/*
 * 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.phoenix.expression;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.sql.Timestamp;
import java.util.List;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.phoenix.query.QueryConstants;
import org.apache.phoenix.schema.SortOrder;
import org.apache.phoenix.schema.tuple.Tuple;
import org.apache.phoenix.schema.types.PDataType;
import org.apache.phoenix.schema.types.PDecimal;
import org.apache.phoenix.schema.types.PDouble;
import org.apache.phoenix.schema.types.PTimestamp;
import org.apache.phoenix.schema.types.PUnsignedTimestamp;
import org.apache.phoenix.util.DateUtil;

/**
 * Class to encapsulate addition arithmetic for {@link org.apache.phoenix.schema.types.PTimestamp}.
 * @since 2.1.3
 */

public class TimestampAddExpression extends AddExpression {

  public TimestampAddExpression() {
  }

  public TimestampAddExpression(List<Expression> children) {
    super(children);
  }

  @Override
  public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
    BigDecimal finalResult = BigDecimal.ZERO;

    for (int i = 0; i < children.size(); i++) {
      if (!children.get(i).evaluate(tuple, ptr)) {
        return false;
      }
      if (ptr.getLength() == 0) {
        return true;
      }
      BigDecimal value;
      PDataType type = children.get(i).getDataType();
      SortOrder sortOrder = children.get(i).getSortOrder();
      if (type == PTimestamp.INSTANCE || type == PUnsignedTimestamp.INSTANCE) {
        value = (BigDecimal) (PDecimal.INSTANCE.toObject(ptr, type, sortOrder));
      } else if (type.isCoercibleTo(PDecimal.INSTANCE)) {
        value = (((BigDecimal) PDecimal.INSTANCE.toObject(ptr, type, sortOrder))
          .multiply(QueryConstants.BD_MILLIS_IN_DAY)).setScale(6, RoundingMode.HALF_UP);
      } else if (type.isCoercibleTo(PDouble.INSTANCE)) {
        value = ((BigDecimal.valueOf(type.getCodec().decodeDouble(ptr, sortOrder)))
          .multiply(QueryConstants.BD_MILLIS_IN_DAY)).setScale(6, RoundingMode.HALF_UP);
      } else {
        value = BigDecimal.valueOf(type.getCodec().decodeLong(ptr, sortOrder));
      }
      finalResult = finalResult.add(value);
    }
    Timestamp ts = DateUtil.getTimestamp(finalResult);
    byte[] resultPtr = new byte[getDataType().getByteSize()];
    PTimestamp.INSTANCE.toBytes(ts, resultPtr, 0);
    ptr.set(resultPtr);
    return true;
  }

  @Override
  public final PDataType getDataType() {
    return PTimestamp.INSTANCE;
  }

  @Override
  public ArithmeticExpression clone(List<Expression> children) {
    return new TimestampAddExpression(children);
  }

}
