/**
 * 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.regionserver;

import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.security.Key;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import javax.crypto.spec.SecretKeySpec;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.Waiter;
import org.apache.hadoop.hbase.client.CompactionState;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.io.crypto.Encryption;
import org.apache.hadoop.hbase.io.crypto.KeyProviderForTesting;
import org.apache.hadoop.hbase.io.crypto.aes.AES;
import org.apache.hadoop.hbase.io.hfile.CacheConfig;
import org.apache.hadoop.hbase.io.hfile.HFile;
import org.apache.hadoop.hbase.security.EncryptionUtil;
import org.apache.hadoop.hbase.security.User;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.testclassification.RegionServerTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Rule;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.junit.rules.TestName;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Category({RegionServerTests.class, MediumTests.class})
public class TestEncryptionKeyRotation {

  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
      HBaseClassTestRule.forClass(TestEncryptionKeyRotation.class);

  private static final Logger LOG = LoggerFactory.getLogger(TestEncryptionKeyRotation.class);
  private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
  private static final Configuration conf = TEST_UTIL.getConfiguration();
  private static final Key initialCFKey;
  private static final Key secondCFKey;

  @Rule
  public TestName name = new TestName();

  static {
    // Create the test encryption keys
    SecureRandom rng = new SecureRandom();
    byte[] keyBytes = new byte[AES.KEY_LENGTH];
    rng.nextBytes(keyBytes);
    String algorithm =
        conf.get(HConstants.CRYPTO_KEY_ALGORITHM_CONF_KEY, HConstants.CIPHER_AES);
    initialCFKey = new SecretKeySpec(keyBytes, algorithm);
    rng.nextBytes(keyBytes);
    secondCFKey = new SecretKeySpec(keyBytes, algorithm);
  }

  @BeforeClass
  public static void setUp() throws Exception {
    conf.setInt("hfile.format.version", 3);
    conf.set(HConstants.CRYPTO_KEYPROVIDER_CONF_KEY, KeyProviderForTesting.class.getName());
    conf.set(HConstants.CRYPTO_MASTERKEY_NAME_CONF_KEY, "hbase");

    // Start the minicluster
    TEST_UTIL.startMiniCluster(1);
  }

  @AfterClass
  public static void tearDown() throws Exception {
    TEST_UTIL.shutdownMiniCluster();
  }

  @Test
  public void testCFKeyRotation() throws Exception {
    // Create the table schema
    HTableDescriptor htd = new HTableDescriptor(TableName.valueOf("default", name.getMethodName()));
    HColumnDescriptor hcd = new HColumnDescriptor("cf");
    String algorithm =
        conf.get(HConstants.CRYPTO_KEY_ALGORITHM_CONF_KEY, HConstants.CIPHER_AES);
    hcd.setEncryptionType(algorithm);
    hcd.setEncryptionKey(EncryptionUtil.wrapKey(conf, "hbase", initialCFKey));
    htd.addFamily(hcd);

    // Create the table and some on disk files
    createTableAndFlush(htd);

    // Verify we have store file(s) with the initial key
    final List<Path> initialPaths = findStorefilePaths(htd.getTableName());
    assertTrue(initialPaths.size() > 0);
    for (Path path: initialPaths) {
      assertTrue("Store file " + path + " has incorrect key",
        Bytes.equals(initialCFKey.getEncoded(), extractHFileKey(path)));
    }

    // Update the schema with a new encryption key
    hcd = htd.getFamily(Bytes.toBytes("cf"));
    hcd.setEncryptionKey(EncryptionUtil.wrapKey(conf,
      conf.get(HConstants.CRYPTO_MASTERKEY_NAME_CONF_KEY, User.getCurrent().getShortName()),
      secondCFKey));
    TEST_UTIL.getAdmin().modifyColumnFamily(htd.getTableName(), hcd);
    Thread.sleep(5000); // Need a predicate for online schema change

    // And major compact
    TEST_UTIL.getAdmin().majorCompact(htd.getTableName());
    // waiting for the major compaction to complete
    TEST_UTIL.waitFor(30000, new Waiter.Predicate<IOException>() {
      @Override
      public boolean evaluate() throws IOException {
        return TEST_UTIL.getAdmin().getCompactionState(htd.getTableName()) ==
            CompactionState.NONE;
      }
    });
    List<Path> pathsAfterCompaction = findStorefilePaths(htd.getTableName());
    assertTrue(pathsAfterCompaction.size() > 0);
    for (Path path: pathsAfterCompaction) {
      assertTrue("Store file " + path + " has incorrect key",
        Bytes.equals(secondCFKey.getEncoded(), extractHFileKey(path)));
    }
    List<Path> compactedPaths = findCompactedStorefilePaths(htd.getTableName());
    assertTrue(compactedPaths.size() > 0);
    for (Path path: compactedPaths) {
      assertTrue("Store file " + path + " retains initial key",
        Bytes.equals(initialCFKey.getEncoded(), extractHFileKey(path)));
    }
  }

  @Test
  public void testMasterKeyRotation() throws Exception {
    // Create the table schema
    HTableDescriptor htd = new HTableDescriptor(TableName.valueOf("default", name.getMethodName()));
    HColumnDescriptor hcd = new HColumnDescriptor("cf");
    String algorithm =
        conf.get(HConstants.CRYPTO_KEY_ALGORITHM_CONF_KEY, HConstants.CIPHER_AES);
    hcd.setEncryptionType(algorithm);
    hcd.setEncryptionKey(EncryptionUtil.wrapKey(conf, "hbase", initialCFKey));
    htd.addFamily(hcd);

    // Create the table and some on disk files
    createTableAndFlush(htd);

    // Verify we have store file(s) with the initial key
    List<Path> storeFilePaths = findStorefilePaths(htd.getTableName());
    assertTrue(storeFilePaths.size() > 0);
    for (Path path: storeFilePaths) {
      assertTrue("Store file " + path + " has incorrect key",
        Bytes.equals(initialCFKey.getEncoded(), extractHFileKey(path)));
    }

    // Now shut down the HBase cluster
    TEST_UTIL.shutdownMiniHBaseCluster();

    // "Rotate" the master key
    conf.set(HConstants.CRYPTO_MASTERKEY_NAME_CONF_KEY, "other");
    conf.set(HConstants.CRYPTO_MASTERKEY_ALTERNATE_NAME_CONF_KEY, "hbase");

    // Start the cluster back up
    TEST_UTIL.startMiniHBaseCluster();
    // Verify the table can still be loaded
    TEST_UTIL.waitTableAvailable(htd.getTableName(), 5000);
    // Double check that the store file keys can be unwrapped
    storeFilePaths = findStorefilePaths(htd.getTableName());
    assertTrue(storeFilePaths.size() > 0);
    for (Path path: storeFilePaths) {
      assertTrue("Store file " + path + " has incorrect key",
        Bytes.equals(initialCFKey.getEncoded(), extractHFileKey(path)));
    }
  }

  private static List<Path> findStorefilePaths(TableName tableName) throws Exception {
    List<Path> paths = new ArrayList<>();
    for (Region region : TEST_UTIL.getRSForFirstRegionInTable(tableName)
        .getRegions(tableName)) {
      for (HStore store : ((HRegion) region).getStores()) {
        for (HStoreFile storefile : store.getStorefiles()) {
          paths.add(storefile.getPath());
        }
      }
    }
    return paths;
  }

  private static List<Path> findCompactedStorefilePaths(TableName tableName) throws Exception {
    List<Path> paths = new ArrayList<>();
    for (Region region : TEST_UTIL.getRSForFirstRegionInTable(tableName)
        .getRegions(tableName)) {
      for (HStore store : ((HRegion) region).getStores()) {
        Collection<HStoreFile> compactedfiles =
            store.getStoreEngine().getStoreFileManager().getCompactedfiles();
        if (compactedfiles != null) {
          for (HStoreFile storefile : compactedfiles) {
            paths.add(storefile.getPath());
          }
        }
      }
    }
    return paths;
  }

  private void createTableAndFlush(HTableDescriptor htd) throws Exception {
    HColumnDescriptor hcd = htd.getFamilies().iterator().next();
    // Create the test table
    TEST_UTIL.getAdmin().createTable(htd);
    TEST_UTIL.waitTableAvailable(htd.getTableName(), 5000);
    // Create a store file
    Table table = TEST_UTIL.getConnection().getTable(htd.getTableName());
    try {
      table.put(new Put(Bytes.toBytes("testrow"))
              .addColumn(hcd.getName(), Bytes.toBytes("q"), Bytes.toBytes("value")));
    } finally {
      table.close();
    }
    TEST_UTIL.getAdmin().flush(htd.getTableName());
  }

  private static byte[] extractHFileKey(Path path) throws Exception {
    HFile.Reader reader = HFile.createReader(TEST_UTIL.getTestFileSystem(), path,
      new CacheConfig(conf), true, conf);
    try {
      Encryption.Context cryptoContext = reader.getFileContext().getEncryptionContext();
      assertNotNull("Reader has a null crypto context", cryptoContext);
      Key key = cryptoContext.getKey();
      assertNotNull("Crypto context has no key", key);
      return key.getEncoded();
    } finally {
      reader.close();
    }
  }

}
