/*

  * 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.shindig.social.opensocial.service;

 import org.apache.shindig.auth.AuthInfo;

 import org.apache.shindig.auth.SecurityToken;

 import org.apache.shindig.common.servlet.InjectedServlet;

 import org.apache.shindig.common.util.ImmediateFuture;

 import org.apache.shindig.social.ResponseError;

 import org.apache.shindig.social.core.util.BeanJsonConverter;

 import org.apache.shindig.social.opensocial.spi.SocialSpiException;

 import com.google.inject.Inject;

 import com.google.inject.name.Named;

 import java.io.IOException;

 import java.util.Collections;

 import java.util.concurrent.ExecutionException;

 import java.util.concurrent.Future;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 /**

  * Common base class for API servlets.

  */

 public abstract class ApiServlet extends InjectedServlet {

   protected static final String DEFAULT_ENCODING = "UTF-8";

   private HandlerDispatcher dispatcher;

   protected BeanJsonConverter jsonConverter;

   protected BeanConverter xmlConverter;

   protected BeanConverter atomConverter;

   @Inject

   public void setHandlerDispatcher(HandlerDispatcher dispatcher) {

     this.dispatcher = dispatcher;

   }

   @Inject

   public void setBeanConverters(

       @Named("shindig.bean.converter.json") BeanConverter jsonConverter,

       @Named("shindig.bean.converter.xml") BeanConverter xmlConverter,

       @Named("shindig.bean.converter.atom") BeanConverter atomConverter) {

     // fix this

     this.jsonConverter = (BeanJsonConverter) jsonConverter;

     this.xmlConverter = xmlConverter;

     this.atomConverter = atomConverter;

   }

   protected SecurityToken getSecurityToken(HttpServletRequest servletRequest) {

     return new AuthInfo(servletRequest).getSecurityToken();

   }

   protected abstract void sendError(HttpServletResponse servletResponse, ResponseItem responseItem)

       throws IOException;

   protected void sendSecurityError(HttpServletResponse servletResponse) throws IOException {

     sendError(servletResponse, new ResponseItem(ResponseError.UNAUTHORIZED,

         "The request did not have a proper security token nor oauth message and unauthenticated "

             + "requests are not allowed"));

   }

   /**

    * Delivers a request item to the appropriate DataRequestHandler.

    */

   protected Future<?> handleRequestItem(RequestItem requestItem,

       HttpServletRequest servletRequest) {

     DataRequestHandler handler = dispatcher.getHandler(requestItem.getService());

     if (handler == null) {

       return ImmediateFuture.errorInstance(new SocialSpiException(ResponseError.NOT_IMPLEMENTED,

           "The service " + requestItem.getService() + " is not implemented"));

     }

     return handler.handleItem(requestItem);

   }

   protected ResponseItem getResponseItem(Future<?> future) {

     ResponseItem response;

     try {

       // TODO: use timeout methods?

       Object result = future != null ? future.get() : null;

       // TODO: null is now a supported return value for post/delete, but

       // is bad for get().

       response = new ResponseItem(result != null ? result : Collections.emptyMap());

     } catch (InterruptedException ie) {

       response = responseItemFromException(ie);

     } catch (ExecutionException ee) {

       response = responseItemFromException(ee.getCause());

     }

     return response;

   }

   protected ResponseItem responseItemFromException(Throwable t) {

     if (t instanceof SocialSpiException) {

       SocialSpiException spe = (SocialSpiException) t;

       return new ResponseItem(spe.getError(), spe.getMessage());

     }

     return new ResponseItem(ResponseError.INTERNAL_ERROR, t.getMessage());

   }

   protected void setCharacterEncodings(HttpServletRequest servletRequest,

       HttpServletResponse servletResponse) throws IOException {

     if (servletRequest.getCharacterEncoding() == null) {

       servletRequest.setCharacterEncoding(DEFAULT_ENCODING);

     }

     servletResponse.setCharacterEncoding(DEFAULT_ENCODING);

   }

 }