/*
    *
    * 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.replication.regionserver;
  
  import java.io.IOException;
  import java.io.InterruptedIOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.TreeMap;
  import java.util.UUID;
  import java.util.concurrent.atomic.AtomicLong;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellScanner;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.Stoppable;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.client.Connection;
  import org.apache.hadoop.hbase.client.ConnectionFactory;
  import org.apache.hadoop.hbase.client.Delete;
  import org.apache.hadoop.hbase.client.Mutation;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.Row;
  import org.apache.hadoop.hbase.client.Table;
  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.WALEntry;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos;
  import org.apache.hadoop.hbase.protobuf.generated.WALProtos.BulkLoadDescriptor;
  import org.apache.hadoop.hbase.protobuf.generated.WALProtos.StoreDescriptor;
  import org.apache.hadoop.hbase.regionserver.wal.WALEdit;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.Pair;
  
  /**
   * <p>
   * This class is responsible for replicating the edits coming
   * from another cluster.
   * </p><p>
   * This replication process is currently waiting for the edits to be applied
   * before the method can return. This means that the replication of edits
   * is synchronized (after reading from WALs in ReplicationSource) and that a
   * single region server cannot receive edits from two sources at the same time
   * </p><p>
   * This class uses the native HBase client in order to replicate entries.
   * </p>
   *
   * TODO make this class more like ReplicationSource wrt log handling
   */
  @InterfaceAudience.Private
  public class ReplicationSink {
  
    private static final Log LOG = LogFactory.getLog(ReplicationSink.class);
    private final Configuration conf;
    // Volatile because of note in here -- look for double-checked locking:
    // http://www.oracle.com/technetwork/articles/javase/bloch-effective-08-qa-140880.html
    private volatile Connection sharedHtableCon;
    private final MetricsSink metrics;
    private final AtomicLong totalReplicatedEdits = new AtomicLong();
    private final Object sharedHtableConLock = new Object();
    // Number of hfiles that we successfully replicated
    private long hfilesReplicated = 0;
    private SourceFSConfigurationProvider provider;
  
    /**
     * Create a sink for replication
     *
     * @param conf                conf object
     * @param stopper             boolean to tell this thread to stop
     * @throws IOException thrown when HDFS goes bad or bad file name
     */
    public ReplicationSink(Configuration conf, Stoppable stopper)
        throws IOException {
     this.conf = HBaseConfiguration.create(conf);
     decorateConf();
     this.metrics = new MetricsSink();
 
     String className =
         conf.get("hbase.replication.source.fs.conf.provider",
           DefaultSourceFSConfigurationProvider.class.getCanonicalName());
     try {
       @SuppressWarnings("rawtypes")
       Class c = Class.forName(className);
       this.provider = (SourceFSConfigurationProvider) c.newInstance();
     } catch (Exception e) {
       throw new IllegalArgumentException("Configured source fs configuration provider class "
           + className + " throws error.", e);
     }
   }
 
   /**
    * decorate the Configuration object to make replication more receptive to delays:
    * lessen the timeout and numTries.
    */
   private void decorateConf() {
     this.conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER,
         this.conf.getInt("replication.sink.client.retries.number", 4));
     this.conf.setInt(HConstants.HBASE_CLIENT_OPERATION_TIMEOUT,
         this.conf.getInt("replication.sink.client.ops.timeout", 10000));
     String replicationCodec = this.conf.get(HConstants.REPLICATION_CODEC_CONF_KEY);
     if (StringUtils.isNotEmpty(replicationCodec)) {
       this.conf.set(HConstants.RPC_CODEC_CONF_KEY, replicationCodec);
     }
    }
 
   /**
    * Replicate this array of entries directly into the local cluster using the native client. Only
    * operates against raw protobuf type saving on a conversion from pb to pojo.
    * @param entries
    * @param cells
    * @param replicationClusterId Id which will uniquely identify source cluster FS client
    *          configurations in the replication configuration directory
    * @param sourceBaseNamespaceDirPath Path that point to the source cluster base namespace
    *          directory
    * @param sourceHFileArchiveDirPath Path that point to the source cluster hfile archive directory
    * @throws IOException If failed to replicate the data
    */
   public void replicateEntries(List<WALEntry> entries, final CellScanner cells,
       String replicationClusterId, String sourceBaseNamespaceDirPath,
       String sourceHFileArchiveDirPath) throws IOException {
     if (entries.isEmpty()) return;
     if (cells == null) throw new NullPointerException("TODO: Add handling of null CellScanner");
     // Very simple optimization where we batch sequences of rows going
     // to the same table.
     try {
       long totalReplicated = 0;
       // Map of table => list of Rows, grouped by cluster id, we only want to flushCommits once per
       // invocation of this method per table and cluster id.
       Map<TableName, Map<List<UUID>, List<Row>>> rowMap =
           new TreeMap<TableName, Map<List<UUID>, List<Row>>>();
 
       // Map of table name Vs list of pair of family and list of hfile paths from its namespace
       Map<String, List<Pair<byte[], List<String>>>> bulkLoadHFileMap = null;
 
       for (WALEntry entry : entries) {
         TableName table =
             TableName.valueOf(entry.getKey().getTableName().toByteArray());
         Cell previousCell = null;
         Mutation m = null;
         int count = entry.getAssociatedCellCount();
         for (int i = 0; i < count; i++) {
           // Throw index out of bounds if our cell count is off
           if (!cells.advance()) {
             throw new ArrayIndexOutOfBoundsException("Expected=" + count + ", index=" + i);
           }
           Cell cell = cells.current();
           // Handle bulk load hfiles replication
           if (CellUtil.matchingQualifier(cell, WALEdit.BULK_LOAD)) {
             if (bulkLoadHFileMap == null) {
               bulkLoadHFileMap = new HashMap<String, List<Pair<byte[], List<String>>>>();
             }
             buildBulkLoadHFileMap(bulkLoadHFileMap, table, cell);
           } else {
             // Handle wal replication
             if (isNewRowOrType(previousCell, cell)) {
               // Create new mutation
               m =
                   CellUtil.isDelete(cell) ? new Delete(cell.getRowArray(), cell.getRowOffset(),
                       cell.getRowLength()) : new Put(cell.getRowArray(), cell.getRowOffset(),
                       cell.getRowLength());
               List<UUID> clusterIds = new ArrayList<UUID>();
               for (HBaseProtos.UUID clusterId : entry.getKey().getClusterIdsList()) {
                 clusterIds.add(toUUID(clusterId));
               }
               m.setClusterIds(clusterIds);
               addToHashMultiMap(rowMap, table, clusterIds, m);
             }
             if (CellUtil.isDelete(cell)) {
               ((Delete) m).addDeleteMarker(cell);
             } else {
               ((Put) m).add(cell);
             }
             previousCell = cell;
           }
         }
         totalReplicated++;
       }
 
       // TODO Replicating mutations and bulk loaded data can be made parallel
       if (!rowMap.isEmpty()) {
         LOG.debug("Started replicating mutations.");
         for (Entry<TableName, Map<List<UUID>, List<Row>>> entry : rowMap.entrySet()) {
           batch(entry.getKey(), entry.getValue().values());
         }
         LOG.debug("Finished replicating mutations.");
       }
 
       if (bulkLoadHFileMap != null && !bulkLoadHFileMap.isEmpty()) {
         LOG.debug("Started replicating bulk loaded data.");
         HFileReplicator hFileReplicator =
             new HFileReplicator(this.provider.getConf(this.conf, replicationClusterId),
                 sourceBaseNamespaceDirPath, sourceHFileArchiveDirPath, bulkLoadHFileMap, conf,
                 getConnection());
         hFileReplicator.replicate();
         LOG.debug("Finished replicating bulk loaded data.");
       }
 
       int size = entries.size();
       this.metrics.setAgeOfLastAppliedOp(entries.get(size - 1).getKey().getWriteTime());
       this.metrics.applyBatch(size + hfilesReplicated, hfilesReplicated);
       this.totalReplicatedEdits.addAndGet(totalReplicated);
     } catch (IOException ex) {
       LOG.error("Unable to accept edit because:", ex);
       throw ex;
     }
   }
 
   private void buildBulkLoadHFileMap(
       final Map<String, List<Pair<byte[], List<String>>>> bulkLoadHFileMap, TableName table,
       Cell cell) throws IOException {
     BulkLoadDescriptor bld = WALEdit.getBulkLoadDescriptor(cell);
     List<StoreDescriptor> storesList = bld.getStoresList();
     int storesSize = storesList.size();
     for (int j = 0; j < storesSize; j++) {
       StoreDescriptor storeDescriptor = storesList.get(j);
       List<String> storeFileList = storeDescriptor.getStoreFileList();
       int storeFilesSize = storeFileList.size();
       hfilesReplicated += storeFilesSize;
       for (int k = 0; k < storeFilesSize; k++) {
         byte[] family = storeDescriptor.getFamilyName().toByteArray();
 
         // Build hfile relative path from its namespace
         String pathToHfileFromNS = getHFilePath(table, bld, storeFileList.get(k), family);
 
         String tableName = table.getNameWithNamespaceInclAsString();
         if (bulkLoadHFileMap.containsKey(tableName)) {
           List<Pair<byte[], List<String>>> familyHFilePathsList = bulkLoadHFileMap.get(tableName);
           boolean foundFamily = false;
           for (int i = 0; i < familyHFilePathsList.size(); i++) {
             Pair<byte[], List<String>> familyHFilePathsPair = familyHFilePathsList.get(i);
             if (Bytes.equals(familyHFilePathsPair.getFirst(), family)) {
               // Found family already present, just add the path to the existing list
               familyHFilePathsPair.getSecond().add(pathToHfileFromNS);
               foundFamily = true;
               break;
             }
           }
           if (!foundFamily) {
             // Family not found, add this family and its hfile paths pair to the list
             addFamilyAndItsHFilePathToTableInMap(family, pathToHfileFromNS, familyHFilePathsList);
           }
         } else {
           // Add this table entry into the map
           addNewTableEntryInMap(bulkLoadHFileMap, family, pathToHfileFromNS, tableName);
         }
       }
     }
   }
 
   private void addFamilyAndItsHFilePathToTableInMap(byte[] family, String pathToHfileFromNS,
       List<Pair<byte[], List<String>>> familyHFilePathsList) {
     List<String> hfilePaths = new ArrayList<String>();
     hfilePaths.add(pathToHfileFromNS);
     familyHFilePathsList.add(new Pair<byte[], List<String>>(family, hfilePaths));
   }
 
   private void addNewTableEntryInMap(
       final Map<String, List<Pair<byte[], List<String>>>> bulkLoadHFileMap, byte[] family,
       String pathToHfileFromNS, String tableName) {
     List<String> hfilePaths = new ArrayList<String>();
     hfilePaths.add(pathToHfileFromNS);
     Pair<byte[], List<String>> newFamilyHFilePathsPair =
         new Pair<byte[], List<String>>(family, hfilePaths);
     List<Pair<byte[], List<String>>> newFamilyHFilePathsList =
         new ArrayList<Pair<byte[], List<String>>>();
     newFamilyHFilePathsList.add(newFamilyHFilePathsPair);
     bulkLoadHFileMap.put(tableName, newFamilyHFilePathsList);
   }
 
   private String getHFilePath(TableName table, BulkLoadDescriptor bld, String storeFile,
       byte[] family) {
     return new StringBuilder(100).append(table.getNamespaceAsString()).append(Path.SEPARATOR)
         .append(table.getQualifierAsString()).append(Path.SEPARATOR)
         .append(Bytes.toString(bld.getEncodedRegionName().toByteArray())).append(Path.SEPARATOR)
         .append(Bytes.toString(family)).append(Path.SEPARATOR).append(storeFile).toString();
   }
 
   /**
    * @param previousCell
    * @param cell
    * @return True if we have crossed over onto a new row or type
    */
   private boolean isNewRowOrType(final Cell previousCell, final Cell cell) {
     return previousCell == null || previousCell.getTypeByte() != cell.getTypeByte() ||
         !CellUtil.matchingRow(previousCell, cell);
   }
 
   private java.util.UUID toUUID(final HBaseProtos.UUID uuid) {
     return new java.util.UUID(uuid.getMostSigBits(), uuid.getLeastSigBits());
   }
 
   /**
    * Simple helper to a map from key to (a list of) values
    * TODO: Make a general utility method
    * @param map
    * @param key1
    * @param key2
    * @param value
    * @return the list of values corresponding to key1 and key2
    */
   private <K1, K2, V> List<V> addToHashMultiMap(Map<K1, Map<K2,List<V>>> map, K1 key1, K2 key2, V value) {
     Map<K2,List<V>> innerMap = map.get(key1);
     if (innerMap == null) {
       innerMap = new HashMap<K2, List<V>>();
       map.put(key1, innerMap);
     }
     List<V> values = innerMap.get(key2);
     if (values == null) {
       values = new ArrayList<V>();
       innerMap.put(key2, values);
     }
     values.add(value);
     return values;
   }
 
   /**
    * stop the thread pool executor. It is called when the regionserver is stopped.
    */
   public void stopReplicationSinkServices() {
     try {
       if (this.sharedHtableCon != null) {
         synchronized (sharedHtableConLock) {
           if (this.sharedHtableCon != null) {
             this.sharedHtableCon.close();
             this.sharedHtableCon = null;
           }
         }
       }
     } catch (IOException e) {
       LOG.warn("IOException while closing the connection", e); // ignoring as we are closing.
     }
   }
 
 
   /**
    * Do the changes and handle the pool
    * @param tableName table to insert into
    * @param allRows list of actions
    * @throws IOException
    */
   protected void batch(TableName tableName, Collection<List<Row>> allRows) throws IOException {
     if (allRows.isEmpty()) {
       return;
     }
     Table table = null;
     try {
       Connection connection = getConnection();
       table = connection.getTable(tableName);
       for (List<Row> rows : allRows) {
         table.batch(rows);
       }
     } catch (InterruptedException ix) {
       throw (InterruptedIOException) new InterruptedIOException().initCause(ix);
     } finally {
       if (table != null) {
         table.close();
       }
     }
   }
 
   private Connection getConnection() throws IOException {
     // See https://en.wikipedia.org/wiki/Double-checked_locking
     Connection connection = sharedHtableCon;
     if (connection == null) {
       synchronized (sharedHtableConLock) {
         connection = sharedHtableCon;
         if (connection == null) {
           connection = sharedHtableCon = ConnectionFactory.createConnection(conf);
         }
       }
     }
     return connection;
   }
 
   /**
    * Get a string representation of this sink's metrics
    * @return string with the total replicated edits count and the date
    * of the last edit that was applied
    */
   public String getStats() {
     return this.totalReplicatedEdits.get() == 0 ? "" : "Sink: " +
       "age in ms of last applied edit: " + this.metrics.refreshAgeOfLastAppliedOp() +
       ", total replicated edits: " + this.totalReplicatedEdits;
   }
 
   /**
    * Get replication Sink Metrics
    * @return MetricsSink
    */
   public MetricsSink getSinkMetrics() {
     return this.metrics;
   }
 }