/***********************************************************************
 * Copyright (c) 2008 by SAP AG, Walldorf. 
 * 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:
 *     SAP AG - initial API and implementation
 ***********************************************************************/
package org.eclipse.jst.jee.model.internal;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.jst.j2ee.model.IModelProvider;
import org.eclipse.jst.j2ee.model.IModelProviderEvent;
import org.eclipse.jst.javaee.web.WebApp;
import org.eclipse.jst.javaee.web.WebFactory;
import org.eclipse.jst.jee.model.internal.common.AbstractMergedModelProvider;
import org.eclipse.jst.jee.model.internal.mergers.ModelElementMerger;
import org.eclipse.jst.jee.model.internal.mergers.ModelException;
import org.eclipse.jst.jee.model.internal.mergers.WebAppMerger;
import org.eclipse.jst.jee.web.Activator;
import org.eclipse.wst.common.project.facet.core.ProjectFacetsManager;

/**
 * @author Kiril Mitov k.mitov@sap.com
 * 
 */
public class Web25MergedModelProvider extends AbstractMergedModelProvider<WebApp> {

	public Web25MergedModelProvider(IProject project) {
		super(project);
	}

	@Override
	protected IModelProvider loadAnnotationModel(WebApp ddModel) throws CoreException {
		return new WebAnnotationReader(ProjectFacetsManager.create(project), ddModel);
	}

	@Override
	protected IModelProvider loadDeploymentDescriptorModel() throws CoreException {
		return new Web25ModelProvider(project);
	}

	private WebApp getAnnotationWebApp() {
		return annotationModelProvider != null ? (WebApp) annotationModelProvider.getModelObject() : null;
	}

	private WebApp getXmlWebApp() {
		return ddProvider != null ? (WebApp) ddProvider.getModelObject() : null;
	}

	public Object getModelObject(IPath modelPath) {
		return null;
	}

	@Override
	public void modify(Runnable runnable, IPath modelPath) {
		/*
		 * Someone has called modify before loading the model. Try to load the
		 * model.
		 */
		if (mergedModel == null)
			getMergedModel();
		if (isDisposed()) {
			return;
		}
		/*
		 * Still not supporting modifications of the merged model. During modify
		 * the model is becoming the ddModel. After modifying the model is
		 * unloaded.
		 */
		WebApp backup = mergedModel;
		try {
			mergedModel = (WebApp) ddProvider.getModelObject();
			ddProvider.modify(runnable, modelPath);
		} finally {
			mergedModel = backup;
		}
		if (mergedModel == null)
			mergedModel = getMergedModel();
		else
			merge(getXmlWebApp(), getAnnotationWebApp());
	}

	private void clearModel(WebApp app) {
		if (app == null) {
			return;
		}
		app.getContextParams().clear();
		app.getDescriptions().clear();
		app.getDisplayNames().clear();
		app.getDistributables().clear();
		app.getEjbLocalRefs().clear();
		app.getEjbRefs().clear();
		app.getEnvEntries().clear();
		app.getErrorPages().clear();
		app.getFilterMappings().clear();
		app.getFilters().clear();
		app.getIcons().clear();
		app.getJspConfigs().clear();
		app.getListeners().clear();
		app.getLocalEncodingMappingsLists().clear();
		app.getLoginConfigs().clear();
		app.getMessageDestinationRefs().clear();
		app.getMessageDestinations().clear();
		app.getMimeMappings().clear();
		app.getPersistenceContextRefs().clear();
		app.getPersistenceUnitRefs().clear();
		app.getPostConstructs().clear();
		app.getPreDestroys().clear();
		app.getResourceEnvRefs().clear();
		app.getResourceRefs().clear();
		app.getSecurityConstraints().clear();
		app.getSecurityRoles().clear();
		app.getServiceRefs().clear();
		app.getServletMappings().clear();
		app.getServlets().clear();
		app.getSessionConfigs().clear();
		app.getWelcomeFileLists().clear();
	}

	@Override
	protected void annotationModelChanged(IModelProviderEvent event) {
		internalModelChanged(event);
	}

	@Override
	protected void xmlModelChanged(IModelProviderEvent event) {
		internalModelChanged(event);
	}

	/*
	 * Notifications from xml and annotation may come in different threads. This
	 * depends on the implementation of the model providers, but to make sure
	 * that no race conditions occurs I am synchronizing this method.
	 */
	private synchronized void internalModelChanged(IModelProviderEvent event) {
		merge(getXmlWebApp(), getAnnotationWebApp());
		notifyListeners(event);
	}

	@Override
	protected WebApp merge(WebApp ddModel, WebApp annotationsModel) {
		try {
			if (mergedModel != ddModel) {
				clearModel(mergedModel);
				mergeWithModel(ddModel);
				mergeWithModel(annotationsModel);
			}
		} catch (ModelException e) {
			Activator.logError(e);
		}
		return mergedModel;
	}

	private void mergeWithModel(WebApp model) throws ModelException {
		if (model == null)
			return;
		WebAppMerger merger = new WebAppMerger(mergedModel, model, ModelElementMerger.ADD);
		merger.process();
	}

	@Override
	protected WebApp createNewModelInstance() {
		return WebFactory.eINSTANCE.createWebApp();
	}

}