/*
    * 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.chaos.actions;
  
  import java.io.IOException;
  import java.util.Random;
  import java.util.Set;
  
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Action that removes a column family.
   */
  public class RemoveColumnAction extends Action {
    private static final Logger LOG =
        LoggerFactory.getLogger(RemoveColumnAction.class);
    private final TableName tableName;
    private final Set<String> protectedColumns;
    private Admin admin;
    private Random random;
  
    public RemoveColumnAction(TableName tableName, Set<String> protectedColumns) {
      this.tableName = tableName;
      this.protectedColumns = protectedColumns;
      random = new Random();
    }
  
    @Override protected Logger getLogger() {
      return LOG;
    }
  
    @Override
    public void init(ActionContext context) throws IOException {
      super.init(context);
      this.admin = context.getHBaseIntegrationTestingUtility().getHBaseAdmin();
    }
  
    @Override
    public void perform() throws Exception {
      HTableDescriptor tableDescriptor = admin.getTableDescriptor(tableName);
      HColumnDescriptor[] columnDescriptors = tableDescriptor.getColumnFamilies();
  
      if (columnDescriptors.length <= (protectedColumns == null ? 1 : protectedColumns.size())) {
        return;
      }
  
      int index = random.nextInt(columnDescriptors.length);
      while(protectedColumns != null &&
            protectedColumns.contains(columnDescriptors[index].getNameAsString())) {
        index = random.nextInt(columnDescriptors.length);
      }
      byte[] colDescName = columnDescriptors[index].getName();
      getLogger().debug("Performing action: Removing " + Bytes.toString(colDescName)+ " from "
          + tableName.getNameAsString());
      tableDescriptor.removeFamily(colDescName);
  
      // Don't try the modify if we're stopping
      if (context.isStopping()) {
        return;
      }
      admin.modifyTable(tableName, tableDescriptor);
    }
  }