on the old version
   *  <li>run tests with systemProperty 'tests.rest.suite', 'old_cluster'
   *  <li>shut down one node
   *  <li>start a node with the new version
   *  <li>run tests with systemProperty 'tests.rest.suite', 'mixed_cluster'
   *  <li>shut down one node on the old version
   *  <li>start a node with the new version
   *  <li>run tests with systemProperty 'tests.rest.suite', 'mixed_cluster' again
   *  <li>shut down the last node with the old version
   *  <li>start a node with the new version
   *  <li>run tests with systemProperty 'tests.rest.suite', 'upgraded_cluster'
   *  <li>shut down the entire cluster
   * </ul>
   *
   * Be careful: gradle dry run spits out tasks in the wrong order but,
   * strangely, running the tasks works properly.
   */
  String baseName = "v${version}"

  Task oldClusterTest = tasks.create(name: "${baseName}#oldClusterTest", type: RestIntegTestTask) {
    mustRunAfter(precommit)
  }

  Object extension = extensions.findByName("${baseName}#oldClusterTestCluster")
  configure(extensions.findByName("${baseName}#oldClusterTestCluster")) {
    bwcVersion = version
    numBwcNodes = 3
    numNodes = 3
    clusterName = 'rolling-upgrade'
    setting 'repositories.url.allowed_urls', 'http://snapshot.test*'
    if (version.onOrAfter('5.3.0')) {
      setting 'http.content_type.required', 'true'
    }
  }

  Task oldClusterTestRunner = tasks.getByName("${baseName}#oldClusterTestRunner")
  oldClusterTestRunner.configure {
    systemProperty 'tests.rest.suite', 'old_cluster'
  }

  Closure configureUpgradeCluster = {String name, Task lastRunner, int stopNode, Closure unicastSeed ->
    configure(extensions.findByName("${baseName}#${name}")) {
      dependsOn lastRunner, "${baseName}#oldClusterTestCluster#node${stopNode}.stop"
      clusterName = 'rolling-upgrade'
      unicastTransportUri = { seedNode, node, ant -> unicastSeed() }
      minimumMasterNodes = { 3 }
      /* Override the data directory so the new node always gets the node we
      * just stopped's data directory. */
      dataDir = { nodeNumber -> oldClusterTest.nodes[stopNode].dataDir }
      setting 'repositories.url.allowed_urls', 'http://snapshot.test*'
      setting 'node.name', "upgraded-node-${stopNode}"
    }
  }

  Task oneThirdUpgradedTest = tasks.create(name: "${baseName}#oneThirdUpgradedTest", type: RestIntegTestTask)

  configureUpgradeCluster("oneThirdUpgradedTestCluster", oldClusterTestRunner, 0,
    // Use all running nodes as seed nodes so there is no race between pinging and the tests
    { oldClusterTest.nodes.get(1).transportUri() + ',' + oldClusterTest.nodes.get(2).transportUri() })

  Task oneThirdUpgradedTestRunner = tasks.getByName("${baseName}#oneThirdUpgradedTestRunner")
  oneThirdUpgradedTestRunner.configure {
    systemProperty 'tests.rest.suite', 'mixed_cluster'
    systemProperty 'tests.first_round', 'true'
    finalizedBy "${baseName}#oldClusterTestCluster#node1.stop"
  }

  Task twoThirdsUpgradedTest = tasks.create(name: "${baseName}#twoThirdsUpgradedTest", type: RestIntegTestTask)

  configureUpgradeCluster("twoThirdsUpgradedTestCluster", oneThirdUpgradedTestRunner, 1,
    // Use all running nodes as seed nodes so there is no race between pinging and the tests
    { oldClusterTest.nodes.get(2).transportUri() + ',' + oneThirdUpgradedTest.nodes.get(0).transportUri() })

  Task twoThirdsUpgradedTestRunner = tasks.getByName("${baseName}#twoThirdsUpgradedTestRunner")
  twoThirdsUpgradedTestRunner.configure {
    systemProperty 'tests.rest.suite', 'mixed_cluster'
    systemProperty 'tests.first_round', 'false'
    finalizedBy "${baseName}#oldClusterTestCluster#node2.stop"
  }

  Task upgradedClusterTest = tasks.create(name: "${baseName}#upgradedClusterTest", type: RestIntegTestTask)

  configureUpgradeCluster("upgradedClusterTestCluster", twoThirdsUpgradedTestRunner, 2,
    // Use all running nodes as seed nodes so there is no race between pinging and the tests
    { oneThirdUpgradedTest.nodes.get(0).transportUri() + ',' + twoThirdsUpgradedTest.nodes.get(0).transportUri() })

  Task upgradedClusterTestRunner = tasks.getByName("${baseName}#upgradedClusterTestRunner")
  upgradedClusterTestRunner.configure {
    systemProperty 'tests.rest.suite', 'upgraded_cluster'
    /*
     * Force stopping all the upgraded nodes after the test runner
     * so they are alive during the test.
     */
    finalizedBy "${baseName}#oneThirdUpgradedTestCluster#stop"
    finalizedBy "${baseName}#twoThirdsUpgradedTestCluster#stop"
  }

  Task versionBwcTest = tasks.create(name: "${baseName}#bwcTest") {
    enabled = project.bwc_tests_enabled
    dependsOn = [upgradedClusterTest]
  }

  if (project.bwc_tests_enabled) {
    bwcTest.dependsOn(versionBwcTest)
  }
}

test.enabled = false // no unit tests for rolling upgrades, only the rest integration test

// basic integ tests includes testing bwc against the most recent version
task integTest {
  if (project.bwc_tests_enabled) {
    for (final def version : bwcVersions.snapshotsWireCompatible) {
      dependsOn "v${version}#bwcTest"
    }
  }
}

check.dependsOn(integTest)