/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, 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 General Public License for more details.
 *
 * You should have received a copy of the GNU 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.
 *
 * http://www.gnu.org/copyleft/gpl.html
 */
package com.festina.gameserver.idfactory;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Stack;
import java.util.logging.Logger;

import com.festina.Config;
import com.festina.L2DatabaseFactory;

/**
 * This class ...
 * 
 * @version $Revision: 1.3.2.1.2.7 $ $Date: 2005/04/11 10:06:12 $
 */
public class StackIDFactory extends IdFactory
{
	private static Logger _log = Logger.getLogger(IdFactory.class.getName());

	private int _curOID;
	private int _tempOID;
	
	private Stack<Integer> _freeOIDStack = new Stack<Integer>();

	protected StackIDFactory()
	{
        super();
        _curOID = FIRST_OID;
        _tempOID = FIRST_OID;

        java.sql.Connection con = null;
        try
        {
            con = L2DatabaseFactory.getInstance().getConnection();
            //con.createStatement().execute("drop table if exists tmp_obj_id");
            
            int[] tmp_obj_ids = extractUsedObjectIDTable();
            if (tmp_obj_ids.length > 0)
            {
                _curOID = tmp_obj_ids[tmp_obj_ids.length-1];
            }
            _log.info("Max Id = " + _curOID);
            
            int N = tmp_obj_ids.length;
            for (int idx = 0; idx < N; idx++)
            {
                N = insertUntil(tmp_obj_ids, idx, N, con);
            }

            _curOID++;
            _log.config("IdFactory: Next usable Object ID is: " + _curOID);
            initialized = true;
        }
        catch (Exception e1)
        {
			e1.printStackTrace();
            _log.severe("ID Factory could not be initialized correctly:" + e1);
        }
        finally
        {
            try { con.close(); } catch (Exception e) {}
        }
	}
    
	private int insertUntil(int[] tmp_obj_ids, int idx, int N,
            java.sql.Connection con) throws SQLException
    {
        int id = tmp_obj_ids[idx];
        if (id == _tempOID)
        {
        	_tempOID++;
            return N;
        }
        // check these IDs not present in DB
        if (Config.BAD_ID_CHECKING)
        {
        for (String check : id_checks)
        {
            PreparedStatement ps = con.prepareStatement(check);
            ps.setInt(1, _tempOID);
            //ps.setInt(1, _curOID);
            ps.setInt(2, id);
            ResultSet rs = ps.executeQuery();
            while (rs.next())
            {
                int badId = rs.getInt(1);
                _log.severe("Bad ID " + badId + " in DB found by: " + check);
                throw new RuntimeException();
            }
            rs.close();
            ps.close();
        }
        }
        
        //int hole = id - _curOID;
        int hole = id - _tempOID;
        if (hole > N - idx) hole = N - idx;
        for (int i = 1; i <= hole; i++)
        {
            //System.out.println("Free ID added " + (_tempOID));
            _freeOIDStack.push(_tempOID);
            _tempOID++;
            //_curOID++;
        }
        if (hole < N - idx) _tempOID++;
        return N - hole;
    }
	
	public static IdFactory getInstance()
	{
        return _instance;
	}


	public synchronized int getNextId()
    {
        	int id;
        	if (!_freeOIDStack.empty())
        		id = _freeOIDStack.pop();
        	else
        	{
        		id = _curOID;
        		_curOID = _curOID+1;
        	}
        	return id;
    }
	
	/**
	 * return a used Object ID back to the pool
	 * @param object ID
	 */
	public synchronized void releaseId(int id)
    {
		_freeOIDStack.push(id);
    }
    
    public int size()
    {
        return FREE_OBJECT_ID_SIZE - _curOID + FIRST_OID + _freeOIDStack.size();
    }
}