/**
 *                                                                            
 * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 *                                                                            
 * All rights reserved. This program and the accompanying materials           
 * are made available under the terms of the Eclipse Public License 2.0        
 * which accompanies this distribution, and is available at                  
 * https://www.eclipse.org/legal/epl-2.0/                                 
 *                                 
 * SPDX-License-Identifier: EPL-2.0                                 
 *                                                                            
 * Contributors:   
 * Christophe Loetz (Loetz GmbH&Co.KG) - initial implementation 
 */

package org.eclipse.osbp.xtext.gridsource.tests;

import com.google.inject.Guice;
import com.google.inject.Injector;
import org.eclipse.osbp.xtext.gridsource.GridSourceRuntimeModule;
import org.eclipse.osbp.xtext.gridsource.GridSourceStandaloneSetup;
import org.eclipse.xtext.testing.GlobalRegistries;
import org.eclipse.xtext.testing.GlobalRegistries.GlobalStateMemento;
import org.eclipse.xtext.testing.IInjectorProvider;
import org.eclipse.xtext.testing.IRegistryConfigurator;

public class GridSourceInjectorProvider implements IInjectorProvider, IRegistryConfigurator {

	protected GlobalStateMemento stateBeforeInjectorCreation;
	protected GlobalStateMemento stateAfterInjectorCreation;
	protected Injector injector;

	static {
		GlobalRegistries.initializeDefaults();
	}

	@Override
	public Injector getInjector() {
		if (injector == null) {
			stateBeforeInjectorCreation = GlobalRegistries.makeCopyOfGlobalState();
			this.injector = internalCreateInjector();
			stateAfterInjectorCreation = GlobalRegistries.makeCopyOfGlobalState();
		}
		return injector;
	}

	protected Injector internalCreateInjector() {
		return new GridSourceStandaloneSetup() {
			@Override
			public Injector createInjector() {
				return Guice.createInjector(createRuntimeModule());
			}
		}.createInjectorAndDoEMFRegistration();
	}

	protected GridSourceRuntimeModule createRuntimeModule() {
		// make it work also with Maven/Tycho and OSGI
		// see https://bugs.eclipse.org/bugs/show_bug.cgi?id=493672
		return new GridSourceRuntimeModule() {
			@Override
			public ClassLoader bindClassLoaderToInstance() {
				return GridSourceInjectorProvider.class
						.getClassLoader();
			}
		};
	}

	@Override
	public void restoreRegistry() {
		stateBeforeInjectorCreation.restoreGlobalState();
	}

	@Override
	public void setupRegistry() {
		getInjector();
		stateAfterInjectorCreation.restoreGlobalState();
	}
}