/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.metaschema.databind.io.json;
   
   import com.fasterxml.jackson.core.JsonFactory;
   import com.fasterxml.jackson.core.JsonParser;
  
  import gov.nist.secauto.metaschema.core.configuration.IConfiguration;
  import gov.nist.secauto.metaschema.core.configuration.IMutableConfiguration;
  import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItem;
  import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItemFactory;
  import gov.nist.secauto.metaschema.core.model.IBoundObject;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.metaschema.databind.io.AbstractDeserializer;
  import gov.nist.secauto.metaschema.databind.io.DeserializationFeature;
  import gov.nist.secauto.metaschema.databind.model.IBoundDefinitionModelAssembly;
  
  import java.io.IOException;
  import java.io.Reader;
  import java.net.URI;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import nl.talsmasoftware.lazy4j.Lazy;
  
  /**
   * Provides support for reading JSON-based data based on a bound Metaschema
   * module.
   *
   * @param <CLASS>
   *          the Java type of the bound object representing the root node to read
   */
  public class DefaultJsonDeserializer<CLASS extends IBoundObject>
      extends AbstractDeserializer<CLASS> {
    private Lazy<JsonFactory> factory;
  
    /**
     * Construct a new JSON deserializer that will parse the bound class identified
     * by the {@code classBinding}.
     *
     * @param definition
     *          the bound class information for the Java type this deserializer is
     *          operating on
     */
    public DefaultJsonDeserializer(@NonNull IBoundDefinitionModelAssembly definition) {
      super(definition);
      resetFactory();
    }
  
    /**
     * For use by subclasses to reset the underlying JSON factory when an important
     * change has occurred that will change how the factory produces a
     * {@link JsonParser}.
     */
    protected final void resetFactory() {
      this.factory = Lazy.lazy(this::newFactoryInstance);
    }
  
    @Override
    protected void configurationChanged(IMutableConfiguration<DeserializationFeature<?>> config) {
      super.configurationChanged(config);
      resetFactory();
    }
  
    /**
     * Get a JSON factory instance.
     * <p>
     * This method can be used by sub-classes to create a customized factory
     * instance.
     *
     * @return the factory
     */
    @NonNull
    protected JsonFactory newFactoryInstance() {
      return JsonFactoryFactory.instance();
    }
  
    /**
     * Get the parser factory associated with this deserializer.
     *
     * @return the factory instance
     */
    @NonNull
    protected JsonFactory getJsonFactory() {
      return ObjectUtils.notNull(factory.get());
    }
  
    /**
     * Using the managed JSON factory, create a new JSON parser instance using the
     * provided reader.
     *
     * @param reader
     *          the reader for the parser to read data from
     * @return the new parser
     * @throws IOException
     *           if an error occurred while creating the parser
     */
   @SuppressWarnings("resource") // reader resource not owned
   @NonNull
   protected final JsonParser newJsonParser(@NonNull Reader reader) throws IOException {
     return ObjectUtils.notNull(getJsonFactory().createParser(reader));
   }
 
   @Override
   protected INodeItem deserializeToNodeItemInternal(@NonNull Reader reader, @NonNull URI documentUri)
       throws IOException {
     INodeItem retval;
     try (JsonParser jsonParser = newJsonParser(reader)) {
       MetaschemaJsonReader parser = new MetaschemaJsonReader(jsonParser, documentUri);
       IBoundDefinitionModelAssembly definition = getDefinition();
       IConfiguration<DeserializationFeature<?>> configuration = getConfiguration();
 
       if (definition.isRoot()
           && configuration.isFeatureEnabled(DeserializationFeature.DESERIALIZE_JSON_ROOT_PROPERTY)) {
         // now parse the root property
         CLASS value = ObjectUtils.requireNonNull(parser.readObjectRoot(
             definition,
             ObjectUtils.notNull(definition.getRootJsonName())));
 
         retval = INodeItemFactory.instance().newDocumentNodeItem(definition, documentUri, value);
       } else {
         // read the top-level definition
         CLASS value = ObjectUtils.asType(parser.readObject(definition));
 
         retval = INodeItemFactory.instance().newAssemblyNodeItem(definition, documentUri, value);
       }
       return retval;
     }
   }
 
   @Override
   public CLASS deserializeToValueInternal(@NonNull Reader reader, @NonNull URI documentUri) throws IOException {
     try (JsonParser jsonParser = newJsonParser(reader)) {
       MetaschemaJsonReader parser = new MetaschemaJsonReader(jsonParser, documentUri);
       IBoundDefinitionModelAssembly definition = getDefinition();
       IConfiguration<DeserializationFeature<?>> configuration = getConfiguration();
 
       CLASS retval;
       if (definition.isRoot()
           && configuration.isFeatureEnabled(DeserializationFeature.DESERIALIZE_JSON_ROOT_PROPERTY)) {
 
         // now parse the root property
         retval = ObjectUtils.requireNonNull(parser.readObjectRoot(
             definition,
             ObjectUtils.notNull(definition.getRootJsonName())));
       } else {
         // read the top-level definition
         retval = ObjectUtils.asType(ObjectUtils.requireNonNull(
             parser.readObject(definition)));
       }
       return retval;
     }
   }
 }