/*
    * Portions of this software was developed by employees of the National Institute
    * of Standards and Technology (NIST), an agency of the Federal Government and is
    * being made available as a public service. Pursuant to title 17 United States
    * Code Section 105, works of NIST employees are not subject to copyright
    * protection in the United States. This software may be subject to foreign
    * copyright. Permission in the United States and in foreign countries, to the
    * extent that NIST may hold copyright, to use, copy, modify, create derivative
    * works, and distribute this software and its documentation without fee is hereby
   * granted on a non-exclusive basis, provided that this notice and disclaimer
   * of warranty appears in all copies.
   *
   * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
   * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
   * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
   * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
   * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
   * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
   * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
   * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
   * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
   * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
   * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
   */
  
  package gov.nist.secauto.metaschema.databind.model.info;
  
  import com.fasterxml.jackson.core.JsonGenerator;
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.core.JsonToken;
  
  import gov.nist.secauto.metaschema.core.datatype.IDataTypeAdapter;
  import gov.nist.secauto.metaschema.core.model.IFieldDefinition;
  import gov.nist.secauto.metaschema.core.model.util.JsonUtil;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.metaschema.databind.io.BindingException;
  import gov.nist.secauto.metaschema.databind.io.json.IJsonParsingContext;
  import gov.nist.secauto.metaschema.databind.io.json.IJsonWritingContext;
  import gov.nist.secauto.metaschema.databind.io.xml.IXmlParsingContext;
  import gov.nist.secauto.metaschema.databind.io.xml.IXmlWritingContext;
  import gov.nist.secauto.metaschema.databind.model.IAssemblyClassBinding;
  import gov.nist.secauto.metaschema.databind.model.IBoundFieldValueInstance;
  import gov.nist.secauto.metaschema.databind.model.IBoundFlagInstance;
  import gov.nist.secauto.metaschema.databind.model.IBoundNamedInstance;
  import gov.nist.secauto.metaschema.databind.model.IBoundNamedModelInstance;
  import gov.nist.secauto.metaschema.databind.model.IClassBinding;
  import gov.nist.secauto.metaschema.databind.model.IFieldClassBinding;
  
  import java.io.IOException;
  import java.util.Collection;
  import java.util.Map;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import javax.xml.namespace.QName;
  import javax.xml.stream.XMLStreamException;
  import javax.xml.stream.events.StartElement;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import nl.talsmasoftware.lazy4j.Lazy;
  
  class ClassDataTypeHandler implements IDataTypeHandler {
    private final boolean jsonKeyRequired;
    @NonNull
    private final IClassBinding classBinding;
  
    @NonNull
    private final Lazy<Map<String, ? extends IBoundNamedInstance>> propertyMap;
  
    /**
     * Generates a mapping of property names to associated Module instances.
     * <p>
     * If {@code requiresJsonKey} is {@code true} then the instance used as the JSON
     * key is not included in the mapping.
     * <p>
     * If the {@code targetDefinition} is an instance of {@link IFieldDefinition}
     * and a JSON value key property is configured, then the value key flag and
     * value are also ommitted from the mapping. Otherwise, the value is included in
     * the mapping.
     *
     * @param targetDefinition
     *          the Module bound definition to generate the instance map for
     * @param requiresJsonKey
     *          if {@code true} then the instance used as the JSON key is not
     *          included in the mapping, or {@code false} otherwise
     * @return a mapping of JSON property to related Module instance
     */
    @NonNull
    private static Map<String, ? extends IBoundNamedInstance> getInstancesToParse(
        @NonNull IClassBinding targetDefinition,
        boolean requiresJsonKey) {
      Collection<? extends IBoundFlagInstance> flags = targetDefinition.getFlagInstances();
      int flagCount = flags.size() - (requiresJsonKey ? 1 : 0);
  
      @SuppressWarnings("resource") Stream<? extends IBoundNamedInstance> instanceStream;
      if (targetDefinition instanceof IAssemblyClassBinding) {
       // use all child instances
       instanceStream = ((IAssemblyClassBinding) targetDefinition).getModelInstances().stream();
     } else if (targetDefinition instanceof IFieldClassBinding) {
       IFieldClassBinding targetFieldDefinition = (IFieldClassBinding) targetDefinition;
 
       IBoundFlagInstance jsonValueKeyFlag = targetFieldDefinition.getJsonValueKeyFlagInstance();
       if (jsonValueKeyFlag == null && flagCount > 0) {
         // the field value is handled as named field
         IBoundFieldValueInstance fieldValue = targetFieldDefinition.getFieldValueInstance();
         instanceStream = Stream.of(fieldValue);
       } else {
         // only the value, with no flags or a JSON value key flag
         instanceStream = Stream.empty();
       }
     } else {
       throw new UnsupportedOperationException(
           String.format("Unsupported class binding type: %s", targetDefinition.getClass().getName()));
     }
 
     if (requiresJsonKey) {
       IBoundFlagInstance jsonKey = targetDefinition.getJsonKeyFlagInstance();
       assert jsonKey != null;
       instanceStream = Stream.concat(
           flags.stream().filter((flag) -> !jsonKey.equals(flag)),
           instanceStream);
     } else {
       instanceStream = Stream.concat(
           flags.stream(),
           instanceStream);
     }
     return ObjectUtils.notNull(instanceStream.collect(
         Collectors.toUnmodifiableMap(
             IBoundNamedInstance::getJsonName,
             Function.identity())));
   }
 
   public ClassDataTypeHandler(
       @Nullable IBoundNamedModelInstance targetInstance,
       @NonNull IClassBinding classBinding) {
     this.classBinding = classBinding;
 
     this.jsonKeyRequired = targetInstance != null && targetInstance.getPropertyInfo().isJsonKeyRequired();
     this.propertyMap = ObjectUtils.notNull(Lazy.lazy(() -> getInstancesToParse(
         classBinding,
         this.jsonKeyRequired)));
   }
 
   @Override
   public IDataTypeAdapter<?> getJavaTypeAdapter() {
     // this is always null
     return null;
   }
 
   @Override
   @NonNull
   public IClassBinding getClassBinding() {
     return classBinding;
   }
 
   @Override
   public boolean isUnwrappedValueAllowedInXml() {
     // classes are always wrapped
     return false;
   }
 
   @Override
   public boolean isJsonKeyRequired() {
     return jsonKeyRequired;
   }
 
   @NonNull
   protected Map<String, ? extends IBoundNamedInstance> getJsonInstanceMap() {
     return ObjectUtils.notNull(propertyMap.get());
   }
 
   @SuppressWarnings("resource") // not owned
   private boolean readItemJsonKey(
       @NonNull Object targetObject,
       IJsonParsingContext context) throws IOException {
     JsonParser parser = context.getReader(); // NOPMD - intentional
     IClassBinding definition = getClassBinding();
 
     IBoundFlagInstance jsonKey = definition.getJsonKeyFlagInstance();
     if (jsonKey == null) {
       throw new IOException(String.format("JSON key not defined for object '%s'%s",
           definition.toCoordinates(), JsonUtil.generateLocationMessage(parser)));
     }
 
     // the field will be the JSON key
     String key = ObjectUtils.notNull(parser.getCurrentName());
 
     Object value = jsonKey.getDefinition().getJavaTypeAdapter().parse(key);
     jsonKey.setValue(targetObject, value.toString());
 
     // advance past the FIELD_NAME
     JsonUtil.assertAndAdvance(parser, JsonToken.FIELD_NAME);
 
     boolean keyObjectWrapper = JsonToken.START_OBJECT.equals(parser.currentToken());
     if (keyObjectWrapper) {
       JsonUtil.assertAndAdvance(parser, JsonToken.START_OBJECT);
     }
 
     return keyObjectWrapper;
   }
 
   @SuppressWarnings({
       "resource", // not owned
       "PMD.NPathComplexity", "PMD.CyclomaticComplexity" // ok
   })
   @Override
   public <T> T readItem(Object parentObject, IJsonParsingContext context)
       throws IOException {
     JsonParser parser = context.getReader(); // NOPMD - intentional
     boolean objectWrapper = JsonToken.START_OBJECT.equals(parser.currentToken());
     if (objectWrapper) {
       JsonUtil.assertAndAdvance(parser, JsonToken.START_OBJECT);
     }
 
     Object targetObject;
     try {
       targetObject = classBinding.newInstance();
       classBinding.callBeforeDeserialize(targetObject, parentObject);
     } catch (BindingException ex) {
       throw new IOException(ex);
     }
 
     IClassBinding definition = getClassBinding();
     boolean readJsonKey = isJsonKeyRequired();
     boolean keyObjectWrapper = false;
     if (readJsonKey) {
       keyObjectWrapper = readItemJsonKey(targetObject, context);
     }
 
     if (keyObjectWrapper || JsonToken.FIELD_NAME.equals(parser.currentToken())) {
       context.readDefinitionValue(definition, targetObject, getJsonInstanceMap());
     } else if (parser.currentToken().isScalarValue()) {
       // this is just a value
       IFieldClassBinding fieldDefinition = (IFieldClassBinding) definition;
       Object fieldValue = fieldDefinition.getJavaTypeAdapter().parse(parser);
       fieldDefinition.getFieldValueInstance().setValue(targetObject, fieldValue);
     }
 
     try {
       classBinding.callAfterDeserialize(targetObject, parentObject);
     } catch (BindingException ex) {
       throw new IOException(ex);
     }
 
     if (keyObjectWrapper) {
       // advance past the END_OBJECT for the JSON key
       JsonUtil.assertAndAdvance(parser, JsonToken.END_OBJECT);
     }
 
     if (objectWrapper) {
       JsonUtil.assertAndAdvance(parser, JsonToken.END_OBJECT);
     }
     return ObjectUtils.asType(targetObject);
   }
 
   @Override
   public Object readItem(Object parentInstance, StartElement start, IXmlParsingContext context)
       throws IOException, XMLStreamException {
     return context.readDefinitionValue(getClassBinding(), parentInstance, start);
   }
 
   @Override
   public void writeItem(Object item, QName currentParentName, IXmlWritingContext context)
       throws IOException, XMLStreamException {
     context.writeDefinitionValue(classBinding, item, currentParentName);
   }
 
   @SuppressWarnings("resource") // not owned
   @Override
   public void writeItem(Object targetObject, IJsonWritingContext context) throws IOException {
     JsonGenerator writer = context.getWriter();
 
     writer.writeStartObject();
 
     IClassBinding definition = getClassBinding();
     boolean writeJsonKey = isJsonKeyRequired();
     if (writeJsonKey) {
       IBoundFlagInstance jsonKey = definition.getJsonKeyFlagInstance();
       assert jsonKey != null;
 
       // the field will be the JSON key
       Object flagValue = jsonKey.getValue(targetObject);
       String key = jsonKey.getValueAsString(flagValue);
       if (key == null) {
         throw new IOException(new NullPointerException("Null key value"));
       }
       writer.writeFieldName(key);
 
       // next the value will be a start object
       writer.writeStartObject();
     }
 
     context.writeDefinitionValue(
         classBinding,
         targetObject,
         getJsonInstanceMap());
 
     if (writeJsonKey) {
       writer.writeEndObject();
     }
 
     writer.writeEndObject();
   }
 
   @Override
   public Object copyItem(@NonNull Object fromItem, Object parentInstance) throws BindingException {
     return classBinding.copyBoundObject(fromItem, parentInstance);
   }
 
 }