/*

     StatCvs - CVS statistics generation 

     Copyright (C) 2002  Lukasz Pekacki <lukasz@pekacki.de>

     http://statcvs.sf.net/

     This library is free software; you can redistribute it and/or

     modify it under the terms of the GNU Lesser General Public

     License as published by the Free Software Foundation; either

     version 2.1 of the License, or (at your option) any later version.

     This library is distributed in the hope that it will be useful,

     but WITHOUT ANY WARRANTY; without even the implied warranty of

     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

     Lesser General Public License for more details.

     You should have received a copy of the GNU Lesser General Public

     License along with this library; if not, write to the Free Software

     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

         $Name:  $ 

         Created on $Date: 2008/04/02 11:22:15 $ 

 */

 package net.sf.statcvs.input;

 import java.util.Date;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.LinkedList;

 import java.util.List;

 import java.util.Map;

 import java.util.SortedSet;

 import net.sf.statcvs.model.Commit;

 import net.sf.statcvs.model.Revision;

 /**

  * Takes a set of revisions, and builds a <code>List</code> of 

  * {@link Commit}s from it. The result list is sorted by date.

  * 

  * The implementation allows for a tolerance of several minutes

  * between individual file commits, but author and message must be identical.

  * 

  * @author Richard Cyganiak

  * @version $Id: CommitListBuilder.java,v 1.5 2008/04/02 11:22:15 benoitx Exp $

  */

 public class CommitListBuilder {

     private static final int MAX_TIME_BETWEEN_CHANGES_MILLISECONDS = 300000;

     private final Iterator revisions;

     private final Map currentCommits = new HashMap();

     private List commits;

     /**

      * Creates a new instance using the given set of {@link Revision}s.

      * The set must be sorted by date, oldest first.

      * 

      * @param revisions a set of {@link Revision}s

      */

     public CommitListBuilder(final SortedSet revisions) {

         this(revisions.iterator());

     }

     public CommitListBuilder(final Iterator revisions) {

         this.revisions = revisions;

     }

     /**

      * Creates a <code>List</code> of {@link Commit}s from the source iterator.

      * The result list will be sorted by date.

      * 

      * @return a new list of {@link Commit} objects

      */

     public List createCommitList() {

         if (commits != null) {

             return commits;

         }

         commits = new LinkedList();

         while (revisions.hasNext()) {

             processRevision((Revision) revisions.next());

         }

         return commits;

     }

     protected void processRevision(final Revision rev) {

         if (rev.getAuthor() == null) {

             return;

         }

         final Commit commit = (Commit) currentCommits.get(rev.getAuthor());

         if (commit == null || !isSameCommit(commit, rev)) {

             addNewCommit(rev);

         } else {

             addRevToCommit(commit, rev);

         }

     }

     protected void addNewCommit(final Revision rev) {

         final Commit newCommit = new Commit(rev);

         currentCommits.put(rev.getAuthor(), newCommit);

         commits.add(newCommit);

     }

     protected void addRevToCommit(final Commit commit, final Revision rev) {

         commit.addRevision(rev);

     }

     /**

      * Returns <code>true</code> if change is part of the commit, that is if

      * they have the same author, the same message, and are within the same

      * timeframe.

      * 

      * @param commit the commit

      * @param rev the revision to check against this commit

      * @return <code>true</code> if change is part of this commit

      */

     public static boolean isSameCommit(final Commit commit, final Revision rev) {

         return commit.getAuthor().equals(rev.getAuthor()) && commit.getComment().equals(rev.getComment()) && isInTimeFrame(commit, rev.getDate());

     }

     /**

      * Returns <code>true</code> if the date lies within the timespan of

      * the commit, plus/minus a tolerance.

      * 

      * @param date the date to check against this commit

      * @return <code>true</code> if the date lies within the timespan of the commit

      */

     public static boolean isInTimeFrame(final Commit commit, final Date date) {

         return date.getTime() > (commit.getDate().getTime() - MAX_TIME_BETWEEN_CHANGES_MILLISECONDS)

                 && (date.getTime() < commit.getDate().getTime() + MAX_TIME_BETWEEN_CHANGES_MILLISECONDS);

     }

 }