/**
 *    '$RCSfile: DocumentDataPackageHandler.java,v $'
 *
 *     '$Author$'
 *       '$Date$'
 *   '$Revision$'
 *
 *  For Details: http://ecoinformatics.org
 *
 * Copyright (c) 2008 The Regents of the University of California.
 * All rights reserved.
 * 
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
 * PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY
 * OF CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
 * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */
package org.ecoinformatics.datamanager.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.ecoinformatics.datamanager.download.AuthenticatedEcogridEndPointInterface;
import org.ecoinformatics.datamanager.download.EcogridEndPointInterface;
import org.ecoinformatics.ecogrid.authenticatedqueryservice.AuthenticatedQueryServiceGetToStreamClient;
import org.ecoinformatics.ecogrid.queryservice.QueryServiceGetToStreamClient;

public class DocumentDownloadUtil {

	public static Log log = LogFactory.getLog(DocumentDownloadUtil.class);
	
	private PipedInputStream inputStream = null;
	private PipedOutputStream outputStream = null;
	

	private void init() {
		//initialize the streams for reading the document from server
		outputStream = new PipedOutputStream();
	    inputStream = new PipedInputStream();
	    
	    try {
			outputStream.connect(inputStream);
		} catch (IOException e1) {
			log.error("could not connect piped streams! " + e1.getMessage());
			e1.printStackTrace();
		}
	}
	
	public InputStream downloadDocument(final String id, final EcogridEndPointInterface endpoint) throws Exception {
		
		init();
		
		log.debug("starting the download");
						
		ExecutorService service = Executors.newSingleThreadExecutor();
		service.execute(
			new Runnable() {
				public void run() {
					long startTime = System.currentTimeMillis();

					try {
						if (endpoint instanceof AuthenticatedEcogridEndPointInterface) {
							AuthenticatedQueryServiceGetToStreamClient authenticatedEcogridClient = 
								new AuthenticatedQueryServiceGetToStreamClient(
				            		new URL(
				            				((AuthenticatedEcogridEndPointInterface)endpoint).getMetacatAuthenticatedEcogridEndPoint()));
							authenticatedEcogridClient.get(
									id,
									((AuthenticatedEcogridEndPointInterface)endpoint).getSessionId(),
									outputStream);
						}
						else {
							QueryServiceGetToStreamClient ecogridClient = 
								new QueryServiceGetToStreamClient(
				            		new URL(
				            				endpoint.getMetacatEcogridEndPoint()));
							ecogridClient.get(id, outputStream);
						}
						outputStream.close();
						
						long endTime = System.currentTimeMillis();
						log.debug((endTime - startTime) + " ms to download document data");
						
						log.debug("Done downloading id=" + id);
						
					} catch (Exception e) {
						log.error("Error getting document from ecogrid: " + e.getMessage());
						e.printStackTrace();
					}
					
				}
			});
		
		//wait for the download to complete
		service.shutdown();
		service.awaitTermination(0, TimeUnit.SECONDS);
			
		log.debug("done with the download");

		return inputStream;
		
	}

}