/*******************************************************************************
 * Copyright (c) 2013 Dirk Fauth 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:
 *    Dirk Fauth <dirk.fauth@googlemail.com> - initial API and implementation
 *******************************************************************************/
package org.eclipse.e4.ui.internal;

import java.util.List;
import java.util.Locale;
import javax.inject.Inject;
import org.eclipse.e4.core.contexts.IEclipseContext;
import org.eclipse.e4.core.internal.services.ResourceBundleHelper;
import org.eclipse.e4.core.internal.services.ServicesActivator;
import org.eclipse.e4.core.services.events.IEventBroker;
import org.eclipse.e4.core.services.nls.ILocaleChangeService;
import org.eclipse.e4.core.services.translation.TranslationService;
import org.eclipse.e4.ui.model.application.MApplication;
import org.eclipse.e4.ui.model.application.ui.MElementContainer;
import org.eclipse.e4.ui.model.application.ui.MLocalizable;
import org.eclipse.e4.ui.model.application.ui.MUIElement;
import org.eclipse.e4.ui.model.application.ui.basic.MTrimBar;
import org.eclipse.e4.ui.model.application.ui.basic.MTrimmedWindow;
import org.eclipse.e4.ui.model.application.ui.basic.MWindow;
import org.osgi.service.log.LogService;

/**
 * Default implementation of {@link ILocaleChangeService} that changes the {@link Locale} in the
 * specified {@link IEclipseContext} and additionally fires an event on the event bus.
 * 
 * @author Dirk Fauth
 * 
 */
@SuppressWarnings("restriction")
public class LocaleChangeServiceImpl implements ILocaleChangeService {

	private static LogService logService = ServicesActivator.getDefault().getLogService();

	MApplication application;

	@Inject
	IEventBroker broker;

	/**
	 * Create a new {@link LocaleChangeServiceImpl} for the given {@link IEclipseContext}.
	 * 
	 * @param application
	 *            The application to retrieve the context from.
	 */
	@Inject
	public LocaleChangeServiceImpl(MApplication application) {
		this.application = application;
	}

	@Override
	public void changeApplicationLocale(Locale locale) {

		// the TranslationService.LOCALE context parameter is specified as String
		// so we put the String representation of the given Locale to the context
		this.application.getContext().set(TranslationService.LOCALE, locale.toString());

		// update model
		updateLocalization(this.application.getChildren());

		// fire event
		broker.post(LOCALE_CHANGE, locale);
	}

	@Override
	public void changeApplicationLocale(String localeString) {
		try {
			Locale locale = ResourceBundleHelper.toLocale(localeString);

			// set the locale to the application context
			// use the resolved locale instead of the given locale string to avoid invalid locales
			// in context
			this.application.getContext().set(TranslationService.LOCALE, locale.toString());

			// update model
			updateLocalization(this.application.getChildren());

			// fire event
			broker.post(LOCALE_CHANGE, locale);
		} catch (Exception e) {
			// performing a locale update failed
			// there is no locale change performed
			if (logService != null)
				logService.log(LogService.LOG_ERROR, e.getMessage()
						+ " - No Locale change will be performed."); //$NON-NLS-1$
		}
	}

	/**
	 * Will iterate over the given list of {@link MUIElement}s and inform them about the Locale
	 * change if necessary.
	 * 
	 * @param children
	 *            The list of {@link MUIElement}s that should be checked for Locale updates.
	 */
	@SuppressWarnings({ "rawtypes", "unchecked" })
	protected void updateLocalization(List<? extends MUIElement> children) {
		for (MUIElement element : children) {
			if (element instanceof MElementContainer) {
				updateLocalization(((MElementContainer) element).getChildren());
			}

			if (element instanceof MWindow) {
				((MWindow) element).getMainMenu().updateLocalization();
				updateLocalization(((MWindow) element).getMainMenu().getChildren());
			}

			if (element instanceof MTrimmedWindow) {
				for (MTrimBar trimBar : ((MTrimmedWindow) element).getTrimBars()) {
					trimBar.updateLocalization();
					updateLocalization(trimBar.getChildren());
				}
			}

			((MLocalizable) element).updateLocalization();
		}
	}

}