package org.apache.maven.mkslib;

/* ====================================================================
 *   Copyright 2005 The Apache Software Foundation.
 *
 *   Licensed 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.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.Map;
import java.util.TreeMap;

import org.apache.maven.changelog.ChangeLog;
import org.apache.maven.changelog.ChangeLogEntry;
import org.apache.maven.changelog.ChangeLogFile;
import org.apache.maven.changelog.ChangeLogParser;

/**
 * This class parse mks log output.
 * 
 * @author <a href="mailto:c.jerolimov@tarent.de">Christoph Jerolimov</a>
 * @version $Id: $
 */
public class MksChangeLogParser implements ChangeLogParser
{
    /**
     * This date/time formatter will be uses to parse a mks date.
     */
    private static final SimpleDateFormat MKS_TIMESTAMP_FORMAT = new SimpleDateFormat(
            "MMM d, yyyy - h:mm a");

    /**
     * Custom date/time formatter. Rounds ChangeLogEntry times to the nearest
     * minute.
     */
    private static final SimpleDateFormat ENTRY_KEY_TIMESTAMP_FORMAT = new SimpleDateFormat(
            "yyyyMMddHHmm");

    /** expecting file name */
    private static final int GET_FILE_NAME = 1;

    /** expecting file revision */
    private static final int GET_FILE_REVISION = 2;

    /** expecting entry revision */
    private static final int WAITFOR_ENTRY_REVISION = 3;

    /** expecting file revision */
    private static final int GET_ENTRY_INFO = 4;

    /** expecting file revision */
    private static final int GET_ENTRY_COMMENT = 5;

    /** rcs entries, in reverse (date, time, author, comment) order */
    private Map entries = new TreeMap(Collections.reverseOrder());

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

    /** current changelog entry */
    private ChangeLogEntry changeLogEntry;

    /** current changelog file */
    private ChangeLogFile changeLogFile;

    public void init(ChangeLog changeLog)
    {
    }

    public void cleanup()
    {
    }

    public void setDateFormatInFile(String dateFormat)
    {
    }

    public Collection parse(InputStream in) throws IOException
    {
        try
        {
            BufferedReader reader = new BufferedReader(
                    new InputStreamReader(in));

            String line;
            while ((line = reader.readLine()) != null)
            {
                if (line.startsWith("========================================"))
                    status = GET_FILE_NAME;

                switch (status)
                {
                    case GET_FILE_NAME:
                        addEntry();
                        processGetFileName(line);
                        break;
                    case GET_FILE_REVISION:
                        processGetFileRevision(line);
                        break;
                    case WAITFOR_ENTRY_REVISION:
                        processWaitForEntryRevision(line);
                        break;
                    case GET_ENTRY_INFO:
                        processGetEntryInfo(line);
                        break;
                    case GET_ENTRY_COMMENT:
                        processGetEntryComment(line);
                        break;
                    default:
                        // wait for next entry
                        break;
                }
            }
            addEntry();
        } catch (RuntimeException e)
        {
            e.printStackTrace();
            throw e;
        } catch (IOException e)
        {
            e.printStackTrace();
            throw e;
        }
        return entries.values();
    }

    protected void processGetFileName(String line)
    {
        if (line.startsWith("member name: "))
        {
            String filename;
            if (line.indexOf(";") == -1)
                filename = line.substring(13);
            else
                filename = line.substring(13, line.indexOf(";"));

            changeLogFile = new ChangeLogFile(filename);
            status = GET_FILE_REVISION;
        }
    }

    protected void processGetFileRevision(String line)
    {
        if (line.startsWith("member:\t"))
        {
            changeLogFile.setRevision(line.substring(8));
            status = WAITFOR_ENTRY_REVISION;
        }
    }

    protected void processWaitForEntryRevision(String line)
    {
        if (line.equals("-----------------------"))
        {
            status = GET_ENTRY_INFO;
        }
    }

    protected void processGetEntryInfo(String line)
    {
        if (line.startsWith("date: "))
        {
            changeLogEntry = new ChangeLogEntry();

            int posAuthor = line.indexOf("; author: ");
            if (posAuthor == -1)
                return;
            int posState = line.indexOf("; state: ");
            if (posState == -1)
                return;

            try
            {
                Date date = MKS_TIMESTAMP_FORMAT.parse(line.substring(6,
                        posAuthor));
                String author = line.substring(posAuthor + 10, posState);

                changeLogEntry.setDate(date);
                changeLogEntry.setAuthor(author);
                status = GET_ENTRY_COMMENT;
            } catch (ParseException e)
            {
                throw new IllegalArgumentException(
                        "I don't understand this date: "
                                + line.substring(6, posAuthor));
            }
        }
    }

    protected void processGetEntryComment(String line)
    {
        if (line.equals("-----------------------"))
        {
            addEntry();
            status = GET_ENTRY_INFO;
            return;
        }
        changeLogEntry.setComment(changeLogEntry.getComment() + line + "\n");
    }

    protected void addEntry()
    {
        if (changeLogEntry == null || changeLogFile == null)
        {
            return;
        }
        // do not add if entry is not populated
        if (changeLogEntry.getAuthor() == null
                || changeLogEntry.getDate() == null)
        {
            return;
        }

        String key = ENTRY_KEY_TIMESTAMP_FORMAT
                .format(changeLogEntry.getDate())
                + changeLogEntry.getAuthor() + changeLogEntry.getComment();

        if (!entries.containsKey(key))
        {
            changeLogEntry.addFile(changeLogFile);
            entries.put(key, changeLogEntry);
        } else
        {
            ((ChangeLogEntry) entries.get(key)).addFile(changeLogFile);
        }
    }
}