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.k.tooling.apt;
  
  import java.io.IOException;
  import java.lang.annotation.Annotation;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.nio.file.StandardOpenOption;
  import java.util.Set;
  import java.util.function.BiConsumer;
  
  import javax.annotation.processing.AbstractProcessor;
  import javax.annotation.processing.RoundEnvironment;
  import javax.annotation.processing.SupportedAnnotationTypes;
  import javax.annotation.processing.SupportedSourceVersion;
  import javax.lang.model.SourceVersion;
  import javax.lang.model.element.Element;
  import javax.lang.model.element.TypeElement;
  import javax.tools.FileObject;
  import javax.tools.StandardLocation;
  
  import org.apache.camel.k.annotation.Customizer;
  import org.apache.camel.k.annotation.LoaderInterceptor;
  
  @SupportedAnnotationTypes({
      "org.apache.camel.k.annotation.Customizer",
      "org.apache.camel.k.annotation.LoaderInterceptor",
  })
  @SupportedSourceVersion(SourceVersion.RELEASE_8)
  public class CamelProcessor extends AbstractProcessor {
  
      @Override
      public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
          for (TypeElement annotation : annotations) {
              Set<? extends Element> ae = roundEnv.getElementsAnnotatedWith(annotation);
              for (Element element: ae) {
                  on(element, LoaderInterceptor.class, (e, a) -> {
                      service(
                          output("META-INF/services/org/apache/camel/k/loader/interceptor/%s", a.value()),
                          e
                      );
                  });
                  on(element, Customizer.class, (e, a) -> {
                      service(
                          output("META-INF/services/org/apache/camel/k/customizer/%s", a.value()),
                          e
                      );
                  });
              }
          }
  
          return false;
      }
  
      // ******************************
      //
      // helpers
      //
      // ******************************
  
      private Path output(String fmt, Object... args) {
          try {
              FileObject result;
  
              try {
                  result = processingEnv.getFiler().getResource(StandardLocation.CLASS_OUTPUT, "", String.format(fmt, args));
              } catch (IOException e) {
                  result = processingEnv.getFiler().createResource(StandardLocation.CLASS_OUTPUT, "", String.format(fmt, args));
              }
  
              Path answer = Paths.get(result.toUri());
  
              if (!Files.exists(answer.getParent())) {
                  Files.createDirectories(answer.getParent());
              }
  
              return answer;
          } catch (IOException e) {
              throw new RuntimeException(e);
          }
      }
  
      private void service(Path target, String type) {
          try {
              Files.write(
                  target,
                  String.format("class=%s", type).getBytes(StandardCharsets.UTF_8),
                  StandardOpenOption.CREATE,
                  StandardOpenOption.TRUNCATE_EXISTING
              );
          } catch (IOException e) {
              throw new RuntimeException(e);
          }
      }
  
      private void service(Path target, TypeElement type) {
          service(target, type.getQualifiedName().toString());
      }
  
      private <T extends Annotation> void on(Element element, Class<T> annotationType, BiConsumer<TypeElement, T> consumer) {
          if (element instanceof TypeElement) {
              T annotation = element.getAnnotation(annotationType);
              if (annotation != null) {
                  consumer.accept((TypeElement) element, annotation);
              }
          }
      }
  }
  