/*
 * 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.
 */
package org.apache.maven.svnlib;

import java.util.Collection;
import java.util.List;
import java.util.ArrayList;
import java.util.Date;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.text.SimpleDateFormat;
import java.io.IOException;
import org.apache.maven.changelog.ChangeLogParser;
import org.apache.maven.changelog.ChangeLogEntry;
import org.apache.tools.ant.types.Commandline;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


/**
 * A Subversion implementation of the {@link org.apache.maven.ChangeLogGenerator}
 * which which overcomess Subversion Bug 752.
 * 
 * This implementation uses the <i>svn log</i> command to retrieve ALL log entries
 * and then filters out those not in the specified date range.
 *
 * @author Niall Pemberton
 * @version $Id$
 * @see <a href="http://subversion.tigris.org/issues/show_bug.cgi?id=752">Subversion Bug 752</a>
 */
public class SvnBug752ChangeLogGenerator extends SvnChangeLogGenerator {
    
    /** Logger */
    private static final Log LOG = LogFactory.getLog(SvnBug752ChangeLogGenerator.class);

    /** First Date to process */
    private Date internalStartDate = new Date((long)0);
    
    /** Last Date to process */
    private Date internalEndDate = new Date();
    
    /**
     * Sets the log start string based on the given date.
     * @param start  date the log started.
     */
    protected void setLogStart(Date start) {
        super.setLogStart(start);
      
        // reset start date to 00:00:00
        SimpleDateFormat yyyyMMdd       = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat yyyyMMddHHmmss = new SimpleDateFormat("yyyy-MM-ddHH:mm:ss z");
        String tempDate = yyyyMMdd.format(start) + "00:00:00 GMT";
        try {
            internalStartDate = yyyyMMddHHmmss.parse(tempDate);
        } catch (Exception e) {
            internalStartDate = start;
        }
    }
    
    /**
     * Sets the log end string based on the given date.
     * @param end  date the log ended.
     */
    protected void setLogEnd(Date end) {
        super.setLogEnd(end);
        
        // reset end date to 23:59:59
        SimpleDateFormat yyyyMMdd       = new SimpleDateFormat("yyyy-MM-dd");
        SimpleDateFormat yyyyMMddHHmmss = new SimpleDateFormat("yyyy-MM-ddHH:mm:ss z");
        String tempDate = yyyyMMdd.format(end) + "23:59:59 GMT";
        try {
            internalEndDate = yyyyMMddHHmmss.parse(tempDate);
        } catch (Exception e) {
            internalEndDate = end;
        }
    }
    
    /**
     * Return a Collection of ChangeLogEntry objects.
     * 
     * This implementations retrieves all log entries, filters
     * them on date and sorts.
     * 
     * @param parser The parser to process the <i>svn log</i> output.
     * @return A Collection of ChangeLogEntry entries parsed
     *         from the <i>svn log</i> output. 
     * @throws IOException When there are issues executing <i>svm</i>.
     */
    public Collection getEntries(ChangeLogParser parser) throws IOException {
        
        // Get All log entries
        super.getEntries(parser);
        
        if (LOG.isInfoEnabled()) {
            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
            LOG.info("Start=[" + format.format(internalStartDate) +
                     "] End=[" + format.format(internalEndDate) + 
                     "] entries=[" + entries.size() +"]");
        }
        
        // Filter the collection on the date range
        List filteredEntries = new ArrayList();
        Iterator iterator = entries.iterator();
        while (iterator.hasNext()) {
            ChangeLogEntry entry = (ChangeLogEntry)iterator.next();
            Date entryDate = entry.getDate();
            if (entryDate.after(internalStartDate) &&
                entryDate.before(internalEndDate)) {
                filteredEntries.add(entry);
            }
        }

        // Create Date Comparator for ChangeLogEntry's
        Comparator comparator = new Comparator() {
            public int compare(Object object1, Object object2) {
                ChangeLogEntry entry1 = (ChangeLogEntry)object1;
                ChangeLogEntry entry2 = (ChangeLogEntry)object2;
                
                // Compare Dates
                int compare = entry1.getDate().compareTo(entry2.getDate());
                
                // Invert so that sort is descending
                return (compare * -1);
            }
        };

        // Sort the entries
        Collections.sort(filteredEntries, comparator);

        if (LOG.isInfoEnabled()) {
            LOG.info("Filtered Entries = " + filteredEntries.size());
        }

        return filteredEntries;
        
    }
    
    /**
     * Construct the command line to execute the <i>svn log</i>
     * command for all revisions.
     * 
     * @return The command to be executed.
     */
    protected Commandline getScmLogCommand() {
        Commandline command = new Commandline();
        command.setExecutable("svn");
        command.createArgument().setValue("log");
        command.createArgument().setValue("-v");
        return command;
    }

}