import java.io.IOError;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Set;

import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.RoundEnvironment;
import javax.annotation.processing.SupportedAnnotationTypes;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.tools.JavaFileObject;

@SupportedAnnotationTypes("*")
public class Processor extends AbstractProcessor {

  @Override
  public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
    if (!roundEnv.processingOver()) {
      for (Element element : roundEnv.getRootElements()) {
        String elementName = element.getSimpleName().toString();
        if (elementName.startsWith("AutoAnnotation_")) {
          continue;
        }
        String name = "AutoAnnotation_" + elementName;
        JavaFileObject jfo;
        try {
          jfo = processingEnv.getFiler().createSourceFile(name, element);
        } catch (IOException e) {
          throw new IOError(e);
        }
        try (OutputStream os = jfo.openOutputStream()) {
          String output = String.format("public @interface %s {}", name);
          os.write(output.getBytes(StandardCharsets.UTF_8));
        } catch (IOException e) {
          throw new IOError(e);
        }
      }
    }
    return false;
  }
}