/*
    *
    * 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;
  
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.ServerName;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  /**
   * This class is responsible for the parsing logic for a znode representing a queue.
   * It will extract the peerId if it's recovered as well as the dead region servers
   * that were part of the queue's history.
   */
  @InterfaceAudience.Private
  public class ReplicationQueueInfo {
    private static final Log LOG = LogFactory.getLog(ReplicationQueueInfo.class);
  
    private final String peerId;
    private final String peerClusterZnode;
    private boolean queueRecovered;
    // List of all the dead region servers that had this queue (if recovered)
    private List<String> deadRegionServers = new ArrayList<String>();
  
    /**
     * The passed znode will be either the id of the peer cluster or
     * the handling story of that queue in the form of id-servername-*
     */
    public ReplicationQueueInfo(String znode) {
      this.peerClusterZnode = znode;
      String[] parts = znode.split("-", 2);
      this.queueRecovered = parts.length != 1;
      this.peerId = this.queueRecovered ?
          parts[0] : peerClusterZnode;
      if (parts.length >= 2) {
        // extract dead servers
        extractDeadServersFromZNodeString(parts[1], this.deadRegionServers);
      }
    }
  
    /**
     * Parse dead server names from znode string servername can contain "-" such as
     * "ip-10-46-221-101.ec2.internal", so we need skip some "-" during parsing for the following
     * cases: 2-ip-10-46-221-101.ec2.internal,52170,1364333181125-<server name>-...
     */
    private static void
        extractDeadServersFromZNodeString(String deadServerListStr, List<String> result) {
  
      if(deadServerListStr == null || result == null || deadServerListStr.isEmpty()) return;
  
      // valid server name delimiter "-" has to be after "," in a server name
      int seenCommaCnt = 0;
      int startIndex = 0;
      int len = deadServerListStr.length();
  
      for (int i = 0; i < len; i++) {
        switch (deadServerListStr.charAt(i)) {
        case ',':
          seenCommaCnt += 1;
          break;
        case '-':
          if(seenCommaCnt>=2) {
            if (i > startIndex) {
              String serverName = deadServerListStr.substring(startIndex, i);
              if(ServerName.isFullServerName(serverName)){
                result.add(serverName);
              } else {
                LOG.error("Found invalid server name:" + serverName);
              }
              startIndex = i + 1;
            }
            seenCommaCnt = 0;
          }
          break;
        default:
          break;
        }
     }
 
     // add tail
     if(startIndex < len - 1){
       String serverName = deadServerListStr.substring(startIndex, len);
       if(ServerName.isFullServerName(serverName)){
         result.add(serverName);
       } else {
         LOG.error("Found invalid server name at the end:" + serverName);
       }
     }
 
     LOG.debug("Found dead servers:" + result);
   }
 
   public List<String> getDeadRegionServers() {
     return Collections.unmodifiableList(this.deadRegionServers);
   }
 
   public String getPeerId() {
     return this.peerId;
   }
 
   public String getPeerClusterZnode() {
     return this.peerClusterZnode;
   }
 
   public boolean isQueueRecovered() {
     return queueRecovered;
   }
 }