/*
 * 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.hive.ql.udf.generic;

import static org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils.PrimitiveGrouping.DATE_GROUP;
import static org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils.PrimitiveGrouping.STRING_GROUP;
import static org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorUtils.PrimitiveGrouping.VOID_GROUP;

import org.apache.hadoop.hive.common.type.Date;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters.Converter;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.IntWritable;

/**
 * GenericUDFQuarter.
 *
 * Returns the quarter of the year for date, in the range 1 to 4.
 *
 */
@Description(name = "quarter", value = "_FUNC_(date/timestamp/string) - Returns the "
    + "quarter of the year for date, in the range 1 to 4.",
    extended = "Example: > SELECT _FUNC_('2015-04-08');\n 2")
public class GenericUDFQuarter extends GenericUDF {
  private transient Converter[] converters = new Converter[1];
  private transient PrimitiveCategory[] inputTypes = new PrimitiveCategory[1];
  private final IntWritable output = new IntWritable();

  @Override
  public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
    checkArgsSize(arguments, 1, 1);
    checkArgPrimitive(arguments, 0);
    checkArgGroups(arguments, 0, inputTypes, STRING_GROUP, DATE_GROUP, VOID_GROUP);
    obtainDateConverter(arguments, 0, inputTypes, converters);

    ObjectInspector outputOI = PrimitiveObjectInspectorFactory.writableIntObjectInspector;
    return outputOI;
  }

  @Override
  public Object evaluate(DeferredObject[] arguments) throws HiveException {
    Date date = getDateValue(arguments, 0, inputTypes, converters);
    if (date == null) {
      return null;
    }
    int month = date.getMonth() - 1;
    int quarter = (month + 3) / 3;

    output.set(quarter);
    return output;
  }

  @Override
  protected String getFuncName() {
    return "quarter";
  }

  @Override
  public String getDisplayString(String[] children) {
    return getStandardDisplayString(getFuncName(), children);
  }
}
