/**
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 */
package thingml.ui.internal;

import com.google.common.collect.Maps;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Module;
import java.util.Collections;
import java.util.Map;
import org.apache.log4j.Logger;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.eclipse.xtext.ui.shared.SharedStateModule;
import org.eclipse.xtext.util.Modules2;
import org.osgi.framework.BundleContext;
import org.thingml.xtext.ThingMLRuntimeModule;
import org.thingml.xtext.ui.ThingMLUiModule;

/**
 * This class was generated. Customizations should only happen in a newly
 * introduced subclass. 
 */
public class ThingmlActivator extends AbstractUIPlugin {

	public static final String ORG_THINGML_XTEXT_THINGML = "org.thingml.xtext.ThingML";
	
	private static final Logger logger = Logger.getLogger(ThingmlActivator.class);
	
	private static ThingmlActivator INSTANCE;
	
	private Map<String, Injector> injectors = Collections.synchronizedMap(Maps.<String, Injector> newHashMapWithExpectedSize(1));
	
	@Override
	public void start(BundleContext context) throws Exception {
		super.start(context);
		INSTANCE = this;
	}
	
	@Override
	public void stop(BundleContext context) throws Exception {
		injectors.clear();
		INSTANCE = null;
		super.stop(context);
	}
	
	public static ThingmlActivator getInstance() {
		return INSTANCE;
	}
	
	public Injector getInjector(String language) {
		synchronized (injectors) {
			Injector injector = injectors.get(language);
			if (injector == null) {
				injectors.put(language, injector = createInjector(language));
			}
			return injector;
		}
	}
	
	protected Injector createInjector(String language) {
		try {
			Module runtimeModule = getRuntimeModule(language);
			Module sharedStateModule = getSharedStateModule();
			Module uiModule = getUiModule(language);
			Module mergedModule = Modules2.mixin(runtimeModule, sharedStateModule, uiModule);
			return Guice.createInjector(mergedModule);
		} catch (Exception e) {
			logger.error("Failed to create injector for " + language);
			logger.error(e.getMessage(), e);
			throw new RuntimeException("Failed to create injector for " + language, e);
		}
	}
	
	protected Module getRuntimeModule(String grammar) {
		if (ORG_THINGML_XTEXT_THINGML.equals(grammar)) {
			return new ThingMLRuntimeModule();
		}
		throw new IllegalArgumentException(grammar);
	}
	
	protected Module getUiModule(String grammar) {
		if (ORG_THINGML_XTEXT_THINGML.equals(grammar)) {
			return new ThingMLUiModule(this);
		}
		throw new IllegalArgumentException(grammar);
	}
	
	protected Module getSharedStateModule() {
		return new SharedStateModule();
	}
	
}