/*
 * Copyright 2010 NCHOVY
 * 
 * Licensed 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.krakenapps.logstorage.engine;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;

public class DateUtil {
	private static int timezoneOffset = Calendar.getInstance().getTimeZone().getRawOffset();

	private DateUtil() {
	}

	public static String getDayText(Date day) {
		SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
		return dateFormat.format(day);
	}

	public static Date getDay(Date date) {
		long time = date.getTime();
		return new Date(time - ((time + timezoneOffset) % 86400000L));

		// Calendar c = Calendar.getInstance();
		// c.setTime(date);
		// c.set(Calendar.HOUR_OF_DAY, 0);
		// c.set(Calendar.MINUTE, 0);
		// c.set(Calendar.SECOND, 0);
		// c.set(Calendar.MILLISECOND, 0);
		// return c.getTime();
	}

	public static List<Date> filt(Collection<Date> dates, Date from, Date to) {
		List<Date> filtered = new ArrayList<Date>();
		// canonicalize
		Date fromDay = null;
		Date toDay = null;

		if (from != null)
			fromDay = getDay(from);
		if (to != null)
			toDay = getDay(to);

		for (Date day : dates) {
			if (fromDay != null && day.before(fromDay))
				continue;

			if (toDay != null && day.after(toDay))
				continue;

			filtered.add(day);
		}

		return filtered;
	}

	public static List<Date> sortByDesc(List<Date> dates) {
		Collections.sort(dates, new Comparator<Date>() {
			@Override
			public int compare(Date o1, Date o2) {
				return (int) (o2.getTime() - o1.getTime());
			}
		});

		return dates;
	}

}