/*
    * 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.core.rest.cxf;
  
  import java.sql.SQLException;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.Set;
  import java.util.stream.Collectors;
  import javax.persistence.EntityExistsException;
  import javax.persistence.PersistenceException;
  import javax.persistence.RollbackException;
  import javax.validation.ValidationException;
  import javax.ws.rs.WebApplicationException;
  import javax.ws.rs.core.HttpHeaders;
  import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Response.ResponseBuilder;
  import javax.ws.rs.ext.ExceptionMapper;
  import javax.ws.rs.ext.Provider;
  import org.apache.commons.lang3.exception.ExceptionUtils;
  import org.apache.cxf.jaxrs.utils.JAXRSUtils;
  import org.apache.cxf.jaxrs.validation.ValidationExceptionMapper;
  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.lib.types.EntityViolationType;
  import org.apache.syncope.common.rest.api.RESTHeaders;
  import org.apache.syncope.core.persistence.api.attrvalue.validation.InvalidEntityException;
  import org.apache.syncope.core.persistence.api.attrvalue.validation.ParsingValidationException;
  import org.apache.syncope.core.persistence.api.dao.DuplicateException;
  import org.apache.syncope.core.persistence.api.dao.MalformedPathException;
  import org.apache.syncope.core.persistence.api.dao.NotFoundException;
  import org.apache.syncope.core.persistence.api.entity.PlainAttr;
  import org.apache.syncope.core.spring.security.DelegatedAdministrationException;
  import org.apache.syncope.core.workflow.api.WorkflowException;
  import org.identityconnectors.framework.common.exceptions.ConfigurationException;
  import org.identityconnectors.framework.common.exceptions.ConnectorException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.core.env.Environment;
  import org.springframework.dao.DataIntegrityViolationException;
  import org.springframework.dao.UncategorizedDataAccessException;
  import org.springframework.security.access.AccessDeniedException;
  import org.springframework.transaction.TransactionSystemException;
  
  @Provider
  public class RestServiceExceptionMapper implements ExceptionMapper<Exception> {
  
      private static final Logger LOG = LoggerFactory.getLogger(RestServiceExceptionMapper.class);
  
      private final ValidationExceptionMapper validationEM = new ValidationExceptionMapper();
  
      private static final String UNIQUE_MSG_KEY = "UniqueConstraintViolation";
  
      private static final Map<String, String> EXCEPTION_CODE_MAP = new HashMap<>() {
  
          private static final long serialVersionUID = -7688359318035249200L;
  
          {
              put("23000", UNIQUE_MSG_KEY);
              put("23505", UNIQUE_MSG_KEY);
          }
      };
  
      protected final Environment env;
  
      public RestServiceExceptionMapper(final Environment env) {
          this.env = env;
      }
  
      @Override
      public Response toResponse(final Exception ex) {
          LOG.error("Exception thrown", ex);
  
          ResponseBuilder builder;
  
          if (ex instanceof AccessDeniedException) {
              // leaves the default exception processing to Spring Security
              builder = null;
          } else if (ex instanceof SyncopeClientException) {
             SyncopeClientException sce = (SyncopeClientException) ex;
             builder = sce.isComposite()
                     ? getSyncopeClientCompositeExceptionResponse(sce.asComposite())
                     : getSyncopeClientExceptionResponse(sce);
         } else if (ex instanceof DelegatedAdministrationException
                 || ExceptionUtils.getRootCause(ex) instanceof DelegatedAdministrationException) {
 
             builder = builder(ClientExceptionType.DelegatedAdministration, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ex instanceof EntityExistsException || ex instanceof DuplicateException
                 || ((ex instanceof PersistenceException || ex instanceof DataIntegrityViolationException)
                 && ex.getCause() instanceof EntityExistsException)) {
 
             builder = builder(ClientExceptionType.EntityExists,
                     getPersistenceErrorMessage(
                             ex instanceof PersistenceException || ex instanceof DataIntegrityViolationException
                                     ? ex.getCause() : ex));
         } else if (ex instanceof DataIntegrityViolationException || ex instanceof UncategorizedDataAccessException) {
             builder = builder(ClientExceptionType.DataIntegrityViolation, getPersistenceErrorMessage(ex));
         } else if (ex instanceof ConnectorException) {
             builder = builder(ClientExceptionType.ConnectorException, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ex instanceof NotFoundException) {
             builder = builder(ClientExceptionType.NotFound, ExceptionUtils.getRootCauseMessage(ex));
         } else {
             builder = processInvalidEntityExceptions(ex);
             if (builder == null) {
                 builder = processBadRequestExceptions(ex);
             }
             // process JAX-RS validation errors
             if (builder == null && ex instanceof ValidationException) {
                 builder = builder(validationEM.toResponse((ValidationException) ex)).
                         header(RESTHeaders.ERROR_CODE, ClientExceptionType.RESTValidation.name()).
                         header(RESTHeaders.ERROR_INFO, ClientExceptionType.RESTValidation.getInfoHeaderValue(
                                 ExceptionUtils.getRootCauseMessage(ex)));
             }
             // process web application exceptions
             if (builder == null && ex instanceof WebApplicationException) {
                 builder = builder(((WebApplicationException) ex).getResponse()).
                         header(RESTHeaders.ERROR_CODE, ClientExceptionType.Unknown.name()).
                         header(RESTHeaders.ERROR_INFO, ClientExceptionType.Unknown.getInfoHeaderValue(
                                 ExceptionUtils.getRootCauseMessage(ex)));
             }
             // ...or just report as InternalServerError
             if (builder == null) {
                 builder = Response.status(Response.Status.INTERNAL_SERVER_ERROR).
                         header(RESTHeaders.ERROR_CODE, ClientExceptionType.Unknown.name()).
                         header(RESTHeaders.ERROR_INFO, ClientExceptionType.Unknown.getInfoHeaderValue(
                                 ExceptionUtils.getRootCauseMessage(ex)));
 
                 ErrorTO error = new ErrorTO();
                 error.setStatus(Response.Status.INTERNAL_SERVER_ERROR.getStatusCode());
                 error.setType(ClientExceptionType.Unknown);
                 error.getElements().add(ExceptionUtils.getRootCauseMessage(ex));
 
                 builder.entity(error);
             }
         }
 
         return Optional.ofNullable(builder).map(ResponseBuilder::build).orElse(null);
     }
 
     private static ResponseBuilder getSyncopeClientExceptionResponse(final SyncopeClientException ex) {
         ResponseBuilder builder = Response.status(ex.getType().getResponseStatus());
         builder.header(RESTHeaders.ERROR_CODE, ex.getType().name());
 
         ErrorTO error = new ErrorTO();
         error.setStatus(ex.getType().getResponseStatus().getStatusCode());
         error.setType(ex.getType());
 
         ex.getElements().forEach(element -> {
             builder.header(RESTHeaders.ERROR_INFO, ex.getType().getInfoHeaderValue(element));
             error.getElements().add(element);
         });
 
         return builder.entity(error);
     }
 
     private static ResponseBuilder getSyncopeClientCompositeExceptionResponse(
             final SyncopeClientCompositeException ex) {
         if (ex.getExceptions().size() == 1) {
             return getSyncopeClientExceptionResponse(ex.getExceptions().iterator().next());
         }
 
         ResponseBuilder builder = Response.status(Response.Status.BAD_REQUEST);
 
         List<ErrorTO> errors = ex.getExceptions().stream().map(sce -> {
             builder.header(RESTHeaders.ERROR_CODE, sce.getType().name());
 
             ErrorTO error = new ErrorTO();
             error.setStatus(sce.getType().getResponseStatus().getStatusCode());
             error.setType(sce.getType());
 
             sce.getElements().forEach(element -> {
                 builder.header(RESTHeaders.ERROR_INFO, sce.getType().getInfoHeaderValue(element));
                 error.getElements().add(element);
             });
 
             return error;
         }).collect(Collectors.toList());
 
         return builder.entity(errors);
     }
 
     private static ResponseBuilder processInvalidEntityExceptions(final Exception ex) {
         InvalidEntityException iee = null;
 
         if (ex instanceof InvalidEntityException) {
             iee = (InvalidEntityException) ex;
         }
         if (ex instanceof TransactionSystemException && ex.getCause() instanceof RollbackException
                 && ex.getCause().getCause() instanceof InvalidEntityException) {
 
             iee = (InvalidEntityException) ex.getCause().getCause();
         }
 
         if (iee != null) {
             ClientExceptionType exType;
             if (iee.getEntityClassSimpleName().endsWith("Policy")) {
                 exType = ClientExceptionType.InvalidPolicy;
             } else if (iee.getEntityClassSimpleName().equals(PlainAttr.class.getSimpleName())) {
                 exType = ClientExceptionType.InvalidValues;
             } else {
                 try {
                     exType = ClientExceptionType.valueOf("Invalid" + iee.getEntityClassSimpleName());
                 } catch (IllegalArgumentException e) {
                     // ignore
                     exType = ClientExceptionType.InvalidEntity;
                 }
             }
 
             ResponseBuilder builder = Response.status(Response.Status.BAD_REQUEST);
             builder.header(RESTHeaders.ERROR_CODE, exType.name());
 
             ErrorTO error = new ErrorTO();
             error.setStatus(exType.getResponseStatus().getStatusCode());
             error.setType(exType);
 
             for (Map.Entry<Class<?>, Set<EntityViolationType>> violation : iee.getViolations().entrySet()) {
                 for (EntityViolationType violationType : violation.getValue()) {
                     builder.header(RESTHeaders.ERROR_INFO,
                             exType.getInfoHeaderValue(violationType.name() + ": " + violationType.getMessage()));
                     error.getElements().add(violationType.name() + ": " + violationType.getMessage());
                 }
             }
 
             return builder;
         }
 
         return null;
     }
 
     private static ResponseBuilder processBadRequestExceptions(final Exception ex) {
         // This exception might be raised by Flowable (if enabled)
         Class<?> ibatisPersistenceException = null;
         try {
             ibatisPersistenceException = Class.forName("org.apache.ibatis.exceptions.PersistenceException");
         } catch (ClassNotFoundException e) {
             // ignore
         }
 
         if (ex instanceof WorkflowException) {
             return builder(ClientExceptionType.Workflow, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ex instanceof PersistenceException) {
             return builder(ClientExceptionType.GenericPersistence, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ibatisPersistenceException != null && ibatisPersistenceException.isAssignableFrom(ex.getClass())) {
             return builder(ClientExceptionType.Workflow, "Currently unavailable. Please try later.");
         } else if (ex instanceof UncategorizedDataAccessException) {
             return builder(ClientExceptionType.DataIntegrityViolation, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ex instanceof ConfigurationException) {
             return builder(ClientExceptionType.InvalidConnIdConf, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ex instanceof ParsingValidationException) {
             return builder(ClientExceptionType.InvalidValues, ExceptionUtils.getRootCauseMessage(ex));
         } else if (ex instanceof MalformedPathException) {
             return builder(ClientExceptionType.InvalidPath, ExceptionUtils.getRootCauseMessage(ex));
         }
 
         return null;
     }
 
     private static ResponseBuilder builder(final ClientExceptionType hType, final String msg) {
         ResponseBuilder builder = Response.status(hType.getResponseStatus()).
                 header(RESTHeaders.ERROR_CODE, hType.name()).
                 header(RESTHeaders.ERROR_INFO, hType.getInfoHeaderValue(msg));
 
         ErrorTO error = new ErrorTO();
         error.setStatus(hType.getResponseStatus().getStatusCode());
         error.setType(hType);
         error.getElements().add(msg);
 
         return builder.entity(error);
     }
 
     /**
      * Overriding {@link JAXRSUtils#fromResponse(javax.ws.rs.core.Response)} in order to avoid setting
      * {@code Content-Type} from original {@code response}.
      *
      * @param response model to construct {@link ResponseBuilder} from
      * @return new {@link ResponseBuilder} instance initialized from given response
      */
     private static ResponseBuilder builder(final Response response) {
         ResponseBuilder builder = JAXRSUtils.toResponseBuilder(response.getStatus());
         builder.entity(response.getEntity());
         response.getMetadata().forEach((key, value) -> {
             if (!HttpHeaders.CONTENT_TYPE.equals(key)) {
                 value.forEach(headerValue -> builder.header(key, headerValue));
             }
         });
 
         return builder;
     }
 
     private String getPersistenceErrorMessage(final Throwable ex) {
         Throwable throwable = ExceptionUtils.getRootCause(ex);
 
         String message = null;
         if (throwable instanceof SQLException) {
             String messageKey = EXCEPTION_CODE_MAP.get(((SQLException) throwable).getSQLState());
             if (messageKey != null) {
                 message = env.getProperty("errMessage." + messageKey);
             }
         } else if (throwable instanceof EntityExistsException || throwable instanceof DuplicateException) {
             message = env.getProperty("errMessage." + UNIQUE_MSG_KEY);
         }
 
         return Optional.ofNullable(message).
                 orElseGet(() -> Optional.ofNullable(ex.getCause()).
                 map(Throwable::getMessage).
                 orElseGet(() -> ex.getMessage()));
     }
 }