/**
 * 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.hive.common.util;

import java.math.BigDecimal;
import java.text.SimpleDateFormat;

/**
 * DateUtils. Thread-safe class
 *
 */
public class DateUtils {

  private static final ThreadLocal<SimpleDateFormat> dateFormatLocal = new ThreadLocal<SimpleDateFormat>() {
    @Override
    protected SimpleDateFormat initialValue() {
      return new SimpleDateFormat("yyyy-MM-dd");
    }
  };

  public static SimpleDateFormat getDateFormat() {
    return dateFormatLocal.get();
  }

  public static final int NANOS_PER_SEC = 1000000000;
  public static final BigDecimal MAX_INT_BD = new BigDecimal(Integer.MAX_VALUE);
  public static final BigDecimal NANOS_PER_SEC_BD = new BigDecimal(NANOS_PER_SEC);

  public static int parseNumericValueWithRange(String fieldName,
      String strVal, int minValue, int maxValue) throws IllegalArgumentException {
    int result = 0;
    if (strVal != null) {
      result = Integer.parseInt(strVal);
      if (result < minValue || result > maxValue) {
        throw new IllegalArgumentException(String.format("%s value %d outside range [%d, %d]",
            fieldName, result, minValue, maxValue));
      }
    }
    return result;
  }

  // From java.util.Calendar
  private static final String[] FIELD_NAME = {
    "ERA", "YEAR", "MONTH", "WEEK_OF_YEAR", "WEEK_OF_MONTH", "DAY_OF_MONTH",
    "DAY_OF_YEAR", "DAY_OF_WEEK", "DAY_OF_WEEK_IN_MONTH", "AM_PM", "HOUR",
    "HOUR_OF_DAY", "MINUTE", "SECOND", "MILLISECOND", "ZONE_OFFSET",
    "DST_OFFSET"
  };

  /**
   * Returns the name of the specified calendar field.
   *
   * @param field the calendar field
   * @return the calendar field name
   * @exception IndexOutOfBoundsException if <code>field</code> is negative,
   * equal to or greater then <code>FIELD_COUNT</code>.
   */
  public static String getFieldName(int field) {
      return FIELD_NAME[field];
  }
}
