content: /*
   * 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.camel.component.knative.ce;
  
  import java.io.InputStream;
  import java.time.ZonedDateTime;
  import java.time.format.DateTimeFormatter;
  import java.util.Map;
  import java.util.Objects;
  import java.util.function.Supplier;
  
  import org.apache.camel.Exchange;
  import org.apache.camel.Processor;
  import org.apache.camel.cloudevents.CloudEvent;
  import org.apache.camel.component.knative.KnativeEndpoint;
  import org.apache.camel.component.knative.spi.Knative;
  import org.apache.camel.component.knative.spi.KnativeResource;
  import org.apache.camel.util.StringHelper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  abstract class AbstractCloudEventProcessor implements CloudEventProcessor {
      private final CloudEvent cloudEvent;
  
      protected AbstractCloudEventProcessor(CloudEvent cloudEvent) {
          this.cloudEvent = cloudEvent;
      }
  
      @Override
      public CloudEvent cloudEvent() {
          return cloudEvent;
      }
  
      @SuppressWarnings("unchecked")
      @Override
      public Processor consumer(KnativeEndpoint endpoint, KnativeResource service) {
          return exchange -> {
              if (Objects.equals(exchange.getIn().getHeader(Exchange.CONTENT_TYPE), Knative.MIME_BATCH_CONTENT_MODE)) {
                  throw new UnsupportedOperationException("Batched CloudEvents are not yet supported");
              }
  
              if (!Objects.equals(exchange.getIn().getHeader(Exchange.CONTENT_TYPE), Knative.MIME_STRUCTURED_CONTENT_MODE)) {
                  final Map<String, Object> headers = exchange.getIn().getHeaders();
  
                  for (CloudEvent.Attribute attribute : cloudEvent.attributes()) {
                      Object val = headers.remove(attribute.http());
                      if (val != null) {
                          headers.put(attribute.id(), val);
                      }
                  }
              } else {
                  try (InputStream is = exchange.getIn().getBody(InputStream.class)) {
                      decodeStructuredContent(exchange, Knative.MAPPER.readValue(is, Map.class));
                  }
              }
          };
      }
  
      protected abstract void decodeStructuredContent(Exchange exchange, Map<String, Object> content);
  
      @Override
      public Processor producer(KnativeEndpoint endpoint, KnativeResource service) {
          final CloudEvent ce = cloudEvent();
          final Logger logger = LoggerFactory.getLogger(getClass());
          final String contentType = service.getContentType();
  
          return exchange -> {
              final Map<String, Object> headers = exchange.getMessage().getHeaders();
  
              for (CloudEvent.Attribute attribute : ce.attributes()) {
                  Object value = headers.get(attribute.id());
                  if (value != null) {
                      headers.putIfAbsent(attribute.http(), value);
                  }
              }
  
              if (contentType != null) {
                  headers.putIfAbsent(Exchange.CONTENT_TYPE, contentType);
              }
  
              //
              // in case of events, if the type of the event is defined as URI param we need
              // to override it to avoid the event type be overridden by Message's headers
              //
              if (endpoint.getType() == Knative.Type.event && endpoint.getTypeId() != null) {
                  final Object eventType = headers.get(CloudEvent.CAMEL_CLOUD_EVENT_TYPE);
                  if (eventType != null) {
                      logger.debug(
                              "Detected the presence of {} header with value {}: it will be ignored and replaced by value set as uri parameter {}",
                              CloudEvent.CAMEL_CLOUD_EVENT_TYPE,
                              eventType,
                              endpoint.getTypeId());
                  }
  
                  headers.put(cloudEvent().mandatoryAttribute(CloudEvent.CAMEL_CLOUD_EVENT_TYPE).http(), endpoint.getTypeId());
              } else {
                  setCloudEventHeader(headers, CloudEvent.CAMEL_CLOUD_EVENT_TYPE, () -> {
                      String eventType = service.getCloudEventType();
                      if (eventType == null) {
                          eventType = endpoint.getConfiguration().getCloudEventsType();
                      }
                      return eventType;
                  });
              }
  
              setCloudEventHeader(headers, CloudEvent.CAMEL_CLOUD_EVENT_ID, exchange::getExchangeId);
              setCloudEventHeader(headers, CloudEvent.CAMEL_CLOUD_EVENT_SOURCE, exchange::getFromRouteId);
              setCloudEventHeader(headers, CloudEvent.CAMEL_CLOUD_EVENT_VERSION, ce::version);
              setCloudEventHeader(headers, CloudEvent.CAMEL_CLOUD_EVENT_TIME, () -> {
                  final ZonedDateTime created = exchange.getClock().asZonedCreationDateTime();
  
                  return DateTimeFormatter.ISO_INSTANT.format(created);
              });
  
              for (Map.Entry<String, String> ceOverride : service.getCeOverrides().entrySet()) {
                  // when using keys in YAML DSL camelCase is being used by default -convert to dash due to CloudEvents spec
                  headers.put(StringHelper.camelCaseToDash(ceOverride.getKey()),
                          exchange.getContext().resolvePropertyPlaceholders(ceOverride.getValue()));
              }
          };
      }
  
      protected void setCloudEventHeader(Map<String, Object> headers, String id, Supplier<Object> supplier) {
          headers.putIfAbsent(cloudEvent().mandatoryAttribute(id).http(), supplier.get());
      }
  }
  