package org.apache.helix.util;
   
   /*
    * 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.
   */
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  import org.apache.helix.HelixException;
  import org.apache.helix.model.IdealState;
  import org.apache.helix.model.StateModelDefinition;
  
  public class RebalanceUtil
  {
    public static Map<String, Object> buildInternalIdealState(IdealState state)
    {
      // Try parse the partition number from name DB_n. If not, sort the partitions and
      // assign id
      Map<String, Integer> partitionIndex = new HashMap<String, Integer>();
      Map<String, String> reversePartitionIndex = new HashMap<String, String>();
      boolean indexInPartitionName = true;
      for (String partitionId : state.getPartitionSet())
      {
        int lastPos = partitionId.lastIndexOf("_");
        if (lastPos < 0)
        {
          indexInPartitionName = false;
          break;
        }
        try
        {
          String idStr = partitionId.substring(lastPos + 1);
          int partition = Integer.parseInt(idStr);
          partitionIndex.put(partitionId, partition);
          reversePartitionIndex.put(state.getResourceName() + "_" + partition, partitionId);
        }
        catch (Exception e)
        {
          indexInPartitionName = false;
          partitionIndex.clear();
          reversePartitionIndex.clear();
          break;
        }
      }
  
      if (indexInPartitionName == false)
      {
        List<String> partitions = new ArrayList<String>();
        partitions.addAll(state.getPartitionSet());
        Collections.sort(partitions);
        for (int i = 0; i < partitions.size(); i++)
        {
          partitionIndex.put(partitions.get(i), i);
          reversePartitionIndex.put(state.getResourceName() + "_" + i, partitions.get(i));
        }
      }
  
      Map<String, List<Integer>> nodeMasterAssignmentMap =
          new TreeMap<String, List<Integer>>();
      Map<String, Map<String, List<Integer>>> combinedNodeSlaveAssignmentMap =
          new TreeMap<String, Map<String, List<Integer>>>();
      for (String partition : state.getPartitionSet())
      {
        List<String> instances = state.getRecord().getListField(partition);
        String master = instances.get(0);
        if (!nodeMasterAssignmentMap.containsKey(master))
        {
          nodeMasterAssignmentMap.put(master, new ArrayList<Integer>());
        }
        if (!combinedNodeSlaveAssignmentMap.containsKey(master))
        {
          combinedNodeSlaveAssignmentMap.put(master, new TreeMap<String, List<Integer>>());
        }
        nodeMasterAssignmentMap.get(master).add(partitionIndex.get(partition));
        for (int i = 1; i < instances.size(); i++)
        {
          String instance = instances.get(i);
          Map<String, List<Integer>> slaveMap = combinedNodeSlaveAssignmentMap.get(master);
          if (!slaveMap.containsKey(instance))
         {
           slaveMap.put(instance, new ArrayList<Integer>());
         }
         slaveMap.get(instance).add(partitionIndex.get(partition));
       }
     }
 
     Map<String, Object> result = new TreeMap<String, Object>();
     result.put("MasterAssignmentMap", nodeMasterAssignmentMap);
     result.put("SlaveAssignmentMap", combinedNodeSlaveAssignmentMap);
     result.put("replicas", Integer.parseInt(state.getReplicas()));
     result.put("partitions", new Integer(state.getRecord().getListFields().size()));
     result.put("reversePartitionIndex", reversePartitionIndex);
     return result;
   }
   public static String[] parseStates(String clusterName, StateModelDefinition stateModDef)
   {
     String[] result = new String[2];
     String masterStateValue = null, slaveStateValue = null;
 
     // StateModelDefinition def = new StateModelDefinition(stateModDef);
 
     List<String> statePriorityList = stateModDef.getStatesPriorityList();
 
     for (String state : statePriorityList)
     {
       String count = stateModDef.getNumInstancesPerState(state);
       if (count.equals("1"))
       {
         if (masterStateValue != null)
         {
           throw new HelixException("Invalid or unsupported state model definition");
         }
         masterStateValue = state;
       }
       else if (count.equalsIgnoreCase("R"))
       {
         if (slaveStateValue != null)
         {
           throw new HelixException("Invalid or unsupported state model definition");
         }
         slaveStateValue = state;
       }
       else if (count.equalsIgnoreCase("N"))
       {
         if (!(masterStateValue == null && slaveStateValue == null))
         {
           throw new HelixException("Invalid or unsupported state model definition");
         }
         masterStateValue = slaveStateValue = state;
       }
     }
     if (masterStateValue == null && slaveStateValue == null)
     {
       throw new HelixException("Invalid or unsupported state model definition");
     }
 
     if (masterStateValue == null)
     {
       masterStateValue = slaveStateValue;
     }
     result[0] = masterStateValue;
     result[1] = slaveStateValue;
     return result;
   }
 }