/* 
    JSPWiki - a JSP-based WikiWiki clone.

    Copyright (C) 2001 Janne Jalkanen (Janne.Jalkanen@iki.fi)

    This program 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 program 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 program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package com.ecyrd.jspwiki;


import java.io.IOException;
import java.io.BufferedReader;
import java.io.StringReader;

/**
 * SearchMatcher performs the task of matching a search query to a page's 
 * contents. This utility class is isolated to simplify WikiPageProvider
 * implementations and to offer an easy target for upgrades. The upcoming(?)
 * TranslatorReader rewrite will presumably invalidate this, among other things.
 *
 * @since 2.1.5
 * @author ebu at ecyrd dot com
 */
// FIXME: Move to the "search" -package
public class SearchMatcher
{
    private QueryItem[] m_queries;
    private WikiEngine m_engine;

    public SearchMatcher( WikiEngine engine, QueryItem[] queries )
    {
        m_engine = engine;
        m_queries = queries;
    }

    /**
     * Compares the page content, available through the given stream, to the
     * query items of this matcher. Returns a search result object describing
     * the quality of the match.
     *
     * <p>This method would benefit of regexps (1.4) and streaming. FIXME!
     */
    public SearchResult matchPageContent( String wikiname, String pageText )
        throws IOException
    {
        if( m_queries == null )
        {
            return( null );
        }

        int scores[] = new int[ m_queries.length ];
        BufferedReader in = new BufferedReader( new StringReader( pageText ) );
        String line = null;
            
        while( (line = in.readLine()) != null )
        {
            line = line.toLowerCase();

            for( int j = 0; j < m_queries.length; j++ )
            {
                int index = -1;
                
                while( (index = line.indexOf( m_queries[j].word, index+1 )) != -1 )
                {
                    if( m_queries[j].type != QueryItem.FORBIDDEN )
                    {
                        scores[j]++; // Mark, found this word n times
                    }
                    else
                    {
                        // Found something that was forbidden.
                        return( null );
                    }
                }
            }
        }
        
        //
        //  Check that we have all required words.
        //
        
        int totalscore = 0;
        
        for( int j = 0; j < scores.length; j++ )
        {
            // Give five points for each occurrence
            // of the word in the wiki name.
            
            if( wikiname.toLowerCase().indexOf( m_queries[j].word ) != -1 &&
                m_queries[j].type != QueryItem.FORBIDDEN )
                scores[j] += 5;
            
            //  Filter out pages if the search word is marked 'required'
            //  but they have no score.
            
            if( m_queries[j].type == QueryItem.REQUIRED && scores[j] == 0 )
            {
                return( null );
            }
            
            //
            //  Count the total score for this page.
            //
            totalscore += scores[j];
        }
        
        if( totalscore > 0 )
        {
            return( new SearchResultImpl( wikiname, totalscore ) );
        }

        return( null );
    }

    public class SearchResultImpl
        implements SearchResult
    {
        int      m_score;
        WikiPage m_page;
        
        public SearchResultImpl( String name, int score )
        {
            m_page  = new WikiPage( m_engine, name );
            m_score = score;
        }
        
        public WikiPage getPage()
        {
            return m_page;
        }
        
        public int getScore()
        {
            return m_score;
        }
    }
    
}