/*******************************************************************************
 * Copyright (c) 2015 RCP Vision (http://www.rcp-vision.com) 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:
 * Vincenzo Caselli - Initial contribution and API
 *******************************************************************************/
package org.eclipse.emf.parsley.web.servlets;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import javax.inject.Inject;
import javax.servlet.http.HttpServletRequest;

import org.eclipse.emf.common.util.URI;
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.parsley.config.Configurator;
import org.eclipse.emf.parsley.resource.ResourceLoader;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

import com.google.inject.Injector;

/**
 * A class for handling singletons at JEE application level
 * 
 * @author Vincenzo Caselli
 * 
 */
public class Application {
	// private static final String HTTP_SESSION = "HTTP_SESSION";
	private static Application application;

	private Map<String, Object> id2objectMap;
	private Map<Object, String> objec2idtMap;

	private Injector injector;
	private ResourceSet resourceSet;
	private Display display;
	private Shell shell;

	@Inject
	private Configurator configurator;
	@Inject
	private ResourceLoader resourceLoader;

	private Application() {
	}

	public static synchronized Application getInstance(HttpServletRequest request) {
		// Application application = (Application)
		// session.getAttribute(HTTP_SESSION);
		if (application == null) {
			// Create and init application object
			application = new Application();
			application.id2objectMap = new HashMap<String, Object>();
			application.objec2idtMap = new HashMap<Object, String>();

			application.injector = (Injector) request.getSession().getServletContext().getAttribute(Injector.class.getName());
			// application.injector = Guice.createInjector(new
			// ParsleyWebGuiceModule(null));
			application.injector.injectMembers(application);
			application.resourceSet = new ResourceSetImpl();

			application.display = new Display();
			application.shell = new Shell(application.display);

		}
		return application;
	}

	public synchronized Resource getResource(String entity) throws IOException {
		URI uri = configurator.createResourceURI(entity);
		if (uri != null) {
			Resource resource = resourceLoader.getResource(resourceSet, uri);
			return resource;
		} else {
			return null;
		}
	}

	public synchronized String put(Object object) {
		String id = objec2idtMap.get(object);
		if (id == null) {
			UUID uid = UUID.randomUUID();
			id = uid.toString();
			id2objectMap.put(id, object);
			objec2idtMap.put(object, id);
		}
		return id;
	}

	public synchronized Object get(String id) {
		return id2objectMap.get(id);
	}

	public Injector getInjector() {
		return injector;
	}

	public Configurator getConfigurator() {
		return configurator;
	}

	public synchronized ResourceLoader getResourceLoader() {
		return resourceLoader;
	}

	public synchronized ResourceSet getResourceSet() {
		return resourceSet;
	}

	public Shell getShell() {
		return shell;
	}

	public Display getDisplay() {
		return display;
	}

}