package org.apache.maven.scm.provider.git.jgit.command.branch;
   
   /*
    * 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.
   */
  
  import org.apache.maven.scm.ScmException;
  import org.apache.maven.scm.ScmFile;
  import org.apache.maven.scm.ScmFileSet;
  import org.apache.maven.scm.ScmFileStatus;
  import org.apache.maven.scm.ScmResult;
  import org.apache.maven.scm.command.branch.AbstractBranchCommand;
  import org.apache.maven.scm.command.branch.BranchScmResult;
  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.apache.maven.scm.provider.git.repository.GitScmProviderRepository;
  import org.codehaus.plexus.util.StringUtils;
  import org.eclipse.jgit.api.Git;
  import org.eclipse.jgit.api.errors.GitAPIException;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.Ref;
  import org.eclipse.jgit.lib.Repository;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.transport.RefSpec;
  import org.eclipse.jgit.treewalk.TreeWalk;
  
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  
  /**
   * @author Dominik Bartholdi (imod)
   * @since 1.9
   */
  public class JGitBranchCommand
      extends AbstractBranchCommand
      implements GitCommand
  {
  
      /**
       * {@inheritDoc}
       */
      @Override
      protected ScmResult executeBranchCommand( ScmProviderRepository repo, ScmFileSet fileSet, String branch,
                                                String message )
          throws ScmException
      {
          if ( branch == null || StringUtils.isEmpty( branch.trim() ) )
          {
              throw new ScmException( "branch name must be specified" );
          }
  
          if ( !fileSet.getFileList().isEmpty() )
          {
              throw new ScmException( "This provider doesn't support branching subsets of a directory" );
          }
  
          Git git = null;
          try
          {
              git = Git.open( fileSet.getBasedir() );
              Ref branchResult = git.branchCreate().setName( branch ).call();
              getLogger().info( "created [" + branchResult.getName() + "]" );
  
              if ( getLogger().isDebugEnabled() )
              {
                  for ( String branchName : getShortLocalBranchNames( git ) )
                  {
                      getLogger().debug( "local branch available: " + branchName );
                  }
              }
  
              if ( repo.isPushChanges() )
              {
                  getLogger().info( "push branch [" + branch + "] to remote..." );
                  JGitUtils.push( getLogger(), git, (GitScmProviderRepository) repo, new RefSpec( Constants.R_HEADS
                      + branch ) );
              }
  
              // search for the tagged files
             final RevWalk revWalk = new RevWalk( git.getRepository() );
             RevCommit commit = revWalk.parseCommit( branchResult.getObjectId() );
             revWalk.release();
 
             final TreeWalk walk = new TreeWalk( git.getRepository() );
             walk.reset(); // drop the first empty tree, which we do not need here
             walk.setRecursive( true );
             walk.addTree( commit.getTree() );
 
             List<ScmFile> files = new ArrayList<ScmFile>();
             while ( walk.next() )
             {
                 files.add( new ScmFile( walk.getPathString(), ScmFileStatus.CHECKED_OUT ) );
             }
             walk.release();
 
             return new BranchScmResult( "JGit branch", files );
 
         }
         catch ( Exception e )
         {
             throw new ScmException( "JGit branch failed!", e );
         }
         finally
         {
             JGitUtils.closeRepo( git );
         }
     }
 
     /**
      * gets a set of names of the available branches in the given repo
      * 
      * @param git the repo to list the branches for
      * @return set of short branch names
      * @throws GitAPIException
      */
     public static Set<String> getShortLocalBranchNames( Git git )
         throws GitAPIException
     {
         Set<String> branches = new HashSet<String>();
         Iterator<Ref> iter = git.branchList().call().iterator();
         while ( iter.hasNext() )
         {
             branches.add( Repository.shortenRefName( iter.next().getName() ) );
         }
         return branches;
     }
 }