/**
 * 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.hdfs.protocol;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Date;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableFactories;
import org.apache.hadoop.io.WritableFactory;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.net.NetworkTopology;
import org.apache.hadoop.net.Node;
import org.apache.hadoop.net.NodeBase;
import org.apache.hadoop.util.StringUtils;

import org.apache.avro.reflect.Nullable;

/** 
 * DatanodeInfo represents the status of a DataNode.
 * This object is used for communication in the
 * Datanode Protocol and the Client Protocol.
 */
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class DatanodeInfo extends DatanodeID implements Node {
  protected long capacity;
  protected long dfsUsed;
  protected long remaining;
  protected long blockPoolUsed;
  protected long lastUpdate;
  protected int xceiverCount;
  protected String location = NetworkTopology.DEFAULT_RACK;

  /** HostName as supplied by the datanode during registration as its 
   * name. Namenode uses datanode IP address as the name.
   */
  @Nullable
  protected String hostName = null;
  
  // administrative states of a datanode
  public enum AdminStates {
    NORMAL("In Service"), 
    DECOMMISSION_INPROGRESS("Decommission In Progress"), 
    DECOMMISSIONED("Decommissioned");

    final String value;

    AdminStates(final String v) {
      this.value = v;
    }

    public String toString() {
      return value;
    }
  }

  @Nullable
  protected AdminStates adminState;


  public DatanodeInfo() {
    super();
    adminState = null;
  }
  
  public DatanodeInfo(DatanodeInfo from) {
    super(from);
    this.capacity = from.getCapacity();
    this.dfsUsed = from.getDfsUsed();
    this.remaining = from.getRemaining();
    this.blockPoolUsed = from.getBlockPoolUsed();
    this.lastUpdate = from.getLastUpdate();
    this.xceiverCount = from.getXceiverCount();
    this.location = from.getNetworkLocation();
    this.adminState = from.adminState;
    this.hostName = from.hostName;
  }

  public DatanodeInfo(DatanodeID nodeID) {
    super(nodeID);
    this.capacity = 0L;
    this.dfsUsed = 0L;
    this.remaining = 0L;
    this.blockPoolUsed = 0L;
    this.lastUpdate = 0L;
    this.xceiverCount = 0;
    this.adminState = null;    
  }
  
  protected DatanodeInfo(DatanodeID nodeID, String location, String hostName) {
    this(nodeID);
    this.location = location;
    this.hostName = hostName;
  }

  /** Constructor */
  public DatanodeInfo(final String name, final String storageID,
      final int infoPort, final int ipcPort,
      final long capacity, final long dfsUsed, final long remaining,
      final long blockPoolUsed, final long lastUpdate, final int xceiverCount,
      final String networkLocation, final String hostName,
      final AdminStates adminState) {
    super(name, storageID, infoPort, ipcPort);

    this.capacity = capacity;
    this.dfsUsed = dfsUsed;
    this.remaining = remaining;
    this.blockPoolUsed = blockPoolUsed;
    this.lastUpdate = lastUpdate;
    this.xceiverCount = xceiverCount;
    this.location = networkLocation;
    this.hostName = hostName;
    this.adminState = adminState;
  }
  
  /** The raw capacity. */
  public long getCapacity() { return capacity; }
  
  /** The used space by the data node. */
  public long getDfsUsed() { return dfsUsed; }

  /** The used space by the block pool on data node. */
  public long getBlockPoolUsed() { return blockPoolUsed; }

  /** The used space by the data node. */
  public long getNonDfsUsed() { 
    long nonDFSUsed = capacity - dfsUsed - remaining;
    return nonDFSUsed < 0 ? 0 : nonDFSUsed;
  }

  /** The used space by the data node as percentage of present capacity */
  public float getDfsUsedPercent() { 
    return DFSUtil.getPercentUsed(dfsUsed, capacity);
  }

  /** The raw free space. */
  public long getRemaining() { return remaining; }

  /** Used space by the block pool as percentage of present capacity */
  public float getBlockPoolUsedPercent() {
    return DFSUtil.getPercentUsed(blockPoolUsed, capacity);
  }
  
  /** The remaining space as percentage of configured capacity. */
  public float getRemainingPercent() { 
    return DFSUtil.getPercentRemaining(remaining, capacity);
  }

  /** The time when this information was accurate. */
  public long getLastUpdate() { return lastUpdate; }

  /** number of active connections */
  public int getXceiverCount() { return xceiverCount; }

  /** Sets raw capacity. */
  public void setCapacity(long capacity) { 
    this.capacity = capacity; 
  }
  
  /** Sets the used space for the datanode. */
  public void setDfsUsed(long dfsUsed) {
    this.dfsUsed = dfsUsed;
  }

  /** Sets raw free space. */
  public void setRemaining(long remaining) { 
    this.remaining = remaining; 
  }

  /** Sets block pool used space */
  public void setBlockPoolUsed(long bpUsed) { 
    this.blockPoolUsed = bpUsed; 
  }

  /** Sets time when this information was accurate. */
  public void setLastUpdate(long lastUpdate) { 
    this.lastUpdate = lastUpdate; 
  }

  /** Sets number of active connections */
  public void setXceiverCount(int xceiverCount) { 
    this.xceiverCount = xceiverCount; 
  }

  /** rack name */
  public synchronized String getNetworkLocation() {return location;}
    
  /** Sets the rack name */
  public synchronized void setNetworkLocation(String location) {
    this.location = NodeBase.normalize(location);
  }
  
  public String getHostName() {
    return (hostName == null || hostName.length()==0) ? getHost() : hostName;
  }
  
  public void setHostName(String host) {
    hostName = host;
  }
  
  /** A formatted string for reporting the status of the DataNode. */
  public String getDatanodeReport() {
    StringBuilder buffer = new StringBuilder();
    long c = getCapacity();
    long r = getRemaining();
    long u = getDfsUsed();
    long nonDFSUsed = getNonDfsUsed();
    float usedPercent = getDfsUsedPercent();
    float remainingPercent = getRemainingPercent();
    String hostName = NetUtils.getHostNameOfIP(name);

    buffer.append("Name: "+ name);
    if(hostName != null)
      buffer.append(" (" + hostName + ")");
    buffer.append("\n");

    if (!NetworkTopology.DEFAULT_RACK.equals(location)) {
      buffer.append("Rack: "+location+"\n");
    }
    buffer.append("Decommission Status : ");
    if (isDecommissioned()) {
      buffer.append("Decommissioned\n");
    } else if (isDecommissionInProgress()) {
      buffer.append("Decommission in progress\n");
    } else {
      buffer.append("Normal\n");
    }
    buffer.append("Configured Capacity: "+c+" ("+StringUtils.byteDesc(c)+")"+"\n");
    buffer.append("DFS Used: "+u+" ("+StringUtils.byteDesc(u)+")"+"\n");
    buffer.append("Non DFS Used: "+nonDFSUsed+" ("+StringUtils.byteDesc(nonDFSUsed)+")"+"\n");
    buffer.append("DFS Remaining: " +r+ " ("+StringUtils.byteDesc(r)+")"+"\n");
    buffer.append("DFS Used%: "+StringUtils.limitDecimalTo2(usedPercent)+"%\n");
    buffer.append("DFS Remaining%: "+StringUtils.limitDecimalTo2(remainingPercent)+"%\n");
    buffer.append("Last contact: "+new Date(lastUpdate)+"\n");
    return buffer.toString();
  }

  /** A formatted string for printing the status of the DataNode. */
  public String dumpDatanode() {
    StringBuilder buffer = new StringBuilder();
    long c = getCapacity();
    long r = getRemaining();
    long u = getDfsUsed();
    buffer.append(name);
    if (!NetworkTopology.DEFAULT_RACK.equals(location)) {
      buffer.append(" "+location);
    }
    if (isDecommissioned()) {
      buffer.append(" DD");
    } else if (isDecommissionInProgress()) {
      buffer.append(" DP");
    } else {
      buffer.append(" IN");
    }
    buffer.append(" " + c + "(" + StringUtils.byteDesc(c)+")");
    buffer.append(" " + u + "(" + StringUtils.byteDesc(u)+")");
    buffer.append(" " + StringUtils.limitDecimalTo2(((1.0*u)/c)*100)+"%");
    buffer.append(" " + r + "(" + StringUtils.byteDesc(r)+")");
    buffer.append(" " + new Date(lastUpdate));
    return buffer.toString();
  }

  /**
   * Start decommissioning a node.
   * old state.
   */
  public void startDecommission() {
    adminState = AdminStates.DECOMMISSION_INPROGRESS;
  }

  /**
   * Stop decommissioning a node.
   * old state.
   */
  public void stopDecommission() {
    adminState = null;
  }

  /**
   * Returns true if the node is in the process of being decommissioned
   */
  public boolean isDecommissionInProgress() {
    return adminState == AdminStates.DECOMMISSION_INPROGRESS;
  }

  /**
   * Returns true if the node has been decommissioned.
   */
  public boolean isDecommissioned() {
    return adminState == AdminStates.DECOMMISSIONED;
  }

  /**
   * Sets the admin state to indicate that decommission is complete.
   */
  public void setDecommissioned() {
    adminState = AdminStates.DECOMMISSIONED;
  }

  /**
   * Retrieves the admin state of this node.
   */
  public AdminStates getAdminState() {
    if (adminState == null) {
      return AdminStates.NORMAL;
    }
    return adminState;
  }

  /**
   * Sets the admin state of this node.
   */
  protected void setAdminState(AdminStates newState) {
    if (newState == AdminStates.NORMAL) {
      adminState = null;
    }
    else {
      adminState = newState;
    }
  }

  private transient int level; //which level of the tree the node resides
  private transient Node parent; //its parent

  /** Return this node's parent */
  public Node getParent() { return parent; }
  public void setParent(Node parent) {this.parent = parent;}
   
  /** Return this node's level in the tree.
   * E.g. the root of a tree returns 0 and its children return 1
   */
  public int getLevel() { return level; }
  public void setLevel(int level) {this.level = level;}

  /////////////////////////////////////////////////
  // Writable
  /////////////////////////////////////////////////
  static {                                      // register a ctor
    WritableFactories.setFactory
      (DatanodeInfo.class,
       new WritableFactory() {
         public Writable newInstance() { return new DatanodeInfo(); }
       });
  }

  /** {@inheritDoc} */
  public void write(DataOutput out) throws IOException {
    super.write(out);

    //TODO: move it to DatanodeID once DatanodeID is not stored in FSImage
    out.writeShort(ipcPort);

    out.writeLong(capacity);
    out.writeLong(dfsUsed);
    out.writeLong(remaining);
    out.writeLong(blockPoolUsed);
    out.writeLong(lastUpdate);
    out.writeInt(xceiverCount);
    Text.writeString(out, location);
    Text.writeString(out, hostName == null? "": hostName);
    WritableUtils.writeEnum(out, getAdminState());
  }

  /** {@inheritDoc} */
  public void readFields(DataInput in) throws IOException {
    super.readFields(in);

    //TODO: move it to DatanodeID once DatanodeID is not stored in FSImage
    this.ipcPort = in.readShort() & 0x0000ffff;

    this.capacity = in.readLong();
    this.dfsUsed = in.readLong();
    this.remaining = in.readLong();
    this.blockPoolUsed = in.readLong();
    this.lastUpdate = in.readLong();
    this.xceiverCount = in.readInt();
    this.location = Text.readString(in);
    this.hostName = Text.readString(in);
    setAdminState(WritableUtils.readEnum(in, AdminStates.class));
  }

  /** Read a DatanodeInfo */
  public static DatanodeInfo read(DataInput in) throws IOException {
    final DatanodeInfo d = new DatanodeInfo();
    d.readFields(in);
    return d;
  }

  @Override
  public int hashCode() {
    // Super implementation is sufficient
    return super.hashCode();
  }
  
  @Override
  public boolean equals(Object obj) {
    // Sufficient to use super equality as datanodes are uniquely identified
    // by DatanodeID
    return (this == obj) || super.equals(obj);
  }
}