/*
    * 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.hadoop.chukwa.util;
  
  import java.sql.SQLException;
  import java.sql.Connection;
  import java.sql.Statement;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.util.List;
  import java.text.SimpleDateFormat;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  public class DatabaseWriter {
    private static Log log = LogFactory.getLog(DatabaseWriter.class);
    private Connection conn = null;
    private Statement stmt = null;
    private PreparedStatement pstmt = null;
    private ResultSet rs = null;
  
    public DatabaseWriter(String host, String user, String password) {
      String jdbc_url = "jdbc:mysql://" + host + "/";
      if (user != null) {
        jdbc_url = jdbc_url + "?user=" + user;
        if (password != null) {
          jdbc_url = jdbc_url + "&password=" + password;
        }
      }
      try {
        // The newInstance() call is a work around for some
        // broken Java implementations
        DriverManagerUtil.loadDriver().newInstance();
      } catch (Exception ex) {
        // handle the error
        log.error(ex, ex);
      }
      try {
        conn = org.apache.hadoop.chukwa.util.DriverManagerUtil.getConnection(jdbc_url);
        log.debug("Initialized JDBC URL: " + jdbc_url);
      } catch (SQLException ex) {
        log.error(ex, ex);
      }
    }
  
    public DatabaseWriter(String cluster) {
      ClusterConfig cc = new ClusterConfig();
      String jdbc_url = cc.getURL(cluster);
      try {
        // The newInstance() call is a work around for some
        // broken Java implementations
        DriverManagerUtil.loadDriver().newInstance();
      } catch (Exception ex) {
        // handle the error
        log.error(ex, ex);
      }
      try {
        conn = org.apache.hadoop.chukwa.util.DriverManagerUtil.getConnection(jdbc_url);
        log.debug("Initialized JDBC URL: " + jdbc_url);
      } catch (SQLException ex) {
        log.error(ex, ex);
      }
    }
  
    public void execute(String query) throws SQLException {
      try {
        stmt = conn.createStatement();
        stmt.execute(query);
      } catch (SQLException ex) {
        // handle any errors
        log.error(ex, ex);
        log.error("SQL Statement:" + query);
        log.error("SQLException: " + ex.getMessage());
        log.error("SQLState: " + ex.getSQLState());
        log.error("VendorError: " + ex.getErrorCode());
        throw ex;
      } finally {
        if (stmt != null) {
          try {
            stmt.close();
          } catch (SQLException sqlEx) {
            // ignore
            log.debug(ExceptionUtil.getStackTrace(sqlEx));
         }
         stmt = null;
       }
     }
   }
 
   public Connection getConnection() {
     return conn;
   }
 
   public ResultSet query(String query, List<Object> parameters) throws SQLException {
     try {
       pstmt = conn.prepareStatement(query);
       for(int i=0;i<parameters.size();i++) {
         int index = i+1;
         pstmt.setObject(index,parameters.get(i));
       }
       rs = pstmt.executeQuery();
     } catch (SQLException ex) {
       // handle any errors
       //only log at debug level because caller will still see exception
       log.debug(ex, ex);
       log.debug("SQL Statement:" + query);
       log.debug("SQLException: " + ex.getMessage());
       log.debug("SQLState: " + ex.getSQLState());
       log.debug("VendorError: " + ex.getErrorCode());
       throw ex;
     }
     return rs;
   }
 
   public ResultSet query(String query) throws SQLException {
     try {
       stmt = conn.createStatement();
       rs = stmt.executeQuery(query);
     } catch (SQLException ex) {
       // handle any errors
       //only log at debug level because caller will still see exception
       log.debug(ex, ex);
       log.debug("SQL Statement:" + query);
       log.debug("SQLException: " + ex.getMessage());
       log.debug("SQLState: " + ex.getSQLState());
       log.debug("VendorError: " + ex.getErrorCode());
       throw ex;
     }
     return rs;
   }
 
   public void close() {
     // it is a good idea to release
     // resources in a finally{} block
     // in reverse-order of their creation
     // if they are no-longer needed
     if (rs != null) {
       try {
         rs.close();
       } catch (SQLException sqlEx) {
         // ignore
         log.debug(ExceptionUtil.getStackTrace(sqlEx));
       }
       rs = null;
     }
     if (stmt != null) {
       try {
         stmt.close();
       } catch (SQLException sqlEx) {
         // ignore
         log.debug(ExceptionUtil.getStackTrace(sqlEx));
       }
       stmt = null;
     }
     if (conn != null) {
       try {
         conn.close();
       } catch (SQLException sqlEx) {
         // ignore
         log.debug(ExceptionUtil.getStackTrace(sqlEx));
       }
       conn = null;
     }
   }
 
   public static String formatTimeStamp(long timestamp) {
     SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
     String format = formatter.format(timestamp);
 
     return format;
   }
 }