/*
 * 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.client;

import java.util.Arrays;
import org.apache.hadoop.hbase.CellComparator;
import org.apache.hadoop.hbase.CellComparatorImpl;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * An implementation of RegionInfo that adds mutable methods so can build a RegionInfo instance.
 * Package private. Use {@link RegionInfoBuilder} creating instances of {@link RegionInfo}s.
 */
@InterfaceAudience.Private
class MutableRegionInfo implements RegionInfo {
  private static final Logger LOG = LoggerFactory.getLogger(MutableRegionInfo.class);
  private static final int MAX_REPLICA_ID = 0xFFFF;

  /**
   * The new format for a region name contains its encodedName at the end. The encoded name also
   * serves as the directory name for the region in the filesystem. New region name format:
   * <tablename>,,<startkey>,<regionIdTimestamp>.<encodedName>. where, <encodedName>
   * is a hex version of the MD5 hash of <tablename>,<startkey>,<regionIdTimestamp> The old
   * region name format: <tablename>,<startkey>,<regionIdTimestamp> For region names in the
   * old format, the encoded name is a 32-bit JenkinsHash integer value (in its decimal notation,
   * string form).
   * <p>
   * **NOTE** The first hbase:meta region, and regions created by an older version of HBase (0.20 or
   * prior) will continue to use the old region name format.
   */

  // This flag is in the parent of a split while the parent is still referenced by daughter
  // regions. We USED to set this flag when we disabled a table but now table state is kept up in
  // zookeeper as of 0.90.0 HBase. And now in DisableTableProcedure, finally we will create bunch
  // of UnassignProcedures and at the last of the procedure we will set the region state to
  // CLOSED, and will not change the offLine flag.
  private boolean offLine;
  private boolean split;
  private final long regionId;
  private final int replicaId;
  private final byte[] regionName;
  private final byte[] startKey;
  private final byte[] endKey;
  private final int hashCode;
  private final String encodedName;
  private final byte[] encodedNameAsBytes;
  private String nameAsString = null;
  private final TableName tableName;

  private static int generateHashCode(final TableName tableName, final byte[] startKey,
    final byte[] endKey, final long regionId, final int replicaId, boolean offLine,
    byte[] regionName) {
    int result = Arrays.hashCode(regionName);
    result = (int) (result ^ regionId);
    result ^= Arrays.hashCode(checkStartKey(startKey));
    result ^= Arrays.hashCode(checkEndKey(endKey));
    result ^= Boolean.valueOf(offLine).hashCode();
    result ^= Arrays.hashCode(tableName.getName());
    result ^= replicaId;
    return result;
  }

  private static byte[] checkStartKey(byte[] startKey) {
    return startKey == null ? HConstants.EMPTY_START_ROW : startKey;
  }

  private static byte[] checkEndKey(byte[] endKey) {
    return endKey == null ? HConstants.EMPTY_END_ROW : endKey;
  }

  private static TableName checkTableName(TableName tableName) {
    if (tableName == null) {
      throw new IllegalArgumentException("TableName cannot be null");
    }
    return tableName;
  }

  private static int checkReplicaId(int regionId) {
    if (regionId > MAX_REPLICA_ID) {
      throw new IllegalArgumentException("ReplicaId cannot be greater than " + MAX_REPLICA_ID);
    }
    return regionId;
  }

  /**
   * Package private constructor used constructing MutableRegionInfo for the first meta regions
   */
  MutableRegionInfo(long regionId, TableName tableName, int replicaId) {
    this(tableName, HConstants.EMPTY_START_ROW, HConstants.EMPTY_END_ROW, false, regionId,
      replicaId, false);
  }

  MutableRegionInfo(final TableName tableName, final byte[] startKey, final byte[] endKey,
    final boolean split, final long regionId, final int replicaId, boolean offLine) {
    this.tableName = checkTableName(tableName);
    this.startKey = checkStartKey(startKey);
    this.endKey = checkEndKey(endKey);
    this.split = split;
    this.regionId = regionId;
    this.replicaId = checkReplicaId(replicaId);
    this.offLine = offLine;
    this.regionName = RegionInfo.createRegionName(this.tableName, this.startKey, this.regionId,
      this.replicaId, !this.tableName.equals(TableName.META_TABLE_NAME));
    this.encodedName = RegionInfo.encodeRegionName(this.regionName);
    this.hashCode = generateHashCode(this.tableName, this.startKey, this.endKey, this.regionId,
      this.replicaId, this.offLine, this.regionName);
    this.encodedNameAsBytes = Bytes.toBytes(this.encodedName);
  }

  /**
   * Returns Return a short, printable name for this region (usually encoded name) for us logging.
   */
  @Override
  public String getShortNameToLog() {
    return RegionInfo.prettyPrint(this.getEncodedName());
  }

  /** Returns the regionId */
  @Override
  public long getRegionId() {
    return regionId;
  }

  /**
   * @return the regionName as an array of bytes.
   * @see #getRegionNameAsString()
   */
  @Override
  public byte[] getRegionName() {
    return regionName;
  }

  /**
   * Returns region name as a String for use in logging, tracing, etc. Expensive enough to compute
   * that we do it on first request and save it. Used often because it's included in trace of every
   * RPC.
   */
  @Override
  public String getRegionNameAsString() {
    if (nameAsString == null) {
      String name = RegionInfo.getRegionNameAsString(this, this.regionName);
      // may race with other threads setting this, but that's ok
      nameAsString = name;
      return name;
    } else {
      return nameAsString;
    }
  }

  /** Returns the encoded region name */
  @Override
  public String getEncodedName() {
    return this.encodedName;
  }

  @Override
  public byte[] getEncodedNameAsBytes() {
    return this.encodedNameAsBytes;
  }

  /** Returns the startKey */
  @Override
  public byte[] getStartKey() {
    return startKey;
  }

  /** Returns the endKey */
  @Override
  public byte[] getEndKey() {
    return endKey;
  }

  /**
   * Get current table name of the region
   */
  @Override
  public TableName getTable() {
    return this.tableName;
  }

  /**
   * Returns true if the given inclusive range of rows is fully contained by this region. For
   * example, if the region is foo,a,g and this is passed ["b","c"] or ["a","c"] it will return
   * true, but if this is passed ["b","z"] it will return false.
   * @throws IllegalArgumentException if the range passed is invalid (ie. end &lt; start)
   */
  @Override
  public boolean containsRange(byte[] rangeStartKey, byte[] rangeEndKey) {
    CellComparator cellComparator = CellComparatorImpl.getCellComparator(tableName);
    if (cellComparator.compareRows(rangeStartKey, rangeEndKey) > 0) {
      throw new IllegalArgumentException("Invalid range: " + Bytes.toStringBinary(rangeStartKey)
        + " > " + Bytes.toStringBinary(rangeEndKey));
    }

    boolean firstKeyInRange = cellComparator.compareRows(rangeStartKey, startKey) >= 0;
    boolean lastKeyInRange = cellComparator.compareRows(rangeEndKey, endKey) < 0
      || Bytes.equals(endKey, HConstants.EMPTY_BYTE_ARRAY);
    return firstKeyInRange && lastKeyInRange;
  }

  /**
   * Return true if the given row falls in this region.
   */
  @Override
  public boolean containsRow(byte[] row) {
    CellComparator cellComparator = CellComparatorImpl.getCellComparator(tableName);
    return cellComparator.compareRows(row, startKey) >= 0
      && (cellComparator.compareRows(row, endKey) < 0
        || Bytes.equals(endKey, HConstants.EMPTY_BYTE_ARRAY));
  }

  /** Returns true if this region is a meta region */
  @Override
  public boolean isMetaRegion() {
    return tableName.equals(TableName.META_TABLE_NAME);
  }

  /** Returns True if has been split and has daughters. */
  @Override
  public boolean isSplit() {
    return this.split;
  }

  /**
   * Change the split status flag.
   * @param split set split status
   */
  public MutableRegionInfo setSplit(boolean split) {
    this.split = split;
    return this;
  }

  /**
   * @return True if this region is offline.
   * @deprecated since 3.0.0 and will be removed in 4.0.0
   * @see <a href="https://issues.apache.org/jira/browse/HBASE-25210">HBASE-25210</a>
   */
  @Override
  @Deprecated
  public boolean isOffline() {
    return this.offLine;
  }

  /**
   * The parent of a region split is offline while split daughters hold references to the parent.
   * Offlined regions are closed.
   * @param offLine Set online/offline status.
   */
  public MutableRegionInfo setOffline(boolean offLine) {
    this.offLine = offLine;
    return this;
  }

  /**
   * @return True if this is a split parent region.
   * @deprecated since 3.0.0 and will be removed in 4.0.0, Use {@link #isSplit()} instead.
   * @see <a href="https://issues.apache.org/jira/browse/HBASE-25210">HBASE-25210</a>
   */
  @Override
  @Deprecated
  public boolean isSplitParent() {
    if (!isSplit()) {
      return false;
    }
    if (!isOffline()) {
      LOG.warn("Region is split but NOT offline: " + getRegionNameAsString());
    }
    return true;
  }

  /**
   * Returns the region replica id
   * @return returns region replica id
   */
  @Override
  public int getReplicaId() {
    return replicaId;
  }

  /**
   * @see Object#toString()
   */
  @Override
  public String toString() {
    return "{ENCODED => " + getEncodedName() + ", " + HConstants.NAME + " => '"
      + Bytes.toStringBinary(this.regionName) + "', STARTKEY => '"
      + Bytes.toStringBinary(this.startKey) + "', ENDKEY => '" + Bytes.toStringBinary(this.endKey)
      + "'" + (isOffline() ? ", OFFLINE => true" : "") + (isSplit() ? ", SPLIT => true" : "")
      + ((replicaId > 0) ? ", REPLICA_ID => " + replicaId : "") + "}";
  }

  /**
   * @see Object#equals(Object)
   */
  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null) {
      return false;
    }
    if (!(o instanceof RegionInfo)) {
      return false;
    }
    return compareTo((RegionInfo) o) == 0;
  }

  /**
   * @see Object#hashCode()
   */
  @Override
  public int hashCode() {
    return this.hashCode;
  }
}