/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software License
 * version 1.1, a copy of which has been included with this distribution in
 * the LICENSE file.
 */
package org.apache.james.util;

import java.text.DateFormat;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

/**
 * I suppose I could access some of the special messages within Sun's implementation of the JavaMail
 * API, but I've always been told not to do that.  This class has one static method that takes a
 * java.util.Date object and returns a nicely formatted String version of this, formatted as per the
 * RFC822 mail date format.
 * @author Serge Knystautas <sergek@lokitech.com>
 * @version 0.9
 */
public class RFC822DateFormat {
    private static DateFormat df;
    private static DecimalFormat tz;

    /**
     * SimpleDateFormat will handle most of this for us, but the
     * timezone won't match, so we do that manually
     *
     * @return java.lang.String
     * @param d Date
     */
    public static String toString(Date d) {
        if (df == null) {
            df = new SimpleDateFormat("EE, d MMM yyyy HH:mm:ss",Locale.US);
        }
        if (tz == null) {
            tz = new DecimalFormat("00");
        }

        StringBuffer sb = new StringBuffer(df.format(d));

        sb.append(' ');

        int min = TimeZone.getDefault().getRawOffset() / 1000 / 60;
        
        if((TimeZone.getDefault().useDaylightTime())&&(TimeZone.getDefault().inDaylightTime(new Date()))){
        	min +=60;
        	}

        if (min >= 0) {
            sb.append('+');
        } else {
            sb.append('-');
        }

        min = Math.abs(min);

        sb.append(tz.format(min / 60));
        sb.append(tz.format(min % 60));

        return sb.toString();
    }
}