/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.metaschema.databind.io;
   
   import gov.nist.secauto.metaschema.core.configuration.DefaultConfiguration;
   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.IDocumentNodeItem;
  import gov.nist.secauto.metaschema.core.model.AbstractResourceResolver;
  import gov.nist.secauto.metaschema.core.model.IBoundObject;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.metaschema.databind.IBindingContext;
  import gov.nist.secauto.metaschema.databind.io.ModelDetector.Result;
  
  import org.eclipse.jdt.annotation.NotOwning;
  import org.eclipse.jdt.annotation.Owning;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URI;
  import java.net.URL;
  import java.util.Map;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * A default implementation of an {@link IBoundLoader}.
   */
  @SuppressWarnings("PMD.CouplingBetweenObjects")
  public class DefaultBoundLoader
      extends AbstractResourceResolver
      implements IBoundLoader {
    /**
     * The number of bytes to read ahead when determining the source format.
     */
    public static final int LOOK_AHEAD_BYTES = 32_768;
    // @NonNull
    // private static final JsonFactory JSON_FACTORY = new JsonFactory();
    // @NonNull
    // private static final XmlFactory XML_FACTORY = new XmlFactory();
    // @NonNull
    // private static final YAMLFactory YAML_FACTORY = new YAMLFactory();
  
    private FormatDetector formatDetector;
  
    private ModelDetector modelDetector;
  
    @NonNull
    private final IBindingContext bindingContext;
    @NonNull
    private final IMutableConfiguration<DeserializationFeature<?>> configuration;
  
    /**
     * Construct a new loader instance, using the provided {@link IBindingContext}.
     *
     * @param bindingContext
     *          the Module binding context to use to load Java types
     */
    public DefaultBoundLoader(@NonNull IBindingContext bindingContext) {
      this.bindingContext = bindingContext;
      this.configuration = new DefaultConfiguration<>();
    }
  
    @NonNull
    private IMutableConfiguration<DeserializationFeature<?>> getConfiguration() {
      return configuration;
    }
  
    @Override
    public boolean isFeatureEnabled(DeserializationFeature<?> feature) {
      return getConfiguration().isFeatureEnabled(feature);
    }
  
    @Override
    public Map<DeserializationFeature<?>, Object> getFeatureValues() {
      return getConfiguration().getFeatureValues();
    }
  
    @Override
    public IBoundLoader applyConfiguration(@NonNull IConfiguration<DeserializationFeature<?>> other) {
      getConfiguration().applyConfiguration(other);
      resetDetector();
      return this;
    }
  
    @SuppressWarnings("PMD.NullAssignment")
    private void resetDetector() {
      // reset the detector
      formatDetector = null;
    }
  
    @Override
    public IBoundLoader set(DeserializationFeature<?> feature, Object value) {
      getConfiguration().set(feature, value);
      resetDetector();
      return this;
   }
 
   @Override
   public IBindingContext getBindingContext() {
     return bindingContext;
   }
 
   @Override
   public Format detectFormat(@NonNull URI uri) throws IOException {
     URI resourceUri = resolve(uri);
     URL resource = resourceUri.toURL();
 
     try (InputStream is = ObjectUtils.notNull(resource.openStream())) {
       return detectFormat(is, uri).getFormat();
     }
   }
 
   @Override
   public FormatDetector.Result detectFormat(InputStream is, URI resource) throws IOException {
     return getFormatDetector().detect(is);
   }
 
   @NonNull
   private FormatDetector getFormatDetector() {
     if (formatDetector == null) {
       formatDetector = new FormatDetector(getConfiguration());
     }
     assert formatDetector != null;
     return formatDetector;
   }
 
   @NonNull
   private ModelDetector getModelDetector() {
     if (modelDetector == null) {
       modelDetector = new ModelDetector(
           getBindingContext(),
           getConfiguration());
     }
     assert modelDetector != null;
     return modelDetector;
   }
 
   @Override
   @Owning
   public Result detectModel(@NotOwning InputStream is, URI resource, Format format) throws IOException {
     return getModelDetector().detect(is, resource, format);
   }
 
   @Override
   public <CLASS extends IBoundObject> CLASS load(@NonNull URI uri) throws IOException {
     URI resourceUri = resolve(uri);
     URL resource = resourceUri.toURL();
 
     try (InputStream is = ObjectUtils.notNull(resource.openStream())) {
       return load(is, uri);
     }
   }
 
   @SuppressWarnings("unchecked")
   @Override
   @NonNull
   public <CLASS extends IBoundObject> CLASS load(
       @NotOwning @NonNull InputStream is,
       @NonNull URI resource)
       throws IOException {
     FormatDetector.Result formatMatch = getFormatDetector().detect(is);
     Format format = formatMatch.getFormat();
 
     try (InputStream formatStream = formatMatch.getDataStream()) {
       try (ModelDetector.Result modelMatch = detectModel(formatStream, resource, format)) {
 
         IDeserializer<?> deserializer = getDeserializer(
             modelMatch.getBoundClass(),
             format,
             getConfiguration());
         try (InputStream modelStream = modelMatch.getDataStream()) {
           return (CLASS) deserializer.deserialize(modelStream, resource);
         }
       }
     }
   }
 
   @Override
   public <CLASS extends IBoundObject> CLASS load(Class<CLASS> clazz, URI uri) throws IOException {
     URI resourceUri = resolve(uri);
     URL resource = resourceUri.toURL();
 
     try (InputStream is = ObjectUtils.notNull(resource.openStream())) {
       return load(clazz, is, resourceUri);
     }
   }
 
   @Override
   public <CLASS extends IBoundObject> CLASS load(Class<CLASS> clazz, InputStream is, URI documentUri)
       throws IOException {
     // we cannot close this stream, since it will cause the underlying stream to be
     // closed
     FormatDetector.Result match = getFormatDetector().detect(is);
     Format format = match.getFormat();
 
     try (InputStream remainingStream = match.getDataStream()) {
       // is autoclosing ok?
       return load(clazz, format, remainingStream, documentUri);
     }
   }
 
   @Override
   @NonNull
   public <CLASS extends IBoundObject> CLASS load(
       @NonNull Class<CLASS> clazz,
       @NonNull Format format,
       @NonNull InputStream is,
       @NonNull URI documentUri) throws IOException {
 
     IDeserializer<CLASS> deserializer = getDeserializer(clazz, format, getConfiguration());
     return deserializer.deserialize(is, documentUri);
   }
 
   @Override
   public IDocumentNodeItem loadAsNodeItem(URI uri) throws IOException {
     URI resourceUri = resolve(uri);
     URL resource = resourceUri.toURL();
 
     try (InputStream is = ObjectUtils.notNull(resource.openStream())) {
       return loadAsNodeItem(is, resourceUri);
     }
   }
 
   @NonNull
   private IDocumentNodeItem loadAsNodeItem(@NonNull InputStream is, @NonNull URI documentUri) throws IOException {
     FormatDetector.Result formatMatch = getFormatDetector().detect(is);
     Format format = formatMatch.getFormat();
 
     try (InputStream formatStream = formatMatch.getDataStream()) {
       return loadAsNodeItem(format, formatStream, documentUri);
     }
   }
 
   @Override
   public IDocumentNodeItem loadAsNodeItem(Format format, URI uri) throws IOException {
     URI resourceUri = resolve(uri);
     URL resource = resourceUri.toURL();
 
     try (InputStream is = ObjectUtils.notNull(resource.openStream())) {
       return loadAsNodeItem(format, is, resourceUri);
     }
   }
 
   @Override
   public IDocumentNodeItem loadAsNodeItem(Format format, InputStream is, URI resource)
       throws IOException {
     try (ModelDetector.Result modelMatch = detectModel(is, resource, format)) {
 
       IDeserializer<?> deserializer = getDeserializer(
           modelMatch.getBoundClass(),
           format,
           getConfiguration());
       try (InputStream modelStream = modelMatch.getDataStream()) {
         return (IDocumentNodeItem) deserializer.deserializeToNodeItem(modelStream, resource);
       }
     }
   }
 
   @NonNull
   private <CLASS extends IBoundObject> IDeserializer<CLASS> getDeserializer(
       @NonNull Class<CLASS> clazz,
       @NonNull Format format,
       @NonNull IConfiguration<DeserializationFeature<?>> config) {
     IDeserializer<CLASS> retval = getBindingContext().newDeserializer(format, clazz);
     retval.applyConfiguration(config);
     return retval;
   }
 }