/*
    * This file is a part of CAST project.
    * (c) Copyright 2007, AGH University of Science & Technology
    * https://caribou.iisg.agh.edu.pl/trac/cast
    *
    * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/legal/epl-v10.html
   */
  /*
   * File: SerializationUtil.java
   * Created: 2007-00-00
   * Author: klewandowski, awos
   * $Id: SerializationUtil.java 3020 2009-07-17 14:41:19Z kpietak $
   */
  
  package pl.edu.agh.cast.backward.resources;
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  
  import org.apache.log4j.Logger;
  import org.eclipse.core.resources.IFile;
  import org.eclipse.core.resources.IResource;
  import org.eclipse.core.runtime.CoreException;
  
  import pl.edu.agh.cast.Activator;
  import pl.edu.agh.cast.model.visual.backward.IDiagram;
  import pl.edu.agh.cast.model.visual.backward.IDiagramSettings;
  
  /**
   * Utility class for model serialization.
   *
   * @author AGH CAST Team
   */
  public final class SerializationUtil {
  
  	private static final Logger LOG = Activator.getLogger();
  
  	/**
  	 * Reads only diagram settings from a file with serialized diagram.
  	 *
  	 * @param file
  	 *            diagram file to read from
  	 * @return diagram settings read, or null in case of an exception
  	 */
  	public static IDiagramSettings readDiagramSettings(IFile file) {
  		ObjectInputStream ois = null;
  		try {
  			ois = new ObjectInputStream(new BufferedInputStream(new FileInputStream(new File(file.getLocationURI()))));
  			IDiagramSettings settings = (IDiagramSettings)ois.readObject();
  			ois.close();
  			ois = null;
  			return settings;
  		} catch (Exception e) {
  			LOG.error("Error occured while reading diagram settings from file " //$NON-NLS-1$
  			        + file.getName(), e);
  		} finally {
  			closeDiagramInput(file, ois);
  		}
  		return null;
  	}
  
  	/**
  	 * Closes diagram input file after reading.
  	 *
  	 * @param file
  	 * @param ois
  	 */
  	private static void closeDiagramInput(IFile file, ObjectInputStream ois) {
  		if (ois != null) {
  			try {
  				ois.close();
  			} catch (IOException e) {
  				LOG.error("Error occured while closing diagram file after reading " //$NON-NLS-1$
  				        + file.getName(), e);
  			}
  		}
  	}
  
  	/**
  	 * Reads the whole diagram from a serialized file.
  	 *
  	 * @param file
  	 *            diagram file to read from
  	 * @return the diagram, or null in case of an exception
  	 */
  	public static IDiagram readDiagram(IFile file) {
  		ObjectInputStream ois = null;
  		try {
  			ois = new ObjectInputStream(new BufferedInputStream(new FileInputStream(new File(file.getLocationURI()))));
  			/*
 			 * read and ignore IDiagramSettings - they're saved at the beginning and inside the diagram
 			 */
 			ois.readObject();
 			// read diagram
 			IDiagram diagram = (IDiagram)ois.readObject();
 			ois.close();
 			ois = null;
 			return diagram;
 		} catch (Exception e) {
 			LOG.error("Error occured while reading diagram " //$NON-NLS-1$
 			        + file.getName(), e);
 		} finally {
 			closeDiagramInput(file, ois);
 		}
 		return null;
 	}
 
 	/**
 	 * Serializes given model.
 	 *
 	 * @param model
 	 *            model to serialize
 	 * @throws IOException
 	 */
 	public static void serializeToFile(final IDiagram model) throws IOException {
 		serializeDiagram(model);
 	}
 
 	/**
 	 * Serializes diagram from given {@link DiagramEditorInput}.
 	 *
 	 * @param input
 	 *            diagram editor input to serialize from
 	 * @throws IOException
 	 */
 	public static void serializeToFile(DiagramEditorInput input) throws IOException {
 		input.getDiagram().setFile(input.getFile());
 		serializeDiagram(input.getDiagram());
 	}
 
 	/**
 	 * Serializes saved models to file.
 	 *
 	 * @param procjet
 	 *            Project to serialize.
 	 */
 	private static void serializeDiagram(final IDiagram diagram) throws IOException {
 
 		File f = new File(diagram.getFile().getLocationURI());
 		f.delete();
 
 		ObjectOutputStream oos = null;
 		try {
 			oos = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(f)));
 			oos.writeObject(diagram.getSettings());
 			oos.writeObject(diagram);
 			oos.close();
 			oos = null;
 		} catch (Exception e) {
 			LOG.error("Error occured while writing diagram to file " //$NON-NLS-1$
 			        + f.getName(), e);
 		} finally {
 			if (oos != null) {
 				try {
 					oos.close();
 				} catch (IOException e) {
 					LOG.error("Error occured while closing diagram file after writing " //$NON-NLS-1$
 					        + f.getName(), e);
 				}
 			}
 		}
 
 		try {
 			diagram.getFile().refreshLocal(IResource.DEPTH_ZERO, null);
 		} catch (CoreException e) {
 			LOG.error("Error refreshing file " + f.getName(), e); //$NON-NLS-1$
 		}
 	}
 
 }