/*
    * Copyright 2013 smartics, Kronseder & Reiner GmbH
    *
    * Licensed 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 de.smartics.resteasy.hypermedia.renderer;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Type;
  import java.util.Locale;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.MultivaluedMap;
  import javax.ws.rs.core.UriInfo;
  import javax.ws.rs.ext.MessageBodyWriter;
  
  import de.smartics.resteasy.hypermedia.resources.ResourceDiscovery;
  import de.smartics.resteasy.hypermedia.resources.Resources;
  
  /**
   * Base implementation to pass rendering information to representation
   * renderers.
   *
   * @param <T> the type of resource whose instances are written to the stream.
   */
  public abstract class AbstractRepresentationBodyWriter<T> implements
      MessageBodyWriter<T>
  {
    // ********************************* Fields *********************************
  
    // --- constants ------------------------------------------------------------
  
    // --- members --------------------------------------------------------------
  
    /**
     * Helper to construct paths.
     */
    @Context
    private UriInfo uriInfo;
  
    /**
     * Provides access to the client request.
     */
    @Context
    private HttpServletRequest httpRequest;
  
    /**
     * Provides access to the client response.
     */
    @Context
    private HttpServletResponse httpResponse;
  
    // ****************************** Initializer *******************************
  
    // ****************************** Constructors ******************************
  
    /**
     * Default constructor.
     */
    protected AbstractRepresentationBodyWriter()
    {
    }
  
    // ****************************** Inner Classes *****************************
  
    // ********************************* Methods ********************************
  
    // --- init -----------------------------------------------------------------
  
    // --- get&set --------------------------------------------------------------
  
    /**
     * Returns access to internationalization information.
     *
     * @return access to internationalization information.
     */
    protected abstract I18nProvider getI18nProvider();
  
    // --- business -------------------------------------------------------------
  
    @Override
    public long getSize(final T t, final Class<?> type, final Type genericType,
        final Annotation[] annotations, final MediaType mediaType)
   {
     return -1;
   }
 
   // CHECKSTYLE:OFF
   @Override
   public void writeTo(final T t, final Class<?> type, final Type genericType,
       final Annotation[] annotations, final MediaType mediaType,
       final MultivaluedMap<String, Object> httpHeaders,
       final OutputStream entityStream) throws IOException,
     WebApplicationException
   {
     final LocalizationProvider l7nProvider = fetchLocalizationProvider();
     final Resources discovery = ResourceDiscovery.createDiscovery(t, uriInfo);
     final ResourceContext context =
         new ResourceContext.Builder().with(httpRequest).with(httpResponse)
             .with(uriInfo).with(l7nProvider).with(discovery).withType(type)
             .withGenericType(genericType).with(annotations).with(mediaType)
             .withHttpHeaders(httpHeaders).build();
     final RepresentationRenderer<T> renderer = create(context, t, entityStream);
     renderer.render();
   }
 
   // CHECKSTYLE:ON
 
   private LocalizationProvider fetchLocalizationProvider()
   {
     final Locale locale = httpRequest.getLocale();
     final LocalizationProvider l7nProvider =
         getI18nProvider().getProvider(locale);
     return l7nProvider;
   }
 
   /**
    * Creates an instance of the representation renderer.
    *
    * @param context the context information to be passed to the representation
    *          renderer.
    * @param domainObject the domain object to render.
    * @param entityStream the stream to write to.
    * @return the representation renderer instance.
    */
   protected abstract RepresentationRenderer<T> create(ResourceContext context,
       T domainObject, OutputStream entityStream);
 
   // --- object basics --------------------------------------------------------
 
 }