/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
*/

package com.klopotek.utils.log;

import java.sql.*;
import java.util.*;
import org.apache.log4j.*;
import org.apache.log4j.helpers.*;
import org.apache.log4j.spi.*;


/**
This class encapsulate the logic which is necessary to log into a table.
Used by JDBCAppender

Author : Thomas Fenner

@since 1.0
*/
public class JDBCLogger
{
	//All columns of the log-table
	private ArrayList logcols = null;
   //Only columns which will be provided by logging
   private String column_list = null;
   //Number of all columns
	private int num = 0;
   //Status for successful execution of method configure()
	private boolean isconfigured = false;
   //Status for ready to do logging with method append()
	private boolean ready = false;
   //This message will be filled with a error-string when method ready() failes, and can be got by calling getMsg()
   private String errormsg = "";

	private Connection con = null;
	private Statement stmt = null;
	private ResultSet rs = null;
   private String table = null;

   //Variables for static SQL-statement logging
   private String sql = null;
	private String new_sql = null;
   private String new_sql_part1 = null;
   private String new_sql_part2 = null;
   private static final String msg_wildcard = "@MSG@";
	private int msg_wildcard_pos = 0;

	/**
	Writes a message into the database table.
	Throws an exception, if an database-error occurs !
	*/
	public void append(String _msg) throws Exception
	{
		if(!ready) if(!ready()) throw new Exception("JDBCLogger::append(), Not ready to append !");

      if(sql != null)
      {
      	appendSQL(_msg);
         return;
      }

		LogColumn logcol;

		rs.moveToInsertRow();

		for(int i=0; i 0)
      {
			new_sql = new_sql_part1 + _msg + new_sql_part2;
      }
		else new_sql = sql;

      try
      {
			stmt.executeUpdate(new_sql);
      }
      catch(Exception e)
      {
      	errormsg = new_sql;
         throw e;
		}
	}


	/**
	Configures this class, by reading in the structure of the log-table
	Throws an exception, if an database-error occurs !
	*/
	public void configureTable(String _table) throws Exception
	{
   	if(isconfigured) return;

		//Fill logcols with META-informations of the table-columns
		stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
		rs = stmt.executeQuery("SELECT * FROM " + _table + " WHERE 1 = 2");

		LogColumn logcol;

		ResultSetMetaData rsmd = rs.getMetaData();

		num = rsmd.getColumnCount();

		logcols = new ArrayList(num);

		for(int i=1; i<=num; i++)
		{
			logcol = new LogColumn();
			logcol.name = rsmd.getColumnName(i).toUpperCase();
			logcol.type = rsmd.getColumnTypeName(i);
			logcol.nullable = (rsmd.isNullable(i) == rsmd.columnNullable);
         logcol.isWritable = rsmd.isWritable(i);
         if(!logcol.isWritable) logcol.ignore = true;
         logcols.add(logcol);
		}

      table = _table;

		isconfigured = true;
	}

	/**
	Configures this class, by storing and parsing the given sql-statement.
	Throws an exception, if somethings wrong !
	*/
	public void configureSQL(String _sql) throws Exception
	{
   	if(isconfigured) return;

		if(!isConnected()) throw new Exception("JDBCLogger::configureSQL(), Not connected to database !");

		if(_sql == null || _sql.trim().equals("")) throw new Exception("JDBCLogger::configureSQL(), Invalid SQL-Statement !");

		sql = _sql.trim();

      stmt = con.createStatement();

		msg_wildcard_pos = sql.indexOf(msg_wildcard);

      if(msg_wildcard_pos > 0)
      {
			new_sql_part1 = sql.substring(0, msg_wildcard_pos-1) + "'";
         //between the message...
         new_sql_part2 = "'" + sql.substring(msg_wildcard_pos+msg_wildcard.length());
		}

		isconfigured = true;
	}

	/**
   Sets a connection. Throws an exception, if the connection is not open !
	*/
	public void setConnection(Connection _con) throws Exception
	{
		con = _con;

		if(!isConnected()) throw new Exception("JDBCLogger::setConnection(), Given connection isnt connected to database !");
	}


	/**
	Sets a columns logtype (LogTypes) and value, which depends on that logtype.
	Throws an exception, if the given arguments arent correct !
   */
	public void setLogType(String _name, int _logtype, Object _value) throws Exception
	{
		if(!isconfigured) throw new Exception("JDBCLogger::setLogType(), Not configured !");

		//setLogType() makes only sense for further configuration of configureTable()
      if(sql != null) return;

      _name = _name.toUpperCase();

		if(_name == null || !(_name.trim().length() > 0)) throw new Exception("JDBCLogger::setLogType(), Missing argument name !");
		if(!LogType.isLogType(_logtype)) throw new Exception("JDBCLogger::setLogType(), Invalid logtype '" + _logtype + "' !");
		if((_logtype != LogType.MSG && _logtype != LogType.EMPTY) && _value == null) throw new Exception("JDBCLogger::setLogType(), Missing argument value !");

  		LogColumn logcol;

		for(int i=0; i