/*
    * Copyright 2018 the original author or authors.
    *
    *  Licensed 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.openehealth.ipf.commons.ihe.fhir.support;
  
  
  import ca.uhn.fhir.rest.api.MethodOutcome;
  import ca.uhn.fhir.rest.api.RestOperationTypeEnum;
  import ca.uhn.fhir.rest.param.TokenParam;
  import org.hl7.fhir.dstu3.model.Reference;
  import org.hl7.fhir.instance.model.api.IBaseCoding;
  import org.hl7.fhir.instance.model.api.IDomainResource;
  import org.hl7.fhir.instance.model.api.IIdType;
  import org.openehealth.ipf.commons.audit.AuditContext;
  import org.openehealth.ipf.commons.audit.codes.EventOutcomeIndicator;
  import org.openehealth.ipf.commons.audit.model.AuditMessage;
  import org.openehealth.ipf.commons.ihe.fhir.Constants;
  import org.openehealth.ipf.commons.ihe.fhir.FhirSearchParameters;
  import org.openehealth.ipf.commons.ihe.fhir.RequestDetailProvider;
  import org.openehealth.ipf.commons.ihe.fhir.audit.GenericFhirAuditDataset;
  import org.openehealth.ipf.commons.ihe.fhir.audit.events.GenericFhirAuditMessageBuilder;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  
  import static java.util.Objects.requireNonNull;
  import static org.openehealth.ipf.commons.ihe.fhir.Constants.*;
  
  /**
   * Generic Audit Strategy for FHIR interfaces. The audit written is built alongside what is
   * defined for IHE FHIR transactions, with the resource type (e.g. Encounter) as event type code.
   *
   * @author Christian Ohr
   */
  public class GenericFhirAuditStrategy<T extends IDomainResource> extends FhirAuditStrategy<GenericFhirAuditDataset> {
  
      private Function<T, Optional<Reference>> patientIdExtractor;
  
      /**
       * @param serverSide         server side auditing
       * @param patientIdExtractor function that extracts a patient reference from a domain resource
       */
      public GenericFhirAuditStrategy(boolean serverSide, Function<T, Optional<Reference>> patientIdExtractor) {
          super(serverSide);
          this.patientIdExtractor = requireNonNull(patientIdExtractor);
      }
  
      @Override
      public GenericFhirAuditDataset createAuditDataset() {
          return new GenericFhirAuditDataset(isServerSide());
      }
  
      @Override
      public GenericFhirAuditDataset enrichAuditDatasetFromRequest(GenericFhirAuditDataset auditDataset, Object request, Map<String, Object> parameters) {
          super.enrichAuditDatasetFromRequest(auditDataset, request, parameters);
  
          String resourceType = (String) parameters.get(FHIR_RESOURCE_TYPE_HEADER);
          if (resourceType == null && RequestDetailProvider.getRequestDetails() != null) {
              resourceType = RequestDetailProvider.getRequestDetails().getResourceName();
          }
          auditDataset.setAffectedResourceType(resourceType);
  
          RestOperationTypeEnum operation = (RestOperationTypeEnum) parameters.get(FHIR_OPERATION_HEADER);
          if (operation == null && RequestDetailProvider.getRequestDetails() != null) {
              operation = RequestDetailProvider.getRequestDetails().getRestOperationType();
          }
          auditDataset.setOperation(operation);
  
          // Domain Resource in the request? Extract Patient ID and Sensitivity at this point
          if (request instanceof IDomainResource) {
              addResourceData(auditDataset, (T) request);
          } else if (request instanceof IIdType) {
              auditDataset.setResourceId((IIdType) request);
          }
  
          if (parameters.containsKey(Constants.FHIR_REQUEST_PARAMETERS)) {
              String query = (String) parameters.get(HTTP_QUERY);
              auditDataset.setQueryString(query);
  
              FhirSearchParameters searchParameter = (FhirSearchParameters) parameters.get(Constants.FHIR_REQUEST_PARAMETERS);
              if (searchParameter != null) {
                  List<TokenParam> tokenParams = searchParameter.getPatientIdParam();
                  if (tokenParams != null) {
                     auditDataset.getPatientIds().addAll(
                             tokenParams.stream()
                                     .map(t -> t.getValueAsQueryToken(searchParameter.getFhirContext()))
                                     .collect(Collectors.toList()));
                 }
             }
         }
         return auditDataset;
     }
 
     @Override
     public boolean enrichAuditDatasetFromResponse(GenericFhirAuditDataset auditDataset, Object response, AuditContext auditContext) {
         // Domain Resource in the request? Extract Patient ID and Sensitivity at this point
         if (response instanceof IDomainResource) {
             addResourceData(auditDataset, (T) response);
         }
         if (response instanceof MethodOutcome) {
             MethodOutcome methodOutcome = (MethodOutcome) response;
             if (methodOutcome.getCreated() != null && methodOutcome.getCreated()) {
                 auditDataset.setEventOutcomeIndicator(EventOutcomeIndicator.Success);
             }
             if (methodOutcome.getOperationOutcome() != null) {
                 super.enrichAuditDatasetFromResponse(auditDataset, methodOutcome.getOperationOutcome(), auditContext);
             } else {
                 auditDataset.setEventOutcomeIndicator(EventOutcomeIndicator.Success);
             }
             if (methodOutcome.getResource() != null && methodOutcome.getResource() instanceof IDomainResource) {
                 addResourceData(auditDataset, (T) methodOutcome.getResource());
             } else if (methodOutcome.getId() != null) {
                 auditDataset.setResourceId(methodOutcome.getId());
                 if (methodOutcome.getId().hasResourceType()) {
                     auditDataset.setAffectedResourceType(methodOutcome.getId().getResourceType());
                 }
             }
         }
         return super.enrichAuditDatasetFromResponse(auditDataset, response, auditContext);
     }
 
     @Override
     public AuditMessage[] makeAuditMessage(AuditContext auditContext, GenericFhirAuditDataset auditDataset) {
         GenericFhirAuditMessageBuilder builder = new GenericFhirAuditMessageBuilder(auditContext, auditDataset)
                 .addPatients(auditDataset);
         if (auditDataset.getAffectedResourceType() != null && auditDataset.getQueryString() != null) {
             builder.addQueryParticipantObject(auditDataset);
         } else if (auditDataset.getResourceId() != null) {
             builder.addResourceParticipantObject(auditDataset);
         }
         return builder.getMessages();
 
     }
 
     private void addResourceData(GenericFhirAuditDataset auditDataset, T resource) {
         auditDataset.setResourceId(resource.getIdElement());
         if (resource.getIdElement().hasResourceType()) {
             auditDataset.setAffectedResourceType(resource.getIdElement().getResourceType());
         }
         patientIdExtractor.apply(resource).ifPresent(patient ->
                 auditDataset.getPatientIds().add(patient.getResource() != null ?
                         patient.getResource().getIdElement().toUnqualifiedVersionless().getValue() :
                         patient.getReference()));
 
         List<? extends IBaseCoding> securityLabels = resource.getMeta().getSecurity();
         if (!securityLabels.isEmpty()) {
             auditDataset.setSecurityLabel(securityLabels.get(0).getCode());
         }
     }
 }