package org.apache.maven.scm.provider.git.gitexe.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 java.io.File;

import org.apache.maven.scm.CommandParameter;
import org.apache.maven.scm.CommandParameters;
import org.apache.maven.scm.ScmBranch;
import org.apache.maven.scm.ScmException;
import org.apache.maven.scm.ScmFileSet;
import org.apache.maven.scm.ScmFileStatus;
import org.apache.maven.scm.ScmResult;
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.gitexe.command.GitCommandLineUtils;
import org.apache.maven.scm.provider.git.gitexe.command.list.GitListCommand;
import org.apache.maven.scm.provider.git.gitexe.command.list.GitListConsumer;
import org.apache.maven.scm.provider.git.gitexe.command.remoteinfo.GitRemoteInfoCommand;
import org.apache.maven.scm.provider.git.repository.GitScmProviderRepository;
import org.codehaus.plexus.util.StringUtils;
import org.codehaus.plexus.util.cli.CommandLineUtils;
import org.codehaus.plexus.util.cli.Commandline;

/**
 * @author <a href="mailto:struberg@yahoo.de">Mark Struberg</a>
 *
 */
public class GitCheckOutCommand
    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/>
     * TODO We currently assume a '.git' directory, so this does not work for --bare repos
     * {@inheritDoc}
     */
    @Override
    public ScmResult executeCommand( ScmProviderRepository repo, ScmFileSet fileSet,
                                     CommandParameters parameters )
        throws ScmException
    {
        ScmVersion version = parameters.getScmVersion( CommandParameter.SCM_VERSION, null );
        boolean binary = parameters.getBoolean( CommandParameter.BINARY, false );
        boolean shallow = parameters.getBoolean( CommandParameter.SHALLOW, false );

        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" );
        }

        int exitCode;

        CommandLineUtils.StringStreamConsumer stdout = new CommandLineUtils.StringStreamConsumer();
        CommandLineUtils.StringStreamConsumer stderr = new CommandLineUtils.StringStreamConsumer();

        String lastCommandLine = "git-nothing-to-do";

        if ( !fileSet.getBasedir().exists() || !( new File( fileSet.getBasedir(), ".git" ).exists() ) )
        {
            if ( fileSet.getBasedir().exists() )
            {
                // git refuses to clone otherwise
                fileSet.getBasedir().delete();
            }

            // no git repo seems to exist, let's clone the original repo
            Commandline clClone = createCloneCommand( repository, fileSet.getBasedir(), version, binary, shallow );

            exitCode = GitCommandLineUtils.execute( clClone, stdout, stderr, getLogger() );
            if ( exitCode != 0 )
            {
                return new CheckOutScmResult( clClone.toString(), "The git-clone command failed.", stderr.getOutput(),
                                              false );
            }
            lastCommandLine = clClone.toString();
        }

        GitRemoteInfoCommand gitRemoteInfoCommand = new GitRemoteInfoCommand();
        gitRemoteInfoCommand.setLogger( getLogger() );
        RemoteInfoScmResult result = gitRemoteInfoCommand.executeRemoteInfoCommand( repository, null, null );

        if ( fileSet.getBasedir().exists() && new File( fileSet.getBasedir(), ".git" ).exists()
            && result.getBranches().size() > 0 )
        {
            // git repo exists, so we must git-pull the changes
            Commandline clPull = createPullCommand( repository, fileSet.getBasedir(), version );

            exitCode = GitCommandLineUtils.execute( clPull, stdout, stderr, getLogger() );
            if ( exitCode != 0 )
            {
                return new CheckOutScmResult( clPull.toString(), "The git-pull command failed.", stderr.getOutput(),
                                              false );
            }
            lastCommandLine = clPull.toString();

            // and now lets do the git-checkout itself
            Commandline clCheckout = createCommandLine( repository, fileSet.getBasedir(), version );

            exitCode = GitCommandLineUtils.execute( clCheckout, stdout, stderr, getLogger() );
            if ( exitCode != 0 )
            {
                return new CheckOutScmResult( clCheckout.toString(), "The git-checkout command failed.",
                                              stderr.getOutput(), false );
            }
            lastCommandLine = clCheckout.toString();
        }

        // and now search for the files
        GitListConsumer listConsumer =
            new GitListConsumer( getLogger(), fileSet.getBasedir(), ScmFileStatus.CHECKED_IN );

        Commandline clList = GitListCommand.createCommandLine( repository, fileSet.getBasedir() );

        exitCode = GitCommandLineUtils.execute( clList, listConsumer, stderr, getLogger() );
        if ( exitCode != 0 )
        {
            return new CheckOutScmResult( clList.toString(), "The git-ls-files command failed.", stderr.getOutput(),
                                          false );
        }

        return new CheckOutScmResult( lastCommandLine, listConsumer.getListedFiles() );
    }

    // ----------------------------------------------------------------------
    //
    // ----------------------------------------------------------------------

    public static Commandline createCommandLine( GitScmProviderRepository repository, File workingDirectory,
                                                 ScmVersion version )
    {
        Commandline cl = GitCommandLineUtils.getBaseGitCommandLine( workingDirectory, "checkout" );

        if ( version != null && StringUtils.isNotEmpty( version.getName() ) )
        {
            cl.createArg().setValue( version.getName() );
        }

        return cl;
    }

    /**
     * create a git-clone repository command
     */
    private Commandline createCloneCommand( GitScmProviderRepository repository, File workingDirectory,
                                            ScmVersion version, boolean binary, boolean shallow )
    {
        Commandline cl = GitCommandLineUtils.getBaseGitCommandLine( workingDirectory.getParentFile(), "clone" );

        forceBinary( cl, binary );

        if ( shallow )
        {
            cl.createArg().setValue( "--depth" );

            cl.createArg().setValue( "1" );
        }

        if ( version != null && ( version instanceof ScmBranch ) )
        {

            cl.createArg().setValue( "--branch" );

            cl.createArg().setValue( version.getName() );
        }

        cl.createArg().setValue( repository.getFetchUrl() );

        cl.createArg().setFile( workingDirectory );

        return cl;
    }

    private void forceBinary( Commandline cl, boolean binary )
    {
        if ( binary )
        {
            cl.createArg().setValue( "-c" );
            cl.createArg().setValue( "core.autocrlf=false" );
        }
    }

    /**
     * create a git-pull repository command
     */
    private Commandline createPullCommand( GitScmProviderRepository repository, File workingDirectory,
                                           ScmVersion version )
    {
        Commandline cl;

        if ( version != null && StringUtils.isNotEmpty( version.getName() ) )
        {
            if ( 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 
                cl = GitCommandLineUtils.getBaseGitCommandLine( workingDirectory, "fetch" );

                cl.createArg().setValue( repository.getFetchUrl() );
            }
            else
            {
                cl = GitCommandLineUtils.getBaseGitCommandLine( workingDirectory, "pull" );

                cl.createArg().setValue( repository.getFetchUrl() );

                cl.createArg().setValue( version.getName() + ":" + version.getName() );
            }
        }
        else
        {
            cl = GitCommandLineUtils.getBaseGitCommandLine( workingDirectory, "pull" );

            cl.createArg().setValue( repository.getFetchUrl() );
            cl.createArg().setValue( "master" );
        }
        return cl;
    }

    /**
     * The overriden {@link #executeCommand(ScmProviderRepository, ScmFileSet, CommandParameters)} in this class will
     * not call this method!
     * <p>
     * {@inheritDoc}
     */
    protected CheckOutScmResult executeCheckOutCommand( ScmProviderRepository repo, ScmFileSet fileSet,
                                                        ScmVersion version, boolean recursive, boolean shallow )
         throws ScmException
     {
         throw new UnsupportedOperationException( "Should not get here" );
     }
}