/*******************************************************************************
 * Copyright (c) 2006, 2007 Oracle. All rights reserved.
 * This program and the accompanying materials are made available under the terms of
 * the Eclipse Public License v1.0, which accompanies this distribution and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 * 
 * Contributors:
 *     Oracle - initial API and implementation
 ******************************************************************************/
package org.eclipse.jpt.core.internal.content.persistence;

import java.io.IOException;
import java.util.Collections;
import org.eclipse.core.resources.IFile;
import org.eclipse.emf.common.notify.Adapter;
import org.eclipse.emf.common.notify.Notification;
import org.eclipse.emf.common.notify.impl.AdapterImpl;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.ResourceSet;
import org.eclipse.jem.util.emf.workbench.WorkbenchResourceHelperBase;
import org.eclipse.jpt.core.internal.IJpaFileContentProvider;
import org.eclipse.jpt.core.internal.IJpaRootContentNode;
import org.eclipse.jpt.core.internal.JptCorePlugin;
import org.eclipse.jpt.core.internal.content.persistence.resource.PersistenceResource;
import org.eclipse.jpt.core.internal.content.persistence.resource.PersistenceXmlResourceFactory;

public class PersistenceXmlJpaFileContentProvider implements IJpaFileContentProvider
{
	public static PersistenceXmlJpaFileContentProvider INSTANCE = new PersistenceXmlJpaFileContentProvider();
	
	
	private IFile resourceFile;
	
	
	/**
	 * Restrict access
	 */
	private PersistenceXmlJpaFileContentProvider() {
		
	}

	public IJpaRootContentNode buildRootContent(IFile resourceFile) {
		PersistenceXmlResourceFactory.register();
		this.resourceFile = resourceFile;
		URI fileURI = URI.createPlatformResourceURI(resourceFile.getFullPath().toString());
		PersistenceResource resource = (PersistenceResource) getResourceSet(resourceFile).getResource(fileURI, true);
		PersistenceXmlRootContentNode root = PersistenceFactory.eINSTANCE.createPersistenceXmlRootContentNode();
		root.setPersistence(resource.getPersistence());
		resource.eAdapters().add(buildRootNodeListener(root));
		return root;
	}
	
	private Adapter buildRootNodeListener(PersistenceXmlRootContentNode root) {
		return new RootAdapter(root);
	}

	protected ResourceSet getResourceSet(IFile file) {
		return WorkbenchResourceHelperBase.getResourceSet(file.getProject());
	}

	public String contentType() {
		return JptCorePlugin.PERSISTENCE_XML_CONTENT_TYPE;
	}
	
	
	private class RootAdapter extends AdapterImpl 
	{
		PersistenceXmlRootContentNode root;
		
		private RootAdapter(PersistenceXmlRootContentNode rootContentNode) {
			super();
			root = rootContentNode;
		}
		
		public void notifyChanged(Notification notification) {
			int featureId = notification.getFeatureID(Resource.class);
			if (featureId == Resource.RESOURCE__CONTENTS) {
				if (notification.getEventType() == Notification.ADD
						|| notification.getEventType() == Notification.REMOVE) {
					PersistenceResource resource = (PersistenceResource) notification.getNotifier();
					root.setPersistence(resource.getPersistence());
				}
			}
			else if (featureId == Resource.RESOURCE__IS_LOADED) {
				if (resourceFile.exists()) {
					// dumb translator is unloading my resource, reload it
					if (notification.getNewBooleanValue() == false) {
						PersistenceResource resource = (PersistenceResource) notification.getNotifier();
						try {
							resource.load(Collections.EMPTY_MAP);
						}
						catch (IOException ioe) {
							// hmmm, log for now
							JptCorePlugin.log(ioe);
						}
					}
				}
			}
		}
	}
}