/*
 * 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.iotdb.db.query.udf.example;

import org.apache.iotdb.tsfile.exception.write.UnSupportedDataTypeException;
import org.apache.iotdb.udf.api.UDTF;
import org.apache.iotdb.udf.api.access.Row;
import org.apache.iotdb.udf.api.collector.PointCollector;
import org.apache.iotdb.udf.api.customizer.config.UDTFConfigurations;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameterValidator;
import org.apache.iotdb.udf.api.customizer.parameter.UDFParameters;
import org.apache.iotdb.udf.api.customizer.strategy.RowByRowAccessStrategy;
import org.apache.iotdb.udf.api.type.Type;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

public class Adder implements UDTF {

  private static final Logger logger = LoggerFactory.getLogger(Adder.class);

  private double addend;

  @Override
  public void validate(UDFParameterValidator validator) throws Exception {
    validator
        .validateInputSeriesNumber(2)
        .validateInputSeriesDataType(0, Type.INT32, Type.INT64, Type.FLOAT, Type.DOUBLE)
        .validateInputSeriesDataType(1, Type.INT32, Type.INT64, Type.FLOAT, Type.DOUBLE);
  }

  @Override
  public void beforeStart(UDFParameters parameters, UDTFConfigurations configurations) {
    logger.debug("Adder#beforeStart");
    addend = parameters.getFloatOrDefault("addend", 0);
    configurations.setOutputDataType(Type.INT64).setAccessStrategy(new RowByRowAccessStrategy());
  }

  @Override
  public void transform(Row row, PointCollector collector) throws Exception {
    if (row.isNull(0) || row.isNull(1)) {
      return;
    }
    collector.putLong(
        row.getTime(), (long) (extractDoubleValue(row, 0) + extractDoubleValue(row, 1) + addend));
  }

  private double extractDoubleValue(Row row, int index) throws IOException {
    double value;
    switch (row.getDataType(index)) {
      case INT32:
        value = row.getInt(index);
        break;
      case INT64:
        value = (double) row.getLong(index);
        break;
      case FLOAT:
        value = row.getFloat(index);
        break;
      case DOUBLE:
        value = row.getDouble(index);
        break;
      default:
        throw new UnSupportedDataTypeException(row.getDataType(index).toString());
    }
    return value;
  }

  @Override
  public void beforeDestroy() {
    logger.debug("Adder#beforeDestroy");
  }
}
