package emissary.test.core.junit5;
   
   import emissary.core.BaseDataObject;
   import emissary.core.IBaseDataObject;
   import emissary.core.IBaseDataObjectHelper;
   import emissary.core.IBaseDataObjectXmlCodecs;
   import emissary.core.IBaseDataObjectXmlCodecs.ElementDecoders;
   import emissary.core.IBaseDataObjectXmlCodecs.ElementEncoders;
   import emissary.place.IServiceProviderPlace;
  import emissary.test.core.junit5.LogbackTester.SimplifiedLogEvent;
  import emissary.util.ByteUtil;
  
  import com.google.errorprone.annotations.ForOverride;
  import org.apache.commons.lang3.ArrayUtils;
  import org.jdom2.Document;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.MethodSource;
  
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map.Entry;
  import java.util.Optional;
  import java.util.TreeMap;
  
  import static org.junit.jupiter.api.Assertions.fail;
  
  /**
   * <p>
   * This test acts similarly to ExtractionTest; however, it compares the entire BDO instead of just what is defined in
   * the XML. In other words, the XML must define exactly the output of the Place, no more and no less. There are methods
   * provided to generate the XML required.
   * </p>
   * 
   * <p>
   * To implement this for a test, you should:
   * </p>
   * <ol>
   * <li>Extend this class</li>
   * <li>Either Override {@link #generateAnswers()} to return true or set the generateAnswers system property to true,
   * which will generate the XML answer files</li>
   * <li>Optionally, to generate answers file without changing code run {@code mvn clean test -DgenerateAnswers=true}</li>
   * <li>Optionally, override the various provided methods if you want to customise the behaviour of providing the IBDO
   * before/after processing</li>
   * <li>Run the tests, which should pass - if they don't, you either have incorrect processing which needs fixing, or you
   * need to further customise the initial/final IBDOs.</li>
   * <li>Once the tests pass, you can remove the overridden method(s) added above.</li>
   * </ol>
   */
  public abstract class RegressionTest extends ExtractionTest {
      /**
       * The list of actual logEvents generated by executing the place.
       */
      protected List<SimplifiedLogEvent> actualSimplifiedLogEvents;
  
      /**
       * Override this or set the generateAnswers system property to true to generate XML for data files.
       * 
       * @return defaults to false if no XML should be generated (i.e. normal case of executing tests) or true to generate
       *         automatically
       */
      @ForOverride
      protected boolean generateAnswers() {
          return Boolean.getBoolean("generateAnswers");
      }
  
      /**
       * Allow the initial IBDO to be overridden - for example, adding additional previous forms
       * 
       * This is used in the simple case to generate an IBDO from the file on disk and override the filename
       * 
       * @param resource path to the dat file
       * @return the initial IBDO
       */
      @ForOverride
      protected IBaseDataObject getInitialIbdo(final String resource) {
          return RegressionTestUtil.getInitialIbdoWithFormInFilename(new ClearDataBaseDataObject(), resource, kff);
      }
  
      /**
       * Allow the initial IBDO to be overridden before serialising to XML.
       * 
       * In the default case, we null out the data in the BDO which will force the data to be loaded from the .dat file
       * instead.
       * 
       * @param resource path to the dat file
       * @param initialIbdo to tweak
       */
      @ForOverride
      protected void tweakInitialIbdoBeforeSerialisation(final String resource, final IBaseDataObject initialIbdo) {
          if (initialIbdo instanceof ClearDataBaseDataObject) {
              ((ClearDataBaseDataObject) initialIbdo).clearData();
          } else {
              fail("Didn't get an expected type of IBaseDataObject");
          }
      }
  
      /**
       * Allow the generated IBDO to be overridden - for example, adding certain field values. Will modify the provided IBDO.
      * 
      * This is used in the simple case to set the current form for the final object to be taken from the file name. If the
      * test worked correctly no change will be made, but if there is a discrepancy this will be highlighted afterwards when
      * the diff takes place.
      * 
      * @param resource path to the dat file
      * @param finalIbdo the existing final BDO after it's been processed by a place
      */
     @ForOverride
     protected void tweakFinalIbdoBeforeSerialisation(final String resource, final IBaseDataObject finalIbdo) {
         RegressionTestUtil.tweakFinalIbdoWithFormInFilename(resource, finalIbdo);
     }
 
     /**
      * Allow the children generated by the place to be overridden before serialising to XML.
      * 
      * In the default case, do nothing.
      * 
      * @param resource path to the dat file
      * @param children to tweak
      */
     @ForOverride
     protected void tweakFinalResultsBeforeSerialisation(final String resource, final List<IBaseDataObject> children) {
         // No-op unless overridden
     }
 
     /**
      * Allows the log events generated by the place to be modified before serialising to XML.
      * 
      * In the default case, do nothing.
      * 
      * @param resource path to the dat file
      * @param simplifiedLogEvents to tweak
      */
     @ForOverride
     protected void tweakFinalLogEventsBeforeSerialisation(final String resource, final List<SimplifiedLogEvent> simplifiedLogEvents) {
         // No-op unless overridden
     }
 
     @Override
     @ForOverride
     protected String getInitialForm(final String resource) {
         return RegressionTestUtil.getInitialFormFromFilename(resource);
     }
 
     /**
      * This method returns the XML element decoders.
      * 
      * @return the XML element decoders.
      */
     protected ElementDecoders getDecoders() {
         return IBaseDataObjectXmlCodecs.DEFAULT_ELEMENT_DECODERS;
     }
 
     /**
      * This method returns the XML element encoders.
      * 
      * @return the XML element encoders.
      */
     protected ElementEncoders getEncoders() {
         return IBaseDataObjectXmlCodecs.SHA256_ELEMENT_ENCODERS;
     }
 
     /**
      * When the data is able to be retrieved from the XML (e.g. when getEncoders() returns the default encoders), then this
      * method should be empty. However, in this case getEncoders() is returning the sha256 encoders which means the original
      * data cannot be retrieved from the XML. Therefore, in order to test equivalence, all of the non-printable data in the
      * IBaseDataObjects needs to be converted to a sha256 hash. The full encoders can be used by overriding the
      * checkAnswersPreHook(...) to be empty and overriding getEncoders() to return the DEFAULT_ELEMENT_ENCODERS.
      */
     @Override
     protected void checkAnswersPreHook(final Document answers, final IBaseDataObject payload, final List<IBaseDataObject> attachments,
             final String tname) {
 
         if (getLogbackLoggerName() != null) {
             checkAnswersPreHookLogEvents(actualSimplifiedLogEvents);
         }
 
         if (!IBaseDataObjectXmlCodecs.SHA256_ELEMENT_ENCODERS.equals(getEncoders())) {
             return;
         }
 
         // touch up alternate views to match how their bytes would have encoded into the answer file
         for (Entry<String, byte[]> entry : new TreeMap<>(payload.getAlternateViews()).entrySet()) {
             Optional<String> viewSha256 = hashBytesIfNonPrintable(entry.getValue());
             viewSha256.ifPresent(s -> payload.addAlternateView(entry.getKey(), s.getBytes(StandardCharsets.UTF_8)));
         }
 
         // touch up primary view if necessary
         Optional<String> payloadSha256 = hashBytesIfNonPrintable(payload.data());
         payloadSha256.ifPresent(s -> payload.setData(s.getBytes(StandardCharsets.UTF_8)));
 
         if (payload.getExtractedRecords() != null) {
             for (final IBaseDataObject extractedRecord : payload.getExtractedRecords()) {
                 Optional<String> recordSha256 = hashBytesIfNonPrintable(extractedRecord.data());
                 recordSha256.ifPresent(s -> extractedRecord.setData(s.getBytes(StandardCharsets.UTF_8)));
             }
         }
 
         if (attachments != null) {
             for (final IBaseDataObject attachment : attachments) {
                 if (ByteUtil.hasNonPrintableValues(attachment.data())) {
                     Optional<String> attachmentSha256 = hashBytesIfNonPrintable(attachment.data());
                     attachmentSha256.ifPresent(s -> attachment.setData(s.getBytes(StandardCharsets.UTF_8)));
                 }
             }
         }
     }
 
     /**
      * This method returns the logger name to capture log events from or null if log events are not to be checked.
      * 
      * @return the logger name to capture log events from or null (the default) if log events are not to be checked.
      */
     protected String getLogbackLoggerName() {
         return null;
     }
 
     /**
      * This method allows log events to be modified prior to checkAnswers being called.
      * 
      * In the default case, do nothing.
      * 
      * @param simplifiedLogEvents the log events to be tweaked.
      */
     protected void checkAnswersPreHookLogEvents(List<SimplifiedLogEvent> simplifiedLogEvents) {
         // No-op unless overridden
     }
 
     /**
      * Generates a SHA 256 hash of the provided bytes if they contain any non-printable characters
      * 
      * @param bytes the bytes to evaluate
      * @return a value optionally containing the generated hash
      */
     protected Optional<String> hashBytesIfNonPrintable(byte[] bytes) {
         if (ArrayUtils.isNotEmpty(bytes) && ByteUtil.containsNonIndexableBytes(bytes)) {
             return Optional.ofNullable(ByteUtil.sha256Bytes(bytes));
         }
 
         return Optional.empty();
     }
 
     protected static class ClearDataBaseDataObject extends BaseDataObject {
         private static final long serialVersionUID = -8728006876784881020L;
 
         protected void clearData() {
             theData = null;
             seekableByteChannelFactory = null;
         }
     }
 
     @ParameterizedTest
     @MethodSource("data")
     @Override
     public void testExtractionPlace(final String resource) {
         logger.debug("Running {} test on resource {}", place.getClass().getName(), resource);
 
         if (generateAnswers()) {
             try {
                 generateAnswerFiles(resource);
             } catch (final Exception e) {
                 logger.error("Error running test {}", resource, e);
                 fail("Unable to generate answer file", e);
             }
         }
 
         // Run the normal extraction/regression tests
         super.testExtractionPlace(resource);
     }
 
     /**
      * Actually generate the answer file for a given resource
      * 
      * Takes initial form and final forms from the filename
      * 
      * @param resource to generate against
      * @throws Exception if an error occurs during processing
      */
     protected void generateAnswerFiles(final String resource) throws Exception {
         // Get the data and create a channel factory to it
         final IBaseDataObject initialIbdo = getInitialIbdo(resource);
         // Clone the BDO to create an 'after' copy
         final IBaseDataObject finalIbdo = IBaseDataObjectHelper.clone(initialIbdo, true);
         // Actually process the BDO and keep the children
         final List<IBaseDataObject> finalResults;
         final List<SimplifiedLogEvent> finalLogEvents;
         if (getLogbackLoggerName() == null) {
             finalResults = place.agentProcessHeavyDuty(finalIbdo);
             finalLogEvents = new ArrayList<>();
         } else {
             try (LogbackTester logbackTester = new LogbackTester(getLogbackLoggerName())) {
                 finalResults = place.agentProcessHeavyDuty(finalIbdo);
                 finalLogEvents = logbackTester.getSimplifiedLogEvents();
             }
         }
 
         // Allow overriding things before serialising to XML
         tweakInitialIbdoBeforeSerialisation(resource, initialIbdo);
         tweakFinalIbdoBeforeSerialisation(resource, finalIbdo);
         tweakFinalResultsBeforeSerialisation(resource, finalResults);
         tweakFinalLogEventsBeforeSerialisation(resource, finalLogEvents);
 
         // Generate the full XML (setup & answers from before & after)
         RegressionTestUtil.writeAnswerXml(resource, initialIbdo, finalIbdo, finalResults, finalLogEvents, getEncoders(),
                 super.answerFileClassRef);
     }
 
     @Override
     protected List<IBaseDataObject> processHeavyDutyHook(IServiceProviderPlace place, IBaseDataObject payload)
             throws Exception {
         if (getLogbackLoggerName() == null) {
             actualSimplifiedLogEvents = new ArrayList<>();
 
             return super.processHeavyDutyHook(place, payload);
         } else {
             try (LogbackTester logbackTester = new LogbackTester(getLogbackLoggerName())) {
                 final List<IBaseDataObject> attachments = super.processHeavyDutyHook(place, payload);
 
                 actualSimplifiedLogEvents = logbackTester.getSimplifiedLogEvents();
 
                 return attachments;
             }
         }
     }
 
     @Override
     protected Document getAnswerDocumentFor(final String resource) {
         // If generating answers, get the src version, otherwise get the normal XML file
         return generateAnswers() ? RegressionTestUtil.getAnswerDocumentFor(resource, super.answerFileClassRef) : super.getAnswerDocumentFor(resource);
     }
 
     @Override
     protected void setupPayload(final IBaseDataObject payload, final Document answers) {
         RegressionTestUtil.setupPayload(payload, answers, getDecoders());
     }
 
     @Override
     protected void checkAnswers(final Document answers, final IBaseDataObject payload,
             final List<IBaseDataObject> attachments, final String tname) {
         RegressionTestUtil.checkAnswers(answers, payload, actualSimplifiedLogEvents, attachments, place.getClass().getName(), getDecoders(),
                 generateAnswers());
     }
 }