package org.apache.maven.scm.provider.starteam.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 java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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;

/**
 * @author <a href="mailto:dantran@gmail.com">Dan T. Tran</a>
 *
 */
public class StarteamDiffConsumer
    implements StreamConsumer
{
    private static final String WORKING_DIR_TOKEN = "(working dir: ";

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

    private static final String REVISION_TOKEN = " Revision: ";

    private static final String ONDISK_TOKEN = " (on disk)";

    private static final String ADDED_LINE_TOKEN = "+";

    private static final String REMOVED_LINE_TOKEN = "-";

    private static final String UNCHANGED_LINE_TOKEN = " ";

    private ScmLogger logger;

    @SuppressWarnings( "unused" )
    private String currentDir = "";

    private boolean diffBlockProcessingStarted = false;

    private boolean revisionBlockStarted = false;

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

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

    /** {@inheritDoc} */
    public void consumeLine( String line )
    {
        int pos = 0;

        if ( logger.isDebugEnabled() )
        {
            logger.debug( line );
        }

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

        if ( line.trim().length() == 0 )
        {
            return;
        }

        if ( ( pos = line.indexOf( WORKING_DIR_TOKEN ) ) != -1 )
        {
            processGetDir( line, pos );

            return;
        }

        if ( line.startsWith( PATCH_SEPARATOR_TOKEN ) )
        {
            diffBlockProcessingStarted = !diffBlockProcessingStarted;

            if ( diffBlockProcessingStarted )
            {
                if ( revisionBlockStarted )
                {
                    throw new IllegalStateException( "Missing second Revision line or local copy line " );
                }
            }

            return;
        }

        if ( ( pos = line.indexOf( REVISION_TOKEN ) ) != -1 )
        {
            if ( revisionBlockStarted )
            {
                revisionBlockStarted = false;
            }
            else
            {
                extractCurrentFile( line, pos );

                revisionBlockStarted = true;
            }

            return;
        }

        if ( ( pos = line.indexOf( ONDISK_TOKEN ) ) != -1 )
        {
            if ( revisionBlockStarted )
            {
                revisionBlockStarted = false;
            }
            else
            {
                throw new IllegalStateException( "Working copy line found at the wrong state " );
            }

            return;
        }

        if ( !diffBlockProcessingStarted )
        {
            if ( logger.isWarnEnabled() )
            {
                logger.warn( "Unparseable line: '" + line + "'" );
            }

            return;
        }

        if ( line.startsWith( ADDED_LINE_TOKEN ) || line.startsWith( REMOVED_LINE_TOKEN )
            || line.startsWith( UNCHANGED_LINE_TOKEN ) )
        {
            // add to buffer
            currentDifference.append( line ).append( "\n" );
        }
        else
        {
            if ( logger.isWarnEnabled() )
            {
                logger.warn( "Unparseable line: '" + line + "'" );
            }
        }
    }

    /**
     * Process the current input line in the Get Directory
     *
     * @param line a line of text from the Starteam log output
     */
    private void processGetDir( String line, int pos )
    {
        String dirPath = line.substring( pos + WORKING_DIR_TOKEN.length(), line.length() - 1 ).replace( '\\', '/' );

        this.currentDir = dirPath;
    }

    private void extractCurrentFile( String line, int pos )
    {
        currentFile = line.substring( 0, pos );

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

        currentDifference = new StringBuilder();

        differences.put( currentFile, currentDifference );
    }

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

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

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

}