/*******************************************************************************
    * 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;
  
  import it.jnrpe.ICommandLine;
  import it.jnrpe.plugin.utils.SshUtils;
  import it.jnrpe.plugins.Metric;
  import it.jnrpe.plugins.MetricGatheringException;
  import it.jnrpe.plugins.PluginBase;
  import it.jnrpe.plugins.annotations.Option;
  import it.jnrpe.plugins.annotations.Plugin;
  import it.jnrpe.plugins.annotations.PluginOptions;
  import it.jnrpe.utils.BadThresholdException;
  import it.jnrpe.utils.thresholds.ThresholdsEvaluatorBuilder;
  
  import java.math.BigDecimal;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import com.jcraft.jsch.Channel;
  import com.jcraft.jsch.Session;
  
  /**
   * Plugin to check ssh connections on a remote host.
   * 
   * @author Frederico Campos
   * 
   */
  
  @Plugin(name = "CHECK_SSH", description = "Try to connect to an SSH server at specified server and port.\n"
  		+ "EXAMPLES:\n"
  		+ "The example will be based upon the following command definition (ini file)\n\n"
  		+ "check_ssh : CHECK_SSH --hostname $ARG1$ --port $ARG2$ --password $ARG3$ \n"
  		+ "check_nrpe -H myjnrpeserver -c check_ssh -a myhostname 22 password")
  @PluginOptions({
  		@Option(shortName = "h", longName = "hostname", description = "IP or hostname", required = true, hasArgs = true, argName = "hostname", optionalArgs = false, option = "hostname"),
  		@Option(shortName = "p", longName = "port", description = "Port number. Default is 22.", required = false, hasArgs = true, argName = "port", optionalArgs = false, option = "port"),
  		@Option(shortName = "u", longName = "username", description = "Username.", required = false, hasArgs = true, argName = "username", optionalArgs = false, option = "username"),
  		@Option(shortName = "P", longName = "password", description = "Password.", required = false, hasArgs = true, argName = "hostname", optionalArgs = false, option = "password"),
  		@Option(shortName = "t", longName = "timeout", description = "Seconds before connection times out (default: 10)", required = false, hasArgs = true, argName = "timeout", optionalArgs = false, option = "timeout") })
  public class CheckSsh extends PluginBase {
  
  	/**
  	 * @TODO
  	 * 
  	 *       - ssh key authentication
  	 * 
  	 *       - remote-version check option
  	 * 
  	 */
  
  	@Override
  	protected String getPluginName() {
  		return "CHECK_SSH";
  	}
  
  	@Override
  	public final void configureThresholdEvaluatorBuilder(
  			final ThresholdsEvaluatorBuilder thrb, final ICommandLine cl)
  			throws BadThresholdException {
  		thrb.withLegacyThreshold("connected", "1:", null, "0");
  	}
  
  	@Override
  	public final Collection<Metric> gatherMetrics(final ICommandLine cl)
  			throws MetricGatheringException {
  		List<Metric> metrics = new ArrayList<Metric>();
  		Session session = null;
  		try {
  			session = SshUtils.getSession(cl);
  			Channel channel = session.openChannel("shell");
  			channel.setInputStream(System.in);
  
  			channel.setOutputStream(System.out);
  			channel.connect();
  			metrics.add(new Metric("connected", "", new BigDecimal(1), null,
  					null));
  			channel.disconnect();
  			session.disconnect();
  
  		} catch (Exception e) {
  			metrics.add(new Metric("connected", e.getMessage(), new BigDecimal(
  					0), null, null));
  			log.debug(e.getMessage(), e);
  		}
 		return metrics;
 	}
 
 }