package org.apache.maven.scm.provider.git.jgit.command.checkout;
   
   /*
    * 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.ScmTag;
  import org.apache.maven.scm.ScmVersion;
  import org.apache.maven.scm.command.checkout.AbstractCheckOutCommand;
  import org.apache.maven.scm.command.checkout.CheckOutScmResult;
  import org.apache.maven.scm.command.remoteinfo.RemoteInfoScmResult;
  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.jgit.command.branch.JGitBranchCommand;
  import org.apache.maven.scm.provider.git.jgit.command.remoteinfo.JGitRemoteInfoCommand;
  import org.apache.maven.scm.provider.git.repository.GitScmProviderRepository;
  import org.codehaus.plexus.util.StringUtils;
  import org.eclipse.jgit.api.CloneCommand;
  import org.eclipse.jgit.api.Git;
  import org.eclipse.jgit.lib.Constants;
  import org.eclipse.jgit.lib.ProgressMonitor;
  import org.eclipse.jgit.revwalk.RevCommit;
  import org.eclipse.jgit.revwalk.RevWalk;
  import org.eclipse.jgit.storage.file.WindowCacheConfig;
  import org.eclipse.jgit.transport.CredentialsProvider;
  import org.eclipse.jgit.treewalk.TreeWalk;
  
  import java.io.File;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Set;
  
  /**
   * @author <a href="mailto:struberg@yahoo.de">Mark Struberg</a>
   * @author Dominik Bartholdi (imod)
   * @since 1.9
   */
  public class JGitCheckOutCommand
      extends AbstractCheckOutCommand
      implements GitCommand
  {
      /**
       * For git, the given repository is a remote one. We have to clone it first if the working directory does not
       * contain a git repo yet, otherwise we have to git-pull it.
       * <p/>
       * {@inheritDoc}
       */
      protected CheckOutScmResult executeCheckOutCommand( ScmProviderRepository repo, ScmFileSet fileSet,
                                                         ScmVersion version, boolean recursive, boolean shallow )
          throws ScmException
      {
          GitScmProviderRepository repository = (GitScmProviderRepository) repo;
  
          if ( GitScmProviderRepository.PROTOCOL_FILE.equals( repository.getFetchInfo().getProtocol() )
              && repository.getFetchInfo().getPath().indexOf( fileSet.getBasedir().getPath() ) >= 0 )
          {
              throw new ScmException( "remote repository must not be the working directory" );
          }
  
          Git git = null;
          try
          {
  
              ProgressMonitor monitor = JGitUtils.getMonitor( getLogger() );
  
              String branch = version != null ? version.getName() : null;
  
              if ( StringUtils.isBlank( branch ) )
              {
                  branch = Constants.MASTER;
              }
  
              getLogger().debug( "try checkout of branch: " + branch );
  
              if ( !fileSet.getBasedir().exists() || !( new File( fileSet.getBasedir(), ".git" ).exists() ) )
              {
                  if ( fileSet.getBasedir().exists() )
                  {
                      // git refuses to clone otherwise
                     fileSet.getBasedir().delete();
                 }
 
                 // FIXME only if windauze
                 WindowCacheConfig cfg = new WindowCacheConfig();
                 cfg.setPackedGitMMAP( false );
                 cfg.install();
 
                 // no git repo seems to exist, let's clone the original repo
                 CredentialsProvider credentials = JGitUtils.getCredentials( (GitScmProviderRepository) repo );
                 getLogger().info( "cloning [" + branch + "] to " + fileSet.getBasedir() );
                 CloneCommand command = Git.cloneRepository().setURI( repository.getFetchUrl() );
                 command.setCredentialsProvider( credentials ).setBranch( branch ).setDirectory( fileSet.getBasedir() );
                 command.setProgressMonitor( monitor );
                 git = command.call();
             }
 
             JGitRemoteInfoCommand remoteInfoCommand = new JGitRemoteInfoCommand();
             remoteInfoCommand.setLogger( getLogger() );
             RemoteInfoScmResult result = remoteInfoCommand.executeRemoteInfoCommand( repository, fileSet, null );
 
             if ( git == null )
             {
                 // deliberately not using JGitUtils.openRepo(), the caller told us exactly where to checkout
                 git = Git.open( fileSet.getBasedir() );
             }
             
             if ( fileSet.getBasedir().exists() && new File( fileSet.getBasedir(), ".git" ).exists()
                 && result.getBranches().size() > 0 )
             {
                 // git repo exists, so we must git-pull the changes
                 CredentialsProvider credentials = JGitUtils.prepareSession( getLogger(), git, repository );
 
                 if ( version != null && StringUtils.isNotEmpty( version.getName() ) && ( version instanceof ScmTag ) )
                 {
                     // A tag will not be pulled but we only fetch all the commits from the upstream repo
                     // This is done because checking out a tag might not happen on the current branch
                     // but create a 'detached HEAD'.
                     // In fact, a tag in git may be in multiple branches. This occurs if
                     // you create a branch after the tag has been created
                     getLogger().debug( "fetch..." );
                     git.fetch().setCredentialsProvider( credentials ).setProgressMonitor( monitor ).call();
                 }
                 else
                 {
                     getLogger().debug( "pull..." );
                     git.pull().setCredentialsProvider( credentials ).setProgressMonitor( monitor ).call();
                 }
             }
 
             Set<String> localBranchNames = JGitBranchCommand.getShortLocalBranchNames( git );
             if ( version instanceof ScmTag )
             {
                 getLogger().info( "checkout tag [" + branch + "] at " + fileSet.getBasedir() );
                 git.checkout().setName( branch ).call();
             }
             else if ( localBranchNames.contains( branch ) )
             {
                 getLogger().info( "checkout [" + branch + "] at " + fileSet.getBasedir() );
                 git.checkout().setName( branch ).call();
             }
             else
             {
                 getLogger().info( "checkout remote branch [" + branch + "] at " + fileSet.getBasedir() );
                 git.checkout().setName( branch ).setCreateBranch( true ).setStartPoint( Constants.DEFAULT_REMOTE_NAME
                                                                                             + "/" + branch ).call();
             }
 
             RevWalk revWalk = new RevWalk( git.getRepository() );
             RevCommit commit = revWalk.parseCommit( git.getRepository().resolve( Constants.HEAD ) );
             revWalk.close();
 
             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> listedFiles = new ArrayList<ScmFile>();
             while ( walk.next() )
             {
                 listedFiles.add( new ScmFile( walk.getPathString(), ScmFileStatus.CHECKED_OUT ) );
             }
             walk.close();
 
             getLogger().debug( "current branch: " + git.getRepository().getBranch() );
 
             return new CheckOutScmResult( "checkout via JGit", listedFiles );
         }
         catch ( Exception e )
         {
             throw new ScmException( "JGit checkout failure!", e );
         }
         finally
         {
             JGitUtils.closeRepo( git );
         }
     }
 
 }