package org.apache.maven.scm.provider.cvslib.command.diff;

/*
 * 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.ScmFile;
import org.apache.maven.scm.ScmFileStatus;
import org.apache.maven.scm.log.ScmLogger;
import org.codehaus.plexus.util.cli.StreamConsumer;

import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author <a href="mailto:brett@apache.org">Brett Porter</a>
 * @author Olivier Lamy
 *
 * @todo share with SVN (3 extra lines can be ignored)
 */
public class CvsDiffConsumer
    implements StreamConsumer
{
    //
    // Index: plugin.jelly
    // ===================================================================
    // RCS file: /home/cvs/maven-scm/maven-scm-providers/maven-scm-provider-cvs/
    //           src/main/resources/META-INF/plexus/components.xml,v
    // retrieving revision 1.2
    // diff -u -r1.2 components.xml
    // --- plugin.jelly        (revision 124799)
    // +++ plugin.jelly        (working copy)
    //

    private static final String RCS_TOKEN = "RCS file: ";

    private static final String RETRIEVING_TOKEN = "retrieving revision ";

    private static final String DIFF_TOKEN = "diff ";

    private static final String INDEX_TOKEN = "Index: ";

    private static final String FILE_SEPARATOR_TOKEN = "===";

    private static final String START_REVISION_TOKEN = "---";

    private static final String END_REVISION_TOKEN = "+++";

    private static final String ADDED_LINE_TOKEN = "+";

    private static final String REMOVED_LINE_TOKEN = "-";

    private static final String UNCHANGED_LINE_TOKEN = " ";

    private static final String CHANGE_SEPARATOR_TOKEN = "@@";

    private static final String NO_NEWLINE_TOKEN = "\\ No newline at end of file";

    private ScmLogger logger;

    private String currentFile;

    private StringBuilder currentDifference;

    private List<ScmFile> changedFiles = new ArrayList<ScmFile>();

    private Map<String, CharSequence> differences = new HashMap<String, CharSequence>();

    private StringBuilder patch = new StringBuilder();

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

    public CvsDiffConsumer( ScmLogger logger, File workingDirectory )
    {
        this.logger = logger;
    }

    // ----------------------------------------------------------------------
    // StreamConsumer Implementation
    // ----------------------------------------------------------------------

    /** {@inheritDoc} */
    public void consumeLine( String line )
    {
        if ( logger.isDebugEnabled() )
        {
            logger.debug( line );
        }

        if ( line.startsWith( INDEX_TOKEN ) )
        {
            // start a new file
            currentFile = line.substring( INDEX_TOKEN.length() );

            changedFiles.add( new ScmFile( currentFile, ScmFileStatus.MODIFIED ) );

            currentDifference = new StringBuilder();

            differences.put( currentFile, currentDifference );

            patch.append( line ).append( "\n" );

            return;
        }

        if ( currentFile == null )
        {
            if ( logger.isWarnEnabled() )
            {
                logger.warn( "Unparseable line: '" + line + "'" );
            }
            patch.append( line ).append( "\n" );
            return;
        }

        if ( line.startsWith( FILE_SEPARATOR_TOKEN ) )
        {
            // skip
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( START_REVISION_TOKEN ) )
        {
            // skip, though could parse to verify filename, start revision
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( END_REVISION_TOKEN ) )
        {
            // skip, though could parse to verify filename, end revision
            patch.append( line ).append( "\n" );
        }
        else if ( line.startsWith( RCS_TOKEN ) )
        {
            // skip, though could parse to verify filename
        }
        else if ( line.startsWith( RETRIEVING_TOKEN ) )
        {
            // skip, though could parse to verify version
        }
        else if ( line.startsWith( DIFF_TOKEN ) )
        {
            // skip, though could parse to verify command
        }
        else if ( line.startsWith( ADDED_LINE_TOKEN ) || line.startsWith( REMOVED_LINE_TOKEN )
            || line.startsWith( UNCHANGED_LINE_TOKEN ) || line.startsWith( CHANGE_SEPARATOR_TOKEN )
            || line.equals( NO_NEWLINE_TOKEN ) )
        {
            // add to buffer
            currentDifference.append( line ).append( "\n" );
            patch.append( line ).append( "\n" );
        }
        else
        {
            if ( logger.isWarnEnabled() )
            {
                logger.warn( "Unparseable line: '" + line + "'" );
            }
            patch.append( line ).append( "\n" );
            // skip to next file
            currentFile = null;
            currentDifference = null;
        }
    }

    public List<ScmFile> getChangedFiles()
    {
        return changedFiles;
    }

    public Map<String, CharSequence> getDifferences()
    {
        return differences;
    }

    public String getPatch()
    {
        return patch.toString();
    }

}