/* (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.adapters;

import java.lang.reflect.Constructor;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.geoserver.config.ServiceInfo;
import org.geoserver.config.impl.GeoServerImpl;
import org.geoserver.ows.HttpServletRequestAware;
import org.vfny.geoserver.util.requests.readers.KvpRequestReader;


/**
 * Wraps an old style {@link KvpRequestReader} in a new
 * {@link org.geoserver.ows.KvpRequestReader}.
 * <p>
 * This class needs to be defined in a spring context like:
 * <pre>
 * <code>
 *   <bean id="getMapKvpReader" class="org.geoserver.ows.adapters.KvpRequestReaderAdapter">
 *      <!-- first argument is the request class -->
 *      <constructor-arg index="0" value="org.vfny.geoserver.wms.requests.GetMapRequest" />
 *
 *      <!-- second argument is the old style kvp reader class -->
 *      <constructor-arg index="1" value="org.vfny.geoserver.wms.requests.GetMapKvpReader" />
 *
 *      <!-- third argument is the old style service -->
 *      <constructor-arg index="2" ref="wmsService" />
 *   <bean>
 * </code>
 * </pre>
 * </p>
 *
 * @author Justin Deoliveira, The Open Planning Project, jdeolive@openplans.org
 *
 */
public class KvpRequestReaderAdapter extends org.geoserver.ows.KvpRequestReader
    implements HttpServletRequestAware {
    Class delegateClass;
    ServiceInfo service;
    HttpServletRequest request;

    public KvpRequestReaderAdapter(Class requestBean, Class delegateClass, ServiceInfo service) {
        super(requestBean);
        this.delegateClass = delegateClass;
        this.service = service;
    }

    public void setHttpRequest(HttpServletRequest request) {
        this.request = request;
    }

    public Object createRequest() throws Exception {
        //simulate the old kvp processin
        Map kvp = new HashMap();
        String paramName;
        String paramValue;

        for (Enumeration pnames = request.getParameterNames(); pnames.hasMoreElements();) {
            paramName = (String) pnames.nextElement();
            paramValue = request.getParameter(paramName);
            kvp.put(paramName.toUpperCase(), paramValue);
        }

        //look for a constructor, may have to walk up teh class hierachy
        Class clazz = GeoServerImpl.unwrap(service).getClass();
        Constructor constructor = null;

        while (clazz != null && constructor == null) {
            try {
                constructor = delegateClass.getConstructor(new Class[] { Map.class, clazz });
            } catch (NoSuchMethodException e) {
                Class[] classes = clazz.getInterfaces();
                for (Class c : classes) {
                	try {
                		constructor = delegateClass.getConstructor(new Class[] { Map.class, c });
                	} catch(NoSuchMethodException e2) {
                		// no harm done
                	}
				}
                clazz = clazz.getSuperclass();
            }
        }
        

        if (constructor == null) {
            throw new IllegalStateException("No appropriate constructor");
        }

        //create an instance of the delegate	
        KvpRequestReader delegate = (KvpRequestReader) constructor.newInstance(new Object[] {
                    kvp, service
                });

        //create the request object
        return delegate.getRequest(request);
    }

    public Object read(Object request, Map kvp, Map rawKvp) throws Exception {
        //request object already initialized, just send it back
        return request;
    }
}