/*
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package l2.universe.gameserver.model.itemauction;

import java.util.Calendar;
import java.util.concurrent.TimeUnit;

import l2.universe.gameserver.templates.StatsSet;

/**
 * 
 * @author Forsaiken
 *
 */
public final class AuctionDateGenerator
{
	public static final String FIELD_INTERVAL = "interval";
	public static final String FIELD_DAY_OF_WEEK = "day_of_week";
	public static final String FIELD_HOUR_OF_DAY = "hour_of_day";
	public static final String FIELD_MINUTE_OF_HOUR = "minute_of_hour";
	
	private static final long MILLIS_IN_WEEK = TimeUnit.MILLISECONDS.convert(7, TimeUnit.DAYS);
	
	private final Calendar _calendar;
	
	private int _interval;
	private int _day_of_week;
	private int _hour_of_day;
	private int _minute_of_hour;
	
	public AuctionDateGenerator(final StatsSet config) throws IllegalArgumentException
	{
		_calendar = Calendar.getInstance();
		_interval = config.getInteger(FIELD_INTERVAL, -1);
		_day_of_week = config.getInteger(FIELD_DAY_OF_WEEK, -1);
		_hour_of_day = config.getInteger(FIELD_HOUR_OF_DAY, -1);
		_minute_of_hour = config.getInteger(FIELD_MINUTE_OF_HOUR, -1);
		
		checkDayOfWeek(-1);
		checkHourOfDay(-1);
		checkMinuteOfHour(0);
	}
	
	public synchronized final long nextDate(final long date)
	{
		_calendar.setTimeInMillis(date);
		_calendar.set(Calendar.MILLISECOND, 0);
		_calendar.set(Calendar.SECOND, 0);
		
		_calendar.set(Calendar.MINUTE, _minute_of_hour);
		_calendar.set(Calendar.HOUR_OF_DAY, _hour_of_day);
		if (_day_of_week > 0)
		{
			_calendar.set(Calendar.DAY_OF_WEEK, _day_of_week);
			return calcDestTime(_calendar.getTimeInMillis(), date, MILLIS_IN_WEEK);
		}
		
		return calcDestTime(_calendar.getTimeInMillis(), date, TimeUnit.MILLISECONDS.convert(_interval, TimeUnit.DAYS));
	}
	
	private final long calcDestTime(long time, final long date, final long add)
	{
		if (time < date)
		{
			time += ((date - time) / add) * add;
			if (time < date)
				time += add;
		}
		return time;
	}
	
	private final void checkDayOfWeek(final int defaultValue)
	{
		if (_day_of_week < 1 || _day_of_week > 7)
		{
			if (defaultValue == -1 && _interval < 1)
				throw new IllegalArgumentException("Illegal params for '" + FIELD_DAY_OF_WEEK + "': " + (_day_of_week == -1 ? "not found" : _day_of_week));
			_day_of_week = defaultValue;
		}
		else if (_interval > 1)
			throw new IllegalArgumentException("Illegal params for '" + FIELD_INTERVAL +"' and '" + FIELD_DAY_OF_WEEK + "': you can use only one, not both");
	}
	
	private final void checkHourOfDay(final int defaultValue)
	{
		if (_hour_of_day < 0 || _hour_of_day > 23)
		{
			if (defaultValue == -1)
				throw new IllegalArgumentException("Illegal params for '" + FIELD_HOUR_OF_DAY + "': " + (_hour_of_day == -1 ? "not found" : _hour_of_day));
			_hour_of_day = defaultValue;
		}
	}
	
	private final void checkMinuteOfHour(final int defaultValue)
	{
		if (_minute_of_hour < 0 || _minute_of_hour > 59)
		{
			if (defaultValue == -1)
				throw new IllegalArgumentException("Illegal params for '" + FIELD_MINUTE_OF_HOUR + "': " + (_minute_of_hour == -1 ? "not found" : _minute_of_hour));
			_minute_of_hour = defaultValue;
		}
	}
}