/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.metaschema.databind;
   
   import gov.nist.secauto.metaschema.core.model.IBoundObject;
   import gov.nist.secauto.metaschema.core.model.MetaschemaException;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.metaschema.databind.io.BindingException;
  import gov.nist.secauto.metaschema.databind.io.Format;
  import gov.nist.secauto.metaschema.databind.io.IDeserializer;
  import gov.nist.secauto.metaschema.databind.io.ISerializer;
  import gov.nist.secauto.metaschema.databind.io.json.DefaultJsonDeserializer;
  import gov.nist.secauto.metaschema.databind.io.json.DefaultJsonSerializer;
  import gov.nist.secauto.metaschema.databind.io.xml.DefaultXmlDeserializer;
  import gov.nist.secauto.metaschema.databind.io.xml.DefaultXmlSerializer;
  import gov.nist.secauto.metaschema.databind.io.yaml.DefaultYamlDeserializer;
  import gov.nist.secauto.metaschema.databind.io.yaml.DefaultYamlSerializer;
  import gov.nist.secauto.metaschema.databind.model.IBoundDefinitionModelAssembly;
  import gov.nist.secauto.metaschema.databind.model.IBoundDefinitionModelComplex;
  import gov.nist.secauto.metaschema.databind.model.IBoundModule;
  import gov.nist.secauto.metaschema.databind.model.metaschema.BindingModuleLoader;
  import gov.nist.secauto.metaschema.databind.model.metaschema.IBindingMetaschemaModule;
  import gov.nist.secauto.metaschema.databind.model.metaschema.IBindingModuleLoader;
  import gov.nist.secauto.metaschema.databind.model.metaschema.ModuleLoadingPostProcessor;
  import gov.nist.secauto.metaschema.databind.model.metaschema.binding.METASCHEMA;
  import gov.nist.secauto.metaschema.databind.model.metaschema.binding.MetaschemaModelModule;
  
  import java.io.IOException;
  import java.net.URI;
  import java.net.URL;
  import java.nio.file.Path;
  import java.util.Collection;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.concurrent.ConcurrentHashMap;
  
  import javax.xml.namespace.QName;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import nl.talsmasoftware.lazy4j.Lazy;
  
  /**
   * The implementation of a {@link IBindingContext} provided by this library.
   * <p>
   * This implementation caches Module information, which can dramatically improve
   * read and write performance at the cost of some memory use. Thus, using the
   * same singleton of this class across multiple I/O operations will improve
   * overall read and write performance when processing the same types of data.
   * <p>
   * Serializers and deserializers provided by this class using the
   * {@link #newSerializer(Format, Class)} and
   * {@link #newDeserializer(Format, Class)} methods will
   * <p>
   * This class is synchronized and is thread-safe.
   */
  @SuppressWarnings("PMD.CouplingBetweenObjects")
  public class DefaultBindingContext implements IBindingContext {
    private static Lazy<DefaultBindingContext> singleton = Lazy.of(DefaultBindingContext::new);
    @NonNull
    private final IModuleLoaderStrategy moduleLoaderStrategy;
    @NonNull
    private final Map<Class<?>, IBoundDefinitionModelComplex> boundClassToStrategyMap = new ConcurrentHashMap<>();
  
    /**
     * Get the singleton instance of this binding context.
     * <p>
     * Note: It is general a better practice to use a new {@link IBindingContext}
     * and reuse that instance instead of this global instance.
     *
     * @return the binding context
     * @see IBindingContext#newInstance()
     */
    @NonNull
    static DefaultBindingContext instance() {
      return ObjectUtils.notNull(singleton.get());
    }
  
    /**
     * Construct a new binding context.
     */
    @SuppressFBWarnings("CT_CONSTRUCTOR_THROW")
    public DefaultBindingContext() {
      this(new SimpleModuleLoaderStrategy());
    }
  
    /**
     * Construct a new binding context.
     *
     * @param strategy
     *          the behavior class to use for loading Metaschema modules
     * @since 2.0.0
     */
    public DefaultBindingContext(@NonNull IBindingContext.IModuleLoaderStrategy strategy) {
      // only allow extended classes
     moduleLoaderStrategy = strategy;
     try {
       registerModule(MetaschemaModelModule.class);
     } catch (MetaschemaException ex) {
       throw new IllegalStateException("Unable to register the builtin Metaschema module.", ex);
     }
   }
 
   @Override
   @NonNull
   public final IModuleLoaderStrategy getModuleLoaderStrategy() {
     return moduleLoaderStrategy;
   }
 
   @Override
   public IBindingModuleLoader newModuleLoader() {
     return new ModuleLoader(this, getModuleLoaderStrategy());
   }
 
   @Override
   @NonNull
   public final IBoundModule registerModule(@NonNull Class<? extends IBoundModule> clazz) throws MetaschemaException {
     IModuleLoaderStrategy strategy = getModuleLoaderStrategy();
     IBoundModule module = strategy.loadModule(clazz, this);
     registerImportedModules(module);
     return strategy.registerModule(module, this);
   }
 
   private void registerImportedModules(@NonNull IBoundModule module) throws MetaschemaException {
     IModuleLoaderStrategy strategy = getModuleLoaderStrategy();
     for (IBoundModule parentModule : module.getImportedModules()) {
       assert parentModule != null;
       registerImportedModules(parentModule);
       strategy.registerModule(parentModule, this);
     }
   }
 
   /**
    * Get the binding matchers that are associated with this class.
    *
    * @return the list of matchers
    */
   @NonNull
   protected Collection<IBindingMatcher> getBindingMatchers() {
     return getModuleLoaderStrategy().getBindingMatchers();
   }
 
   @Override
   public final IBoundDefinitionModelComplex registerClassBinding(IBoundDefinitionModelComplex definition) {
     Class<?> clazz = definition.getBoundClass();
     return boundClassToStrategyMap.computeIfAbsent(clazz, k -> definition);
   }
 
   @Override
   public final IBoundDefinitionModelComplex getBoundDefinitionForClass(@NonNull Class<? extends IBoundObject> clazz) {
     return moduleLoaderStrategy.getBoundDefinitionForClass(clazz, this);
   }
 
   /**
    * {@inheritDoc}
    * <p>
    * A serializer returned by this method is thread-safe.
    */
   @Override
   public <CLASS extends IBoundObject> ISerializer<CLASS> newSerializer(
       @NonNull Format format,
       @NonNull Class<CLASS> clazz) {
     Objects.requireNonNull(format, "format");
     IBoundDefinitionModelAssembly definition;
     try {
       definition = IBoundDefinitionModelAssembly.class.cast(getBoundDefinitionForClass(clazz));
     } catch (ClassCastException ex) {
       throw new IllegalStateException(
           String.format("Class '%s' is not a bound assembly.", clazz.getClass().getName()), ex);
     }
     if (definition == null) {
       throw new IllegalStateException(String.format("Class '%s' is not bound", clazz.getClass().getName()));
     }
     ISerializer<CLASS> retval;
     switch (format) {
     case JSON:
       retval = new DefaultJsonSerializer<>(definition);
       break;
     case XML:
       retval = new DefaultXmlSerializer<>(definition);
       break;
     case YAML:
       retval = new DefaultYamlSerializer<>(definition);
       break;
     default:
       throw new UnsupportedOperationException(String.format("Unsupported format '%s'", format));
     }
     return retval;
   }
 
   /**
    * {@inheritDoc}
    * <p>
    * A deserializer returned by this method is thread-safe.
    */
   @Override
   public <CLASS extends IBoundObject> IDeserializer<CLASS> newDeserializer(
       @NonNull Format format,
       @NonNull Class<CLASS> clazz) {
     IBoundDefinitionModelAssembly definition;
     try {
       definition = IBoundDefinitionModelAssembly.class.cast(getBoundDefinitionForClass(clazz));
     } catch (ClassCastException ex) {
       throw new IllegalStateException(
           String.format("Class '%s' is not a bound assembly.", clazz.getClass().getName()),
           ex);
     }
     if (definition == null) {
       throw new IllegalStateException(String.format("Class '%s' is not bound", clazz.getName()));
     }
     IDeserializer<CLASS> retval;
     switch (format) {
     case JSON:
       retval = new DefaultJsonDeserializer<>(definition);
       break;
     case XML:
       retval = new DefaultXmlDeserializer<>(definition);
       break;
     case YAML:
       retval = new DefaultYamlDeserializer<>(definition);
       break;
     default:
       throw new UnsupportedOperationException(String.format("Unsupported format '%s'", format));
     }
 
     return retval;
   }
 
   @Override
   public Class<? extends IBoundObject> getBoundClassForRootXmlQName(@NonNull QName rootQName) {
     Class<? extends IBoundObject> retval = null;
     for (IBindingMatcher matcher : getBindingMatchers()) {
       retval = matcher.getBoundClassForXmlQName(rootQName);
       if (retval != null) {
         break;
       }
     }
     return retval;
   }
 
   @Override
   public Class<? extends IBoundObject> getBoundClassForRootJsonName(@NonNull String rootName) {
     Class<? extends IBoundObject> retval = null;
     for (IBindingMatcher matcher : getBindingMatchers()) {
       retval = matcher.getBoundClassForJsonName(rootName);
       if (retval != null) {
         break;
       }
     }
     return retval;
   }
 
   @Override
   public <CLASS extends IBoundObject> CLASS deepCopy(@NonNull CLASS other, IBoundObject parentInstance)
       throws BindingException {
     IBoundDefinitionModelComplex definition = getBoundDefinitionForClass(other.getClass());
     if (definition == null) {
       throw new IllegalStateException(String.format("Class '%s' is not bound", other.getClass().getName()));
     }
     return ObjectUtils.asType(definition.deepCopyItem(other, parentInstance));
   }
 
   /**
    * Used to prevent finalizer attacks as recommended in SEI CERT Rule OBJ-11.
    * This is needed because the class is non-final and the constructor can throw.
    */
   @Override
   @SuppressWarnings({
       "PMD.EmptyFinalizer",
       "checkstyle:NoFinalizer" })
   protected final void finalize() {
     // Do nothing
   }
 
   private static class ModuleLoader
       extends BindingModuleLoader {
 
     public ModuleLoader(
         @NonNull IBindingContext bindingContext,
         @NonNull ModuleLoadingPostProcessor postProcessor) {
       super(bindingContext, postProcessor);
     }
 
     @Override
     public IBindingMetaschemaModule load(URI resource) throws MetaschemaException, IOException {
       IBindingMetaschemaModule module = super.load(resource);
       getBindingContext().registerModule(module);
       return module;
     }
 
     @Override
     public IBindingMetaschemaModule load(Path path) throws MetaschemaException, IOException {
       IBindingMetaschemaModule module = super.load(path);
       getBindingContext().registerModule(module);
       return module;
     }
 
     @Override
     public IBindingMetaschemaModule load(URL url) throws MetaschemaException, IOException {
       IBindingMetaschemaModule module = super.load(url);
       getBindingContext().registerModule(module);
       return module;
     }
 
     @Override
     protected IBindingMetaschemaModule newModule(
         URI resource,
         METASCHEMA binding,
         List<? extends IBindingMetaschemaModule> importedModules) throws MetaschemaException {
       return super.newModule(resource, binding, importedModules);
     }
   }
 }