content: /*
   * 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.ambari.server.utils;
  
  import java.text.ParseException;
  import java.text.SimpleDateFormat;
  import java.util.Calendar;
  import java.util.Date;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * Static Helper methods for datetime conversions
   */
  public class DateUtils {
  
    public static final String ALLOWED_DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ssz";
  
    /**
     * Milliseconds to readable format in current server timezone
     * @param timestamp
     * @return
     */
    public static String convertToReadableTime(Long timestamp) {
      SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
      return dateFormat.format(new Date(timestamp));
    }
  
    /**
     * Convert time in given format to milliseconds
     * @return
     */
    public static Long convertToTimestamp(String time, String format) {
      SimpleDateFormat dateFormat = new SimpleDateFormat(format);
      try {
        Date date = dateFormat.parse(time);
        return date.getTime();
      } catch (ParseException e) {
        e.printStackTrace();
      }
      return null;
    }
  
    /**
     * Convert from supported format to Date
     * @param date
     * @return
     * @throws ParseException
     */
    public static Date convertToDate(String date) throws ParseException {
      SimpleDateFormat sdf = new SimpleDateFormat(ALLOWED_DATE_FORMAT);
      return sdf.parse(date);
    }
  
    /**
     * Convert Date to allowed format
     * @param date
     * @return
     * @throws ParseException
     */
    public static String convertDateToString(Date date) throws ParseException {
      SimpleDateFormat sdf = new SimpleDateFormat(ALLOWED_DATE_FORMAT);
      return sdf.format(date);
    }
  
    /**
     * Get difference in minutes between old date and now
     * @param oldTime
     * @return
     */
    public static Long getDateDifferenceInMinutes(Date oldTime) {
      long diff = Math.abs(oldTime.getTime() - new Date().getTime());
      return diff / (60 * 1000) % 60;
    }
  
    /**
     * Check if given time is in the future
     * @param time
     * @return
     */
    public static boolean isFutureTime(Date time) {
      Date now = new Date();
      return time.after(now);
    }
  
    /**
     * Returns a date given period before now
     *
     * @param periodString is a string indicating a time period. Example '1y2m3w4d5y'
     * means 1 year, 2 months, 3 weeks, 4 days, 5 hours.
     * @return
     */
    public static Date getDateSpecifiedTimeAgo(String periodString) {
      String pattern = "((\\d+)([hdwmy]))";
      Pattern findPattern = Pattern.compile(pattern);
      Pattern matchPattern = Pattern.compile(pattern+"+");
  
      Map<String, Integer> qualifierToConstant = new HashMap<String, Integer>() {{
          put("h",   Calendar.HOUR);
          put("d",    Calendar.DATE);
          put("w",   Calendar.WEEK_OF_YEAR);
          put("m",  Calendar.MONTH);
          put("y",   Calendar.YEAR);
      }};
  
      if(!matchPattern.matcher(periodString).matches()) {
        throw new IllegalArgumentException(String.format("Invalid string for indicating period %s", periodString));
      }
  
      Calendar calendar = Calendar.getInstance();
      Matcher m = findPattern.matcher(periodString);
  
      while (m.find()) {
        int amount = Integer.parseInt(m.group(2));
        int unit = qualifierToConstant.get(m.group(3));
        calendar.add(unit, -amount);
      }
      return calendar.getTime();
    }
  }
  