/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.
 */
package org.apache.hadoop.hbase.thrift;

import static org.apache.hadoop.hbase.thrift.Constants.THRIFT_SUPPORT_PROXYUSER_KEY;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;

import java.io.File;
import java.nio.file.Paths;
import java.security.Principal;
import java.security.PrivilegedExceptionAction;
import java.util.Set;

import javax.security.auth.Subject;
import javax.security.auth.kerberos.KerberosTicket;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.security.HBaseKerberosUtils;
import org.apache.hadoop.hbase.testclassification.ClientTests;
import org.apache.hadoop.hbase.testclassification.LargeTests;
import org.apache.hadoop.hbase.thrift.generated.Hbase;
import org.apache.hadoop.security.authentication.util.KerberosName;
import org.apache.http.HttpHeaders;
import org.apache.http.auth.AuthSchemeProvider;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.KerberosCredentials;
import org.apache.http.client.config.AuthSchemes;
import org.apache.http.config.Lookup;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.impl.auth.SPNegoSchemeFactory;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.kerby.kerberos.kerb.client.JaasKrbUtil;
import org.apache.kerby.kerberos.kerb.server.SimpleKdcServer;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.transport.THttpClient;
import org.ietf.jgss.GSSCredential;
import org.ietf.jgss.GSSManager;
import org.ietf.jgss.GSSName;
import org.ietf.jgss.Oid;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.experimental.categories.Category;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Start the HBase Thrift HTTP server on a random port through the command-line
 * interface and talk to it from client side with SPNEGO security enabled.
 *
 * Supplemental test to TestThriftSpnegoHttpServer which falls back to the original
 * Kerberos principal and keytab configuration properties, not the separate
 * SPNEGO-specific properties.
 */
@Category({ClientTests.class, LargeTests.class})
public class TestThriftSpnegoHttpFallbackServer extends TestThriftHttpServer {
  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
    HBaseClassTestRule.forClass(TestThriftSpnegoHttpFallbackServer.class);

  private static final Logger LOG =
    LoggerFactory.getLogger(TestThriftSpnegoHttpFallbackServer.class);

  private static SimpleKdcServer kdc;
  private static File serverKeytab;
  private static File clientKeytab;

  private static String clientPrincipal;
  private static String serverPrincipal;
  private static String spnegoServerPrincipal;

  private static SimpleKdcServer buildMiniKdc() throws Exception {
    SimpleKdcServer kdc = new SimpleKdcServer();

    File kdcDir = Paths.get(TEST_UTIL.getRandomDir().toString()).toAbsolutePath().toFile();
    kdcDir.mkdirs();
    kdc.setWorkDir(kdcDir);

    kdc.setKdcHost(HConstants.LOCALHOST);
    int kdcPort = HBaseTestingUtility.randomFreePort();
    kdc.setAllowTcp(true);
    kdc.setAllowUdp(false);
    kdc.setKdcTcpPort(kdcPort);

    LOG.info("Starting KDC server at " + HConstants.LOCALHOST + ":" + kdcPort);

    kdc.init();

    return kdc;
  }

  private static void addSecurityConfigurations(Configuration conf) {
    KerberosName.setRules("DEFAULT");

    HBaseKerberosUtils.setKeytabFileForTesting(serverKeytab.getAbsolutePath());

    conf.setBoolean(THRIFT_SUPPORT_PROXYUSER_KEY, true);
    conf.setBoolean(Constants.USE_HTTP_CONF_KEY, true);

    conf.set(Constants.THRIFT_KERBEROS_PRINCIPAL_KEY, serverPrincipal);
    conf.set(Constants.THRIFT_KEYTAB_FILE_KEY, serverKeytab.getAbsolutePath());

    HBaseKerberosUtils.setSecuredConfiguration(conf, spnegoServerPrincipal,
      spnegoServerPrincipal);
    conf.set("hadoop.proxyuser.HTTP.hosts", "*");
    conf.set("hadoop.proxyuser.HTTP.groups", "*");
    conf.set(Constants.THRIFT_KERBEROS_PRINCIPAL_KEY, spnegoServerPrincipal);
  }

  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    kdc = buildMiniKdc();
    kdc.start();

    File keytabDir = Paths.get(TEST_UTIL.getRandomDir().toString()).toAbsolutePath().toFile();
    keytabDir.mkdirs();

    clientPrincipal = "client@" + kdc.getKdcConfig().getKdcRealm();
    clientKeytab = new File(keytabDir, clientPrincipal + ".keytab");
    kdc.createAndExportPrincipals(clientKeytab, clientPrincipal);

    serverPrincipal = "hbase/" + HConstants.LOCALHOST + "@" + kdc.getKdcConfig().getKdcRealm();
    serverKeytab = new File(keytabDir, serverPrincipal.replace('/', '_') + ".keytab");

    spnegoServerPrincipal = "HTTP/" + HConstants.LOCALHOST + "@" + kdc.getKdcConfig().getKdcRealm();
    // Add SPNEGO principal to server keytab
    kdc.createAndExportPrincipals(serverKeytab, serverPrincipal, spnegoServerPrincipal);

    TEST_UTIL.getConfiguration().setBoolean(Constants.USE_HTTP_CONF_KEY, true);
    addSecurityConfigurations(TEST_UTIL.getConfiguration());

    TestThriftHttpServer.setUpBeforeClass();
  }

  @AfterClass
  public static void tearDownAfterClass() throws Exception {
    TestThriftHttpServer.tearDownAfterClass();

    try {
      if (null != kdc) {
        kdc.stop();
        kdc = null;
      }
    } catch (Exception e) {
      LOG.info("Failed to stop mini KDC", e);
    }
  }

  @Override
  protected void talkToThriftServer(String url, int customHeaderSize) throws Exception {
    // Close httpClient and THttpClient automatically on any failures
    try (
      CloseableHttpClient httpClient = createHttpClient();
      THttpClient tHttpClient = new THttpClient(url, httpClient)
    ) {
      tHttpClient.open();
      if (customHeaderSize > 0) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < customHeaderSize; i++) {
          sb.append("a");
        }
        tHttpClient.setCustomHeader(HttpHeaders.USER_AGENT, sb.toString());
      }

      TProtocol prot = new TBinaryProtocol(tHttpClient);
      Hbase.Client client = new Hbase.Client(prot);
      TestThriftServer.createTestTables(client);
      TestThriftServer.checkTableList(client);
      TestThriftServer.dropTestTables(client);
    }
  }

  private CloseableHttpClient createHttpClient() throws Exception {
    final Subject clientSubject = JaasKrbUtil.loginUsingKeytab(clientPrincipal, clientKeytab);
    final Set<Principal> clientPrincipals = clientSubject.getPrincipals();
    // Make sure the subject has a principal
    assertFalse("Found no client principals in the clientSubject.",
      clientPrincipals.isEmpty());

    // Get a TGT for the subject (might have many, different encryption types). The first should
    // be the default encryption type.
    Set<KerberosTicket> privateCredentials =
      clientSubject.getPrivateCredentials(KerberosTicket.class);
    assertFalse("Found no private credentials in the clientSubject.",
      privateCredentials.isEmpty());
    KerberosTicket tgt = privateCredentials.iterator().next();
    assertNotNull("No kerberos ticket found.", tgt);

    // The name of the principal
    final String clientPrincipalName = clientPrincipals.iterator().next().getName();

    return Subject.doAs(clientSubject, (PrivilegedExceptionAction<CloseableHttpClient>) () -> {
      // Logs in with Kerberos via GSS
      GSSManager gssManager = GSSManager.getInstance();
      // jGSS Kerberos login constant
      Oid oid = new Oid("1.2.840.113554.1.2.2");
      GSSName gssClient = gssManager.createName(clientPrincipalName, GSSName.NT_USER_NAME);
      GSSCredential credential = gssManager.createCredential(gssClient,
        GSSCredential.DEFAULT_LIFETIME, oid, GSSCredential.INITIATE_ONLY);

      Lookup<AuthSchemeProvider> authRegistry = RegistryBuilder.<AuthSchemeProvider>create()
        .register(AuthSchemes.SPNEGO, new SPNegoSchemeFactory(true, true))
        .build();

      BasicCredentialsProvider credentialsProvider = new BasicCredentialsProvider();
      credentialsProvider.setCredentials(AuthScope.ANY, new KerberosCredentials(credential));

      return HttpClients.custom()
        .setDefaultAuthSchemeRegistry(authRegistry)
        .setDefaultCredentialsProvider(credentialsProvider)
        .build();
    });
  }
}
