/*
 * 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.qpid.disttest.client;

import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;
import org.apache.qpid.disttest.message.ParticipantResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ParticipantExecutor
{
    private static final Logger LOGGER = LoggerFactory.getLogger(ParticipantExecutor.class);

    private static final ExecutorService SHARED_UNBOUNDED_THREAD_POOL = Executors.newCachedThreadPool(new DaemonThreadFactory());

    private Executor _executor = SHARED_UNBOUNDED_THREAD_POOL;

    private Client _client;

    private final Participant _participant;

    private final ParticipantResultFactory _factory;

    public ParticipantExecutor(Participant participant)
    {
        _participant = participant;
        _factory = new ParticipantResultFactory();
    }

    /**
     * Schedules the test participant to be run in a background thread.
     */
    public void start(Client client)
    {
        _client = client;

        LOGGER.info("Starting test participant in background thread: " + this);
        _executor.execute(new ParticipantRunnable());
    }

    public String getParticipantName()
    {
        return _participant.getName();
    }

    void setExecutor(Executor executor)
    {
        _executor = executor;
    }

    private class ParticipantRunnable implements Runnable
    {
        @Override
        public final void run()
        {
            Thread currentThread = Thread.currentThread();
            final String initialThreadName = currentThread.getName();
            currentThread.setName(initialThreadName + "-" + getParticipantName());

            try
            {
                runParticipantAndSendResults();
            }
            finally
            {
                currentThread.setName(initialThreadName);
            }
        }

        private void runParticipantAndSendResults()
        {
            ParticipantResult result = null;
            try
            {
                if (LOGGER.isInfoEnabled())
                {
                    LOGGER.info("About to run participant " + _participant);
                }
                result = _participant.doIt(_client.getClientName());
            }
            catch (Throwable t)
            {
                String errorMessage = "Unhandled error: " + t.getMessage();
                LOGGER.error(errorMessage, t);
                result = _factory.createForError(_participant.getName(), _client.getClientName(), errorMessage);
            }
            finally
            {
                _client.sendResults(result);
                _participant.releaseResources();
            }
        }
    }

    private static final class DaemonThreadFactory implements ThreadFactory
    {
        @Override
        public Thread newThread(Runnable r)
        {
            Thread thread = new Thread(r);
            thread.setDaemon(true);
            return thread;
        }
    }

    @Override
    public String toString()
    {
        return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE)
        .append("participantName", getParticipantName())
        .append("client", _client)
        .toString();
    }
}
