/*

 * Copyright (c) 2015, 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.ssl;

import java.io.IOException;

import java.util.List;

import java.util.Collections;

import java.util.ArrayList;

import java.util.Objects;

import javax.net.ssl.SSLException;

/*

 * RFC6066 defines the TLS extension,"status_request" (type 0x5),

 * which allows the client to request that the server perform OCSP

 * on the client's behalf.

 * The "extension data" field of this extension contains a

 * "CertificateStatusRequest" structure:

 *

 *      struct {

 *          CertificateStatusType status_type;

 *          select (status_type) {

 *              case ocsp: OCSPStatusRequest;

 *          } request;

 *      } CertificateStatusRequest;

 *

 *      enum { ocsp(1), (255) } CertificateStatusType;

 *

 *      struct {

 *          ResponderID responder_id_list<0..2^16-1>;

 *          Extensions  request_extensions;

 *      } OCSPStatusRequest;

 *

 *      opaque ResponderID<1..2^16-1>;

 *      opaque Extensions<0..2^16-1>;

 */

final class CertStatusReqListV2Extension extends HelloExtension {

    private final List<CertStatusReqItemV2> itemList;

    private final int itemListLength;

    /**

     * Construct a default {@code CertStatusReqListV2Extension}.  The default

     * object results in a status_request_v2 extension where the extension

     * data segment is zero-length.  This is used primarily in ServerHello

     * messages where the server asserts it can do RFC 6961 status stapling.

     */

    CertStatusReqListV2Extension() {

        super(ExtensionType.EXT_STATUS_REQUEST_V2);

        itemList = Collections.emptyList();

        itemListLength = 0;

    }

    /**

     * Construct a {@code CertStatusReqListV2Extension} from a provided list

     *      of {@code CertStatusReqItemV2} objects.

     *

     * @param reqList a {@code List} containing one or more

     *      {@code CertStatusReqItemV2} objects to be included in this TLS

     *      Hello extension.  Passing an empty list will result in the encoded

     *      extension having a zero-length extension_data segment, and is

     *      the same as using the default constructor.

     *

     * @throws NullPointerException if reqList is {@code null}

     */

    CertStatusReqListV2Extension(List<CertStatusReqItemV2> reqList) {

        super(ExtensionType.EXT_STATUS_REQUEST_V2);

        Objects.requireNonNull(reqList,

                "Unallowed null value for certificate_status_req_list");

        itemList = Collections.unmodifiableList(new ArrayList<>(reqList));

        itemListLength = calculateListLength();

    }

    /**

     *  Construct the {@code CertStatusReqListV2Extension} object from data

     *      read from a {@code HandshakeInputStream}

     *

     * @param s the {@code HandshakeInputStream} providing the encoded data

     * @param len the length of the extension data

     *

     * @throws IOException if any decoding errors happen during object

     *      construction.

     */

    CertStatusReqListV2Extension(HandshakeInStream s, int len)

            throws IOException {

        super(ExtensionType.EXT_STATUS_REQUEST_V2);

        if (len <= 0) {

            // Handle the empty extension data case (from a ServerHello)

            itemList = Collections.emptyList();

            itemListLength = 0;

        } else {

            List<CertStatusReqItemV2> workingList = new ArrayList<>();

            itemListLength = s.getInt16();

            if (itemListLength <= 0) {

                throw new SSLException("certificate_status_req_list length " +

                        "must be greater than zero (received length: " +

                        itemListLength + ")");

            }

            int totalRead = 0;

            CertStatusReqItemV2 reqItem;

            do {

                reqItem = new CertStatusReqItemV2(s);

                totalRead += reqItem.length();

            } while (workingList.add(reqItem) && totalRead < itemListLength);

            // If for some reason the add returns false, we may not have read

            // all the necessary bytes from the stream.  Check this and throw

            // an exception if we terminated the loop early.

            if (totalRead != itemListLength) {

                throw new SSLException("Not all certificate_status_req_list " +

                        "bytes were read: expected " + itemListLength +

                        ", read " + totalRead);

            }

            itemList = Collections.unmodifiableList(workingList);

        }

    }

    /**

     * Get the list of {@code CertStatusReqItemV2} objects for this extension

     *

     * @return an unmodifiable list of {@code CertStatusReqItemV2} objects

     */

    List<CertStatusReqItemV2> getRequestItems() {

        return itemList;

    }

    /**

     * Return the length of the encoded extension, including extension type

     *      and extension length fields.

     *

     * @return the length in bytes, including the extension type and

     *      extension_data length.

     */

    @Override

    int length() {

        return (itemList.isEmpty() ? 4 : itemListLength + 6);

    }

    /**

     * Send the encoded {@code CertStatusReqListV2Extension} through a

     *      {@code HandshakeOutputStream}

     *

     * @param s the {@code HandshakeOutputStream} used to send the encoded data

     *

     * @throws IOException if any errors occur during the encoding process

     */

    @Override

    void send(HandshakeOutStream s) throws IOException {

        s.putInt16(type.id);

        s.putInt16(this.length() - 4);

        if (itemListLength > 0) {

            s.putInt16(itemListLength);

            for (CertStatusReqItemV2 item : itemList) {

                item.send(s);

            }

        }

    }

    /**

     * Create a string representation of this

     *      {@code CertStatusReqListV2Extension}

     *

     * @return the string representation of this

     *      {@code CertStatusReqListV2Extension}

     */

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder("Extension ").append(type);

        for (CertStatusReqItemV2 item : itemList) {

            sb.append("\n").append(item);

        }

        return sb.toString();

    }

    /**

     * Determine the length of the certificate_status_req_list field in

     * the status_request_v2 extension.

     *

     * @return the total encoded length of all items in the list, or 0 if the

     *      encapsulating extension_data is zero-length (from a ServerHello)

     */

    private int calculateListLength() {

        int listLen = 0;

        for (CertStatusReqItemV2 item : itemList) {

            listLen += item.length();

        }

        return listLen;

    }

}