// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

package org.xbill.DNS;

/**
 * Routines for converting time values to and from YYYYMMDDHHMMSS format.
 *
 * @author Brian Wellington
 */

import java.util.*;
import java.text.*;

final class FormattedTime {

    private static NumberFormat w2, w4;

    static {
        w2 = new DecimalFormat();
        w2.setMinimumIntegerDigits(2);

        w4 = new DecimalFormat();
        w4.setMinimumIntegerDigits(4);
        w4.setGroupingUsed(false);
    }

    private FormattedTime() {
    }

    /**
     * Converts a Date into a formatted string.
     *
     * @param date The Date to convert.
     * @return The formatted string.
     */
    public static String
    format(Date date) {
        Calendar c = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
        StringBuffer sb = new StringBuffer();

        c.setTime(date);
        sb.append(w4.format(c.get(Calendar.YEAR)));
        sb.append(w2.format(c.get(Calendar.MONTH) + 1));
        sb.append(w2.format(c.get(Calendar.DAY_OF_MONTH)));
        sb.append(w2.format(c.get(Calendar.HOUR_OF_DAY)));
        sb.append(w2.format(c.get(Calendar.MINUTE)));
        sb.append(w2.format(c.get(Calendar.SECOND)));
        return sb.toString();
    }

    /**
     * Parses a formatted time string into a Date.
     *
     * @param s The string, in the form YYYYMMDDHHMMSS.
     * @return The Date object.
     * @throws TextParseExcetption The string was invalid.
     */
    public static Date
    parse(String s) throws TextParseException {
        if (s.length() != 14) {
            throw new TextParseException("Invalid time encoding: " + s);
        }

        Calendar c = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
        c.clear();
        try {
            int year = Integer.parseInt(s.substring(0, 4));
            int month = Integer.parseInt(s.substring(4, 6)) - 1;
            int date = Integer.parseInt(s.substring(6, 8));
            int hour = Integer.parseInt(s.substring(8, 10));
            int minute = Integer.parseInt(s.substring(10, 12));
            int second = Integer.parseInt(s.substring(12, 14));
            c.set(year, month, date, hour, minute, second);
        } catch (NumberFormatException e) {
            throw new TextParseException("Invalid time encoding: " + s);
        }
        return c.getTime();
    }

}
