/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.syncope.sra.predicates;
  
  import com.fasterxml.jackson.databind.JsonNode;
  import java.util.List;
  import org.springframework.cloud.gateway.handler.AsyncPredicate;
  import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
  import org.springframework.http.codec.HttpMessageReader;
  import org.springframework.web.reactive.function.server.HandlerStrategies;
  import org.springframework.web.reactive.function.server.ServerRequest;
  import org.springframework.web.server.ServerWebExchange;
  import reactor.core.publisher.Mono;
  
  /**
   * Inspired by {@link org.springframework.cloud.gateway.handler.predicate.ReadBodyPredicateFactory}.
   */
  public class BodyPropertyMatchingRoutePredicateFactory extends CustomRoutePredicateFactory {
  
      private static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject";
  
      private static final List<HttpMessageReader<?>> MESSAGE_READERS =
              HandlerStrategies.withDefaults().messageReaders();
  
      @Override
      public AsyncPredicate<ServerWebExchange> applyAsync(final Config config) {
          return exchange -> {
              JsonNode cachedBody = exchange.getAttribute(CACHE_REQUEST_BODY_OBJECT_KEY);
              if (cachedBody == null) {
                  return ServerWebExchangeUtils.cacheRequestBodyAndRequest(
                          exchange, serverHttpRequest -> ServerRequest.create(
                                  exchange.mutate().request(serverHttpRequest).build(), MESSAGE_READERS).
                                  bodyToMono(JsonNode.class).
                                  doOnNext(objectValue -> exchange.getAttributes().
                                  put(CACHE_REQUEST_BODY_OBJECT_KEY, objectValue)).
                                  map(objectValue -> objectValue.has(config.getData())));
              } else {
                  return Mono.just(cachedBody.has(config.getData()));
              }
          };
      }
  }