/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.log4j.db;

import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.db.dialect.SQLDialect;
import org.apache.log4j.db.dialect.Util;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LocationInfo;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.xml.DOMConfigurator;
import org.apache.log4j.xml.UnrecognizedElementHandler;
import org.w3c.dom.Element;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;


/**
 * The DBAppender inserts loggin events into three database tables in a format
 * independent of the Java programming language. The three tables that
 * DBAppender inserts to must exists before DBAppender can be used. These tables
 * may be created with the help of SQL scripts found in the
 * <em>src/java/org/apache/log4j/db/dialect</em> directory. There is a
 * specific script for each of the most popular database systems. If the script
 * for your particular type of database system is missing, it should be quite
 * easy to write one, taking example on the already existing scripts. If you
 * send them to us, we will gladly include missing scripts in future releases.
 *
 * <p>
 * If the JDBC driver you are using supports the
 * {@link java.sql.Statement#getGeneratedKeys}method introduced in JDBC 3.0
 * specification, then you are all set. Otherwise, there must be an
 * {@link SQLDialect}appropriate for your database system. Currently, we have
 * dialects for PostgreSQL, MySQL, Oracle and MsSQL. As mentioed previously, an
 * SQLDialect is required only if the JDBC driver for your database system does
 * not support the {@link java.sql.Statement#getGeneratedKeys getGeneratedKeys}
 * method.
 * </p>
 *
 * <table border="1" cellpadding="4">
 * <caption>supported dialects</caption>
 * <tr>
 * <th>RDBMS</th>
 * <th>supports <br><code>getGeneratedKeys()</code> method</th>
 * <th>specific <br>SQLDialect support</th>
 * <tr>
 * <tr>
 * <td>PostgreSQL</td>
 * <td align="center">NO</td>
 * <td>present and used</td>
 * <tr>
 * <tr>
 * <td>MySQL</td>
 * <td align="center">YES</td>
 * <td>present, but not actually needed or used</td>
 * <tr>
 * <tr>
 * <td>Oracle</td>
 * <td align="center">YES</td>
 * <td>present, but not actually needed or used</td>
 * <tr>
 * <tr>
 * <td>DB2</td>
 * <td align="center">YES</td>
 * <td>not present, and not needed or used</td>
 * <tr>
 * <tr>
 * <td>MsSQL</td>
 * <td align="center">YES</td>
 * <td>not present, and not needed or used</td>
 * <tr>
 * <tr>
 *   <td>HSQL</td>
 *    <td align="center">NO</td>
 *    <td>present and used</td>
 * <tr>
 *
 * </table>
 * <p>
 * <b>Performance: </b> Experiments show that writing a single event into the
 * database takes approximately 50 milliseconds, on a "standard" PC. If pooled
 * connections are used, this figure drops to under 10 milliseconds. Note that
 * most JDBC drivers already ship with connection pooling support.
 * </p>
 *
 *
 *
 * <p>
 * <b>Configuration </b> DBAppender can be configured programmatically, or using
 * {@link org.apache.log4j.xml.DOMConfigurator JoranConfigurator}. Example
 * scripts can be found in the <em>tests/input/db</em> directory.
 *
 * @author Ceki G&uuml;lc&uuml;
 * @author Ray DeCampo
 */
public class DBAppender extends AppenderSkeleton implements UnrecognizedElementHandler {
  static final String insertPropertiesSQL =
    "INSERT INTO  logging_event_property (event_id, mapped_key, mapped_value) VALUES (?, ?, ?)";
  static final String insertExceptionSQL =
    "INSERT INTO  logging_event_exception (event_id, i, trace_line) VALUES (?, ?, ?)";
  static final String insertSQL;
  private static final Method GET_GENERATED_KEYS_METHOD;


  static {
    StringBuffer sql = new StringBuffer();
    sql.append("INSERT INTO logging_event (");
    sql.append("sequence_number, ");
    sql.append("timestamp, ");
    sql.append("rendered_message, ");
    sql.append("logger_name, ");
    sql.append("level_string, ");
    sql.append("ndc, ");
    sql.append("thread_name, ");
    sql.append("reference_flag, ");
    sql.append("caller_filename, ");
    sql.append("caller_class, ");
    sql.append("caller_method, ");
    sql.append("caller_line) ");
    sql.append(" VALUES (?, ?, ? ,?, ?, ?, ?, ?, ?, ?, ?, ?)");
    insertSQL = sql.toString();
    //
    //   PreparedStatement.getGeneratedKeys added in JDK 1.4
    //
    Method getGeneratedKeysMethod;
    try {
        getGeneratedKeysMethod = PreparedStatement.class.getMethod("getGeneratedKeys", null);
    } catch(Exception ex) {
        getGeneratedKeysMethod = null;
    }
    GET_GENERATED_KEYS_METHOD = getGeneratedKeysMethod;
  }

  ConnectionSource connectionSource;
  boolean cnxSupportsGetGeneratedKeys = false;
  boolean cnxSupportsBatchUpdates = false;
  SQLDialect sqlDialect;
  boolean locationInfo = false;
  

  public DBAppender() {
      super(false);
  }

  public void activateOptions() {
    LogLog.debug("DBAppender.activateOptions called");

    if (connectionSource == null) {
      throw new IllegalStateException(
        "DBAppender cannot function without a connection source");
    }

    sqlDialect = Util.getDialectFromCode(connectionSource.getSQLDialectCode());
    if (GET_GENERATED_KEYS_METHOD != null) {
        cnxSupportsGetGeneratedKeys = connectionSource.supportsGetGeneratedKeys();
    } else {
        cnxSupportsGetGeneratedKeys = false;
    }
    cnxSupportsBatchUpdates = connectionSource.supportsBatchUpdates();
    if (!cnxSupportsGetGeneratedKeys && (sqlDialect == null)) {
      throw new IllegalStateException(
        "DBAppender cannot function if the JDBC driver does not support getGeneratedKeys method *and* without a specific SQL dialect");
    }
    
    // all nice and dandy on the eastern front
    super.activateOptions();
  }

  /**
   * @return Returns the connectionSource.
   */
  public ConnectionSource getConnectionSource() {
    return connectionSource;
  }

  /**
   * @param connectionSource
   *          The connectionSource to set.
   */
  public void setConnectionSource(ConnectionSource connectionSource) {
    LogLog.debug("setConnectionSource called for DBAppender");
    this.connectionSource = connectionSource;
  }

  protected void append(LoggingEvent event) {
      Connection connection = null;
      try {
          connection = connectionSource.getConnection();
          connection.setAutoCommit(false);
          
          PreparedStatement insertStatement;
          if (cnxSupportsGetGeneratedKeys) {
        	  insertStatement = connection.prepareStatement(insertSQL, Statement.RETURN_GENERATED_KEYS);
          } else {
              insertStatement = connection.prepareStatement(insertSQL);
          }

/*          insertStatement.setLong(1, event.getSequenceNumber());*/
		  insertStatement.setLong(1, 0);
		
          insertStatement.setLong(2, event.getTimeStamp());
          insertStatement.setString(3, event.getRenderedMessage());
          insertStatement.setString(4, event.getLoggerName());
          insertStatement.setString(5, event.getLevel().toString());
          insertStatement.setString(6, event.getNDC());
          insertStatement.setString(7, event.getThreadName());
          insertStatement.setShort(8, DBHelper.computeReferenceMask(event));
          
          LocationInfo li;
          
          if (event.locationInformationExists() || locationInfo) {
              li = event.getLocationInformation();
          } else {
              li = LocationInfo.NA_LOCATION_INFO;
          }
          
          insertStatement.setString(9, li.getFileName());
          insertStatement.setString(10, li.getClassName());
          insertStatement.setString(11, li.getMethodName());
          insertStatement.setString(12, li.getLineNumber());
          
          int updateCount = insertStatement.executeUpdate();
          if (updateCount != 1) {
              LogLog.warn("Failed to insert loggingEvent");
          }
          
          ResultSet rs = null;
          Statement idStatement = null;
          boolean gotGeneratedKeys = false;
          if (cnxSupportsGetGeneratedKeys) {
              try {
                  rs = (ResultSet) GET_GENERATED_KEYS_METHOD.invoke(insertStatement, null);
                  gotGeneratedKeys = true;
              } catch(InvocationTargetException ex) {
                  Throwable target = ex.getTargetException();
                  if (target instanceof SQLException) {
                      throw (SQLException) target;
                  }
                  throw ex; 
              } catch(IllegalAccessException ex) {
                  LogLog.warn("IllegalAccessException invoking PreparedStatement.getGeneratedKeys", ex);
              }
          }
          
          if (!gotGeneratedKeys) {
              insertStatement.close();
              insertStatement = null;
              
              idStatement = connection.createStatement();
              idStatement.setMaxRows(1);
              rs = idStatement.executeQuery(sqlDialect.getSelectInsertId());
          }
          
          // A ResultSet cursor is initially positioned before the first row; the 
          // first call to the method next makes the first row the current row
          rs.next();
          int eventId = rs.getInt(1);
          
          rs.close();

          // we no longer need the insertStatement
          if(insertStatement != null) {
              insertStatement.close();
              insertStatement = null;
          }

          if(idStatement != null) {
              idStatement.close();
              idStatement = null;
          }

          Set propertiesKeys = event.getPropertyKeySet();
          
          if (propertiesKeys.size() > 0) {
              PreparedStatement insertPropertiesStatement =
                  connection.prepareStatement(insertPropertiesSQL);
              
              for (Iterator i = propertiesKeys.iterator(); i.hasNext();) {
                  String key = (String) i.next();
                  String value = event.getProperty(key);
                  
                  //LogLog.info("id " + eventId + ", key " + key + ", value " + value);
                  insertPropertiesStatement.setInt(1, eventId);
                  insertPropertiesStatement.setString(2, key);
                  insertPropertiesStatement.setString(3, value);
                  
                  if (cnxSupportsBatchUpdates) {
                      insertPropertiesStatement.addBatch();
                  } else {
                      insertPropertiesStatement.execute();
                  }
              }
              
              if (cnxSupportsBatchUpdates) {
                  insertPropertiesStatement.executeBatch();
              }
              
              insertPropertiesStatement.close();
              insertPropertiesStatement = null;
          }
          
          String[] strRep = event.getThrowableStrRep();
          
          if (strRep != null) {
              LogLog.debug("Logging an exception");
              
              PreparedStatement insertExceptionStatement =
                  connection.prepareStatement(insertExceptionSQL);
              
              for (short i = 0; i < strRep.length; i++) {
                  insertExceptionStatement.setInt(1, eventId);
                  insertExceptionStatement.setShort(2, i);
                  insertExceptionStatement.setString(3, strRep[i]);
                  if (cnxSupportsBatchUpdates) {
                      insertExceptionStatement.addBatch();
                  } else {
                      insertExceptionStatement.execute();
                  }
              }
              if (cnxSupportsBatchUpdates) {
                  insertExceptionStatement.executeBatch();
              }
              insertExceptionStatement.close();
              insertExceptionStatement = null;
          }
          
          connection.commit();
      } catch (Throwable sqle) {
          LogLog.error("problem appending event", sqle);
      } finally {
          DBHelper.closeConnection(connection);
      }
  }

  public void close() {
    closed = true;
  }

  /**
   * Returns value of the <b>LocationInfo </b> property which determines whether
   * caller's location info is written to the database.
   */
  public boolean getLocationInfo() {
    return locationInfo;
  }

  /**
   * If true, the information written to the database will include caller's
   * location information. Due to performance concerns, by default no location
   * information is written to the database.
   */
  public void setLocationInfo(boolean locationInfo) {
    this.locationInfo = locationInfo;
  }

    /**
     * Gets whether appender requires a layout.
     * @return false
     */
  public boolean requiresLayout() {
      return false;
  }

    /**
     * {@inheritDoc}
     */
  public boolean parseUnrecognizedElement(Element element, Properties props) throws Exception {
        if ("connectionSource".equals(element.getNodeName())) {
            Object instance =
                    DOMConfigurator.parseElement(element, props, ConnectionSource.class);
            if (instance instanceof ConnectionSource) {
               ConnectionSource source = (ConnectionSource) instance;
               source.activateOptions();
               setConnectionSource(source);
            }
            return true;
        }
        return false;
  }
}