/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed 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.undertow.protocols.ssl;

import io.undertow.UndertowLogger;
import io.undertow.UndertowOptions;
import io.undertow.connector.ByteBufferPool;
import org.xnio.ChannelListener;
import org.xnio.ChannelListeners;
import org.xnio.IoUtils;
import org.xnio.Option;
import org.xnio.OptionMap;
import org.xnio.Options;
import org.xnio.Sequence;
import org.xnio.SslClientAuthMode;
import org.xnio.StreamConnection;
import org.xnio.Xnio;
import org.xnio.XnioExecutor;
import org.xnio.XnioIoThread;
import org.xnio.XnioWorker;
import org.xnio.channels.AcceptingChannel;
import org.xnio.ssl.SslConnection;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLParameters;

/**
 * @author Stuart Douglas
 */
class UndertowAcceptingSslChannel implements AcceptingChannel<SslConnection> {

    private final UndertowXnioSsl ssl;
    private final AcceptingChannel<? extends StreamConnection> tcpServer;

    private volatile SslClientAuthMode clientAuthMode;
    private volatile int useClientMode;
    private volatile int enableSessionCreation;
    private volatile String[] cipherSuites;
    private volatile String[] protocols;

    @SuppressWarnings("rawtypes")
    private static final AtomicReferenceFieldUpdater<UndertowAcceptingSslChannel, SslClientAuthMode> clientAuthModeUpdater = AtomicReferenceFieldUpdater.newUpdater(UndertowAcceptingSslChannel.class, SslClientAuthMode.class, "clientAuthMode");
    @SuppressWarnings("rawtypes")
    private static final AtomicIntegerFieldUpdater<UndertowAcceptingSslChannel> useClientModeUpdater = AtomicIntegerFieldUpdater.newUpdater(UndertowAcceptingSslChannel.class, "useClientMode");
    @SuppressWarnings("rawtypes")
    private static final AtomicIntegerFieldUpdater<UndertowAcceptingSslChannel> enableSessionCreationUpdater = AtomicIntegerFieldUpdater.newUpdater(UndertowAcceptingSslChannel.class, "enableSessionCreation");

    private final ChannelListener.Setter<AcceptingChannel<SslConnection>> closeSetter;
    private final ChannelListener.Setter<AcceptingChannel<SslConnection>> acceptSetter;
    protected final boolean startTls;
    protected final ByteBufferPool applicationBufferPool;
    private final boolean useCipherSuitesOrder;

    UndertowAcceptingSslChannel(final UndertowXnioSsl ssl, final AcceptingChannel<? extends StreamConnection> tcpServer, final OptionMap optionMap, final ByteBufferPool applicationBufferPool, final boolean startTls) {
        this.tcpServer = tcpServer;
        this.ssl = ssl;
        this.applicationBufferPool = applicationBufferPool;
        this.startTls = startTls;
        clientAuthMode = optionMap.get(Options.SSL_CLIENT_AUTH_MODE);
        useClientMode = optionMap.get(Options.SSL_USE_CLIENT_MODE, false) ? 1 : 0;
        enableSessionCreation = optionMap.get(Options.SSL_ENABLE_SESSION_CREATION, true) ? 1 : 0;
        final Sequence<String> enabledCipherSuites = optionMap.get(Options.SSL_ENABLED_CIPHER_SUITES);
        cipherSuites = enabledCipherSuites != null ? enabledCipherSuites.toArray(new String[enabledCipherSuites.size()]) : null;
        final Sequence<String> enabledProtocols = optionMap.get(Options.SSL_ENABLED_PROTOCOLS);
        protocols = enabledProtocols != null ? enabledProtocols.toArray(new String[enabledProtocols.size()]) : null;
        //noinspection ThisEscapedInObjectConstruction
        closeSetter = ChannelListeners.<AcceptingChannel<SslConnection>>getDelegatingSetter(tcpServer.getCloseSetter(), this);
        //noinspection ThisEscapedInObjectConstruction
        acceptSetter = ChannelListeners.<AcceptingChannel<SslConnection>>getDelegatingSetter(tcpServer.getAcceptSetter(), this);
        useCipherSuitesOrder = optionMap.get(UndertowOptions.SSL_USER_CIPHER_SUITES_ORDER, false);
    }

    private static final Set<Option<?>> SUPPORTED_OPTIONS = Option.setBuilder()
            .add(Options.SSL_CLIENT_AUTH_MODE)
            .add(Options.SSL_USE_CLIENT_MODE)
            .add(Options.SSL_ENABLE_SESSION_CREATION)
            .add(Options.SSL_ENABLED_CIPHER_SUITES)
            .add(Options.SSL_ENABLED_PROTOCOLS)
            .create();

    public <T> T setOption(final Option<T> option, final T value) throws IllegalArgumentException, IOException {
        if (option == Options.SSL_CLIENT_AUTH_MODE) {
            return option.cast(clientAuthModeUpdater.getAndSet(this, Options.SSL_CLIENT_AUTH_MODE.cast(value)));
        } else if (option == Options.SSL_USE_CLIENT_MODE) {
            final Boolean valueObject = Options.SSL_USE_CLIENT_MODE.cast(value);
            if (valueObject != null) return option.cast(Boolean.valueOf(useClientModeUpdater.getAndSet(this, valueObject.booleanValue() ? 1 : 0) != 0));
        } else if (option == Options.SSL_ENABLE_SESSION_CREATION) {
            final Boolean valueObject = Options.SSL_ENABLE_SESSION_CREATION.cast(value);
            if (valueObject != null) return option.cast(Boolean.valueOf(enableSessionCreationUpdater.getAndSet(this, valueObject.booleanValue() ? 1 : 0) != 0));
        } else if (option == Options.SSL_ENABLED_CIPHER_SUITES) {
            final Sequence<String> seq = Options.SSL_ENABLED_CIPHER_SUITES.cast(value);
            String[] old = this.cipherSuites;
            this.cipherSuites = seq == null ? null : seq.toArray(new String[seq.size()]);
            return option.cast(old);
        } else if (option == Options.SSL_ENABLED_PROTOCOLS) {
            final Sequence<String> seq = Options.SSL_ENABLED_PROTOCOLS.cast(value);
            String[] old = this.protocols;
            this.protocols = seq == null ? null : seq.toArray(new String[seq.size()]);
            return option.cast(old);
        } else {
            return tcpServer.setOption(option, value);
        }
        throw UndertowLogger.ROOT_LOGGER.nullParameter("value");
    }

    public XnioWorker getWorker() {
        return tcpServer.getWorker();
    }

    public UndertowSslConnection accept() throws IOException {
        final StreamConnection tcpConnection = tcpServer.accept();
        if (tcpConnection == null) {
            return null;
        }
        try {
            final InetSocketAddress peerAddress = tcpConnection.getPeerAddress(InetSocketAddress.class);
            final SSLEngine engine = ssl.getSslContext().createSSLEngine(getHostNameNoResolve(peerAddress), peerAddress.getPort());

            if(useCipherSuitesOrder) {
                SSLParameters sslParameters = engine.getSSLParameters();
                sslParameters.setUseCipherSuitesOrder(true);
                engine.setSSLParameters(sslParameters);
            }
            final boolean clientMode = useClientMode != 0;
            engine.setUseClientMode(clientMode);
            if (!clientMode) {
                final SslClientAuthMode clientAuthMode = UndertowAcceptingSslChannel.this.clientAuthMode;
                if (clientAuthMode != null) switch (clientAuthMode) {
                    case NOT_REQUESTED:
                        engine.setNeedClientAuth(false);
                        engine.setWantClientAuth(false);
                        break;
                    case REQUESTED:
                        engine.setWantClientAuth(true);
                        break;
                    case REQUIRED:
                        engine.setNeedClientAuth(true);
                        break;
                    default:
                        throw new IllegalStateException();
                }
            }
            engine.setEnableSessionCreation(enableSessionCreation != 0);
            final String[] cipherSuites = UndertowAcceptingSslChannel.this.cipherSuites;
            if (cipherSuites != null) {
                final Set<String> supported = new HashSet<>(Arrays.asList(engine.getSupportedCipherSuites()));
                if(supported.isEmpty()) {
                    engine.setEnabledCipherSuites(cipherSuites);
                } else {
                    final List<String> finalList = new ArrayList<>();
                    for (String name : cipherSuites) {
                        if (supported.contains(name)) {
                            finalList.add(name);
                        }
                    }
                    engine.setEnabledCipherSuites(finalList.toArray(new String[finalList.size()]));
                }
            }
            final String[] protocols = UndertowAcceptingSslChannel.this.protocols;
            if (protocols != null) {
                final Set<String> supported = new HashSet<>(Arrays.asList(engine.getSupportedProtocols()));
                if(supported.isEmpty()) {
                    engine.setEnabledProtocols(protocols);
                } else {
                    final List<String> finalList = new ArrayList<>();
                    for (String name : protocols) {
                        if (supported.contains(name)) {
                            finalList.add(name);
                        }
                    }
                    engine.setEnabledProtocols(finalList.toArray(new String[finalList.size()]));
                }
            }
            return accept(tcpConnection, engine);
        } catch (IOException | RuntimeException e) {
            IoUtils.safeClose(tcpConnection);
            UndertowLogger.REQUEST_LOGGER.failedToAcceptSSLRequest(e);
            return null;
        }
    }

    protected UndertowSslConnection accept(StreamConnection tcpServer, SSLEngine sslEngine) throws IOException {
        return new UndertowSslConnection(tcpServer, sslEngine, applicationBufferPool, ssl.getDelegatedTaskExecutor());
    }

    public ChannelListener.Setter<? extends AcceptingChannel<SslConnection>> getCloseSetter() {
        return closeSetter;
    }

    public boolean isOpen() {
        return tcpServer.isOpen();
    }

    public void close() throws IOException {
        tcpServer.close();
    }

    public boolean supportsOption(final Option<?> option) {
        return SUPPORTED_OPTIONS.contains(option) || tcpServer.supportsOption(option);
    }

    public <T> T getOption(final Option<T> option) throws IOException {
        if (option == Options.SSL_CLIENT_AUTH_MODE) {
            return option.cast(clientAuthMode);
        } else if (option == Options.SSL_USE_CLIENT_MODE) {
            return option.cast(Boolean.valueOf(useClientMode != 0));
        } else if (option == Options.SSL_ENABLE_SESSION_CREATION) {
            return option.cast(Boolean.valueOf(enableSessionCreation != 0));
        } else if (option == Options.SSL_ENABLED_CIPHER_SUITES) {
            final String[] cipherSuites = this.cipherSuites;
            return cipherSuites == null ? null : option.cast(Sequence.of(cipherSuites));
        } else if (option == Options.SSL_ENABLED_PROTOCOLS) {
            final String[] protocols = this.protocols;
            return protocols == null ? null : option.cast(Sequence.of(protocols));
        } else {
            return tcpServer.getOption(option);
        }
    }

    public ChannelListener.Setter<? extends AcceptingChannel<SslConnection>> getAcceptSetter() {
        return acceptSetter;
    }

    public SocketAddress getLocalAddress() {
        return tcpServer.getLocalAddress();
    }

    public <A extends SocketAddress> A getLocalAddress(final Class<A> type) {
        return tcpServer.getLocalAddress(type);
    }

    public void suspendAccepts() {
        tcpServer.suspendAccepts();
    }

    public void resumeAccepts() {
        tcpServer.resumeAccepts();
    }

    @Override
    public boolean isAcceptResumed() {
        return tcpServer.isAcceptResumed();
    }

    public void wakeupAccepts() {
        tcpServer.wakeupAccepts();
    }

    public void awaitAcceptable() throws IOException {
        tcpServer.awaitAcceptable();
    }

    public void awaitAcceptable(final long time, final TimeUnit timeUnit) throws IOException {
        tcpServer.awaitAcceptable(time, timeUnit);
    }

    @Deprecated
    public XnioExecutor getAcceptThread() {
        return tcpServer.getAcceptThread();
    }

    public XnioIoThread getIoThread() {
        return tcpServer.getIoThread();
    }


    private static String getHostNameNoResolve(InetSocketAddress socketAddress) {
        if (Xnio.NIO2) {
            return socketAddress.getHostString();
        } else {
            String hostName;
            if (socketAddress.isUnresolved()) {
                hostName = socketAddress.getHostName();
            } else {
                final InetAddress address = socketAddress.getAddress();
                final String string = address.toString();
                final int slash = string.indexOf('/');
                if (slash == -1 || slash == 0) {
                    // unresolved both ways
                    hostName = string.substring(slash + 1);
                } else {
                    // has a cached host name
                    hostName = string.substring(0, slash);
                }
            }
            return hostName;
        }
    }
}
