/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.tomcat.util.net;

import java.io.IOException;
import java.security.cert.X509Certificate;

/**
 * Defines an interface to interact with SSL sessions.
 */
public interface SSLSupport {
    /**
     * The Request attribute key for the cipher suite.
     */
    String CIPHER_SUITE_KEY = "jakarta.servlet.request.cipher_suite";

    /**
     * The Request attribute key for the key size.
     */
    String KEY_SIZE_KEY = "jakarta.servlet.request.key_size";

    /**
     * The Request attribute key for the client certificate chain.
     */
    String CERTIFICATE_KEY = "jakarta.servlet.request.X509Certificate";

    /**
     * The Request attribute key for the session id. This one is a Tomcat extension to the Servlet spec.
     */
    String SESSION_ID_KEY = "jakarta.servlet.request.ssl_session_id";

    /**
     * The request attribute key for the session manager. This one is a Tomcat extension to the Servlet spec.
     */
    String SESSION_MGR = "jakarta.servlet.request.ssl_session_mgr";

    /**
     * The request attribute key under which the String indicating the protocol that created the SSL socket is recorded
     * - e.g. TLSv1 or TLSv1.2 etc.
     */
    String PROTOCOL_VERSION_KEY = "org.apache.tomcat.util.net.secure_protocol_version";

    /**
     * The request attribute key under which the String indicating the ciphers requested by the client are recorded.
     */
    String REQUESTED_CIPHERS_KEY = "org.apache.tomcat.util.net.secure_requested_ciphers";

    /**
     * The request attribute key under which the String indicating the protocols requested by the client are recorded.
     */
    String REQUESTED_PROTOCOL_VERSIONS_KEY = "org.apache.tomcat.util.net.secure_requested_protocol_versions";

    /**
     * The cipher suite being used on this connection.
     *
     * @return The name of the cipher suite as returned by the SSL/TLS implementation
     *
     * @throws IOException If an error occurs trying to obtain the cipher suite
     */
    String getCipherSuite() throws IOException;

    /**
     * The client certificate chain (if any).
     *
     * @return The certificate chain presented by the client with the peer's certificate first, followed by those of any
     *             certificate authorities
     *
     * @throws IOException If an error occurs trying to obtain the certificate chain
     */
    X509Certificate[] getPeerCertificateChain() throws IOException;

    /**
     * The server certificate chain (if any) that were sent to the peer.
     *
     * @return The certificate chain sent with the server certificate first, followed by those of any certificate
     *             authorities
     */
    default X509Certificate[] getLocalCertificateChain() {
        return null;
    }

    /**
     * Get the key size. What we're supposed to put here is ill-defined by the Servlet spec (S 4.7 again). There are at
     * least 4 potential values that might go here: (a) The size of the encryption key (b) The size of the MAC key (c)
     * The size of the key-exchange key (d) The size of the signature key used by the server Unfortunately, all of these
     * values are nonsensical.
     *
     * @return The effective key size for the current cipher suite
     *
     * @throws IOException If an error occurs trying to obtain the key size
     */
    Integer getKeySize() throws IOException;

    /**
     * The current session Id.
     *
     * @return The current SSL/TLS session ID
     *
     * @throws IOException If an error occurs trying to obtain the session ID
     */
    String getSessionId() throws IOException;

    /**
     * Returns the protocol string indicating how the SSL socket was created e.g. TLSv1 or TLSv1.2 etc.
     *
     * @return the protocol string
     * @throws IOException If an error occurs trying to obtain the protocol information from the socket
     */
    String getProtocol() throws IOException;

    /**
     * Returns the list of SSL/TLS protocol versions requested by the client.
     *
     * @return the list of requested protocols
     * @throws IOException If an error occurs trying to obtain the client requested protocol information from the socket
     */
    String getRequestedProtocols() throws IOException;

    /**
     * Returns the list of SSL/TLS ciphers requested by the client.
     *
     * @return the list of requested ciphers
     * @throws IOException If an error occurs trying to obtain the client request cipher information from the socket
     */
    String getRequestedCiphers() throws IOException;
}
