/*
    * 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.scm.provider.git.jgit.command.info;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.LinkedList;
  import java.util.List;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.maven.scm.CommandParameters;
  import org.apache.maven.scm.ScmException;
  import org.apache.maven.scm.ScmFileSet;
  import org.apache.maven.scm.ScmResult;
  import org.apache.maven.scm.command.AbstractCommand;
  import org.apache.maven.scm.command.info.InfoItem;
  import org.apache.maven.scm.command.info.InfoScmResult;
  import org.apache.maven.scm.provider.ScmProviderRepository;
  import org.apache.maven.scm.provider.git.command.GitCommand;
  import org.apache.maven.scm.provider.git.jgit.command.JGitUtils;
  import org.eclipse.jgit.api.Git;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.ObjectId;
  import org.eclipse.jgit.lib.PersonIdent;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevSort;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
  import org.eclipse.jgit.treewalk.filter.PathFilter;
  import org.eclipse.jgit.treewalk.filter.TreeFilter;
  
  /**
   * @since 1.9.5
   */
  public class JGitInfoCommand extends AbstractCommand implements GitCommand {
      @Override
      protected ScmResult executeCommand(
              ScmProviderRepository repository, ScmFileSet fileSet, CommandParameters parameters) throws ScmException {
          File basedir = fileSet.getBasedir();
          Git git = null;
          try {
              git = JGitUtils.openRepo(basedir);
              ObjectId objectId = git.getRepository().resolve(Constants.HEAD);
              if (objectId == null) {
                  throw new ScmException("Cannot resolve HEAD in git repository at " + basedir);
              }
  
              List<InfoItem> infoItems = new LinkedList<>();
              if (fileSet.getFileList().isEmpty()) {
                  RevCommit headCommit = git.getRepository().parseCommit(objectId);
                  infoItems.add(getInfoItem(headCommit, fileSet.getBasedir()));
              } else {
                  // iterate over all files
                  for (File file : JGitUtils.getWorkingCopyRelativePaths(
                          git.getRepository().getWorkTree(), fileSet)) {
                      infoItems.add(getInfoItem(git.getRepository(), objectId, file));
                  }
              }
              return new InfoScmResult(infoItems, new ScmResult("JGit.resolve(HEAD)", "", objectId.toString(), true));
          } catch (Exception e) {
              throw new ScmException("JGit resolve failure!", e);
          } finally {
              JGitUtils.closeRepo(git);
          }
      }
  
      protected InfoItem getInfoItem(Repository repository, ObjectId headObjectId, File file) throws IOException {
          RevCommit commit = getMostRecentCommitForPath(repository, headObjectId, JGitUtils.toNormalizedFilePath(file));
          return getInfoItem(commit, file);
      }
  
      protected InfoItem getInfoItem(RevCommit fileCommit, File file) {
          InfoItem infoItem = new InfoItem();
          infoItem.setPath(file.getPath());
          infoItem.setRevision(StringUtils.trim(fileCommit.name()));
          infoItem.setURL(file.toPath().toUri().toASCIIString());
          PersonIdent authorIdent = fileCommit.getAuthorIdent();
          infoItem.setLastChangedDateTime(authorIdent
                  .getWhen()
                  .toInstant()
                  .atZone(authorIdent.getTimeZone().toZoneId()));
          infoItem.setLastChangedAuthor(authorIdent.getName() + " <" + authorIdent.getEmailAddress() + ">");
         return infoItem;
     }
 
     private RevCommit getMostRecentCommitForPath(Repository repository, ObjectId headObjectId, String path)
             throws IOException {
         RevCommit latestCommit = null;
         try (RevWalk revWalk = new RevWalk(repository)) {
             RevCommit headCommit = revWalk.parseCommit(headObjectId);
             revWalk.markStart(headCommit);
             revWalk.sort(RevSort.COMMIT_TIME_DESC);
             revWalk.setTreeFilter(AndTreeFilter.create(PathFilter.create(path), TreeFilter.ANY_DIFF));
             latestCommit = revWalk.next();
         }
         return latestCommit;
     }
 }