/*
    * 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.maven.model.root;
  
  import javax.inject.Named;
  
  import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.Optional;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  @Named
  public class DefaultRootLocator implements RootLocator {
      private final Logger logger = LoggerFactory.getLogger(getClass());
  
      @Override
      public Path findRoot(Path basedir) {
          Path rootDirectory = basedir;
          while (rootDirectory != null && !isRootDirectory(rootDirectory)) {
              rootDirectory = rootDirectory.getParent();
          }
          return rootDirectory;
      }
  
      @Override
      public Path findMandatoryRoot(Path basedir) {
          Path rootDirectory = findRoot(basedir);
          Optional<Path> rdf = getRootDirectoryFallback();
          if (rootDirectory == null) {
              rootDirectory = rdf.orElseThrow(() -> new IllegalStateException(getNoRootMessage()));
          } else {
              if (rdf.isPresent()) {
                  try {
                      if (!Files.isSameFile(rootDirectory, rdf.get())) {
                          logger.warn("Project root directory and multiModuleProjectDirectory are not aligned");
                      }
                  } catch (IOException e) {
                      throw new IllegalStateException("findMandatoryRoot failed", e);
                  }
              }
          }
          return rootDirectory;
      }
  
      protected Optional<Path> getRootDirectoryFallback() {
          String mmpd = System.getProperty("maven.multiModuleProjectDirectory");
          if (mmpd != null) {
              return Optional.of(getCanonicalPath(Paths.get(mmpd)));
          }
          return Optional.empty();
      }
  
      protected Path getCanonicalPath(Path path) {
          return path.toAbsolutePath().normalize();
      }
  
      public boolean isRootDirectory(Path dir) {
          return Files.isDirectory(dir.resolve(".mvn"));
      }
  }