/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 *

 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

 */

package sun.security.krb5.internal;

import java.util.TimeZone;

import sun.security.util.*;

import sun.security.krb5.Config;

import sun.security.krb5.KrbException;

import sun.security.krb5.Asn1Exception;

import java.util.Date;

import java.util.GregorianCalendar;

import java.util.Calendar;

import java.io.IOException;

/**

 * Implements the ASN.1 KerberosTime type.

 *

 * <xmp>

 * KerberosTime    ::= GeneralizedTime -- with no fractional seconds

 * </xmp>

 *

 * The timestamps used in Kerberos are encoded as GeneralizedTimes. A

 * KerberosTime value shall not include any fractional portions of the

 * seconds.  As required by the DER, it further shall not include any

 * separators, and it shall specify the UTC time zone (Z).

 *

 * <p>

 * This definition reflects the Network Working Group RFC 4120

 * specification available at

 * <a href="http://www.ietf.org/rfc/rfc4120.txt">

 * http://www.ietf.org/rfc/rfc4120.txt</a>.

 *

 * The implementation also includes the microseconds info so that the

 * same class can be used as a precise timestamp in Authenticator etc.

 */

public class KerberosTime implements Cloneable {

    private long kerberosTime; // milliseconds since epoch, a Date.getTime() value

    private int  microSeconds; // the last three digits of the microsecond value

    // The time when this class is loaded. Used in setNow()

    private static final long initMilli = System.currentTimeMillis();

    private static final long initMicro = System.nanoTime() / 1000;

    private static long syncTime;

    private static boolean DEBUG = Krb5.DEBUG;

    public static final boolean NOW = true;

    public static final boolean UNADJUSTED_NOW = false;

    public KerberosTime(long time) {

        kerberosTime = time;

    }

    private KerberosTime(long time, int micro) {

        kerberosTime = time;

        microSeconds = micro;

    }

    public Object clone() {

        return new KerberosTime(kerberosTime, microSeconds);

    }

    // This constructor is used in the native code

    // src/windows/native/sun/security/krb5/NativeCreds.c

    public KerberosTime(String time) throws Asn1Exception {

        kerberosTime = toKerberosTime(time);

    }

    /**

     * Constructs a KerberosTime object.

     * @param encoding a DER-encoded data.

     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded data.

     */

    public KerberosTime(DerValue encoding) throws Asn1Exception, IOException {

        GregorianCalendar calendar = new GregorianCalendar();

        Date temp = encoding.getGeneralizedTime();

        kerberosTime = temp.getTime();

    }

    private static long toKerberosTime(String time) throws Asn1Exception {

        // this method only used by KerberosTime class.

        // ASN.1 GeneralizedTime format:

        // "19700101000000Z"

        //  |   | | | | | |

        //  0   4 6 8 | | |

        //           10 | |

        //             12 |

        //               14

        if (time.length() != 15)

            throw new Asn1Exception(Krb5.ASN1_BAD_TIMEFORMAT);

        if (time.charAt(14) != 'Z')

            throw new Asn1Exception(Krb5.ASN1_BAD_TIMEFORMAT);

        int year = Integer.parseInt(time.substring(0, 4));

        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));

        calendar.clear(); // so that millisecond is zero

        calendar.set(year,

                     Integer.parseInt(time.substring(4, 6)) - 1,

                     Integer.parseInt(time.substring(6, 8)),

                     Integer.parseInt(time.substring(8, 10)),

                     Integer.parseInt(time.substring(10, 12)),

                     Integer.parseInt(time.substring(12, 14)));

        //The Date constructor assumes the setting are local relative

        //and converts the time to UTC before storing it.  Since we

        //want the internal representation to correspond to local

        //and not UTC time we subtract the UTC time offset.

        return (calendar.getTime().getTime());

    }

    // should be moved to sun.security.krb5.util class

    public static String zeroPad(String s, int length) {

        StringBuffer temp = new StringBuffer(s);

        while (temp.length() < length)

            temp.insert(0, '0');

        return temp.toString();

    }

    public KerberosTime(Date time) {

        kerberosTime = time.getTime(); // (time.getTimezoneOffset() * 60000L);

    }

    public KerberosTime(boolean initToNow) {

        if (initToNow) {

            setNow();

        }

    }

    /**

     * Returns a string representation of KerberosTime object.

     * @return a string representation of this object.

     */

    public String toGeneralizedTimeString() {

        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));

        calendar.clear();

        calendar.setTimeInMillis(kerberosTime);

        return zeroPad(Integer.toString(calendar.get(Calendar.YEAR)), 4) +

            zeroPad(Integer.toString(calendar.get(Calendar.MONTH) + 1), 2) +

            zeroPad(Integer.toString(calendar.get(Calendar.DAY_OF_MONTH)), 2) +

            zeroPad(Integer.toString(calendar.get(Calendar.HOUR_OF_DAY)), 2) +

            zeroPad(Integer.toString(calendar.get(Calendar.MINUTE)), 2) +

            zeroPad(Integer.toString(calendar.get(Calendar.SECOND)), 2) + 'Z';

    }

    /**

     * Encodes this object to a byte array.

     * @return a byte array of encoded data.

     * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded data.

     */

    public byte[] asn1Encode() throws Asn1Exception, IOException {

        DerOutputStream out = new DerOutputStream();

        out.putGeneralizedTime(this.toDate());

        return out.toByteArray();

    }

    public long getTime() {

        return kerberosTime;

    }

    public void setTime(Date time) {

        kerberosTime = time.getTime(); // (time.getTimezoneOffset() * 60000L);

        microSeconds = 0;

    }

    public void setTime(long time) {

        kerberosTime = time;

        microSeconds = 0;

    }

    public Date toDate() {

        Date temp = new Date(kerberosTime);

        temp.setTime(temp.getTime());

        return temp;

    }

    public void setNow() {

        long microElapsed = System.nanoTime() / 1000 - initMicro;

        setTime(initMilli + microElapsed/1000);

        microSeconds = (int)(microElapsed % 1000);

    }

    public int getMicroSeconds() {

        Long temp_long = new Long((kerberosTime % 1000L) * 1000L);

        return temp_long.intValue() + microSeconds;

    }

    public void setMicroSeconds(int usec) {

        microSeconds = usec % 1000;

        Integer temp_int = new Integer(usec);

        long temp_long = temp_int.longValue() / 1000L;

        kerberosTime = kerberosTime - (kerberosTime % 1000L) + temp_long;

    }

    public void setMicroSeconds(Integer usec) {

        if (usec != null) {

            microSeconds = usec.intValue() % 1000;

            long temp_long = usec.longValue() / 1000L;

            kerberosTime = kerberosTime - (kerberosTime % 1000L) + temp_long;

        }

    }

    public boolean inClockSkew(int clockSkew) {

        KerberosTime now = new KerberosTime(KerberosTime.NOW);

        if (java.lang.Math.abs(kerberosTime - now.kerberosTime) >

            clockSkew * 1000L)

            return false;

        return true;

    }

    public boolean inClockSkew() {

        return inClockSkew(getDefaultSkew());

    }

    public boolean inClockSkew(int clockSkew, KerberosTime now) {

        if (java.lang.Math.abs(kerberosTime - now.kerberosTime) >

            clockSkew * 1000L)

            return false;

        return true;

    }

    public boolean inClockSkew(KerberosTime time) {

        return inClockSkew(getDefaultSkew(), time);

    }

    public boolean greaterThanWRTClockSkew(KerberosTime time, int clockSkew) {

        if ((kerberosTime - time.kerberosTime) > clockSkew * 1000L)

            return true;

        return false;

    }

    public boolean greaterThanWRTClockSkew(KerberosTime time) {

        return greaterThanWRTClockSkew(time, getDefaultSkew());

    }

    public boolean greaterThan(KerberosTime time) {

        return kerberosTime > time.kerberosTime ||

            kerberosTime == time.kerberosTime &&

                    microSeconds > time.microSeconds;

    }

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (!(obj instanceof KerberosTime)) {

            return false;

        }

        return kerberosTime == ((KerberosTime)obj).kerberosTime &&

                microSeconds == ((KerberosTime)obj).microSeconds;

    }

    public int hashCode() {

        int result = 37 * 17 + (int)(kerberosTime ^ (kerberosTime >>> 32));

        return result * 17 + microSeconds;

    }

    public boolean isZero() {

        return kerberosTime == 0 && microSeconds == 0;

    }

    public int getSeconds() {

        Long temp_long = new Long(kerberosTime / 1000L);

        return temp_long.intValue();

    }

    public void setSeconds(int sec) {

        Integer temp_int = new Integer(sec);

        kerberosTime = temp_int.longValue() * 1000L;

    }

    /**

     * Parse (unmarshal) a kerberostime from a DER input stream.  This form

     * parsing might be used when expanding a value which is part of

     * a constructed sequence and uses explicitly tagged type.

     *

     * @exception Asn1Exception on error.

     * @param data the Der input stream value, which contains one or more marshaled value.

     * @param explicitTag tag number.

     * @param optional indicates if this data field is optional

     * @return an instance of KerberosTime.

     *

     */

    public static KerberosTime parse(DerInputStream data, byte explicitTag, boolean optional) throws Asn1Exception, IOException {

        if ((optional) && (((byte)data.peekByte() & (byte)0x1F)!= explicitTag))

            return null;

        DerValue der = data.getDerValue();

        if (explicitTag != (der.getTag() & (byte)0x1F))  {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        else {

            DerValue subDer = der.getData().getDerValue();

            return new KerberosTime(subDer);

        }

    }

    public static int getDefaultSkew() {

        int tdiff = Krb5.DEFAULT_ALLOWABLE_CLOCKSKEW;

        try {

            Config c = Config.getInstance();

            if ((tdiff = c.getDefaultIntValue("clockskew",

                                              "libdefaults")) == Integer.MIN_VALUE) {   //value is not defined

                tdiff = Krb5.DEFAULT_ALLOWABLE_CLOCKSKEW;

            }

        } catch (KrbException e) {

            if (DEBUG) {

                System.out.println("Exception in getting clockskew from " +

                                   "Configuration " +

                                   "using default value " +

                                   e.getMessage());

            }

        }

        return tdiff;

    }

    public String toString() {

        return toGeneralizedTimeString();

    }

}