package org.apache.maven.scm.provider.clearcase.command.changelog;

/*
 * 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.ChangeFile;
import org.apache.maven.scm.ChangeSet;
import org.apache.maven.scm.log.ScmLogger;
import org.apache.maven.scm.util.AbstractConsumer;

import java.util.ArrayList;
import java.util.List;

/**
 * @author <a href="mailto:evenisse@apache.org">Emmanuel Venisse</a>
 * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
 * @author Olivier Lamy
 *
 */
public class ClearCaseChangeLogConsumer
    extends AbstractConsumer
{
    /**
     * Formatter used to parse Clearcase date/timestamp.
     */
    private static final String CLEARCASE_TIMESTAMP_PATTERN = "yyyyMMdd.HHmmss";

    private static final String NAME_TAG = "NAME:";

    private static final String USER_TAG = "USER:";

    private static final String DATE_TAG = "DATE:";

    private static final String COMMENT_TAG = "COMM:";

    private static final String REVISION_TAG = "REVI:";
    
    private List<ChangeSet> entries = new ArrayList<ChangeSet>();

    // state machine constants for reading clearcase lshistory command output

    /**
     * expecting file information
     */
    private static final int GET_FILE = 1;

    /**
     * expecting date
     */
    private static final int GET_DATE = 2;

    /**
     * expecting comments
     */
    private static final int GET_COMMENT = 3;

    /**
     * expecting revision
     */
    private static final int GET_REVISION = 4;

    /**
     * current status of the parser
     */
    private int status = GET_FILE;

    /**
     * the current log entry being processed by the parser
     */
    private ChangeSet currentChange = null;

    /**
     * the current file being processed by the parser
     */
    private ChangeFile currentFile = null;

    private String userDatePattern;

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

    public ClearCaseChangeLogConsumer( ScmLogger logger, String userDatePattern )
    {
        super( logger );

        this.userDatePattern = userDatePattern;
    }

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

    public List<ChangeSet> getModifications()
    {
        return entries;
    }

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

    /** {@inheritDoc} */
    public void consumeLine( String line )
    {
        switch ( getStatus() )
        {
            case GET_FILE:
                processGetFile( line );
                break;
            case GET_DATE:
                processGetDate( line );
                break;
            case GET_COMMENT:
                processGetCommentAndUser( line );
                break;
            case GET_REVISION:
                processGetRevision( line );
                break;
            default:
                if ( getLogger().isWarnEnabled() )
                {
                    getLogger().warn( "Unknown state: " + status );
                }
        }
    }

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

    /**
     * Process the current input line in the Get File state.
     *
     * @param line a line of text from the clearcase log output
     */
    private void processGetFile( String line )
    {
        if ( line.startsWith( NAME_TAG ) )
        {
            setCurrentChange( new ChangeSet() );
            setCurrentFile( new ChangeFile( line.substring( NAME_TAG.length(), line.length() ) ) );
            setStatus( GET_DATE );
        }
    }

    /**
     * Process the current input line in the Get Date state.
     *
     * @param line a line of text from the clearcase log output
     */
    private void processGetDate( String line )
    {
        if ( line.startsWith( DATE_TAG ) )
        {
            getCurrentChange().setDate(
                parseDate( line.substring( DATE_TAG.length() ), userDatePattern, CLEARCASE_TIMESTAMP_PATTERN ) );

            setStatus( GET_COMMENT );
        }
    }

    /**
     * Process the current input line in the Get Comment state.
     *
     * @param line a line of text from the clearcase log output
     */
    private void processGetCommentAndUser( String line )
    {
        if ( line.startsWith( COMMENT_TAG ) )
        {
            String comm = line.substring( COMMENT_TAG.length() );

            getCurrentChange().setComment( getCurrentChange().getComment() + comm + "\n" );
        }
        else if ( line.startsWith( USER_TAG ) )
        {
            getCurrentChange().setAuthor( line.substring( USER_TAG.length() ) );

            // add entry, and set state to get file
            getCurrentChange().addFile( getCurrentFile() );

            entries.add( getCurrentChange() );

            setStatus( GET_REVISION );
        }
        else
        {
            // keep gathering comments
            getCurrentChange().setComment( getCurrentChange().getComment() + line + "\n" );
        }
    }
    
    /**
     * Process the current input line in the Get Revision.
     *
     * @param line a line of text from the clearcase log output
     */
    private void processGetRevision( String line )
    {
        if ( line.startsWith( REVISION_TAG ) )
        {
            getCurrentChange().setRevision( line.substring( REVISION_TAG.length() ) );

            setStatus( GET_FILE );
        }
    }

    /**
     * Getter for property currentFile.
     *
     * @return Value of property currentFile.
     */
    private ChangeFile getCurrentFile()
    {
        return currentFile;
    }

    /**
     * Setter for property currentFile.
     *
     * @param currentFile New value of property currentFile.
     */
    private void setCurrentFile( ChangeFile currentFile )
    {
        this.currentFile = currentFile;
    }

    /**
     * Getter for property currentChange.
     *
     * @return Value of property currentChange.
     */
    private ChangeSet getCurrentChange()
    {
        return currentChange;
    }

    /**
     * Setter for property currentLogEntry.
     *
     * @param currentChange New value of property currentLogEntry.
     */
    private void setCurrentChange( ChangeSet currentChange )
    {
        this.currentChange = currentChange;
    }

    /**
     * Getter for property status.
     *
     * @return Value of property status.
     */
    private int getStatus()
    {
        return status;
    }

    /**
     * Setter for property status.
     *
     * @param status New value of property status.
     */
    private void setStatus( int status )
    {
        this.status = status;
    }
}