/*
 * Copyright 2014 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 io.netty.handler.ssl;

import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.CoreMatchers.nullValue;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.junit.Assume.assumeTrue;

import java.io.File;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import javax.net.ssl.SSLEngine;
import javax.xml.bind.DatatypeConverter;

import org.junit.Test;

import io.netty.bootstrap.Bootstrap;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.DefaultEventLoopGroup;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.embedded.EmbeddedChannel;
import io.netty.channel.local.LocalAddress;
import io.netty.channel.local.LocalChannel;
import io.netty.channel.local.LocalServerChannel;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
import io.netty.handler.ssl.util.SelfSignedCertificate;
import io.netty.util.DomainNameMapping;
import io.netty.util.DomainNameMappingBuilder;
import io.netty.util.Mapping;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.ReferenceCounted;
import io.netty.util.concurrent.Promise;
import io.netty.util.internal.ObjectUtil;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

@RunWith(Parameterized.class)
public class SniHandlerTest {

    private static ApplicationProtocolConfig newApnConfig() {
        return new ApplicationProtocolConfig(
                ApplicationProtocolConfig.Protocol.ALPN,
                // NO_ADVERTISE is currently the only mode supported by both OpenSsl and JDK providers.
                ApplicationProtocolConfig.SelectorFailureBehavior.NO_ADVERTISE,
                // ACCEPT is currently the only mode supported by both OpenSsl and JDK providers.
                ApplicationProtocolConfig.SelectedListenerFailureBehavior.ACCEPT,
                "myprotocol");
    }

    private static void assumeApnSupported(SslProvider provider) {
        switch (provider) {
            case OPENSSL:
            case OPENSSL_REFCNT:
                assumeTrue(OpenSsl.isAlpnSupported());
                break;
            case JDK:
                assumeTrue(JdkAlpnSslEngine.isAvailable());
                break;
            default:
                throw new Error();
        }
    }

    private static SslContext makeSslContext(SslProvider provider, boolean apn) throws Exception {
        if (apn) {
            assumeApnSupported(provider);
        }

        File keyFile = new File(SniHandlerTest.class.getResource("test_encrypted.pem").getFile());
        File crtFile = new File(SniHandlerTest.class.getResource("test.crt").getFile());

        SslContextBuilder sslCtxBuilder = SslContextBuilder.forServer(crtFile, keyFile, "12345")
                .sslProvider(provider);
        if (apn) {
            sslCtxBuilder.applicationProtocolConfig(newApnConfig());
        }
        return sslCtxBuilder.build();
    }

    private static SslContext makeSslClientContext(SslProvider provider, boolean apn) throws Exception {
        if (apn) {
            assumeApnSupported(provider);
        }

        File crtFile = new File(SniHandlerTest.class.getResource("test.crt").getFile());

        SslContextBuilder sslCtxBuilder = SslContextBuilder.forClient().trustManager(crtFile).sslProvider(provider);
        if (apn) {
            sslCtxBuilder.applicationProtocolConfig(newApnConfig());
        }
        return sslCtxBuilder.build();
    }

    @Parameterized.Parameters(name = "{index}: sslProvider={0}")
    public static Iterable<? extends Object> data() {
        List<SslProvider> params = new ArrayList<SslProvider>(3);
        if (OpenSsl.isAvailable()) {
            params.add(SslProvider.OPENSSL);
            params.add(SslProvider.OPENSSL_REFCNT);
        }
        params.add(SslProvider.JDK);
        return params;
    }

    private final SslProvider provider;

    public SniHandlerTest(SslProvider provider) {
        this.provider = provider;
    }

    @Test
    public void testServerNameParsing() throws Exception {
        SslContext nettyContext = makeSslContext(provider, false);
        SslContext leanContext = makeSslContext(provider, false);
        SslContext leanContext2 = makeSslContext(provider, false);

        try {
            DomainNameMapping<SslContext> mapping = new DomainNameMappingBuilder<SslContext>(nettyContext)
                    .add("*.netty.io", nettyContext)
                    // input with custom cases
                    .add("*.LEANCLOUD.CN", leanContext)
                    // a hostname conflict with previous one, since we are using order-sensitive config,
                    // the engine won't be used with the handler.
                    .add("chat4.leancloud.cn", leanContext2)
                    .build();

            SniHandler handler = new SniHandler(mapping);
            EmbeddedChannel ch = new EmbeddedChannel(handler);

            // hex dump of a client hello packet, which contains hostname "CHAT4。LEANCLOUD。CN"
            String tlsHandshakeMessageHex1 = "16030100";
            // part 2
            String tlsHandshakeMessageHex = "bd010000b90303a74225676d1814ba57faff3b366" +
                    "3656ed05ee9dbb2a4dbb1bb1c32d2ea5fc39e0000000100008c0000001700150000164348" +
                    "415434E380824C45414E434C4F5544E38082434E000b000403000102000a00340032000e0" +
                    "00d0019000b000c00180009000a0016001700080006000700140015000400050012001300" +
                    "0100020003000f0010001100230000000d0020001e0601060206030501050205030401040" +
                    "20403030103020303020102020203000f00010133740000";

            try {
                // Push the handshake message.
                // Decode should fail because SNI error
                ch.writeInbound(Unpooled.wrappedBuffer(DatatypeConverter.parseHexBinary(tlsHandshakeMessageHex1)));
                ch.writeInbound(Unpooled.wrappedBuffer(DatatypeConverter.parseHexBinary(tlsHandshakeMessageHex)));
                fail();
            } catch (DecoderException e) {
                // expected
            }

            // This should produce an alert
            assertTrue(ch.finish());

            assertThat(handler.hostname(), is("chat4.leancloud.cn"));
            assertThat(handler.sslContext(), is(leanContext));

            for (;;) {
                Object msg = ch.readOutbound();
                if (msg == null) {
                    break;
                }
                ReferenceCountUtil.release(msg);
            }
        } finally {
            releaseAll(leanContext, leanContext2, nettyContext);
        }
    }

    @Test
    public void testFallbackToDefaultContext() throws Exception {
        SslContext nettyContext = makeSslContext(provider, false);
        SslContext leanContext = makeSslContext(provider, false);
        SslContext leanContext2 = makeSslContext(provider, false);

        try {
            DomainNameMapping<SslContext> mapping = new DomainNameMappingBuilder<SslContext>(nettyContext)
                    .add("*.netty.io", nettyContext)
                    // input with custom cases
                    .add("*.LEANCLOUD.CN", leanContext)
                    // a hostname conflict with previous one, since we are using order-sensitive config,
                    // the engine won't be used with the handler.
                    .add("chat4.leancloud.cn", leanContext2)
                    .build();

            SniHandler handler = new SniHandler(mapping);
            EmbeddedChannel ch = new EmbeddedChannel(handler);

            // invalid
            byte[] message = {22, 3, 1, 0, 0};

            try {
                // Push the handshake message.
                ch.writeInbound(Unpooled.wrappedBuffer(message));
            } catch (Exception e) {
                // expected
            }

            assertThat(ch.finish(), is(false));
            assertThat(handler.hostname(), nullValue());
            assertThat(handler.sslContext(), is(nettyContext));
        } finally {
            releaseAll(leanContext, leanContext2, nettyContext);
        }
    }

    @Test
    public void testSniWithApnHandler() throws Exception {
        SslContext nettyContext = makeSslContext(provider, true);
        SslContext sniContext = makeSslContext(provider, true);
        final SslContext clientContext = makeSslClientContext(provider, true);
        try {
            final CountDownLatch serverApnDoneLatch = new CountDownLatch(1);
            final CountDownLatch clientApnDoneLatch = new CountDownLatch(1);

            final DomainNameMapping<SslContext> mapping = new DomainNameMappingBuilder<SslContext>(nettyContext)
                    .add("*.netty.io", nettyContext)
                    .add("sni.fake.site", sniContext).build();
            final SniHandler handler = new SniHandler(mapping);
            EventLoopGroup group = new NioEventLoopGroup(2);
            Channel serverChannel = null;
            Channel clientChannel = null;
            try {
                ServerBootstrap sb = new ServerBootstrap();
                sb.group(group);
                sb.channel(NioServerSocketChannel.class);
                sb.childHandler(new ChannelInitializer<Channel>() {
                    @Override
                    protected void initChannel(Channel ch) throws Exception {
                        ChannelPipeline p = ch.pipeline();
                        // Server side SNI.
                        p.addLast(handler);
                        // Catch the notification event that APN has completed successfully.
                        p.addLast(new ApplicationProtocolNegotiationHandler("foo") {
                            @Override
                            protected void configurePipeline(ChannelHandlerContext ctx, String protocol) {
                                serverApnDoneLatch.countDown();
                            }
                        });
                    }
                });

                Bootstrap cb = new Bootstrap();
                cb.group(group);
                cb.channel(NioSocketChannel.class);
                cb.handler(new ChannelInitializer<Channel>() {
                    @Override
                    protected void initChannel(Channel ch) throws Exception {
                        ch.pipeline().addLast(new SslHandler(clientContext.newEngine(
                                ch.alloc(), "sni.fake.site", -1)));
                        // Catch the notification event that APN has completed successfully.
                        ch.pipeline().addLast(new ApplicationProtocolNegotiationHandler("foo") {
                            @Override
                            protected void configurePipeline(ChannelHandlerContext ctx, String protocol) {
                                clientApnDoneLatch.countDown();
                            }
                        });
                    }
                });

                serverChannel = sb.bind(new InetSocketAddress(0)).sync().channel();

                ChannelFuture ccf = cb.connect(serverChannel.localAddress());
                assertTrue(ccf.awaitUninterruptibly().isSuccess());
                clientChannel = ccf.channel();

                assertTrue(serverApnDoneLatch.await(5, TimeUnit.SECONDS));
                assertTrue(clientApnDoneLatch.await(5, TimeUnit.SECONDS));
                assertThat(handler.hostname(), is("sni.fake.site"));
                assertThat(handler.sslContext(), is(sniContext));
            } finally {
                if (serverChannel != null) {
                    serverChannel.close().sync();
                }
                if (clientChannel != null) {
                    clientChannel.close().sync();
                }
                group.shutdownGracefully(0, 0, TimeUnit.MICROSECONDS);
            }
        } finally {
            releaseAll(clientContext, nettyContext, sniContext);
        }
    }

    @Test(timeout = 10L * 1000L)
    public void testReplaceHandler() throws Exception {
        switch (provider) {
            case OPENSSL:
            case OPENSSL_REFCNT:
                final String sniHost = "sni.netty.io";
                LocalAddress address = new LocalAddress("testReplaceHandler-" + Math.random());
                EventLoopGroup group = new DefaultEventLoopGroup(1);
                Channel sc = null;
                Channel cc = null;
                SslContext sslContext = null;

                SelfSignedCertificate cert = new SelfSignedCertificate();

                try {
                    final SslContext sslServerContext = SslContextBuilder
                            .forServer(cert.key(), cert.cert())
                            .sslProvider(provider)
                            .build();

                    final Mapping<String, SslContext> mapping = new Mapping<String, SslContext>() {
                        @Override
                        public SslContext map(String input) {
                            return sslServerContext;
                        }
                    };

                    final Promise<Void> releasePromise = group.next().newPromise();

                    final SniHandler handler = new SniHandler(mapping) {
                        @Override
                        protected void replaceHandler(ChannelHandlerContext ctx,
                                                      String hostname, final SslContext sslContext)
                                throws Exception {

                            boolean success = false;
                            try {
                                // The SniHandler's replaceHandler() method allows us to implement custom behavior.
                                // As an example, we want to release() the SslContext upon channelInactive() or rather
                                // when the SslHandler closes it's SslEngine. If you take a close look at SslHandler
                                // you'll see that it's doing it in the #handlerRemoved0() method.

                                SSLEngine sslEngine = sslContext.newEngine(ctx.alloc());
                                try {
                                    SslHandler customSslHandler = new CustomSslHandler(sslContext, sslEngine) {
                                        @Override
                                        public void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {
                                            try {
                                                super.handlerRemoved0(ctx);
                                            } finally {
                                                releasePromise.trySuccess(null);
                                            }
                                        }
                                    };
                                    ctx.pipeline().replace(this, CustomSslHandler.class.getName(), customSslHandler);
                                    success = true;
                                } finally {
                                    if (!success) {
                                        ReferenceCountUtil.safeRelease(sslEngine);
                                    }
                                }
                            } finally {
                                if (!success) {
                                    ReferenceCountUtil.safeRelease(sslContext);
                                    releasePromise.cancel(true);
                                }
                            }
                        }
                    };

                    ServerBootstrap sb = new ServerBootstrap();
                    sc = sb.group(group).channel(LocalServerChannel.class)
                            .childHandler(new ChannelInitializer<Channel>() {
                        @Override
                        protected void initChannel(Channel ch) throws Exception {
                            ch.pipeline().addFirst(handler);
                        }
                    }).bind(address).syncUninterruptibly().channel();

                    sslContext = SslContextBuilder.forClient().sslProvider(provider)
                            .trustManager(InsecureTrustManagerFactory.INSTANCE).build();

                    Bootstrap cb = new Bootstrap();
                    cc = cb.group(group).channel(LocalChannel.class).handler(new SslHandler(
                            sslContext.newEngine(ByteBufAllocator.DEFAULT, sniHost, -1)))
                            .connect(address).syncUninterruptibly().channel();

                    cc.writeAndFlush(Unpooled.wrappedBuffer("Hello, World!".getBytes()))
                            .syncUninterruptibly();

                    // Notice how the server's SslContext refCnt is 1
                    assertEquals(1, ((ReferenceCounted) sslServerContext).refCnt());

                    // The client disconnects
                    cc.close().syncUninterruptibly();
                    if (!releasePromise.awaitUninterruptibly(10L, TimeUnit.SECONDS)) {
                        throw new IllegalStateException("It doesn't seem #replaceHandler() got called.");
                    }

                    // We should have successfully release() the SslContext
                    assertEquals(0, ((ReferenceCounted) sslServerContext).refCnt());
                } finally {
                    if (cc != null) {
                        cc.close().syncUninterruptibly();
                    }
                    if (sc != null) {
                        sc.close().syncUninterruptibly();
                    }
                    if (sslContext != null) {
                        ReferenceCountUtil.release(sslContext);
                    }
                    group.shutdownGracefully();

                    cert.delete();
                }
            case JDK:
                return;
            default:
                throw new Error();
        }
    }

    /**
     * This is a {@link SslHandler} that will call {@code release()} on the {@link SslContext} when
     * the client disconnects.
     *
     * @see SniHandlerTest#testReplaceHandler()
     */
    private static class CustomSslHandler extends SslHandler {
        private final SslContext sslContext;

        public CustomSslHandler(SslContext sslContext, SSLEngine sslEngine) {
            super(sslEngine);
            this.sslContext = ObjectUtil.checkNotNull(sslContext, "sslContext");
        }

        @Override
        public void handlerRemoved0(ChannelHandlerContext ctx) throws Exception {
            super.handlerRemoved0(ctx);
            ReferenceCountUtil.release(sslContext);
        }
    }

    private static void releaseAll(SslContext... contexts) {
        for (SslContext ctx: contexts) {
            ReferenceCountUtil.release(ctx);
        }
    }
}
