import org.elasticsearch.gradle.BuildPlugin
import org.elasticsearch.gradle.LoggedExec
import org.elasticsearch.gradle.info.BuildParams

import javax.net.ssl.HttpsURLConnection
import javax.net.ssl.KeyManagerFactory
import javax.net.ssl.SSLContext
import javax.net.ssl.TrustManagerFactory
import java.nio.charset.StandardCharsets
import java.security.KeyStore
import java.security.SecureRandom

// Tell the tests we're running with ssl enabled
integTest.runner {
  systemProperty 'tests.ssl.enabled', 'true'
}

// needed to be consistent with ssl host checking
Object san = new SanEvaluator()

// location of generated keystores and certificates
File keystoreDir = new File(project.buildDir, 'keystore')

// Generate the node's keystore
File nodeKeystore = file("$keystoreDir/test-node.jks")
task createNodeKeyStore(type: LoggedExec) {
  doFirst {
    if (nodeKeystore.parentFile.exists() == false) {
      nodeKeystore.parentFile.mkdirs()
    }
    if (nodeKeystore.exists()) {
      delete nodeKeystore
    }
  }
  executable = "${BuildParams.runtimeJavaHome}/bin/keytool"
  standardInput = new ByteArrayInputStream('FirstName LastName\nUnit\nOrganization\nCity\nState\nNL\nyes\n\n'.getBytes('UTF-8'))
  args '-genkey',
          '-alias', 'test-node',
          '-keystore', nodeKeystore,
          '-keyalg', 'RSA',
          '-keysize', '2048',
          '-validity', '712',
          '-dname', 'CN=smoke-test-plugins-ssl',
          '-keypass', 'keypass',
          '-storepass', 'keypass',
          '-ext', san
}

// Generate the client's keystore
File clientKeyStore = file("$keystoreDir/test-client.jks")
task createClientKeyStore(type: LoggedExec) {
  doFirst {
    if (clientKeyStore.parentFile.exists() == false) {
      clientKeyStore.parentFile.mkdirs()
    }
    if (clientKeyStore.exists()) {
      delete clientKeyStore
    }
  }
  executable = "${BuildParams.runtimeJavaHome}/bin/keytool"
  standardInput = new ByteArrayInputStream('FirstName LastName\nUnit\nOrganization\nCity\nState\nNL\nyes\n\n'.getBytes('UTF-8'))
  args '-genkey',
          '-alias', 'test-client',
          '-keystore', clientKeyStore,
          '-keyalg', 'RSA',
          '-keysize', '2048',
          '-validity', '712',
          '-dname', 'CN=smoke-test-plugins-ssl',
          '-keypass', 'keypass',
          '-storepass', 'keypass',
          '-ext', san
}

// Export the node's certificate
File nodeCertificate = file("$keystoreDir/test-node.cert")
task exportNodeCertificate(type: LoggedExec) {
  dependsOn createNodeKeyStore
  doFirst {
    if (nodeCertificate.parentFile.exists() == false) {
      nodeCertificate.parentFile.mkdirs()
    }
    if (nodeCertificate.exists()) {
      delete nodeCertificate
    }
  }
  executable = "${BuildParams.runtimeJavaHome}/bin/keytool"
  args '-export',
          '-alias', 'test-node',
          '-keystore', nodeKeystore,
          '-storepass', 'keypass',
          '-file', nodeCertificate
}

// Import the node certificate in the client's keystore
task importNodeCertificateInClientKeyStore(type: LoggedExec) {
  dependsOn createClientKeyStore, exportNodeCertificate
  executable = "${BuildParams.runtimeJavaHome}/bin/keytool"
  args '-import',
          '-alias', 'test-node',
          '-keystore', clientKeyStore,
          '-storepass', 'keypass',
          '-file', nodeCertificate,
          '-noprompt'
}

// Export the client's certificate
File clientCertificate = file("$keystoreDir/test-client.cert")
task exportClientCertificate(type: LoggedExec) {
  dependsOn createClientKeyStore
  doFirst {
    if (clientCertificate.parentFile.exists() == false) {
      clientCertificate.parentFile.mkdirs()
    }
    if (clientCertificate.exists()) {
      delete clientCertificate
    }
  }
  executable = "${BuildParams.runtimeJavaHome}/bin/keytool"
  args '-export',
          '-alias', 'test-client',
          '-keystore', clientKeyStore,
          '-storepass', 'keypass',
          '-file', clientCertificate
}

// Import the client certificate in the node's keystore
task importClientCertificateInNodeKeyStore(type: LoggedExec) {
  dependsOn createNodeKeyStore, exportClientCertificate
  executable = "${BuildParams.runtimeJavaHome}/bin/keytool"
  args '-import',
          '-alias', 'test-client',
          '-keystore', nodeKeystore,
          '-storepass', 'keypass',
          '-file', clientCertificate,
          '-noprompt'
}

forbiddenPatterns {
  exclude '**/*.cert'
}

// Add keystores to test classpath: it expects it there
sourceSets.test.resources.srcDir(keystoreDir)
processTestResources.dependsOn(importNodeCertificateInClientKeyStore, importClientCertificateInNodeKeyStore)

integTest.runner {
  dependsOn(importClientCertificateInNodeKeyStore)
  onlyIf {
    // Do not attempt to form a cluster in a FIPS JVM, as doing so with a JKS keystore will fail.
    // TODO Revisit this when SQL CLI client can handle key/certificate instead of only Keystores.
    // https://github.com/elastic/elasticsearch/issues/32306
    BuildParams.inFipsJvm == false
  }
}

testClusters.integTest {
  // The setup that we actually want
  setting 'xpack.license.self_generated.type', 'trial'
  setting 'xpack.security.http.ssl.enabled', 'true'
  setting 'xpack.security.transport.ssl.enabled', 'true'

  // ceremony to set up ssl
  setting 'xpack.security.transport.ssl.keystore.path', 'test-node.jks'
  setting 'xpack.security.http.ssl.keystore.path', 'test-node.jks'
  keystore 'xpack.security.transport.ssl.keystore.secure_password', 'keypass'
  keystore 'xpack.security.http.ssl.keystore.secure_password', 'keypass'


  // copy keystores into config/
  extraConfigFile nodeKeystore.name, nodeKeystore
  extraConfigFile clientKeyStore.name, clientKeyStore
}


/** A lazy evaluator to find the san to use for certificate generation. */
class SanEvaluator {

  private static String san = null

  String toString() {
    synchronized (SanEvaluator.class) {
      if (san == null) {
        san = getSubjectAlternativeNameString()
      }
    }
    return san
  }

  // Code stolen from NetworkUtils/InetAddresses/NetworkAddress to support SAN
  /** Return all interfaces (and subinterfaces) on the system */
  private static List<NetworkInterface> getInterfaces() throws SocketException {
    List<NetworkInterface> all = new ArrayList<>();
    addAllInterfaces(all, Collections.list(NetworkInterface.getNetworkInterfaces()));
    Collections.sort(all, new Comparator<NetworkInterface>() {
      @Override
      public int compare(NetworkInterface left, NetworkInterface right) {
        return Integer.compare(left.getIndex(), right.getIndex());
      }
    });
    return all;
  }

  /** Helper for getInterfaces, recursively adds subinterfaces to {@code target} */
  private static void addAllInterfaces(List<NetworkInterface> target, List<NetworkInterface> level) {
    if (!level.isEmpty()) {
      target.addAll(level);
      for (NetworkInterface intf : level) {
        addAllInterfaces(target, Collections.list(intf.getSubInterfaces()));
      }
    }
  }

  private static String getSubjectAlternativeNameString() {
    List<InetAddress> list = new ArrayList<>();
    for (NetworkInterface intf : getInterfaces()) {
      if (intf.isUp()) {
        // NOTE: some operating systems (e.g. BSD stack) assign a link local address to the loopback interface
        // while technically not a loopback address, some of these treat them as one (e.g. OS X "localhost") so we must too,
        // otherwise things just won't work out of box. So we include all addresses from loopback interfaces.
        for (InetAddress address : Collections.list(intf.getInetAddresses())) {
          if (intf.isLoopback() || address.isLoopbackAddress()) {
            list.add(address);
          }
        }
      }
    }
    if (list.isEmpty()) {
      throw new IllegalArgumentException("no up-and-running loopback addresses found, got " + getInterfaces());
    }

    StringBuilder builder = new StringBuilder("san=");
    for (int i = 0; i < list.size(); i++) {
      InetAddress address = list.get(i);
      String hostAddress;
      if (address instanceof Inet6Address) {
        hostAddress = compressedIPV6Address((Inet6Address)address);
      } else {
        hostAddress = address.getHostAddress();
      }
      builder.append("ip:").append(hostAddress);
      String hostname = address.getHostName();
      if (hostname.equals(address.getHostAddress()) == false) {
        builder.append(",dns:").append(hostname);
      }

      if (i != (list.size() - 1)) {
        builder.append(",");
      }
    }

    return builder.toString();
  }

  private static String compressedIPV6Address(Inet6Address inet6Address) {
    byte[] bytes = inet6Address.getAddress();
    int[] hextets = new int[8];
    for (int i = 0; i < hextets.length; i++) {
      hextets[i] = (bytes[2 * i] & 255) << 8 | bytes[2 * i + 1] & 255;
    }
    compressLongestRunOfZeroes(hextets);
    return hextetsToIPv6String(hextets);
  }

  /**
   * Identify and mark the longest run of zeroes in an IPv6 address.
   *
   * <p>Only runs of two or more hextets are considered.  In case of a tie, the
   * leftmost run wins.  If a qualifying run is found, its hextets are replaced
   * by the sentinel value -1.
   *
   * @param hextets {@code int[]} mutable array of eight 16-bit hextets
   */
  private static void compressLongestRunOfZeroes(int[] hextets) {
    int bestRunStart = -1;
    int bestRunLength = -1;
    int runStart = -1;
    for (int i = 0; i < hextets.length + 1; i++) {
      if (i < hextets.length && hextets[i] == 0) {
        if (runStart < 0) {
          runStart = i;
        }
      } else if (runStart >= 0) {
        int runLength = i - runStart;
        if (runLength > bestRunLength) {
          bestRunStart = runStart;
          bestRunLength = runLength;
        }
        runStart = -1;
      }
    }
    if (bestRunLength >= 2) {
      Arrays.fill(hextets, bestRunStart, bestRunStart + bestRunLength, -1);
    }
  }

  /**
   * Convert a list of hextets into a human-readable IPv6 address.
   *
   * <p>In order for "::" compression to work, the input should contain negative
   * sentinel values in place of the elided zeroes.
   *
   * @param hextets {@code int[]} array of eight 16-bit hextets, or -1s
   */
  private static String hextetsToIPv6String(int[] hextets) {
    /*
     * While scanning the array, handle these state transitions:
     *   start->num => "num"     start->gap => "::"
     *   num->num   => ":num"    num->gap   => "::"
     *   gap->num   => "num"     gap->gap   => ""
     */
    StringBuilder buf = new StringBuilder(39);
    boolean lastWasNumber = false;
    for (int i = 0; i < hextets.length; i++) {
      boolean thisIsNumber = hextets[i] >= 0;
      if (thisIsNumber) {
        if (lastWasNumber) {
          buf.append(':');
        }
        buf.append(Integer.toHexString(hextets[i]));
      } else {
        if (i == 0 || lastWasNumber) {
          buf.append("::");
        }
      }
      lastWasNumber = thisIsNumber;
    }
    return buf.toString();
  }
}