/*
 * 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.http.ssl;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.math.BigInteger;
import java.net.URL;
import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.SignatureException;
import java.security.cert.Certificate;
import java.security.cert.CertificateEncodingException;
import java.security.cert.X509Certificate;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import javax.security.auth.x500.X500Principal;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseCommonTestingUtil;
import org.apache.hadoop.security.ssl.FileBasedKeyStoresFactory;
import org.apache.hadoop.security.ssl.SSLFactory;
import org.bouncycastle.x509.X509V1CertificateGenerator;

public final class KeyStoreTestUtil {
  private KeyStoreTestUtil() {
  }

  public static String getClasspathDir(Class<?> klass) throws Exception {
    String file = klass.getName();
    file = file.replace('.', '/') + ".class";
    URL url = Thread.currentThread().getContextClassLoader().getResource(file);
    String baseDir = url.toURI().getPath();
    baseDir = baseDir.substring(0, baseDir.length() - file.length() - 1);
    return baseDir;
  }

  /**
   * Create a self-signed X.509 Certificate.
   * @param dn        the X.509 Distinguished Name, eg "CN=Test, L=London, C=GB"
   * @param pair      the KeyPair
   * @param days      how many days from now the Certificate is valid for
   * @param algorithm the signing algorithm, eg "SHA1withRSA"
   * @return the self-signed certificate
   */
  public static X509Certificate generateCertificate(String dn, KeyPair pair, int days,
    String algorithm) throws CertificateEncodingException, InvalidKeyException,
    IllegalStateException, NoSuchProviderException, NoSuchAlgorithmException, SignatureException {
    Date from = new Date();
    Date to = new Date(from.getTime() + days * 86400000L);
    BigInteger sn = new BigInteger(64, new SecureRandom());
    KeyPair keyPair = pair;
    X509V1CertificateGenerator certGen = new X509V1CertificateGenerator();
    X500Principal dnName = new X500Principal(dn);

    certGen.setSerialNumber(sn);
    certGen.setIssuerDN(dnName);
    certGen.setNotBefore(from);
    certGen.setNotAfter(to);
    certGen.setSubjectDN(dnName);
    certGen.setPublicKey(keyPair.getPublic());
    certGen.setSignatureAlgorithm(algorithm);
    X509Certificate cert = certGen.generate(pair.getPrivate());
    return cert;
  }

  public static KeyPair generateKeyPair(String algorithm) throws NoSuchAlgorithmException {
    KeyPairGenerator keyGen = KeyPairGenerator.getInstance(algorithm);
    keyGen.initialize(1024);
    return keyGen.genKeyPair();
  }

  private static KeyStore createEmptyKeyStore() throws GeneralSecurityException, IOException {
    return createEmptyKeyStore("jks");
  }

  private static KeyStore createEmptyKeyStore(String keyStoreType)
    throws GeneralSecurityException, IOException {
    KeyStore ks = KeyStore.getInstance(keyStoreType);
    ks.load(null, null); // initialize
    return ks;
  }

  private static void saveKeyStore(KeyStore ks, String filename, String password)
    throws GeneralSecurityException, IOException {
    FileOutputStream out = new FileOutputStream(filename);
    try {
      ks.store(out, password.toCharArray());
    } finally {
      out.close();
    }
  }

  /**
   * Creates a keystore with a single key and saves it to a file. This method will use the same
   * password for the keystore and for the key. This method will always generate a keystore file in
   * JKS format.
   * @param filename   String file to save
   * @param password   String store password to set on keystore
   * @param alias      String alias to use for the key
   * @param privateKey Key to save in keystore
   * @param cert       Certificate to use as certificate chain associated to key
   * @throws GeneralSecurityException for any error with the security APIs
   * @throws IOException              if there is an I/O error saving the file
   */
  public static void createKeyStore(String filename, String password, String alias, Key privateKey,
    Certificate cert) throws GeneralSecurityException, IOException {
    createKeyStore(filename, password, password, alias, privateKey, cert);
  }

  /**
   * Creates a keystore with a single key and saves it to a file. This method will always generate a
   * keystore file in JKS format.
   * @param filename    String file to save
   * @param password    String store password to set on keystore
   * @param keyPassword String key password to set on key
   * @param alias       String alias to use for the key
   * @param privateKey  Key to save in keystore
   * @param cert        Certificate to use as certificate chain associated to key
   * @throws GeneralSecurityException for any error with the security APIs
   * @throws IOException              if there is an I/O error saving the file
   */
  public static void createKeyStore(String filename, String password, String keyPassword,
    String alias, Key privateKey, Certificate cert) throws GeneralSecurityException, IOException {
    createKeyStore(filename, password, keyPassword, alias, privateKey, cert, "JKS");
  }

  /**
   * Creates a keystore with a single key and saves it to a file.
   * @param filename     String file to save
   * @param password     String store password to set on keystore
   * @param keyPassword  String key password to set on key
   * @param alias        String alias to use for the key
   * @param privateKey   Key to save in keystore
   * @param cert         Certificate to use as certificate chain associated to key
   * @param keystoreType String keystore file type (e.g. "JKS")
   * @throws GeneralSecurityException for any error with the security APIs
   * @throws IOException              if there is an I/O error saving the file
   */
  public static void createKeyStore(String filename, String password, String keyPassword,
    String alias, Key privateKey, Certificate cert, String keystoreType)
    throws GeneralSecurityException, IOException {
    KeyStore ks = createEmptyKeyStore(keystoreType);
    ks.setKeyEntry(alias, privateKey, keyPassword.toCharArray(), new Certificate[] { cert });
    saveKeyStore(ks, filename, password);
  }

  /**
   * Creates a truststore with a single certificate and saves it to a file. This method uses the
   * default JKS truststore type.
   * @param filename String file to save
   * @param password String store password to set on truststore
   * @param alias    String alias to use for the certificate
   * @param cert     Certificate to add
   * @throws GeneralSecurityException for any error with the security APIs
   * @throws IOException              if there is an I/O error saving the file
   */
  public static void createTrustStore(String filename, String password, String alias,
    Certificate cert) throws GeneralSecurityException, IOException {
    createTrustStore(filename, password, alias, cert, "JKS");
  }

  /**
   * Creates a truststore with a single certificate and saves it to a file.
   * @param filename       String file to save
   * @param password       String store password to set on truststore
   * @param alias          String alias to use for the certificate
   * @param cert           Certificate to add
   * @param trustStoreType String keystore file type (e.g. "JKS")
   * @throws GeneralSecurityException for any error with the security APIs
   * @throws IOException              if there is an I/O error saving the file
   */
  public static void createTrustStore(String filename, String password, String alias,
    Certificate cert, String trustStoreType) throws GeneralSecurityException, IOException {
    KeyStore ks = createEmptyKeyStore(trustStoreType);
    ks.setCertificateEntry(alias, cert);
    saveKeyStore(ks, filename, password);
  }

  public static <T extends Certificate> void createTrustStore(String filename, String password,
    Map<String, T> certs) throws GeneralSecurityException, IOException {
    KeyStore ks = createEmptyKeyStore();
    for (Map.Entry<String, T> cert : certs.entrySet()) {
      ks.setCertificateEntry(cert.getKey(), cert.getValue());
    }
    saveKeyStore(ks, filename, password);
  }

  public static void cleanupSSLConfig(Configuration conf) throws Exception {
    File f = new File(conf.get(FileBasedKeyStoresFactory.resolvePropertyName(SSLFactory.Mode.SERVER,
      FileBasedKeyStoresFactory.SSL_TRUSTSTORE_LOCATION_TPL_KEY)));
    f.delete();
    f = new File(conf.get(FileBasedKeyStoresFactory.resolvePropertyName(SSLFactory.Mode.SERVER,
      FileBasedKeyStoresFactory.SSL_KEYSTORE_LOCATION_TPL_KEY)));
    f.delete();

    String clientKeyStore =
      conf.get(FileBasedKeyStoresFactory.resolvePropertyName(SSLFactory.Mode.CLIENT,
        FileBasedKeyStoresFactory.SSL_KEYSTORE_LOCATION_TPL_KEY));
    if (clientKeyStore != null) {
      f = new File(clientKeyStore);
      f.delete();
    }
    f = new File(KeyStoreTestUtil.getClasspathDir(KeyStoreTestUtil.class) + "/"
      + conf.get(SSLFactory.SSL_CLIENT_CONF_KEY));
    f.delete();
    f = new File(KeyStoreTestUtil.getClasspathDir(KeyStoreTestUtil.class) + "/"
      + conf.get(SSLFactory.SSL_SERVER_CONF_KEY));
    f.delete();
  }

  /**
   * Performs complete setup of SSL configuration in preparation for testing an SSLFactory. This
   * includes keys, certs, keystores, truststores, the server SSL configuration file, the client SSL
   * configuration file, and the master configuration file read by the SSLFactory.
   * @param keystoresDir  String directory to save keystores
   * @param sslConfDir    String directory to save SSL configuration files
   * @param conf          Configuration master configuration to be used by an SSLFactory, which will
   *                      be mutated by this method
   * @param useClientCert boolean true to make the client present a cert in the SSL handshake
   */
  public static void setupSSLConfig(String keystoresDir, String sslConfDir, Configuration conf,
    boolean useClientCert) throws Exception {
    String clientKS = keystoresDir + "/clientKS.jks";
    String clientPassword = "clientP";
    String serverKS = keystoresDir + "/serverKS.jks";
    String serverPassword = "serverP";
    String trustKS = keystoresDir + "/trustKS.jks";
    String trustPassword = "trustP";

    File sslClientConfFile = new File(sslConfDir + "/ssl-client-" + System.nanoTime() + "-"
      + HBaseCommonTestingUtil.getRandomUUID() + ".xml");
    File sslServerConfFile = new File(sslConfDir + "/ssl-server-" + System.nanoTime() + "-"
      + HBaseCommonTestingUtil.getRandomUUID() + ".xml");

    Map<String, X509Certificate> certs = new HashMap<>();

    if (useClientCert) {
      KeyPair cKP = KeyStoreTestUtil.generateKeyPair("RSA");
      X509Certificate cCert =
        KeyStoreTestUtil.generateCertificate("CN=localhost, O=client", cKP, 30, "SHA1withRSA");
      KeyStoreTestUtil.createKeyStore(clientKS, clientPassword, "client", cKP.getPrivate(), cCert);
      certs.put("client", cCert);
    }

    KeyPair sKP = KeyStoreTestUtil.generateKeyPair("RSA");
    X509Certificate sCert =
      KeyStoreTestUtil.generateCertificate("CN=localhost, O=server", sKP, 30, "SHA1withRSA");
    KeyStoreTestUtil.createKeyStore(serverKS, serverPassword, "server", sKP.getPrivate(), sCert);
    certs.put("server", sCert);

    KeyStoreTestUtil.createTrustStore(trustKS, trustPassword, certs);

    Configuration clientSSLConf =
      createClientSSLConfig(clientKS, clientPassword, clientPassword, trustKS);
    Configuration serverSSLConf =
      createServerSSLConfig(serverKS, serverPassword, serverPassword, trustKS);

    saveConfig(sslClientConfFile, clientSSLConf);
    saveConfig(sslServerConfFile, serverSSLConf);

    conf.set(SSLFactory.SSL_HOSTNAME_VERIFIER_KEY, "ALLOW_ALL");
    conf.set(SSLFactory.SSL_CLIENT_CONF_KEY, sslClientConfFile.getName());
    conf.set(SSLFactory.SSL_SERVER_CONF_KEY, sslServerConfFile.getName());
    conf.set("dfs.https.server.keystore.resource", sslServerConfFile.getName());

    conf.setBoolean(SSLFactory.SSL_REQUIRE_CLIENT_CERT_KEY, useClientCert);
  }

  /**
   * Creates SSL configuration for a client.
   * @param clientKS    String client keystore file
   * @param password    String store password, or null to avoid setting store password
   * @param keyPassword String key password, or null to avoid setting key password
   * @param trustKS     String truststore file
   * @return Configuration for client SSL
   */
  public static Configuration createClientSSLConfig(String clientKS, String password,
    String keyPassword, String trustKS) {
    Configuration clientSSLConf =
      createSSLConfig(SSLFactory.Mode.CLIENT, clientKS, password, keyPassword, trustKS);
    return clientSSLConf;
  }

  /**
   * Creates SSL configuration for a server.
   * @param serverKS    String server keystore file
   * @param password    String store password, or null to avoid setting store password
   * @param keyPassword String key password, or null to avoid setting key password
   * @param trustKS     String truststore file
   * @return Configuration for server SSL
   */
  public static Configuration createServerSSLConfig(String serverKS, String password,
    String keyPassword, String trustKS) throws IOException {
    Configuration serverSSLConf =
      createSSLConfig(SSLFactory.Mode.SERVER, serverKS, password, keyPassword, trustKS);
    return serverSSLConf;
  }

  /**
   * Creates SSL configuration.
   * @param mode        SSLFactory.Mode mode to configure
   * @param keystore    String keystore file
   * @param password    String store password, or null to avoid setting store password
   * @param keyPassword String key password, or null to avoid setting key password
   * @param trustKS     String truststore file
   * @return Configuration for SSL
   */
  private static Configuration createSSLConfig(SSLFactory.Mode mode, String keystore,
    String password, String keyPassword, String trustKS) {
    String trustPassword = "trustP";

    Configuration sslConf = new Configuration(false);
    if (keystore != null) {
      sslConf.set(FileBasedKeyStoresFactory.resolvePropertyName(mode,
        FileBasedKeyStoresFactory.SSL_KEYSTORE_LOCATION_TPL_KEY), keystore);
    }
    if (password != null) {
      sslConf.set(FileBasedKeyStoresFactory.resolvePropertyName(mode,
        FileBasedKeyStoresFactory.SSL_KEYSTORE_PASSWORD_TPL_KEY), password);
    }
    if (keyPassword != null) {
      sslConf.set(FileBasedKeyStoresFactory.resolvePropertyName(mode,
        FileBasedKeyStoresFactory.SSL_KEYSTORE_KEYPASSWORD_TPL_KEY), keyPassword);
    }
    if (trustKS != null) {
      sslConf.set(FileBasedKeyStoresFactory.resolvePropertyName(mode,
        FileBasedKeyStoresFactory.SSL_TRUSTSTORE_LOCATION_TPL_KEY), trustKS);
    }
    if (trustPassword != null) {
      sslConf.set(FileBasedKeyStoresFactory.resolvePropertyName(mode,
        FileBasedKeyStoresFactory.SSL_TRUSTSTORE_PASSWORD_TPL_KEY), trustPassword);
    }
    sslConf.set(FileBasedKeyStoresFactory.resolvePropertyName(mode,
      FileBasedKeyStoresFactory.SSL_TRUSTSTORE_RELOAD_INTERVAL_TPL_KEY), "1000");

    return sslConf;
  }

  /**
   * Saves configuration to a file.
   * @param file File to save
   * @param conf Configuration contents to write to file
   * @throws IOException if there is an I/O error saving the file
   */
  public static void saveConfig(File file, Configuration conf) throws IOException {
    Writer writer = new FileWriter(file);
    try {
      conf.writeXml(writer);
    } finally {
      writer.close();
    }
  }
}