/*
    * 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.syncope.client.lib;
  
  import java.security.AccessControlException;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  import javax.ws.rs.BadRequestException;
  import javax.ws.rs.ForbiddenException;
  import javax.ws.rs.core.GenericType;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.ext.Provider;
  import javax.xml.ws.WebServiceException;
  import org.apache.commons.lang3.StringUtils;
  import org.apache.cxf.jaxrs.client.ResponseExceptionMapper;
  import org.apache.syncope.common.lib.SyncopeClientCompositeException;
  import org.apache.syncope.common.lib.SyncopeClientException;
  import org.apache.syncope.common.lib.to.ErrorTO;
  import org.apache.syncope.common.lib.types.ClientExceptionType;
  import org.apache.syncope.common.rest.api.RESTHeaders;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  @Provider
  public class RestClientExceptionMapper implements ResponseExceptionMapper<Exception> {
  
      private static final Logger LOG = LoggerFactory.getLogger(RestClientExceptionMapper.class);
  
      @Override
      public Exception fromResponse(final Response response) {
          int statusCode = response.getStatus();
          String message = response.getHeaderString(RESTHeaders.ERROR_INFO);
  
          Exception ex;
          SyncopeClientCompositeException scce = checkSyncopeClientCompositeException(response);
          if (scce != null) {
              // 1. Check for client (possibly composite) exception in HTTP header
              ex = scce.getExceptions().size() == 1
                      ? scce.getExceptions().iterator().next()
                      : scce;
          } else if (statusCode == Response.Status.UNAUTHORIZED.getStatusCode()) {
              // 2. Map SC_UNAUTHORIZED
              ex = new AccessControlException(StringUtils.isBlank(message)
                      ? "Remote unauthorized exception"
                      : message);
          } else if (statusCode == Response.Status.FORBIDDEN.getStatusCode()) {
              // 3. Map SC_FORBIDDEN
              ex = new ForbiddenException(StringUtils.isBlank(message)
                      ? "Remote forbidden exception"
                      : message);
          } else if (statusCode == Response.Status.BAD_REQUEST.getStatusCode()) {
              // 4. Map SC_BAD_REQUEST
              ex = StringUtils.isBlank(message)
                      ? new BadRequestException()
                      : new BadRequestException(message);
          } else {
              // 5. All other codes are mapped to runtime exception with HTTP code information
              ex = new WebServiceException(String.format("Remote exception with status code: %s",
                      Response.Status.fromStatusCode(statusCode).name()));
          }
          LOG.error("Exception thrown", ex);
          return ex;
      }
  
      private static SyncopeClientCompositeException checkSyncopeClientCompositeException(final Response response) {
          SyncopeClientCompositeException compException = SyncopeClientException.buildComposite();
  
          // Attempts to read ErrorTO or List<ErrorTO> as entity...
          List<ErrorTO> errors = null;
          try {
              ErrorTO error = response.readEntity(ErrorTO.class);
              if (error != null) {
                  errors = List.of(error);
              }
          } catch (Exception e) {
              LOG.debug("Could not read {}, attempting to read composite...", ErrorTO.class.getName(), e);
          }
          if (errors == null) {
              try {
                  errors = response.readEntity(new GenericType<>() {
                  });
              } catch (Exception e) {
                 LOG.debug("Could not read {} list, attempting to read headers...", ErrorTO.class.getName(), e);
             }
         }
 
         // ...if not possible, attempts to parse response headers
         if (errors == null) {
             List<String> exTypesInHeaders = response.getStringHeaders().get(RESTHeaders.ERROR_CODE);
             if (exTypesInHeaders == null) {
                 LOG.debug("No " + RESTHeaders.ERROR_CODE + " provided");
                 return null;
             }
             List<String> exInfos = response.getStringHeaders().get(RESTHeaders.ERROR_INFO);
 
             Set<String> handledExceptions = new HashSet<>();
             exTypesInHeaders.forEach(exTypeAsString -> {
                 ClientExceptionType exceptionType = null;
                 try {
                     exceptionType = ClientExceptionType.fromHeaderValue(exTypeAsString);
                 } catch (IllegalArgumentException e) {
                     LOG.error("Unexpected value of " + RESTHeaders.ERROR_CODE + ": " + exTypeAsString, e);
                 }
                 if (exceptionType != null) {
                     handledExceptions.add(exTypeAsString);
 
                     SyncopeClientException clientException = SyncopeClientException.build(exceptionType);
                     if (exInfos != null && !exInfos.isEmpty()) {
                         for (String element : exInfos) {
                             if (element.startsWith(exceptionType.name())) {
                                 clientException.getElements().add(StringUtils.substringAfter(element, ":"));
                             }
                         }
                     }
                     compException.addException(clientException);
                 }
             });
 
             exTypesInHeaders.removeAll(handledExceptions);
             if (!exTypesInHeaders.isEmpty()) {
                 LOG.error("Unmanaged exceptions: " + exTypesInHeaders);
             }
         } else {
             for (ErrorTO error : errors) {
                 SyncopeClientException clientException = SyncopeClientException.build(error.getType());
                 clientException.getElements().addAll(error.getElements());
                 compException.addException(clientException);
             }
         }
 
         if (compException.hasExceptions()) {
             return compException;
         }
 
         return null;
     }
 }