/*
 *  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 javax.net.ssl;

import java.io.IOException;
import java.net.Socket;
import java.security.NoSuchAlgorithmException;
import java.security.Security;
import javax.net.SocketFactory;
import org.apache.harmony.security.fortress.Services;

/**
 * The abstract factory implementation to create {@code SSLSocket}s.
 */
public abstract class SSLSocketFactory extends SocketFactory {
    // FIXME EXPORT CONTROL

    // The default SSL socket factory
    private static SocketFactory defaultSocketFactory;

    private static int lastCacheVersion = -1;

    /**
     * Returns the default {@code SSLSocketFactory} instance. The default is
     * defined by the security property {@code 'ssl.SocketFactory.provider'}.
     *
     * @return the default ssl socket factory instance.
     */
    public static synchronized SocketFactory getDefault() {
        int newCacheVersion = Services.getCacheVersion();
        if (defaultSocketFactory != null && lastCacheVersion == newCacheVersion) {
            return defaultSocketFactory;
        }
        lastCacheVersion = newCacheVersion;

        String newName = Security.getProperty("ssl.SocketFactory.provider");
        if (newName != null) {
            /* The cache could have been invalidated, but the provider name didn't change. This
             * will be the most common state, so check for it early without resetting the default
             * SocketFactory.
             */
            if (defaultSocketFactory != null) {
                if (newName.equals(defaultSocketFactory.getClass().getName())) {
                    return defaultSocketFactory;
                } else {
                    defaultSocketFactory = null;
                }
            }

            ClassLoader cl = Thread.currentThread().getContextClassLoader();
            if (cl == null) {
                cl = ClassLoader.getSystemClassLoader();
            }
            try {
                final Class<?> sfc = Class.forName(newName, true, cl);
                defaultSocketFactory = (SocketFactory) sfc.newInstance();
            } catch (Exception e) {
                System.logW("Could not create " + newName + " with ClassLoader "
                        + cl.toString() + ": " + e.getMessage());
            }
        } else {
            defaultSocketFactory = null;
        }

        if (defaultSocketFactory == null) {
            SSLContext context;
            try {
                context = SSLContext.getDefault();
            } catch (NoSuchAlgorithmException e) {
                context = null;
            }
            if (context != null) {
                defaultSocketFactory = context.getSocketFactory();
            }
        }

        if (defaultSocketFactory == null) {
            // Use internal implementation
            defaultSocketFactory = new DefaultSSLSocketFactory("No SSLSocketFactory installed");
        }

        return defaultSocketFactory;
    }

    /**
     * Creates a new {@code SSLSocketFactory}.
     */
    public SSLSocketFactory() {
    }

    /**
     * Returns the names of the cipher suites that are enabled by default.
     *
     * @return the names of the cipher suites that are enabled by default.
     */
    public abstract String[] getDefaultCipherSuites();

    /**
     * Returns the names of the cipher suites that are supported and could be
     * enabled for an SSL connection.
     *
     * @return the names of the cipher suites that are supported.
     */
    public abstract String[] getSupportedCipherSuites();

    /**
     * Creates an {@code SSLSocket} over the specified socket that is connected
     * to the specified host at the specified port.
     *
     * @param s
     *            the socket.
     * @param host
     *            the host.
     * @param port
     *            the port number.
     * @param autoClose
     *            {@code true} if socket {@code s} should be closed when the
     *            created socket is closed, {@code false} if the socket
     *            {@code s} should be left open.
     * @return the creates ssl socket.
     * @throws IOException
     *             if creating the socket fails.
     * @throws java.net.UnknownHostException
     *             if the host is unknown.
     */
    public abstract Socket createSocket(Socket s, String host, int port, boolean autoClose)
            throws IOException;
}