/***********************************************************************
 * This file is part of iDempiere ERP Open Source                      *
 * http://www.idempiere.org                                            *
 *                                                                     *
 * Copyright (C) Contributors                                          *
 *                                                                     *
 * This program is free software; you can redistribute it and/or       *
 * modify it under the terms of the GNU General Public License         *
 * as published by the Free Software Foundation; either version 2      *
 * of the License, or (at your option) any later version.              *
 *                                                                     *
 * This program is distributed in the hope that it will be useful,     *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of      *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the        *
 * GNU General Public License for more details.                        *
 *                                                                     *
 * You should have received a copy of the GNU General Public License   *
 * along with this program; if not, write to the Free Software         *
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,          *
 * MA 02110-1301, USA.                                                 *
 *                                                                     *
 * Contributors:                                                       *
 * - hengsin                         								   *
 **********************************************************************/
package org.idempiere.jaxrs.provider.xmlbeans;

/**
 * @author hengsin
 *
 */
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.net.HttpURLConnection;
import java.util.HashMap;
import java.util.Map;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.Provider;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;

import org.apache.cxf.jaxrs.provider.xmlbeans.XMLBeanStreamSerializer;
import org.apache.cxf.jaxrs.provider.xmlbeans.XMLBeansElementProvider;
import org.apache.xmlbeans.XmlObject;
import org.codehaus.jettison.mapped.Configuration;
import org.codehaus.jettison.mapped.MappedXMLOutputFactory;
import org.idempiere.jettison.mapped.CustomMappedNamespaceConvention;
import org.idempiere.jettison.mapped.MappedXMLInputFactory;

/**
 * JSON provider for XMLBeans data objects.
 */
@Produces("application/json")
@Consumes("application/json")
@Provider
public class XMLBeansJSONProvider extends XMLBeansElementProvider {

    private static final String AD_INTERFACE_1_0_NAMESPACE = "http://idempiere.org/ADInterface/1_0";

	/** {@inheritDoc} */
    @Override
    public XmlObject readFrom(Class<XmlObject> type, Type genericType, 
                              Annotation[] annotations, MediaType m, 
        MultivaluedMap<String, String> headers, InputStream is)
        throws IOException {
        XmlObject result = null;

        try {

        	Map<String, String> nstojns = new HashMap<String, String>();
            nstojns.put(AD_INTERFACE_1_0_NAMESPACE, "");

            Configuration conf = new Configuration(nstojns);
            conf.setIgnoreNamespaces(false);
            CustomMappedNamespaceConvention convention = new CustomMappedNamespaceConvention(conf);
            convention.addNamespacePrefix("i", AD_INTERFACE_1_0_NAMESPACE);
            MappedXMLInputFactory factory = new MappedXMLInputFactory(convention);            
            XMLStreamReader xsr = factory.createXMLStreamReader(is);
            result = parseXmlBean(type, xsr);

            xsr.close();
        } catch (XMLStreamException e) {
            throw new WebApplicationException(HttpURLConnection.HTTP_INTERNAL_ERROR);
        }

        return result;
    }

    /**
     * Create an XMLBean data object using a stream <code>Reader</code>
     * 
     * @param type declared type of the desired XMLBean data object
     * @param reader
     * @return an instance of the required object, otherwise null
     */
    protected XmlObject parseXmlBean(Class<?> type, XMLStreamReader xsr) {
        XmlObject result = null;

        // get static XMLBeans Factory field
        Field factory = getFactory(type);

        try {

            // get factory method parse(InputStream)
            Method m = factory.getType().getMethod("parse", XMLStreamReader.class);
            Object[] args = {xsr};
            Object obj = m.invoke(factory.get(type), args);

            if (obj instanceof XmlObject) {            	            	
                result = (XmlObject)obj;                
            }

        } catch (NoSuchMethodException nsme) {
            nsme.printStackTrace();
        } catch (InvocationTargetException ite) {
            ite.printStackTrace();
        } catch (IllegalAccessException iae) {
            iae.printStackTrace();
        }

        return result;
    }
    
    /**
     * Locate the static XMLBean <code>Factory</code> field.
     * 
     * @param type
     * @return the Factory field if present, otherwise null.
     */
    private Field getFactory(Class<?> type) {
        Field factory = null;
        try {
        	factory = type.getDeclaredField("Factory");
		} catch (NoSuchFieldException e) {
			e.printStackTrace();
		} catch (SecurityException e) {
			e.printStackTrace();
		}
        
        return factory;
    }
    
    /** {@inheritDoc} */
    @Override
    public void writeTo(XmlObject obj, Class<?> cls, Type genericType, Annotation[] annotations,  
                        MediaType m, MultivaluedMap<String, Object> headers, OutputStream os) {

        try {

            // Set up the JSON StAX implementation
            Map<String, String> nstojns = new HashMap<String, String>();
            Configuration conf = new Configuration(nstojns);
            conf.setIgnoreNamespaces(true);
            XMLOutputFactory factory = new MappedXMLOutputFactory(conf);
            XMLStreamWriter xsw = factory.createXMLStreamWriter(os);
            xsw.writeStartDocument();
            if (obj instanceof XmlObject) {

                XmlObject xObj = obj;
                XMLBeanStreamSerializer ser = new XMLBeanStreamSerializer();
                ser.serialize(xObj, xsw);
            }

            xsw.flush();
            xsw.close();

        } catch (XMLStreamException e) {
            throw new WebApplicationException(HttpURLConnection.HTTP_INTERNAL_ERROR);
        } catch (IOException ioe) {
            throw new WebApplicationException(HttpURLConnection.HTTP_INTERNAL_ERROR);
        }
    }    
}