//------------------------------------------------------------------------------
// Copyright (c) 2005, 2006 IBM Corporation 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:
// IBM Corporation - initial implementation
//------------------------------------------------------------------------------
package org.eclipse.epf.persistence.util;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;

import org.eclipse.core.resources.IResource;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.epf.common.serviceability.EPFVersions;
import org.eclipse.epf.common.serviceability.VersionUtil;
import org.eclipse.epf.persistence.FileManager;
import org.eclipse.epf.persistence.migration.internal.Migrator;
import org.eclipse.epf.uma.ContentDescription;
import org.eclipse.epf.uma.DescribableElement;
import org.eclipse.epf.uma.MethodElement;
import org.eclipse.epf.uma.UmaPackage;
import org.osgi.framework.Version;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;

/**
 * Utility class with static helper methods for library persistence
 * 
 * @author Phong Nguyen Le
 * @since 1.0
 */
public class PersistenceUtil {

	/**
	 * Gets the current namespace URI of UMA.
	 */
	public static final String getUMANsURI() {
		return UmaPackage.eNS_URI;
	}

	public static final String getUMANsURI(String libPath) {
		try {
			DocumentBuilder builder = DocumentBuilderFactory.newInstance()
					.newDocumentBuilder();
			Document doc = builder.parse(new File(libPath));
			Element root = doc.getDocumentElement();
			String nsURI = root.getAttribute("xmlns:com.ibm.uma"); //$NON-NLS-1$
			if (nsURI == null || nsURI.equals("")) { //$NON-NLS-1$
				nsURI = root.getAttribute("xmlns:org.eclipse.epf.uma"); //$NON-NLS-1$
			}
			return nsURI;
		} catch (ParserConfigurationException e) {
			e.printStackTrace();
		} catch (FactoryConfigurationError e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

	public static final boolean conversionRequired(String libPath) {
		String currentNsURI = PersistenceUtil.getUMANsURI();
		String libNsURI = PersistenceUtil.getUMANsURI(libPath);
		if (currentNsURI.equals(libNsURI))
			return false;
		if (Migrator.OLD_UMA_NS_URI.equals(libNsURI))
			return true;
		return false;
	}

	public static final IResource getWorkspaceResource(Object obj) {
		Resource resource = null;
		if (obj instanceof DescribableElement) {
			DescribableElement e = (DescribableElement) obj;
			ContentDescription content = e.getPresentation();
			resource = content.eResource();
			if (resource == null) {
				resource = e.eResource();
			}
		} else if (obj instanceof EObject) {
			resource = ((EObject) obj).eResource();
		} else if (obj instanceof Resource) {
			resource = (Resource) obj;
		}
		if (resource != null && resource.getURI().isFile()) {
			return FileManager.getResourceForLocation(resource.getURI()
					.toFileString());
		}
		return null;
	}

	public static final Collection<EObject> getProxies(EObject obj) {
		Collection<EObject> proxies = new ArrayList<EObject>();
		for (Iterator iter = obj.eAllContents(); iter.hasNext();) {
			EObject o = (EObject) iter.next();
			if (o.eIsProxy()) {
				proxies.add(o);
			}
		}
		return proxies;
	}

	/**
	 * Checks the primary tool version stored in the given resource
	 * 
	 * @param resource
	 * @return <li> < 0 if the version of the primary tool stored in the given resource is missing or older than current
	 *         <li> 0 if the primary tool version in the given resource matches the current version
	 *         <li> > 0 if  the primary tool version in the given resource is newer than the current version
	 */
	public static final int checkToolVersion(Resource resource) {
		File file = new File(resource.getURI().toFileString());
		Map fileVersionMap = VersionUtil.readVersionsFromFile(file);
		if(fileVersionMap != null) {
			String version = (String) fileVersionMap.get(VersionUtil.getPrimaryToolID());
			if(version != null) {
				EPFVersions versions = VersionUtil.getVersions(VersionUtil.getPrimaryToolID());
				return versions.getCurrentVersion().compareToolVersionTo(new Version(version));
			}
		}
		return -1;
	}

	/**
	 * Gets the first method element in contents of the given resource.
	 *  
	 * @param resource
	 * @return
	 */
	public static MethodElement getMethodElement(Resource resource) {
		for (Iterator iter = resource.getContents().iterator(); iter.hasNext();) {
			Object element = iter.next();
			if (element instanceof MethodElement) {
				return (MethodElement) element;
			}
		}
		return null;
	}
	
}