/*
    * 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: Mapper.java
   * Created: 2008-07-12
   * Author: apohllo
   * $Id: XMLSaver.java 2232 2009-01-04 22:59:53Z apohllo $
   */
  
  package pl.edu.agh.cast.model.mapper.internal;
  
  import java.io.BufferedOutputStream;
  import java.io.BufferedWriter;
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.UnsupportedEncodingException;
  import java.io.Writer;
  import java.text.DateFormat;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  
  import org.eclipse.core.resources.IProject;
  
  import pl.edu.agh.cast.model.base.BasePlugin;
  import pl.edu.agh.cast.model.base.IDataSet;
  import pl.edu.agh.cast.model.base.IModel;
  import pl.edu.agh.cast.model.base.IRelation;
  import pl.edu.agh.cast.model.mapper.Mappable;
  import pl.edu.agh.cast.model.mapper.Mapper;
  import pl.edu.agh.cast.resources.BaseProjectUtil;
  
  /**
   * Limited version of base model saver - allows only saving of DataSets. The DataSets are stored as separate XML files
   * in their project's directory. The saved structure is limited - any links which go beyond DataSet - Relation - Entity
   * relationships are discarded.
   *
   * The identifiers of mappable elements are unique only within the DataSet.
   *
   * @author AGH CAST Team
   *
   */
  public class XMLSaver extends AbstractSaver {
  
  	/**
       *
       */
  	private static final String QUOTE_W_SPACE = "' "; //$NON-NLS-1$
  
  	/**
       *
       */
  	private static final String GT_W_NEW_LINE = ">\n"; //$NON-NLS-1$
  
  	/**
  	 * Tag fragment: lower than with slash
  	 */
  	private static final String LT_W_SLASH = "</"; //$NON-NLS-1$
  
  	/**
  	 * Tag fragment: quote + greater than + new line
  	 */
  	private static final String GT_W_QUOTE_AND_NEW_LINE = "'>\n"; //$NON-NLS-1$
  
  	/**
  	 * Tag fragment: equals and quote
  	 */
  	private static final String EQUAL_W_QUOTE = "='"; //$NON-NLS-1$
  
  	/**
  	 * Tag fragment: single space
  	 */
  	private static final String SINGLE_SPACE = " "; //$NON-NLS-1$
  
  	/**
  	 * Tag fragment: lower than
  	 */
  	private static final String LT = "<"; //$NON-NLS-1$
  
  	/**
  	 * The name of the file where model properties are stored.
  	 */
  	public static final String MODEL_PROPS = "project.props"; //$NON-NLS-1$
  
  	private static final String UTF_8 = "UTF-8"; //$NON-NLS-1$
  
  	private static final String ISO_8859_2 = "ISO-8859-2"; //$NON-NLS-1$
  
  	private static final String CP_1250 = "CP1250"; //$NON-NLS-1$
 
 	/**
 	 * The extension of the model file.
 	 */
 	public static final String EXTENSION = ".xml"; //$NON-NLS-1$
 
 	/**
 	 * The name of the directory where the project is stored.
 	 */
 	public static final String ROOT = "model"; //$NON-NLS-1$
 
 	/**
 	 * The name of the field which holds the type of the node.
 	 */
 	public static final String TYPE = "type"; //$NON-NLS-1$
 
 	/**
 	 * The name of the field which holds the id of the node.
 	 */
 	public static final String ID = "id"; //$NON-NLS-1$
 
 	/**
 	 * The format of the date.
 	 */
 	public static final DateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //$NON-NLS-1$
 
 	/**
 	 * The name of the field used to indicate the source of the relation.
 	 */
 	public static final String SOURCE = "src"; //$NON-NLS-1$
 
 	/**
 	 * The name of the field used to indicate the target of the relation.
 	 */
 	public static final String TARGET = "dst"; //$NON-NLS-1$
 
 	private StringBuilder buffer = new StringBuilder();
 
 	private long lastId = 1;
 
 	private IProject project;
 
 	private OutputStream file;
 
 	/**
 	 * The parameterized constructor.
 	 *
 	 * @param object
 	 *            The object to save.
 	 * @param force
 	 *            The force flag.
 	 * @param project
 	 *            The project which is owner of the object.
 	 */
 	public XMLSaver(Mappable object, boolean force, IProject project) {
 		super(object, force);
 		this.project = project;
 	}
 
 	/**
 	 *
 	 * {@inheritDoc}
 	 *
 	 * @see pl.edu.agh.cast.model.mapper.Saver#save()
 	 */
 	public boolean save() {
 		try {
 			if (primaryObject instanceof IDataSet) {
 				IDataSet dataSet = (IDataSet)primaryObject;
 				saveModelProps(dataSet.getModel());
 				save(dataSet);
 			} else if (primaryObject instanceof IModel) {
 				saveModelProps((IModel)primaryObject);
 				for (IDataSet dataSet : ((IModel)primaryObject).getDataSets()) {
 					save(dataSet);
 				}
 			}
 			return true;
 		} catch (Exception e) {
 			e.printStackTrace();
 			return false;
 		}
 	}
 
 	private void saveModelProps(IModel model) throws IOException {
 		if (project != null) {
 			BaseProjectUtil.setProperty(project, BaseProjectUtil.PROJECT_ID_PROPERTY, model.getName());
 		} else {
 			// this solution is used only in tests, when there is
 			// no instance of Eclipse environment
 			Writer projectProps = new BufferedWriter(new FileWriter(dirFor(project) + MODEL_PROPS));
 			projectProps.write(model.getName());
 			projectProps.close();
 		}
 	}
 
 	private void save(IDataSet dataSet) throws Exception {
 		file = new BufferedOutputStream(new FileOutputStream(fileFor(project, dataSet.getId())));
 		buffer.append("<?xml version='1.0' ?>\n"); //$NON-NLS-1$
 		buffer.append(LT);
 		buffer.append(ROOT);
 		buffer.append(SINGLE_SPACE);
 		buffer.append(ID);
 		buffer.append(EQUAL_W_QUOTE);
 		buffer.append(dataSet.getModel().getId());
 		buffer.append(GT_W_QUOTE_AND_NEW_LINE);
 		store(null);
 		saveMappable(dataSet);
 		for (IRelation relation : dataSet.getRelations()) {
 			saveMappable(relation.getSource());
 			saveMappable(relation.getTarget());
 			saveRelation(relation);
 		}
 		buffer.append(LT_W_SLASH);
 		buffer.append(ROOT);
 		buffer.append(GT_W_NEW_LINE);
 		store(null);
 		file.close();
 	}
 
 	/**
 	 * For given project returns the directory where the model is stored.
 	 *
 	 * @param project
 	 *            The project name.
 	 * @return The directory object.
 	 */
 	public static String dirFor(IProject project) {
 		String path = getProjectPath(project);
 		File dir = new File(path);
 		if (!dir.exists()) {
 			dir.mkdir();
 		}
 		if (!path.substring(path.length() - 1).equals(File.separator)) {
 			path += File.separator;
 		}
 		return path;
 	}
 
 	/**
 	 * Returns the path to the file which holds data set with given id.
 	 *
 	 * @param project
 	 *            the project where the data set is stored.
 	 * @param id
 	 *            The id of the data set.
 	 * @return The path to the file.
 	 */
 	public static String fileFor(IProject project, String id) {
 		// seems stupid? thanks to ingenious Windows (r) path separator
 		return dirFor(project) + id.replaceAll("[^a-zA-Z0-9_]", "_") + EXTENSION; //$NON-NLS-1$ //$NON-NLS-2$
 	}
 
 	private static String getProjectPath(IProject project) {
 		if (project == null) {
 			return Mapper.DEFAULT_PATH;
 		} else {
 			return project.getLocation().toOSString() + File.separator + Mapper.DEFAULT_FOLDER;
 		}
 
 	}
 
 	private void saveMappable(Mappable mappable) throws Exception {
 		if (stored.contains(mappable)) {
 			return;
 		}
 		buffer.append(LT);
 		buffer.append(Helper.mappedTypeName(mappable.getClass()));
 		buffer.append(SINGLE_SPACE);
 		buffer.append(ID);
 		buffer.append(EQUAL_W_QUOTE);
 		mappable.setMid(lastId);
 		buffer.append(lastId++);
 		buffer.append(GT_W_QUOTE_AND_NEW_LINE);
 		appendAttributesXML(mappable, mappable.getClass());
 		buffer.append(LT_W_SLASH);
 		buffer.append(Helper.mappedTypeName(mappable.getClass()));
 		buffer.append(GT_W_NEW_LINE);
 		store(mappable);
 	}
 
 	private void saveRelation(IRelation relation) throws Exception {
 		if (stored.contains(relation)) {
 			return;
 		}
 		buffer.append(LT);
 		buffer.append(Helper.mappedTypeName(relation.getClass()));
 		buffer.append(SINGLE_SPACE);
 		buffer.append(ID);
 		buffer.append(EQUAL_W_QUOTE);
 		relation.setMid(lastId);
 		buffer.append(lastId++);
 		buffer.append(QUOTE_W_SPACE);
 		buffer.append(SOURCE);
 		buffer.append(EQUAL_W_QUOTE);
 		buffer.append(relation.getSource().getMid());
 		buffer.append(QUOTE_W_SPACE);
 		buffer.append(TARGET);
 		buffer.append(EQUAL_W_QUOTE);
 		buffer.append(relation.getTarget().getMid());
 		buffer.append(GT_W_QUOTE_AND_NEW_LINE);
 		appendAttributesXML(relation, relation.getClass());
 		buffer.append(LT_W_SLASH);
 		buffer.append(Helper.mappedTypeName(relation.getClass()));
 		buffer.append(GT_W_NEW_LINE);
 		store(relation);
 	}
 
 	private void store(Mappable mappable) throws IOException {
 		// System.out.println(_buffer.toString());
 		String value = buffer.toString();
 		buffer.setLength(0);
 		value = convertToUTF(value);
 		file.write(value.getBytes(UTF_8));
 		if (mappable != null) {
 			stored.add(mappable);
 		}
 	}
 
 	private String convertToUTF(String value) {
 		String valueCopy = value + ""; //$NON-NLS-1$
 		boolean shouldConvert = false;
 		// the opposite is ISO-8859-2
 		boolean windowsEncoding = false;
 		for (byte byteValue : valueCopy.getBytes()) {
 			if (byteValue < 0) {
 				int code = 256 + byteValue;
 				// UTF codes - if found, stop analysis
 				// XXX && and || not in parenthesis seems to be bug
 				if (code == 195 || code == 196 || code == 197 && !shouldConvert) {
 					break;
 				}
 				// WIN and ISO common codes
 				if (code == 191 || code == 243 || code == 179 || code == 230 || code == 234 || code == 241
 				        || code == 175 || code == 211 || code == 163 || code == 198 || code == 202 || code == 209) {
 					shouldConvert = true;
 				}
 				// strict ISO codes
 				if (code == 182 || code == 177 || code == 188 || code == 166 || code == 161 || code == 172) {
 					shouldConvert = true;
 					break;
 				}
 				if (code == 156 || code == 185 || code == 159 || code == 140 || code == 165 || code == 143) {
 					shouldConvert = true;
 					windowsEncoding = true;
 					break;
 				}
 			}
 		}
 		try {
 			if (shouldConvert) {
 				if (windowsEncoding) {
 					valueCopy = new String(value.getBytes(), CP_1250);
 				} else {
 					valueCopy = new String(value.getBytes(), ISO_8859_2);
 				}
 			}
 		} catch (UnsupportedEncodingException ex) {
 			BasePlugin.getLogger().error("Cannot save file as UTF", ex); //$NON-NLS-1$
 			return valueCopy;
 		}
 		return valueCopy;
 	}
 
 	private void appendAttributesXML(Mappable mappable, Class klass) throws Exception {
 		if (Helper.isSuperMapped(klass)) {
 			appendAttributesXML(mappable, klass.getSuperclass());
 		}
 		for (AttributeEntry entry : Helper.getMappedAttributes(klass)) {
 			Object value = entry.getMethod().invoke(mappable);
 			String attributeName = entry.getAnnotation().name();
 			if (attributeName.equals("")) { //$NON-NLS-1$
 				attributeName = entry.getMethod().getName();
 			}
 			buffer.append(LT);
 			buffer.append(attributeName);
 			buffer.append(SINGLE_SPACE);
 			buffer.append(TYPE);
 			buffer.append(EQUAL_W_QUOTE);
 			buffer.append(entry.getMethod().getReturnType().getCanonicalName());
 			buffer.append("'>"); //$NON-NLS-1$
 			if (value instanceof Date) {
 				buffer.append(DATE_FORMAT.format((Date)value));
 			} else {
 				buffer.append(value);
 			}
 			buffer.append(LT_W_SLASH);
 			buffer.append(attributeName);
 			buffer.append(GT_W_NEW_LINE);
 		}
 	}
 }