/*
 * Copyright 2012 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.channel.sctp.oio;

import com.sun.nio.sctp.SctpChannel;
import com.sun.nio.sctp.SctpServerChannel;
import io.netty.channel.ChannelException;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelMetadata;
import io.netty.channel.ChannelOutboundBuffer;
import io.netty.channel.ChannelPromise;
import io.netty.channel.oio.AbstractOioMessageChannel;
import io.netty.channel.sctp.DefaultSctpServerChannelConfig;
import io.netty.channel.sctp.SctpServerChannelConfig;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

SctpServerChannel implementation which use blocking mode to accept new connections and create the OioSctpChannel for them. Be aware that not all operations systems support SCTP. Please refer to the documentation of your operation system, to understand what you need to do to use it. Also this feature is only supported on Java 7+. /**
 * {@link io.netty.channel.sctp.SctpServerChannel} implementation which use blocking mode to accept new
 * connections and create the {@link OioSctpChannel} for them.
 *
 * Be aware that not all operations systems support SCTP. Please refer to the documentation of your operation system,
 * to understand what you need to do to use it. Also this feature is only supported on Java 7+.
 */
public class OioSctpServerChannel extends AbstractOioMessageChannel
        implements io.netty.channel.sctp.SctpServerChannel {

    private static final InternalLogger logger =
            InternalLoggerFactory.getInstance(OioSctpServerChannel.class);

    private static final ChannelMetadata METADATA = new ChannelMetadata(false, 1);

    private static SctpServerChannel newServerSocket() {
        try {
            return SctpServerChannel.open();
        } catch (IOException e) {
            throw new ChannelException("failed to create a sctp server channel", e);
        }
    }

    private final SctpServerChannel sch;
    private final SctpServerChannelConfig config;
    private final Selector selector;

    
Create a new instance with an new SctpServerChannel /**
     * Create a new instance with an new {@link SctpServerChannel}
     */
    public OioSctpServerChannel() {
        this(newServerSocket());
    }

    
Create a new instance from the given SctpServerChannel 
Params:
sch –  the SctpServerChannel which is used by this instance/**
     * Create a new instance from the given {@link SctpServerChannel}
     *
     * @param sch    the {@link SctpServerChannel} which is used by this instance
     */
    public OioSctpServerChannel(SctpServerChannel sch) {
        super(null);
        if (sch == null) {
            throw new NullPointerException("sctp server channel");
        }

        this.sch = sch;
        boolean success = false;
        try {
            sch.configureBlocking(false);
            selector = Selector.open();
            sch.register(selector, SelectionKey.OP_ACCEPT);
            config = new OioSctpServerChannelConfig(this, sch);
            success = true;
        } catch (Exception e) {
            throw new ChannelException("failed to initialize a sctp server channel", e);
        } finally {
            if (!success) {
                try {
                    sch.close();
                } catch (IOException e) {
                    logger.warn("Failed to close a sctp server channel.", e);
                }
            }
        }
    }

    @Override
    public ChannelMetadata metadata() {
        return METADATA;
    }

    @Override
    public SctpServerChannelConfig config() {
        return config;
    }

    @Override
    public InetSocketAddress remoteAddress() {
        return null;
    }

    @Override
    public InetSocketAddress localAddress() {
        return (InetSocketAddress) super.localAddress();
    }

    @Override
    public boolean isOpen() {
        return sch.isOpen();
    }

    @Override
    protected SocketAddress localAddress0() {
        try {
            Iterator<SocketAddress> i = sch.getAllLocalAddresses().iterator();
            if (i.hasNext()) {
                return i.next();
            }
        } catch (IOException e) {
            // ignore
        }
        return null;
    }

    @Override
    public Set<InetSocketAddress> allLocalAddresses() {
        try {
            final Set<SocketAddress> allLocalAddresses = sch.getAllLocalAddresses();
            final Set<InetSocketAddress> addresses = new LinkedHashSet<InetSocketAddress>(allLocalAddresses.size());
            for (SocketAddress socketAddress : allLocalAddresses) {
                addresses.add((InetSocketAddress) socketAddress);
            }
            return addresses;
        } catch (Throwable ignored) {
            return Collections.emptySet();
        }
    }

    @Override
    public boolean isActive() {
        return isOpen() && localAddress0() != null;
    }

    @Override
    protected void doBind(SocketAddress localAddress) throws Exception {
        sch.bind(localAddress, config.getBacklog());
    }

    @Override
    protected void doClose() throws Exception {
        try {
            selector.close();
        } catch (IOException e) {
            logger.warn("Failed to close a selector.", e);
        }
        sch.close();
    }

    @Override
    protected int doReadMessages(List<Object> buf) throws Exception {
        if (!isActive()) {
            return -1;
        }

        SctpChannel s = null;
        int acceptedChannels = 0;
        try {
            final int selectedKeys = selector.select(SO_TIMEOUT);
            if (selectedKeys > 0) {
                final Iterator<SelectionKey> selectionKeys = selector.selectedKeys().iterator();
                for (;;) {
                    SelectionKey key = selectionKeys.next();
                    selectionKeys.remove();
                    if (key.isAcceptable()) {
                        s = sch.accept();
                        if (s != null) {
                            buf.add(new OioSctpChannel(this, s));
                            acceptedChannels ++;
                        }
                    }
                    if (!selectionKeys.hasNext()) {
                        return acceptedChannels;
                    }
                }
            }
        } catch (Throwable t) {
            logger.warn("Failed to create a new channel from an accepted sctp channel.", t);
            if (s != null) {
                try {
                    s.close();
                } catch (Throwable t2) {
                    logger.warn("Failed to close a sctp channel.", t2);
                }
            }
        }

        return acceptedChannels;
    }

    @Override
    public ChannelFuture bindAddress(InetAddress localAddress) {
        return bindAddress(localAddress, newPromise());
    }

    @Override
    public ChannelFuture bindAddress(final InetAddress localAddress, final ChannelPromise promise) {
        if (eventLoop().inEventLoop()) {
            try {
                sch.bindAddress(localAddress);
                promise.setSuccess();
            } catch (Throwable t) {
                promise.setFailure(t);
            }
        } else {
            eventLoop().execute(new Runnable() {
                @Override
                public void run() {
                    bindAddress(localAddress, promise);
                }
            });
        }
        return promise;
    }

    @Override
    public ChannelFuture unbindAddress(InetAddress localAddress) {
        return unbindAddress(localAddress, newPromise());
    }

    @Override
    public ChannelFuture unbindAddress(final InetAddress localAddress, final ChannelPromise promise) {
        if (eventLoop().inEventLoop()) {
            try {
                sch.unbindAddress(localAddress);
                promise.setSuccess();
            } catch (Throwable t) {
                promise.setFailure(t);
            }
        } else {
            eventLoop().execute(new Runnable() {
                @Override
                public void run() {
                    unbindAddress(localAddress, promise);
                }
            });
        }
        return promise;
    }

    @Override
    protected void doConnect(
            SocketAddress remoteAddress, SocketAddress localAddress) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected SocketAddress remoteAddress0() {
        return null;
    }

    @Override
    protected void doDisconnect() throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected void doWrite(ChannelOutboundBuffer in) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected Object filterOutboundMessage(Object msg) throws Exception {
        throw new UnsupportedOperationException();
    }

    private final class OioSctpServerChannelConfig extends DefaultSctpServerChannelConfig {
        private OioSctpServerChannelConfig(OioSctpServerChannel channel, SctpServerChannel javaChannel) {
            super(channel, javaChannel);
        }

        @Override
        protected void autoReadCleared() {
            clearReadPending();
        }
    }
}