/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.    
 */

package org.apache.tuscany.sca.databinding.jaxb;

import java.lang.annotation.Annotation;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.namespace.QName;

import org.apache.tuscany.sca.databinding.ExceptionHandler;
import org.apache.tuscany.sca.databinding.impl.BaseDataBinding;
import org.apache.tuscany.sca.databinding.impl.DOMHelper;
import org.apache.tuscany.sca.interfacedef.DataType;
import org.apache.tuscany.sca.interfacedef.util.XMLType;
import org.w3c.dom.Document;

/**
 * JAXB DataBinding
 */
public class JAXBDataBinding extends BaseDataBinding {
    public static final String NAME = JAXBElement.class.getName();
    public static final String[] ALIASES = new String[] {"jaxb"};

    public static final String ROOT_NAMESPACE = "http://tuscany.apache.org/xmlns/sca/databinding/jaxb/1.0";
    public static final QName ROOT_ELEMENT = new QName(ROOT_NAMESPACE, "root");

    public JAXBDataBinding() {
        super(NAME, ALIASES, JAXBElement.class);
    }

    @Override
    public boolean introspect(DataType dataType, Annotation[] annotations) {
        Object physical = dataType.getPhysical();
        if (!(physical instanceof Class)) {
            return false;
        }
        Class javaType = (Class)physical;
        if (JAXBElement.class.isAssignableFrom(javaType)) {
            Type type = javaType.getGenericSuperclass();
            if (type instanceof ParameterizedType) {
                ParameterizedType parameterizedType = ((ParameterizedType)type);
                Type rawType = parameterizedType.getRawType();
                if (rawType == JAXBElement.class) {
                    Type actualType = parameterizedType.getActualTypeArguments()[0];
                    if (actualType instanceof Class) {
                        XMLType xmlType = JAXBContextHelper.getXmlTypeName((Class)actualType);
                        dataType.setLogical(xmlType);
                        dataType.setDataBinding(getName());
                        return true;
                    }
                }
            }
            dataType.setLogical(XMLType.UNKNOWN);
            dataType.setDataBinding(getName());
            return true;
        }

        XMLType xmlType = JAXBContextHelper.getXmlTypeName(javaType);
        if (xmlType == null) {
            return false;
        }
        dataType.setLogical(xmlType);
        dataType.setDataBinding(getName());
        return true;
    }

    @SuppressWarnings("unchecked")
    @Override
    public Object copy(Object arg) {
        try {
            boolean isElement = false;
            Class cls = arg.getClass();
            if (arg instanceof JAXBElement) {
                isElement = true;
                cls = ((JAXBElement)arg).getDeclaredType();
            } else {
                arg = new JAXBElement(ROOT_ELEMENT, Object.class, arg);
            }
            JAXBContext context = JAXBContext.newInstance(cls);
            Document doc = DOMHelper.newDocument();
            context.createMarshaller().marshal(arg, doc);
            JAXBElement<?> element = context.createUnmarshaller().unmarshal(doc, cls);
            return isElement ? element : element.getValue();
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    @Override
    public ExceptionHandler getExceptionHandler() {
        return new JAXBExceptionHandler();
    }

}