/*
 * 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 org.dcache.ftp.client.extended.GridFTPServerFacade;

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

public class StripeContextManager
{

    static final Logger logger =
            LoggerFactory.getLogger(StripeContextManager.class);

    protected final int stripes;
    protected final StripeTransferContext[] contextList;
    protected int stripeQuitTokens = 0;
    protected Object contextQuitToken = new Object();

    public StripeContextManager(int stripes,
                                SocketPool pool,
                                GridFTPServerFacade facade)
    {
        this.stripes = stripes;
        contextList = new StripeTransferContext[stripes];
        for (int i = 0; i < stripes; i++) {
            contextList[i] = new StripeTransferContext(this);
            contextList[i].setSocketPool(pool);
            contextList[i].setTransferThreadManager(
                    facade.createTransferThreadManager());
        }
    }

    /**
     * return number of stripes
     **/
    public int getStripes()
    {
        return stripes;
    }

    public EBlockParallelTransferContext getStripeContext(int stripe)
    {
        return contextList[stripe];
    }

    public Object getQuitToken()
    {
        int i = 0;
        while (i < stripes) {
            logger.debug("examining stripe " + i);
            if (contextList[i].getStripeQuitToken() != null) {
                // obtained quit token from one stripe.
                stripeQuitTokens++;
                logger.debug("obtained stripe quit token. Total = " + stripeQuitTokens + "; total needed = " + stripes);
            }
            i++;
        }
        if (stripeQuitTokens == stripes) {
            // obtained quit tokens from all stripes.
            // ready to release the quit token. But make sure not to do it twice.
            // This section only returns non-nul the first time it is entered.
            if (contextQuitToken == null) {
                logger.debug("not releasing the quit token.");
            } else {
                logger.debug("releasing the quit token.");
            }
            Object myToken = contextQuitToken;
            contextQuitToken = null;
            return myToken;
        } else {
            // not all stripes ready to quit
            logger.debug("not releasing the quit token. ");
            return null;
        }
    }

    class StripeTransferContext extends EBlockParallelTransferContext
    {

        final StripeContextManager mgr;

        public StripeTransferContext(StripeContextManager mgr)
        {
            this.mgr = mgr;
        }

        /**
         * @return non-null if this stripe received or sent all the EODs
         **/
        public Object getStripeQuitToken()
        {
            Object token = super.getQuitToken();
            StripeContextManager.logger.debug(
                    (token != null) ? "stripe released the quit token" : "stripe did not release the quit token");
            return token;
        }

        /**
         * @return non-null if all EODs in all stripes have been transferred.
         **/
        @Override
        public Object getQuitToken()
        {
            return mgr.getQuitToken();
        }
    }
}