/* (c) 2014 Open Source Geospatial Foundation - all rights reserved
 * (c) 2001 - 2013 OpenPlans
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.ows.kvp;

import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.emf.ecore.EFactory;
import org.eclipse.emf.ecore.EObject;
import org.geoserver.ows.KvpRequestReader;
import org.geoserver.ows.util.OwsUtils;
import org.geoserver.platform.ServiceException;
import org.geotools.xml.EMFUtils;


/**
 * Web Feature Service Key Value Pair Request reader.
 * <p>
 * This request reader makes use of the Eclipse Modelling Framework
 * reflection api.
 * </p>
 * @author Justin Deoliveira, The Open Planning Project
 * @author Andrea Aime, TOPP
 *
 */
public class EMFKvpRequestReader extends KvpRequestReader {
    /**
     * Factory used to create model objects / requests.
     */
    protected EFactory factory;

    /**
     * Creates the Wfs Kvp Request reader.
     *
     * @param requestBean The request class, which must be an emf class.
     */
    public EMFKvpRequestReader(Class requestBean, EFactory factory) {
        super(requestBean);

        //make sure an eobject is passed in
        if (!EObject.class.isAssignableFrom(requestBean)) {
            String msg = "Request bean must be an EObject";
            throw new IllegalArgumentException(msg);
        }

        this.factory = factory;
    }

    /**
     * Reflectivley creates the request bean instance.
     */
    public Object createRequest() {
        String className = getRequestBean().getName();

        //strip off package
        int index = className.lastIndexOf('.');

        if (index != -1) {
            className = className.substring(index + 1);
        }

        Method create = OwsUtils.method(factory.getClass(), "create" + className);

        try {
            return create.invoke(factory, null);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public Object read(Object request, Map kvp, Map rawKvp) throws Exception {
        //use emf reflection
        EObject eObject = (EObject) request;

        for (Iterator e = kvp.entrySet().iterator(); e.hasNext();) {
            Map.Entry entry = (Map.Entry) e.next();
            String property = (String) entry.getKey();
            Object value = entry.getValue();

            //respect the filter
            if ( filter( property ) ) {
                continue;
            }
            
            if (EMFUtils.has(eObject, property)) {
                try {
                    //check for a collection
                    if ( EMFUtils.isCollection(eObject, property) ) {
                        EMFUtils.add(eObject, property, value);
                    }
                    else {
                        EMFUtils.set(eObject, property, value);    
                    }
                } catch(Exception ex) {
                    throw new ServiceException("Failed to set property " + property 
                            + " in request object using value " + value 
                            + (value != null ? " of type " + value.getClass() : ""), ex, 
                            ServiceException.INVALID_PARAMETER_VALUE, property);
                }
            }
        }

        return request;
    }
}