/*
 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
 * 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.
 */

package sun.security.timestamp;

import java.io.IOException;
import java.math.BigInteger;
import java.util.Date;
import sun.security.util.DerValue;
import sun.security.util.ObjectIdentifier;
import sun.security.x509.AlgorithmId;

/**
 * This class provides the timestamp token info resulting from a successful
 * timestamp request, as defined in
 * <a href="http://www.ietf.org/rfc/rfc3161.txt">RFC 3161</a>.
 *
 * The timestampTokenInfo ASN.1 type has the following definition:
 * <pre>
 *
 *     TSTInfo ::= SEQUENCE {
 *         version                INTEGER  { v1(1) },
 *         policy                 TSAPolicyId,
 *         messageImprint         MessageImprint,
 *           -- MUST have the same value as the similar field in
 *           -- TimeStampReq
 *         serialNumber           INTEGER,
 *          -- Time-Stamping users MUST be ready to accommodate integers
 *          -- up to 160 bits.
 *         genTime                GeneralizedTime,
 *         accuracy               Accuracy                 OPTIONAL,
 *         ordering               BOOLEAN             DEFAULT FALSE,
 *         nonce                  INTEGER                  OPTIONAL,
 *           -- MUST be present if the similar field was present
 *           -- in TimeStampReq.  In that case it MUST have the same value.
 *         tsa                    [0] GeneralName          OPTIONAL,
 *         extensions             [1] IMPLICIT Extensions  OPTIONAL }
 *
 *     Accuracy ::= SEQUENCE {
 *         seconds        INTEGER           OPTIONAL,
 *         millis     [0] INTEGER  (1..999) OPTIONAL,
 *         micros     [1] INTEGER  (1..999) OPTIONAL  }
 *
 * </pre>
 *
 * @since 1.5
 * @see Timestamper
 * @author Vincent Ryan
 */

public class TimestampToken {

    private int version;
    private ObjectIdentifier policy;
    private BigInteger serialNumber;
    private AlgorithmId hashAlgorithm;
    private byte[] hashedMessage;
    private Date genTime;
    private BigInteger nonce;

    /**
     * Constructs an object to store a timestamp token.
     *
     * @param status A buffer containing the ASN.1 BER encoding of the
     *               TSTInfo element defined in RFC 3161.
     */
    public TimestampToken(byte[] timestampTokenInfo) throws IOException {
        if (timestampTokenInfo == null) {
            throw new IOException("No timestamp token info");
        }
        parse(timestampTokenInfo);
    }

    /**
     * Extract the date and time from the timestamp token.
     *
     * @return The date and time when the timestamp was generated.
     */
    public Date getDate() {
        return genTime;
    }

    public AlgorithmId getHashAlgorithm() {
        return hashAlgorithm;
    }

    // should only be used internally, otherwise return a clone
    public byte[] getHashedMessage() {
        return hashedMessage;
    }

    public BigInteger getNonce() {
        return nonce;
    }

    public String getPolicyID() {
        return policy.toString();
    }

    public BigInteger getSerialNumber() {
        return serialNumber;
    }

    /*
     * Parses the timestamp token info.
     *
     * @param timestampTokenInfo A buffer containing an ASN.1 BER encoded
     *                           TSTInfo.
     * @throws IOException The exception is thrown if a problem is encountered
     *         while parsing.
     */
    private void parse(byte[] timestampTokenInfo) throws IOException {

        DerValue tstInfo = new DerValue(timestampTokenInfo);
        if (tstInfo.tag != DerValue.tag_Sequence) {
            throw new IOException("Bad encoding for timestamp token info");
        }
        // Parse version
        version = tstInfo.data.getInteger();

        // Parse policy
        policy = tstInfo.data.getOID();

        // Parse messageImprint
        DerValue messageImprint = tstInfo.data.getDerValue();
        hashAlgorithm = AlgorithmId.parse(messageImprint.data.getDerValue());
        hashedMessage = messageImprint.data.getOctetString();

        // Parse serialNumber
        serialNumber = tstInfo.data.getBigInteger();

        // Parse genTime
        genTime = tstInfo.data.getGeneralizedTime();

        // Parse optional elements, if present
        while (tstInfo.data.available() > 0) {
            DerValue d = tstInfo.data.getDerValue();
            if (d.tag == DerValue.tag_Integer) {    // must be the nonce
                nonce = d.getBigInteger();
                break;
            }

            // Additional fields:
            // Parse accuracy
            // Parse ordering
            // Parse tsa
            // Parse extensions
        }
    }
}