/*****************************************************************************
 * Copyright (c) 2017 Christian W. Damus and others.
 * 
 * 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:
 *   Christian W. Damus - Initial API and implementation
 *   
 *****************************************************************************/

package org.eclipse.papyrus.interoperability.rsa.internal;

import java.io.IOException;

import org.eclipse.emf.common.util.EList;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.ResourceSet;
import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl;
import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.papyrus.infra.emf.utils.EMFHelper;
import org.eclipse.papyrus.interoperability.rsa.Activator;
import org.eclipse.papyrus.interoperability.rsa.RSAToPapyrusParameters.Config;
import org.eclipse.papyrus.interoperability.rsa.RSAToPapyrusParameters.RSAToPapyrusParametersFactory;

/**
 * Persistence manager for the basic import configuration properties.
 */
public class ConfigurationManager {

	private ResourceSet rset = new ResourceSetImpl();
	private Resource configResource;
	private Config config;

	public ConfigurationManager() {
		super();

		// Load or create the configuration resource in the workspace metadata
		URI configURI = URI.createFileURI(Activator.getDefault().getStateLocation().toOSString())
				.appendSegment("config.xmi"); //$NON-NLS-1$
		try {
			configResource = rset.getResource(configURI, true);
		} catch (Exception e) {
			// Doesn't exist. Fine. We insist
			configResource = rset.getResource(configURI, false);
		}

		// Get or create the configuration in the configuration resource
		EList<EObject> contents = configResource.getContents();
		if (!contents.isEmpty() && (contents.get(0) instanceof Config)) {
			config = (Config) contents.get(0);
		} else {
			config = RSAToPapyrusParametersFactory.eINSTANCE.createConfig();
			contents.clear();
			contents.add(config);
		}
	}

	public void dispose() {
		config = null;
		configResource = null;
		EMFHelper.unload(rset);
	}

	public void loadConfig(Config config) {
		EcoreUtil.Copier copier = new EcoreUtil.Copier() {
			private static final long serialVersionUID = 1L;

			@Override
			protected EObject createCopy(EObject eObject) {
				return (eObject == ConfigurationManager.this.config)
						? config
						: super.createCopy(eObject);
			}
		};

		copier.copy(this.config);
	}

	public void saveConfig(Config newConfig) {
		try {
			if (newConfig == null) {
				// Delete the saved configuration
				configResource.delete(null);
			} else if (!EcoreUtil.equals(config, newConfig)) {
				EcoreUtil.replace(config, EcoreUtil.copy(newConfig));
				configResource.save(null);
			}
		} catch (IOException e) {
			Activator.log.error(e);
		}
	}
}