/*
 * 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 org.apache.tomcat.util.net;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ByteChannel;
import java.nio.channels.SocketChannel;

import org.apache.tomcat.util.net.NioEndpoint.Poller;
import org.apache.tomcat.util.net.SecureNioChannel.ApplicationBufferHandler;
import java.nio.channels.Selector;
import java.nio.channels.SelectionKey;

/**
 * 
 * Base class for a SocketChannel wrapper used by the endpoint.
 * This way, logic for a SSL socket channel remains the same as for
 * a non SSL, making sure we don't need to code for any exception cases.
 * 
 * @author Filip Hanik
 * @version 1.0
 */
public class NioChannel implements ByteChannel{

    protected static ByteBuffer emptyBuf = ByteBuffer.allocate(0);

    protected SocketChannel sc = null;

    protected ApplicationBufferHandler bufHandler;

    protected Poller poller;

    public NioChannel(SocketChannel channel, ApplicationBufferHandler bufHandler) throws IOException {
        this.sc = channel;
        this.bufHandler = bufHandler;
    }

    public void reset() throws IOException {
        bufHandler.getReadBuffer().clear();
        bufHandler.getWriteBuffer().clear();
    }
    
    public int getBufferSize() {
        if ( bufHandler == null ) return 0;
        int size = 0;
        size += bufHandler.getReadBuffer()!=null?bufHandler.getReadBuffer().capacity():0;
        size += bufHandler.getWriteBuffer()!=null?bufHandler.getWriteBuffer().capacity():0;
        return size;
    }

    /**
     * returns true if the network buffer has 
     * been flushed out and is empty
     * @return boolean
     */
    public boolean flush(Selector s) throws IOException {
        return true; //no network buffer in the regular channel
    }


    /**
     * Closes this channel.
     *
     * @throws IOException If an I/O error occurs
     * @todo Implement this java.nio.channels.Channel method
     */
    public void close() throws IOException {
        getIOChannel().socket().close();
        getIOChannel().close();
    }

    public void close(boolean force) throws IOException {
        if (isOpen() || force ) close();
    }
    /**
     * Tells whether or not this channel is open.
     *
     * @return <tt>true</tt> if, and only if, this channel is open
     * @todo Implement this java.nio.channels.Channel method
     */
    public boolean isOpen() {
        return sc.isOpen();
    }

    /**
     * Writes a sequence of bytes to this channel from the given buffer.
     *
     * @param src The buffer from which bytes are to be retrieved
     * @return The number of bytes written, possibly zero
     * @throws IOException If some other I/O error occurs
     * @todo Implement this java.nio.channels.WritableByteChannel method
     */
    public int write(ByteBuffer src) throws IOException {
        return sc.write(src);
    }

    /**
     * Reads a sequence of bytes from this channel into the given buffer.
     *
     * @param dst The buffer into which bytes are to be transferred
     * @return The number of bytes read, possibly zero, or <tt>-1</tt> if the channel has reached end-of-stream
     * @throws IOException If some other I/O error occurs
     * @todo Implement this java.nio.channels.ReadableByteChannel method
     */
    public int read(ByteBuffer dst) throws IOException {
        return sc.read(dst);
    }

    public Object getAttachment(boolean remove) {
        Poller pol = getPoller();
        Selector sel = pol!=null?pol.getSelector():null;
        SelectionKey key = sel!=null?getIOChannel().keyFor(sel):null;
        Object att = key!=null?key.attachment():null;
        if (key != null && att != null && remove ) key.attach(null);
        return att;
    }
    /**
     * getBufHandler
     *
     * @return ApplicationBufferHandler
     * @todo Implement this org.apache.tomcat.util.net.SecureNioChannel method
     */
    public ApplicationBufferHandler getBufHandler() {
        return bufHandler;
    }

    public Poller getPoller() {
        return poller;
    }
    /**
     * getIOChannel
     *
     * @return SocketChannel
     * @todo Implement this org.apache.tomcat.util.net.SecureNioChannel method
     */
    public SocketChannel getIOChannel() {
        return sc;
    }

    /**
     * isClosing
     *
     * @return boolean
     * @todo Implement this org.apache.tomcat.util.net.SecureNioChannel method
     */
    public boolean isClosing() {
        return false;
    }

    /**
     * isInitHandshakeComplete
     *
     * @return boolean
     * @todo Implement this org.apache.tomcat.util.net.SecureNioChannel method
     */
    public boolean isInitHandshakeComplete() {
        return true;
    }

    public int handshake(boolean read, boolean write) throws IOException {
        return 0;
    }

    public void setPoller(Poller poller) {
        this.poller = poller;
    }

    public void setIOChannel(SocketChannel IOChannel) {
        this.sc = IOChannel;
    }

    public String toString() {
        return super.toString()+":"+this.sc.toString();
    }

}
