/*

  * 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.SecurityToken;

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

 import org.apache.shindig.social.ResponseError;

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

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

 import com.google.common.collect.Lists;

 import org.apache.commons.io.IOUtils;

 import org.apache.commons.lang.StringUtils;

 import org.json.JSONArray;

 import org.json.JSONException;

 import org.json.JSONObject;

 import java.io.IOException;

 import java.util.List;

 import java.util.concurrent.Future;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 /**

  * JSON-RPC handler servlet.

  */

 public class JsonRpcServlet extends ApiServlet {

   @Override

   protected void doGet(HttpServletRequest servletRequest,

       HttpServletResponse servletResponse)

       throws ServletException, IOException {

     SecurityToken token = getSecurityToken(servletRequest);

     if (token == null) {

       sendSecurityError(servletResponse);

       return;

     }

     try {

       setCharacterEncodings(servletRequest, servletResponse);

       JSONObject request = JsonConversionUtil.fromRequest(servletRequest);

       dispatch(request, servletRequest, servletResponse, token);

     } catch (JSONException je) {

       // FIXME

     }

   }

   @Override

   protected void doPost(HttpServletRequest servletRequest,

       HttpServletResponse servletResponse)

       throws ServletException, IOException {

     SecurityToken token = getSecurityToken(servletRequest);

     if (token == null) {

       sendSecurityError(servletResponse);

       return;

     }

     setCharacterEncodings(servletRequest, servletResponse);

     servletResponse.setContentType("application/json");

     try {

       String content = IOUtils.toString(servletRequest.getInputStream(),

           servletRequest.getCharacterEncoding());

       if ((content.indexOf('[') != -1) && content.indexOf('[') < content.indexOf('{')) {

         // Is a batch

         JSONArray batch = new JSONArray(content);

         dispatchBatch(batch, servletRequest, servletResponse, token);

       } else {

         JSONObject request = new JSONObject(content);

         dispatch(request, servletRequest, servletResponse, token);

       }

     } catch (JSONException je) {

       sendBadRequest(je, servletResponse);

     }

   }

   protected void dispatchBatch(JSONArray batch, HttpServletRequest servletRequest,

       HttpServletResponse servletResponse, SecurityToken token) throws JSONException, IOException {

     // Use linked hash map to preserve order

     List<Future<?>> responses = Lists.newArrayListWithExpectedSize(batch.length());

     // Gather all Futures.  We do this up front so that

     // the first call to get() comes after all futures are created,

     // which allows for implementations that batch multiple Futures

     // into single requests.

     for (int i = 0; i < batch.length(); i++) {

       JSONObject batchObj = batch.getJSONObject(i);

       RpcRequestItem requestItem = new RpcRequestItem(batchObj, token, jsonConverter);

       responses.add(handleRequestItem(requestItem, servletRequest));

     }

     // Resolve each Future into a response.

     // TODO: should use shared deadline across each request

     JSONArray result = new JSONArray();

     for (int i = 0; i < batch.length(); i++) {

       JSONObject batchObj = batch.getJSONObject(i);

       String key = null;

       if (batchObj.has("id")) {

         key = batchObj.getString("id");

       }

       result.put(getJSONResponse(key, getResponseItem(responses.get(i))));

     }

     servletResponse.getWriter().write(result.toString());

   }

   protected void dispatch(JSONObject request, HttpServletRequest servletRequest,

       HttpServletResponse servletResponse, SecurityToken token) throws JSONException, IOException {

     String key = null;

     if (request.has("id")) {

       key = request.getString("id");

     }

     RpcRequestItem requestItem = new RpcRequestItem(request, token, jsonConverter);

     // Resolve each Future into a response.

     // TODO: should use shared deadline across each request

     ResponseItem response = getResponseItem(handleRequestItem(requestItem, servletRequest));

     JSONObject result = getJSONResponse(key, response);

     servletResponse.getWriter().write(result.toString());

   }

   private JSONObject getJSONResponse(String key, ResponseItem responseItem) throws JSONException {

     JSONObject result = new JSONObject();

     if (key != null) {

       result.put("id", key);

     }

     if (responseItem.getError() != null) {

       result.put("error", getErrorJson(responseItem));

     } else {

       Object response = responseItem.getResponse();

       JSONObject converted = (JSONObject) jsonConverter.convertToJson(response);

       if (response instanceof RestfulCollection) {

         // FIXME this is a little hacky because of the field names in the RestfulCollection

         converted.put("list", converted.remove("entry"));

         result.put("data", converted);

       } else if (response instanceof DataCollection) {

         if (converted.has("entry")) {

           result.put("data", converted.get("entry"));

         }

       } else {

         result.put("data", converted);

       }

     }

     return result;

   }

   // TODO(doll): Refactor the responseItem so that the fields on it line up with this format.

   // Then we can use the general converter to output the response to the client and we won't

   // be harcoded to json.

   private JSONObject getErrorJson(ResponseItem responseItem) throws JSONException {

     JSONObject error = new JSONObject();

     error.put("code", responseItem.getError().getHttpErrorCode());

     String message = responseItem.getError().toString();

     if (StringUtils.isNotBlank(responseItem.getErrorMessage())) {

       message += ": " + responseItem.getErrorMessage();

     }

     error.put("message", message);

     return error;

   }

   @Override

   protected void sendError(HttpServletResponse servletResponse, ResponseItem responseItem)

       throws IOException {

     try {

       JSONObject error = getErrorJson(responseItem);

       servletResponse.getWriter().write(error.toString());

     } catch (JSONException je) {

       // This really shouldn't ever happen

       servletResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,

           "Error generating error response " + je.getMessage());

     }

   }

   private void sendBadRequest(Throwable t, HttpServletResponse response) throws IOException {

     sendError(response, new ResponseItem(ResponseError.BAD_REQUEST,

         "Invalid batch - " + t.getMessage()));

   }

 }