/*
 * Copyright 2011 The Netty Project
 *
 * The Netty Project 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.jboss.netty.example.securechat;

import java.security.KeyStore;
import java.security.Security;

import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.TrustManager;

import org.jboss.netty.handler.ssl.SslHandler;

/**
 * Creates a bogus {@link SSLContext}.  A client-side context created by this
 * factory accepts any certificate even if it is invalid.  A server-side context
 * created by this factory sends a bogus certificate defined in {@link SecureChatKeyStore}.
 * <p>
 * You will have to create your context differently in a real world application.
 *
 * <h3>Client Certificate Authentication</h3>
 *
 * To enable client certificate authentication:
 * <ul>
 * <li>Enable client authentication on the server side by calling
 *     {@link SSLEngine#setNeedClientAuth(boolean)} before creating
 *     {@link SslHandler}.</li>
 * <li>When initializing an {@link SSLContext} on the client side,
 *     specify the {@link KeyManager} that contains the client certificate as
 *     the first argument of {@link SSLContext#init(KeyManager[], javax.net.ssl.TrustManager[], java.security.SecureRandom)}.</li>
 * <li>When initializing an {@link SSLContext} on the server side,
 *     specify the proper {@link TrustManager} as the second argument of
 *     {@link SSLContext#init(KeyManager[], javax.net.ssl.TrustManager[], java.security.SecureRandom)}
 *     to validate the client certificate.</li>
 * </ul>
 */
public final class SecureChatSslContextFactory {

    private static final String PROTOCOL = "TLS";
    private static final SSLContext SERVER_CONTEXT;
    private static final SSLContext CLIENT_CONTEXT;

    static {
        String algorithm = Security.getProperty("ssl.KeyManagerFactory.algorithm");
        if (algorithm == null) {
            algorithm = "SunX509";
        }

        SSLContext serverContext = null;
        SSLContext clientContext = null;
        try {
            KeyStore ks = KeyStore.getInstance("JKS");
            ks.load(SecureChatKeyStore.asInputStream(),
                    SecureChatKeyStore.getKeyStorePassword());

            // Set up key manager factory to use our key store
            KeyManagerFactory kmf = KeyManagerFactory.getInstance(algorithm);
            kmf.init(ks, SecureChatKeyStore.getCertificatePassword());

            // Initialize the SSLContext to work with our key managers.
            serverContext = SSLContext.getInstance(PROTOCOL);
            serverContext.init(kmf.getKeyManagers(), null, null);
        } catch (Exception e) {
            throw new Error(
                    "Failed to initialize the server-side SSLContext", e);
        }

        try {
            clientContext = SSLContext.getInstance(PROTOCOL);
            clientContext.init(null, SecureChatTrustManagerFactory.getTrustManagers(), null);
        } catch (Exception e) {
            throw new Error(
                    "Failed to initialize the client-side SSLContext", e);
        }

        SERVER_CONTEXT = serverContext;
        CLIENT_CONTEXT = clientContext;
    }

    public static SSLContext getServerContext() {
        return SERVER_CONTEXT;
    }

    public static SSLContext getClientContext() {
        return CLIENT_CONTEXT;
    }

    private SecureChatSslContextFactory() {
        // Unused
    }
}