/**
    * This file Copyright (c) 2012-2018 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.rest;
  
  import static javax.ws.rs.core.Response.Status.INTERNAL_SERVER_ERROR;
  
  import javax.ws.rs.BadRequestException;
  import javax.ws.rs.NotAcceptableException;
  import javax.ws.rs.NotAllowedException;
  import javax.ws.rs.NotAuthorizedException;
  import javax.ws.rs.NotFoundException;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.container.ResourceInfo;
  import javax.ws.rs.core.Context;
  import javax.ws.rs.core.MediaType;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Response.StatusType;
  import javax.ws.rs.ext.ExceptionMapper;
  import javax.ws.rs.ext.Provider;
  
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Maps exceptions encountered to response status codes.
   */
  @Provider
  public class RestExceptionMapper implements ExceptionMapper<Throwable> {
      private static final Logger log = LoggerFactory.getLogger(RestExceptionMapper.class);
  
      @Context
      private ResourceInfo resourceInfo;
  
      @Override
      public Response toResponse(Throwable exception) {
          StatusType status = INTERNAL_SERVER_ERROR;
          String errorCode = "unknown";
          String errorMessage = exception.getMessage();
  
          if (exception instanceof WebApplicationException) {
              if (exception instanceof NotAuthorizedException) {
                  errorCode = "notAuthorized";
              } else if (exception instanceof BadRequestException) {
                  errorCode = "badRequest";
              } else if (exception instanceof NotAllowedException) {
                  errorCode = "methodNotAllowed";
              } else if (exception instanceof NotAcceptableException) {
                  errorCode = "notAcceptable";
              } else if (exception instanceof NotFoundException) {
                  errorCode = "notFound";
              } else {
                  try {
                      Class<?> restEasyReaderEx = Class.forName("org.jboss.resteasy.spi.ReaderException");
                      Class<?> restEasyWriterEx = Class.forName("org.jboss.resteasy.spi.WriterException");
                      if (restEasyReaderEx.isAssignableFrom(exception.getClass())) {
                          errorCode = "readerError";
                      } else if (restEasyWriterEx.isAssignableFrom(exception.getClass())) {
                          errorCode = "writerError";
                      }
                  } catch (ClassNotFoundException e) {
                      // do nothing, cannot be a RESTEasy-specific exception then
                  }
              }
  
              // Trim sensitive information of JAX-RS implementation.
              if (errorMessage.startsWith("RESTEASY")) {
                  errorMessage = StringUtils.substringAfter(errorMessage, ": ");
             }
 
             Response response = ((WebApplicationException) exception).getResponse();
             status = response.getStatusInfo();
 
             /**
              * If requested media type is not supported, JSON is returned as fallback.
              * For example, curl -i -X GET '.../.rest/delivery/website/v1' -u username:password -H "Accept: application/something".
              *
              * If no resource method is matched, JSON is returned as fallback.
              * For example, a request like ".../.rest/delivery/something" (without "v1" part) doesn't match any resource.
              */
             if (exception instanceof NotAcceptableException
                     || resourceInfo.getResourceMethod() == null) {
                 return Response.status(status)
                         .type(MediaType.APPLICATION_JSON)
                         .entity(new RestError(errorCode, errorMessage))
                         .build();
             }
         }
 
         log.error("Exception thrown executing REST endpoint, returning {}", status.getStatusCode(), exception);
 
         return Response.status(status)
                 .entity(new RestError(errorCode, errorMessage))
                 .build();
     }
 }