/*
    *
    * 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.client.coprocessor;
  
  import java.io.IOException;
  import java.math.BigDecimal;
  import java.math.RoundingMode;
  
  import org.apache.hadoop.hbase.util.ByteStringer;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
  import org.apache.hadoop.hbase.coprocessor.ColumnInterpreter;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.BigDecimalMsg;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.EmptyMsg;
  import org.apache.hadoop.hbase.util.Bytes;
  
  /**
   * ColumnInterpreter for doing Aggregation's with BigDecimal columns. This class
   * is required at the RegionServer also.
   *
   */
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
  @InterfaceStability.Evolving
  public class BigDecimalColumnInterpreter extends ColumnInterpreter<BigDecimal, BigDecimal,
    EmptyMsg, BigDecimalMsg, BigDecimalMsg> {
  
    @Override
    public BigDecimal getValue(byte[] colFamily, byte[] colQualifier, Cell kv)
        throws IOException {
      if (kv == null || CellUtil.cloneValue(kv) == null) {
        return null;
      }
      return Bytes.toBigDecimal(kv.getValueArray(), kv.getValueOffset(), kv.getValueLength()).
          setScale(2, RoundingMode.HALF_EVEN);
    }
  
    @Override
    public BigDecimal add(BigDecimal bd1, BigDecimal bd2) {
      if (bd1 == null ^ bd2 == null) {
        return (bd1 == null) ? bd2 : bd1; // either of one is null.
      }
      if (bd1 == null) {
        return null;
      }
      return bd1.add(bd2);
    }
  
    @Override
    public int compare(final BigDecimal bd1, final BigDecimal bd2) {
      if (bd1 == null ^ bd2 == null) {
        return bd1 == null ? -1 : 1; // either of one is null.
      }
      if (bd1 == null) {
        return 0; // both are null
      }
      return bd1.compareTo(bd2); // natural ordering.
    }
  
    @Override
    public BigDecimal getMaxValue() {
      return BigDecimal.valueOf(Double.MAX_VALUE);
    }
  
    @Override
    public BigDecimal increment(BigDecimal bd) {
      return bd == null ? null : (bd.add(BigDecimal.ONE));
    }
  
    @Override
    public BigDecimal multiply(BigDecimal bd1, BigDecimal bd2) {
      return (bd1 == null || bd2 == null) ? null : bd1.multiply(bd2)
          .setScale(2,RoundingMode.HALF_EVEN);
    }
  
    @Override
    public BigDecimal getMinValue() {
      return BigDecimal.valueOf(Double.MIN_VALUE);
    }
  
    @Override
   public double divideForAvg(BigDecimal bd1, Long l2) {
     return (l2 == null || bd1 == null) ? Double.NaN : (bd1.doubleValue() / l2
         .doubleValue());
   }
 
   @Override
   public BigDecimal castToReturnType(BigDecimal bd) {
     return bd;
   }
 
   @Override
   public BigDecimal castToCellType(BigDecimal bd) {
     return bd;
   }
 
   @Override
   public EmptyMsg getRequestData() {
     return EmptyMsg.getDefaultInstance();
   }
 
   @Override
   public void initialize(EmptyMsg msg) {
     //nothing
   }
 
   private BigDecimalMsg getProtoForType(BigDecimal t) {
     BigDecimalMsg.Builder builder = BigDecimalMsg.newBuilder();
     return builder.setBigdecimalMsg(ByteStringer.wrap(Bytes.toBytes(t))).build();
   }
   
   @Override
   public BigDecimalMsg getProtoForCellType(BigDecimal t) {
     return getProtoForType(t);
   }
 
   @Override
   public BigDecimalMsg getProtoForPromotedType(BigDecimal s) {
     return getProtoForType(s);
   }
 
   @Override
   public BigDecimal getPromotedValueFromProto(BigDecimalMsg r) {
     return Bytes.toBigDecimal(r.getBigdecimalMsg().toByteArray());
   }
 
   @Override
   public BigDecimal getCellValueFromProto(BigDecimalMsg q) {
     return Bytes.toBigDecimal(q.getBigdecimalMsg().toByteArray());
   }
 }