/*******************************************************************************
    * Copyright (c) 2007, 2014 Massimiliano Ziccardi
    *
    * Licensed 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 it.jnrpe.plugin.mysql;
  
  import it.jnrpe.ICommandLine;
  import it.jnrpe.Status;
  import it.jnrpe.plugins.Metric;
  import it.jnrpe.plugins.MetricGatheringException;
  import it.jnrpe.plugins.PluginBase;
  import it.jnrpe.utils.BadThresholdException;
  import it.jnrpe.utils.thresholds.ThresholdsEvaluatorBuilder;
  
  import java.math.BigDecimal;
  import java.sql.Connection;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.sql.Statement;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * This plugin tests connections to a MySql server.
   * 
   * @author Frederico Campos
   */
  public class CheckMysql extends PluginBase {
  
  	/**
  	 * Configures the threshold evaluator. This plugin supports both the legacy
  	 * threshold format and the new format specification.
  	 * 
  	 * @param thrb
  	 *            - the evaluator to be configured
  	 * @param cl
  	 *            - the received command line
  	 * @throws BadThresholdException
  	 *             - if the threshold can't be parsed
  	 */
  	@Override
  	public final void configureThresholdEvaluatorBuilder(
  			final ThresholdsEvaluatorBuilder thrb, final ICommandLine cl)
  			throws BadThresholdException {
  		if (cl.hasOption("th")) {
  			super.configureThresholdEvaluatorBuilder(thrb, cl);
  		} else {
  			thrb.withLegacyThreshold("time", null,
  					cl.getOptionValue("warning"), cl.getOptionValue("critical"))
  					.withLegacyThreshold("secondsBehindMaster", null,
  							cl.getOptionValue("warning"),
  							cl.getOptionValue("critical"));
  		}
  	}
  
  	/**
  	 * Execute and gather metrics.
  	 * 
  	 * @param cl
  	 *            - The command line parameters
  	 * @throws MetricGatheringException
  	 *             - If any error occurs during metric gathering process
  	 * @return the gathered metrics
  	 */
  	@Override
  	public final Collection<Metric> gatherMetrics(final ICommandLine cl)
  			throws MetricGatheringException {
  		List<Metric> metrics = new ArrayList<Metric>();
  		Mysql mysql = new Mysql(cl);
  		long start = System.currentTimeMillis();
  		long elapsed = 0L;
  		Connection conn = null;
  		try {
  			conn = mysql.getConnection();
  			elapsed = (System.currentTimeMillis() - start) / 1000L;
  		} catch (ClassNotFoundException e) {
  			log.error("Mysql driver library not found into the classpath: "
  					+ "download and put it in the same directory "
  					+ "of this plugin");
  			throw new MetricGatheringException(
  					"Error accessing the MySQL server "
  							+ "- JDBC driver not installed", Status.CRITICAL, e);
  		} catch (Exception e) {
  			log.error("Error accessing the MySQL server", e);
  			throw new MetricGatheringException(
 					"Error accessing the MySQL server - " + e.getMessage(),
 					Status.CRITICAL, e);
 		}
 
 		if (cl.hasOption("check-slave")) {
 			metrics.add(checkSlave(cl, mysql, conn));
 		} else {
 			metrics.add(new Metric("time", "Connection took " + elapsed
 					+ " secs. ", new BigDecimal(elapsed), new BigDecimal(0),
 					null));
 		}
 		mysql.closeConnection(conn);
 		return metrics;
 	}
 
 	/**
 	 * Check the status of mysql slave thread.
 	 * 
 	 * @param cl
 	 *            The command line
 	 * @param mysql
 	 *            MySQL connection mgr object
 	 * @param conn
 	 *            The SQL connection
 	 * @return ReturnValue -
 	 * @throws MetricGatheringException
 	 *             -
 	 */
 	private Metric checkSlave(final ICommandLine cl, final Mysql mysql,
 			final Connection conn) throws MetricGatheringException {
 		Metric metric = null;
 		try {
 			Map<String, Integer> status = getSlaveStatus(conn);
 			if (status.isEmpty()) {
 				mysql.closeConnection(conn);
 				throw new MetricGatheringException(
 						"CHECK_MYSQL - WARNING: No slaves defined. ",
 						Status.CRITICAL, null);
 			}
 
 			// check if slave is running
 			int slaveIoRunning = status.get("Slave_IO_Running");
 			int slaveSqlRunning = status.get("Slave_SQL_Running");
 			int secondsBehindMaster = status.get("Seconds_Behind_Master");
 
 			if (slaveIoRunning == 0 || slaveSqlRunning == 0) {
 				mysql.closeConnection(conn);
 				throw new MetricGatheringException(
 						"CHECK_MYSQL - CRITICAL: Slave status unavailable. ",
 						Status.CRITICAL, null);
 			}
 			String slaveResult = "Slave IO: " + slaveIoRunning + " Slave SQL: "
 					+ slaveSqlRunning + " Seconds Behind Master: "
 					+ secondsBehindMaster;
 
 			metric = new Metric("secondsBehindMaster", slaveResult,
 					new BigDecimal(secondsBehindMaster), null, null);
 		} catch (SQLException e) {
 			log.warn(
 					"Error executing the CheckMysql plugin: " + e.getMessage(),
 					e);
 			throw new MetricGatheringException(
 					"CHECK_MYSQL - CRITICAL: Unable to check slave status:  - "
 							+ e.getMessage(), Status.CRITICAL, e);
 		}
 
 		return metric;
 
 	}
 
 	/**
 	 * Get slave statuses.
 	 * 
 	 * @param conn
 	 *            The database connection
 	 * @return The slave status info
 	 * @throws SQLException
 	 *             -
 	 */
 	private Map<String, Integer> getSlaveStatus(final Connection conn)
 			throws SQLException {
 		Map<String, Integer> map = new HashMap<String, Integer>();
 		String query = "show slave status;";
 		Statement statement = null;
 		ResultSet rs = null;
 		try {
 			if (conn != null) {
 				statement = conn.createStatement();
 				rs = statement.executeQuery(query);
 				while (rs.next()) {
 					map.put("Slave_IO_Running", rs.getInt("Slave_IO_Running"));
 					map.put("Slave_SQL_Running", rs.getInt("Slave_SQL_Running"));
 					map.put("Seconds_Behind_Master",
 							rs.getInt("Seconds_Behind_Master"));
 				}
 			}
 		} finally {
 			if (statement != null) {
 				statement.close();
 			}
 		}
 		return map;
 	}
 
 	@Override
 	protected final String getPluginName() {
 		return "CHECK_MYSQL";
 	}
 }