/*
 * 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.wicket.markup.html.link;

import org.apache.wicket.IRequestListener;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.handler.resource.ResourceReferenceRequestHandler;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.request.resource.IResource;
import org.apache.wicket.request.resource.IResource.Attributes;
import org.apache.wicket.request.resource.ResourceReference;

/**
 * A link to any ResourceReference.
 * 
 * @author Jonathan Locke
 * @param <T>
 *            type of model object
 */
public class ResourceLink<T> extends Link<T> implements IRequestListener
{
        private static final long serialVersionUID = 1L;

        /** The Resource reference */
        private final ResourceReference resourceReference;

        /** The Resource */
        private final IResource resource;

        /** The resource parameters */
        private final PageParameters resourceParameters;


        /**
         * Constructs an ResourceLink from an resourcereference. That resource reference will bind its
         * resource to the current SharedResources.
         * 
         * @param id
         *            See Component
         * @param resourceReference
         *            The shared resource to link to
         */
        public ResourceLink(final String id, final ResourceReference resourceReference)
        {
                this(id, resourceReference, null);
        }

        /**
         * Constructs an ResourceLink from an resourcereference. That resource reference will bind its
         * resource to the current SharedResources.
         * 
         * @param id
         *            See Component
         * @param resourceReference
         *            The shared resource to link to
         * @param resourceParameters
         *            The resource parameters
         */
        public ResourceLink(final String id, final ResourceReference resourceReference,
                PageParameters resourceParameters)
        {
                super(id);
                this.resourceReference = resourceReference;
                this.resourceParameters = resourceParameters;
                resource = null;
        }

        /**
         * Constructs a link directly to the provided resource.
         * 
         * @param id
         *            See Component
         * @param resource
         *            The resource
         */
        public ResourceLink(final String id, final IResource resource)
        {
                super(id);
                this.resource = resource;
                resourceReference = null;
                resourceParameters = null;
        }

        @Override
        public void onClick()
        {
        }

        @Override
        public boolean rendersPage()
        {
                return false;
        }
        
        /**
         * For {@link ResourceReference}s this link is stateless.
         * 
         * @return <code>true</code> if a resourceReference was provided to the
         *         constructor
         * 
         * @see ResourceLink#ResourceLink(String, ResourceReference)
         * @see ResourceLink#ResourceLink(String, ResourceReference, PageParameters)
         */
        @Override
        protected boolean getStatelessHint()
        {
                return resourceReference != null;
        }   

        @Override
        protected final CharSequence getURL()
        {
                if (resourceReference != null)
                {
                        // TODO post 1.2: should we have support for locale changes when the
                        // resource reference (or resource??) is set manually..
                        // We should get a new resource reference for the current locale
                        // then
                        // that points to the same resource but with another locale if it
                        // exists.
                        // something like
                        // SharedResource.getResourceReferenceForLocale(resourceReference);
                        if (resourceReference.canBeRegistered())
                        {
                                getApplication().getResourceReferenceRegistry().registerResourceReference(
                                        resourceReference);
                        }

                        return getRequestCycle().urlFor(
                                new ResourceReferenceRequestHandler(resourceReference, resourceParameters));
                }
                return urlForListener(resourceParameters);
        }
        
        @Override
        public final void onRequest()
        {
                Attributes a = new Attributes(RequestCycle.get().getRequest(), RequestCycle.get()
                        .getResponse(), null);
                resource.respond(a);
                
                super.onRequest();
        }       
}