/*
 * Copyright 1999-2006 University of Chicago
 * 
 * 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 org.dcache.ftp.client.dc;

import java.io.DataOutputStream;
import java.io.OutputStream;
import java.io.IOException;

import org.dcache.ftp.client.Buffer;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class EBlockImageDCWriter
        extends EBlockAware
        implements DataChannelWriter
{

    static final Logger logger = LoggerFactory.getLogger(EBlockImageDCWriter.class);
    protected DataOutputStream output;

    @Override
    public void setDataStream(OutputStream out)
    {
        output = new DataOutputStream(out);
    }

    @Override
    public void write(Buffer buf)
            throws IOException
    {
        long offset = buf.getOffset();
        if (offset < 0) {
            throw new IOException("Invalid offset: " + offset);
        }

        output.writeByte(0);
        logger.debug("buffer length: " + buf.getLength());
        output.writeLong(buf.getLength());
        logger.debug("offset: " + offset);
        output.writeLong(offset);
        output.write(buf.getBuffer(), 0, buf.getLength());
        //output.flush();
        logger.debug("wrote the buffer");

    }

    @Override
    public void endOfData() throws IOException
    {
        byte desc;
        //the first data channel to quit
        // will send EOF. There musn't be more than
        // 1 EOF per stripe.
        synchronized (context) {
            if (context.eodsTransferred == 0) {
                desc = EOF | EOD;
                output.writeByte(desc);
                output.writeLong(0);
                output.writeLong(context.eodsTotal);
                logger.debug("wrote EOF (expected EODS: "
                             + context.eodsTotal + ") and EOD");
            } else {
                desc = EOD;
                output.writeByte(desc);
                output.writeLong(0);
                output.writeLong(0);
                logger.debug("wrote EOD");
            }
            context.eodTransferred();
        }
        // important to flush, otherwise transfer will hang
        // with data and EOD remaining in the output buffer
        output.flush();
    }

    public static void close(DataOutputStream myOutput)
            throws IOException
    {
        byte desc;
        // EOF and EOD have already been sent
        desc = WILL_CLOSE;
        myOutput.writeByte(desc);
        myOutput.writeLong(0);
        myOutput.writeLong(0);
        logger.debug("Wrote WILL_CLOSE, closing the socket");

        // close the socket
        myOutput.close();
    }

    @Override
    public void close() throws IOException
    {
        close(output);
    }

}