/*
    * The contents of this file are subject to the terms of the Common Development and
    * Distribution License (the License). You may not use this file except in compliance with the
    * License.
    *
    * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
    * specific language governing permission and limitations under the License.
    *
    * When distributing Covered Software, include this CDDL Header Notice in each file and include
   * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
   * Header, with the fields enclosed by brackets [] replaced by your own identifying
   * information: "Portions copyright [year] [name of copyright owner]".
   *
   * Copyright 2016 ForgeRock AS.
   */
  
  package org.forgerock.json.resource;
  
  import static org.forgerock.api.models.ApiDescription.*;
  import static org.forgerock.api.models.Paths.*;
  import static org.forgerock.api.models.VersionedPath.*;
  import static org.forgerock.util.Reject.*;
  
  import org.forgerock.api.models.ApiDescription;
  import org.forgerock.api.models.Resource;
  import org.wrensecurity.guava.common.base.Optional;
  import org.forgerock.http.ApiProducer;
  import org.forgerock.services.context.Context;
  import org.forgerock.services.descriptor.Describable;
  
  /**
   * A resource handler that implements describable for a possibly annotated type. This class should be used by internal
   * CREST {@link RequestHandler}s that are wrapping a type that uses (or may use) annotations to describe its API - for
   * example, the Interface handlers and Annotated handlers that the {@link Resources} class uses.
   * <p>
   * Note that this class does not support the API changing once it has been defined.
   * </p>
   */
  final class DescribableResourceHandler implements Describable<ApiDescription, Request> {
  
      private final ApiDescription definitionDescriptions;
      private ApiDescription api;
      private Optional<Resource> resource;
  
      DescribableResourceHandler() {
          // This ApiDescription can have a dummy ID and version because we are never going to expose it - it is used to
          // collect top-level definitions that are referenced in the resource. Any referenced definitions and errors
          // are added to the ApiDescription that has a proper ID and version (once they are known) in the api method
          // below.
          this.definitionDescriptions = apiDescription().id("fake:id").version("0.0").build();
      }
  
      ApiDescription getDefinitionDescriptions() {
          return definitionDescriptions;
      }
  
      void describes(Resource resource) {
          rejectStateIfTrue(this.resource != null, "Already described API");
          this.resource = Optional.fromNullable(resource);
      }
  
      @Override
      public final ApiDescription api(ApiProducer<ApiDescription> producer) {
          rejectStateIfTrue(resource == null, "Not yet described API");
          if (api == null && resource.isPresent()) {
              api = producer.addApiInfo(ApiDescription.apiDescription().id("fake:id").version("0.0")
                      .definitions(definitionDescriptions.getDefinitions())
                      .errors(definitionDescriptions.getErrors())
                      .services(definitionDescriptions.getServices())
                      .paths(paths().put("", versionedPath().put(UNVERSIONED, resource.get()).build()).build())
                      .build());
          }
          return api;
      }
  
      @Override
      public ApiDescription handleApiRequest(Context context, Request request) {
          rejectStateIfTrue(api == null, "Not ready for API Descriptor requests");
          return api;
      }
  
      @Override
      public void addDescriptorListener(Describable.Listener listener) {
          // No-op: change to API not supported.
      }
  
      @Override
      public void removeDescriptorListener(Describable.Listener listener) {
          // No-op: change to API not supported.
      }
  }