/*******************************************************************************
 * Copyright (C) 2007 The University of Manchester
 *
 *  Modifications to the initial code base are copyright of their
 *  respective authors, or their employers as appropriate.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public License
 *  as published by the Free Software Foundation; either version 2.1 of
 *  the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 ******************************************************************************/
package net.sf.taverna.t2.workbench.file.impl;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Arrays;
import java.util.Date;
import java.util.List;

import org.apache.taverna.workbench.file.AbstractDataflowPersistenceHandler;
import org.apache.taverna.workbench.file.DataflowInfo;
import org.apache.taverna.workbench.file.DataflowPersistenceHandler;
import org.apache.taverna.workbench.file.FileType;
import org.apache.taverna.workbench.file.exceptions.OpenException;

import org.apache.log4j.Logger;

import org.apache.taverna.scufl2.api.container.WorkflowBundle;
import org.apache.taverna.scufl2.api.io.ReaderException;
import org.apache.taverna.scufl2.api.io.WorkflowBundleIO;

public class T2DataflowOpener extends AbstractDataflowPersistenceHandler
		implements DataflowPersistenceHandler {
	private static final T2FlowFileType T2_FLOW_FILE_TYPE = new T2FlowFileType();
	private static Logger logger = Logger.getLogger(T2DataflowOpener.class);

	private WorkflowBundleIO workflowBundleIO;

	@SuppressWarnings("resource")
	@Override
	public DataflowInfo openDataflow(FileType fileType, Object source)
			throws OpenException {
		if (!getOpenFileTypes().contains(fileType))
			throw new OpenException("Unsupported file type "
					+ fileType);
		InputStream inputStream;
		Date lastModified = null;
		Object canonicalSource = source;
		if (source instanceof InputStream)
			inputStream = (InputStream) source;
		else if (source instanceof File)
			try {
				inputStream = new FileInputStream((File) source);
			} catch (FileNotFoundException e) {
				throw new OpenException("Could not open file " + source + ":\n" + e.getLocalizedMessage(), e);
			}
		else if (source instanceof URL) {
			URL url = ((URL) source);
			try {
				URLConnection connection = url.openConnection();
				connection.setRequestProperty("Accept", "text/xml");
				inputStream = connection.getInputStream();
				if (connection.getLastModified() != 0)
					lastModified = new Date(connection.getLastModified());
			} catch (IOException e) {
				throw new OpenException("Could not open connection to URL "
						+ source+ ":\n" + e.getLocalizedMessage(), e);
			}
			try {
				if (url.getProtocol().equalsIgnoreCase("file"))
					canonicalSource = new File(url.toURI());
			} catch (URISyntaxException e) {
				logger.warn("Invalid file URI created from " + url);
			}
		} else {
			throw new OpenException("Unsupported source type "
					+ source.getClass());
		}

		final WorkflowBundle workflowBundle;
		try {
			workflowBundle = openDataflowStream(inputStream);
		} finally {
			try {
				if (!(source instanceof InputStream))
					// We created the stream, we'll close it
					inputStream.close();
			} catch (IOException ex) {
				logger.warn("Could not close inputstream " + inputStream, ex);
			}
		}
		if (canonicalSource instanceof File)
			return new FileDataflowInfo(T2_FLOW_FILE_TYPE,
					(File) canonicalSource, workflowBundle);
		return new DataflowInfo(T2_FLOW_FILE_TYPE, canonicalSource,
				workflowBundle, lastModified);
	}

	protected WorkflowBundle openDataflowStream(InputStream workflowXMLstream)
			throws OpenException {
		WorkflowBundle workflowBundle;
		try {
			workflowBundle = workflowBundleIO.readBundle(workflowXMLstream, null);
		} catch (ReaderException e) {
			throw new OpenException("Could not read the workflow", e);
		} catch (IOException e) {
			throw new OpenException("Could not open the workflow file for parsing", e);
		} catch (Exception e) {
			throw new OpenException("Error while opening workflow", e);
		}

		return workflowBundle;
	}

	@Override
	public List<FileType> getOpenFileTypes() {
		return Arrays.<FileType> asList(new T2FlowFileType());
	}

	@Override
	public List<Class<?>> getOpenSourceTypes() {
		return Arrays.<Class<?>> asList(InputStream.class, URL.class,
				File.class);
	}

	public void setWorkflowBundleIO(WorkflowBundleIO workflowBundleIO) {
		this.workflowBundleIO = workflowBundleIO;
	}
}