/*******************************************************************************
 * Copyright (c) 2007 Oracle Corporation.
 * 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:
 *    Oracle - initial API and implementation
 *    
 ********************************************************************************/
package org.eclipse.jst.jsf.common.metadata.internal;

import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.emf.common.util.EList;
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.ecore.util.BasicExtendedMetaData;
import org.eclipse.emf.ecore.util.ExtendedMetaData;
import org.eclipse.emf.ecore.xmi.ClassNotFoundException;
import org.eclipse.emf.ecore.xmi.FeatureNotFoundException;
import org.eclipse.emf.ecore.xmi.IllegalValueException;
import org.eclipse.emf.ecore.xmi.PackageNotFoundException;
import org.eclipse.emf.ecore.xmi.UnresolvedReferenceException;
import org.eclipse.emf.ecore.xmi.XMIException;
import org.eclipse.emf.ecore.xmi.XMLResource;
import org.eclipse.emf.ecore.xmi.impl.XMLResourceFactoryImpl;
import org.eclipse.jst.jsf.common.JSFCommonPlugin;
import org.eclipse.jst.jsf.common.metadata.internal.util.MetadataResourceImpl;
import org.eclipse.jst.jsf.common.metadata.query.ITaglibDomainMetaDataModelContext;

/**
 * Singleton that produces and loads standard metadata models.  
 * All models are loaded into the same ResourceSet 
 *
 * see Model
 */
public class StandardModelFactory {
	private static StandardModelFactory INSTANCE;
	private static boolean DEBUG_MD_LOAD = false;
	private ExtendedMetaData extendedMetaData;
	private ResourceSet resourceSet;

	
	/**
	 * @return singleton instance of the metadata model factory
	 */
	public synchronized static StandardModelFactory getInstance(){
		if (INSTANCE == null){
			INSTANCE = new StandardModelFactory();
			INSTANCE.init();	
			
			if (JSFCommonPlugin.getPlugin().isDebugging()){
				DEBUG_MD_LOAD = Boolean.valueOf(Platform.getDebugOption(JSFCommonPlugin.PLUGIN_ID+"/debug/metadataload")).booleanValue();
			}
		}
		return INSTANCE;
	}
	
	private void init() {
		resourceSet = new ResourceSetImpl();
		
	    extendedMetaData = new BasicExtendedMetaData(resourceSet.getPackageRegistry());
		
		// Register the appropriate resource factory to handle all file extensions.
		//
		resourceSet.getResourceFactoryRegistry().getExtensionToFactoryMap().put
			(Resource.Factory.Registry.DEFAULT_EXTENSION, 
			 new XMLResourceFactoryImpl());

		//relying on the org.eclipse.emf.ecore.generated_package ext-pt to register traits
	}

	private StandardModelFactory() {		
		super();
	}
	
	/**
	 * Factory method that probably belongs somewhere else!
	 * @param key
	 * @param strategy
	 * @return an empty MetaDataModel
	 */
	public MetaDataModel createModel(ModelKeyDescriptor key, IDomainLoadingStrategy strategy){
		return new MetaDataModel(key, strategy);
	}

	/**
	 * Factory method that probably belongs somewhere else!
	 * @param modelContext 
	 * @return a ModelKeyDescriptor for the context
	 */
	public ModelKeyDescriptor createModelKeyDescriptor(final ITaglibDomainMetaDataModelContext modelContext) {
		return new ModelKeyDescriptor(modelContext.getProject(), modelContext.getDomainID(), modelContext.getURI());
	}
	
	/**
	 * @param inputStream
	 * @param provider
	 * @param uri 
	 * @return the root of the standard model from the resource as an EList
	 * @throws IOException
	 */
	public EList loadStandardFileResource(final InputStream inputStream, final IMetaDataSourceModelProvider provider, final org.eclipse.emf.common.util.URI uri) throws IOException {
		final XMLResource res = new MetadataResourceImpl(provider); 		
		res.setURI(uri);
		resourceSet.getResources().add(res);
		setLoadOptions(res);
		res.load(inputStream, null);
		if (DEBUG_MD_LOAD)
			reportErrors(res);
		final EList root = res.getContents();		
		return root;	
	}

	private void reportErrors(Resource res) {
		EList<Resource.Diagnostic> errs = res.getErrors();
		if (! errs.isEmpty()){
			for (Iterator<Resource.Diagnostic> it= errs.iterator();it.hasNext();){				
				StandardModelErrorMessageFactory.logErrorMessage(it.next());
			}		
		}
	}
	/**
	 * Sets default load options for the resource
	 * @param resource 
	 */
	protected void setLoadOptions(XMLResource resource) {
		Map options = resource.getDefaultLoadOptions();
//		options.put(XMLResource.OPTION_SAVE_TYPE_INFORMATION, true);
		options.put(XMLResource.OPTION_SCHEMA_LOCATION, Boolean.TRUE);
		options.put(XMLResource.OPTION_EXTENDED_META_DATA, extendedMetaData);
		options.put(XMLResource.OPTION_RESOURCE_HANDLER, resource);
		options.put(XMLResource.OPTION_LAX_FEATURE_PROCESSING, Boolean.TRUE);
		options.put(XMLResource.OPTION_RECORD_UNKNOWN_FEATURE, Boolean.FALSE);//turning this off so that res.getErrors() has values to check!  bizarre that I should need to do this.
//		options.put(XMLResource.OPTION_DOM_USE_NAMESPACES_IN_SCOPE, Boolean.TRUE);
	}


	static class StandardModelErrorMessageFactory {
		
		/**
		 * Simply logs all messages against JSFCommonPlugin, for now.
		 * @param diagnostic
		 */
		public static void logErrorMessage(Resource.Diagnostic diagnostic) {	
			//should be XMIException
			if (diagnostic instanceof XMIException) {
				XMIException ex = (XMIException)diagnostic;				
				String msg = createMessage(ex);
				JSFCommonPlugin.log(IStatus.ERROR, msg);
//				System.out.println(msg);
			}
			else {
				JSFCommonPlugin.log(IStatus.ERROR, diagnostic.toString());//do better???
//				System.out.println(diagnostic.toString());	
			}
		}

		private static String createMessage(XMIException ex) {
			
			StringBuffer buf = new StringBuffer("Metadata Load Error: ")
				.append(ex.getClass().getSimpleName()).append(": ");
			
			if (ex instanceof PackageNotFoundException)
				buf.append(((PackageNotFoundException)ex).uri());			
			else if (ex instanceof ClassNotFoundException)
				buf.append(((ClassNotFoundException)ex).getName());
			else if (ex instanceof FeatureNotFoundException)
				buf.append(((FeatureNotFoundException)ex).getName());
			else if (ex instanceof IllegalValueException)
				buf.append(((IllegalValueException)ex).getValue().toString());
			else if (ex instanceof UnresolvedReferenceException)
				buf.append(((UnresolvedReferenceException)ex).getReference());	
			else
				buf.append(ex.getMessage());
			
			buf.append(" in ").append(ex.getLocation()).append(": Line = ")
				.append(ex.getLine()).append(": Column = ").append(ex.getColumn());
			return buf.toString();
		}
	}
}