package org.codehaus.gmavenplus.mojo;
   
   import org.apache.maven.project.MavenProject;
   import org.apache.maven.shared.model.fileset.FileSet;
   import org.apache.maven.shared.model.fileset.util.FileSetManager;
   
   import java.io.File;
   import java.lang.reflect.Field;
   import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.nio.file.Path;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Objects;
  import java.util.Set;
  
  import static java.util.Collections.singletonList;
  
  
  /**
   * This mojo provides access to the Groovy sources (including stubs).
   *
   * @author Keegan Witt
   */
  public abstract class AbstractGroovyStubSourcesMojo extends AbstractGroovySourcesMojo {
  
      /**
       * Removes the source roots from the project, using reflection to avoid breaking changes in Maven 4.
       *
       * @param project the Maven project
       * @param scopeToRemove the scope to remove (main or test)
       * @param sourceDirectory the source directory to remove
       * @throws ClassNotFoundException when a class needed cannot be found
       * @throws NoSuchFieldException when a field needed cannot be found
       * @throws NoSuchMethodException when a method needed cannot be found
       * @throws IllegalAccessException when a method needed cannot be accessed
       */
      protected static void removeSourceRoot(MavenProject project, String scopeToRemove, File sourceDirectory)
              throws ClassNotFoundException, NoSuchFieldException, NoSuchMethodException, IllegalAccessException {
          Class<?> sourceRoot = project.getClass().getClassLoader().loadClass("org.apache.maven.api.SourceRoot");
          Path path = project.getBasedir().toPath().resolve(sourceDirectory.getAbsolutePath()).normalize();
          Field field = project.getClass().getDeclaredField("sources");
          field.setAccessible(true);
          Method scope = sourceRoot.getMethod("scope");
          Method language = sourceRoot.getMethod("language");
          Method directory = sourceRoot.getMethod("directory");
          Method id = project.getClass().getClassLoader().loadClass("org.apache.maven.api.ExtensibleEnum").getMethod("id");
          Collection<?> sources = (Collection<?>) field.get(project);
          sources.removeIf(source -> {
              try {
                  return Objects.equals(id.invoke(scope.invoke(source)), scopeToRemove)
                          && Objects.equals(id.invoke(language.invoke(source)), "java")
                          && Objects.equals(directory.invoke(source), path);
              } catch (IllegalAccessException | InvocationTargetException ex) {
                  throw new RuntimeException(ex);
              }
          });
      }
  
      /**
       * Gets the set of stub files in specified directory.
       *
       * @param outputDirectory the directory to write stubs to
       * @return The set of stub files in specified directory
       */
      protected Set<File> getStubs(File outputDirectory) {
          Set<File> files = new HashSet<>();
          FileSetManager fileSetManager = new FileSetManager();
  
          FileSet fileSet = new FileSet();
          fileSet.setDirectory(outputDirectory.getAbsolutePath());
          fileSet.setIncludes(singletonList(JAVA_SOURCES_PATTERN));
          for (String file : fileSetManager.getIncludedFiles(fileSet)) {
              files.add(new File(outputDirectory, file));
          }
  
          return files;
      }
  
  }