/**
    * 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.master.procedure;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.NamespaceDescriptor;
  import org.apache.hadoop.hbase.NamespaceNotFoundException;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.master.TableNamespaceManager;
  import org.apache.hadoop.hbase.procedure2.StateMachineProcedure;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProcedureProtos;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProcedureProtos.ModifyNamespaceState;
  
  /**
   * The procedure to add a namespace to an existing table.
   */
  @InterfaceAudience.Private
  public class ModifyNamespaceProcedure
      extends StateMachineProcedure<MasterProcedureEnv, ModifyNamespaceState>
      implements TableProcedureInterface {
    private static final Log LOG = LogFactory.getLog(ModifyNamespaceProcedure.class);
  
    private final AtomicBoolean aborted = new AtomicBoolean(false);
  
    private NamespaceDescriptor oldNsDescriptor;
    private NamespaceDescriptor newNsDescriptor;
    private Boolean traceEnabled;
  
    public ModifyNamespaceProcedure() {
      this.oldNsDescriptor = null;
      this.traceEnabled = null;
    }
  
    public ModifyNamespaceProcedure(final MasterProcedureEnv env,
        final NamespaceDescriptor newNsDescriptor) {
      this.oldNsDescriptor = null;
      this.newNsDescriptor = newNsDescriptor;
      this.traceEnabled = null;
      this.setOwner(env.getRequestUser().getUGI().getShortUserName());
    }
  
    @Override
    protected Flow executeFromState(final MasterProcedureEnv env, final ModifyNamespaceState state)
        throws InterruptedException {
      if (isTraceEnabled()) {
        LOG.trace(this + " execute state=" + state);
      }
  
      try {
        switch (state) {
        case MODIFY_NAMESPACE_PREPARE:
          prepareModify(env);
          setNextState(ModifyNamespaceState.MODIFY_NAMESPACE_UPDATE_NS_TABLE);
          break;
        case MODIFY_NAMESPACE_UPDATE_NS_TABLE:
          insertIntoNSTable(env);
          setNextState(ModifyNamespaceState.MODIFY_NAMESPACE_UPDATE_ZK);
          break;
        case MODIFY_NAMESPACE_UPDATE_ZK:
          updateZKNamespaceManager(env);
          return Flow.NO_MORE_STATE;
        default:
          throw new UnsupportedOperationException(this + " unhandled state=" + state);
        }
      } catch (IOException e) {
        LOG.warn("Error trying to modify the namespace" + newNsDescriptor.getName()
          + " (in state=" + state + ")", e);
  
        setFailure("master-modify-namespace", e);
      }
      return Flow.HAS_MORE_STATE;
    }
  
    @Override
    protected void rollbackState(final MasterProcedureEnv env, final ModifyNamespaceState state)
       throws IOException {
     if (isTraceEnabled()) {
       LOG.trace(this + " rollback state=" + state);
     }
     try {
       switch (state) {
       case MODIFY_NAMESPACE_UPDATE_ZK:
         rollbackZKNamespaceManagerChange(env);
         break;
       case MODIFY_NAMESPACE_UPDATE_NS_TABLE:
         rollbackUpdateInNSTable(env);
         break;
       case MODIFY_NAMESPACE_PREPARE:
         break; // nothing to do
       default:
         throw new UnsupportedOperationException(this + " unhandled state=" + state);
       }
     } catch (IOException e) {
       // This will be retried. Unless there is a bug in the code,
       // this should be just a "temporary error" (e.g. network down)
       LOG.warn("Failed rollback attempt step " + state + " for creating the namespace "
           + newNsDescriptor.getName(), e);
       throw e;
     }
   }
 
   @Override
   protected ModifyNamespaceState getState(final int stateId) {
     return ModifyNamespaceState.valueOf(stateId);
   }
 
   @Override
   protected int getStateId(final ModifyNamespaceState state) {
     return state.getNumber();
   }
 
   @Override
   protected ModifyNamespaceState getInitialState() {
     return ModifyNamespaceState.MODIFY_NAMESPACE_PREPARE;
   }
 
   @Override
   protected void setNextState(ModifyNamespaceState state) {
     if (aborted.get()) {
       setAbortFailure("modify-namespace", "abort requested");
     } else {
       super.setNextState(state);
     }
   }
 
   @Override
   public boolean abort(final MasterProcedureEnv env) {
     aborted.set(true);
     return true;
   }
 
   @Override
   public void serializeStateData(final OutputStream stream) throws IOException {
     super.serializeStateData(stream);
 
     MasterProcedureProtos.ModifyNamespaceStateData.Builder modifyNamespaceMsg =
         MasterProcedureProtos.ModifyNamespaceStateData.newBuilder().setNamespaceDescriptor(
           ProtobufUtil.toProtoNamespaceDescriptor(this.newNsDescriptor));
     if (this.oldNsDescriptor != null) {
       modifyNamespaceMsg.setUnmodifiedNamespaceDescriptor(
         ProtobufUtil.toProtoNamespaceDescriptor(this.oldNsDescriptor));
     }
     modifyNamespaceMsg.build().writeDelimitedTo(stream);
   }
 
   @Override
   public void deserializeStateData(final InputStream stream) throws IOException {
     super.deserializeStateData(stream);
 
     MasterProcedureProtos.ModifyNamespaceStateData modifyNamespaceMsg =
         MasterProcedureProtos.ModifyNamespaceStateData.parseDelimitedFrom(stream);
     newNsDescriptor =
         ProtobufUtil.toNamespaceDescriptor(modifyNamespaceMsg.getNamespaceDescriptor());
     if (modifyNamespaceMsg.hasUnmodifiedNamespaceDescriptor()) {
       oldNsDescriptor =
           ProtobufUtil.toNamespaceDescriptor(modifyNamespaceMsg.getUnmodifiedNamespaceDescriptor());
     }
   }
 
   @Override
   public void toStringClassDetails(StringBuilder sb) {
     sb.append(getClass().getSimpleName());
     sb.append(" (Namespace=");
     sb.append(newNsDescriptor.getName());
     sb.append(")");
   }
 
   @Override
   protected boolean acquireLock(final MasterProcedureEnv env) {
     if (env.waitInitialized(this)) return false;
     return env.getProcedureQueue().tryAcquireNamespaceExclusiveLock(this, getNamespaceName());
   }
 
   @Override
   protected void releaseLock(final MasterProcedureEnv env) {
     env.getProcedureQueue().releaseNamespaceExclusiveLock(this, getNamespaceName());
   }
 
   @Override
   public TableName getTableName() {
     return TableName.NAMESPACE_TABLE_NAME;
   }
 
   @Override
   public TableOperationType getTableOperationType() {
     return TableOperationType.EDIT;
   }
 
   private String getNamespaceName() {
     return newNsDescriptor.getName();
   }
 
   /**
    * Action before any real action of adding namespace.
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void prepareModify(final MasterProcedureEnv env) throws IOException {
     if (getTableNamespaceManager(env).doesNamespaceExist(newNsDescriptor.getName()) == false) {
       throw new NamespaceNotFoundException(newNsDescriptor.getName());
     }
     getTableNamespaceManager(env).validateTableAndRegionCount(newNsDescriptor);
 
     // This is used for rollback
     oldNsDescriptor = getTableNamespaceManager(env).get(newNsDescriptor.getName());
   }
 
   /**
    * Insert/update the row into namespace table
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void insertIntoNSTable(final MasterProcedureEnv env) throws IOException {
     getTableNamespaceManager(env).insertIntoNSTable(newNsDescriptor);
   }
 
   /**
    * rollback the row into namespace table
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void rollbackUpdateInNSTable(final MasterProcedureEnv env) throws IOException {
     if (oldNsDescriptor != null) {
       getTableNamespaceManager(env).insertIntoNSTable(oldNsDescriptor);
     }
   }
 
   /**
    * Update Zookeeper.
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void updateZKNamespaceManager(final MasterProcedureEnv env) throws IOException {
     getTableNamespaceManager(env).updateZKNamespaceManager(newNsDescriptor);
   }
 
   /**
    * Update Zookeeper during undo.
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void rollbackZKNamespaceManagerChange(final MasterProcedureEnv env) throws IOException {
     if (oldNsDescriptor != null) {
       getTableNamespaceManager(env).updateZKNamespaceManager(oldNsDescriptor);
     }
   }
 
   private TableNamespaceManager getTableNamespaceManager(final MasterProcedureEnv env) {
     return env.getMasterServices().getTableNamespaceManager();
   }
   /**
    * The procedure could be restarted from a different machine. If the variable is null, we need to
    * retrieve it.
    * @return traceEnabled
    */
   private Boolean isTraceEnabled() {
     if (traceEnabled == null) {
       traceEnabled = LOG.isTraceEnabled();
     }
     return traceEnabled;
   }
 }