/*******************************************************************************
    * 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.commands;
  
  import it.jnrpe.JNRPELIB;
  import it.jnrpe.ReturnValue;
  import it.jnrpe.Status;
  import it.jnrpe.events.EventsUtil;
  import it.jnrpe.events.IJNRPEEventListener;
  import it.jnrpe.events.LogEvent;
  import it.jnrpe.plugins.IPluginRepository;
  import it.jnrpe.plugins.PluginProxy;
  
  import java.util.Collection;
  import java.util.regex.Matcher;
  
  /**
   * This class is used to invoke a command.
   * 
   * @author Massimiliano Ziccardi
   * 
   */
  public final class CommandInvoker {
  	/**
  	 * <code>true</code> if the variable parameters ($ARG?$) must be
  	 * interpolated.
  	 */
  	private final boolean acceptParams;
  
  	/**
  	 * The plugin repository to be used to find the plugins.
  	 */
  	private final IPluginRepository pluginRepository;
  
  	/**
  	 * The command repository to be used to find the commands.
  	 */
  	private final CommandRepository commandRepository;
  
  	/**
  	 * The listeners.
  	 */
  	private final Collection<IJNRPEEventListener> listenersList;
  
  	/**
  	 * Builds and initializes the {@link CommandInvoker} object.
  	 * 
  	 * @param pluginRepo
  	 *            The plugin repository containing all the plugins that must be
  	 *            used by this invoker.
  	 * @param commandRepo
  	 *            The command repository containing all the commands that must
  	 *            be used by this invoker.
  	 * @param listeners
  	 *            All the listeners
  	 */
  	public CommandInvoker(final IPluginRepository pluginRepo,
  			final CommandRepository commandRepo, final boolean acceptParams,
  			final Collection<IJNRPEEventListener> listeners) {
  		this.acceptParams = acceptParams;
  		pluginRepository = pluginRepo;
  		commandRepository = commandRepo;
  		listenersList = listeners;
  	}
  
  	/**
  	 * This method executes built in commands or builds a CommandDefinition to.
  	 * execute external commands (plugins). The methods also expands the $ARG?$
  	 * macros.
  	 * 
  	 * @param commandName
  	 *            The name of the command, as configured in the server
  	 *            configuration XML
  	 * @param argsAry
  	 *            The arguments to pass to the command as configured in the
  	 *            server configuration XML (with the $ARG?$ macros)
  	 * @return The result of the command
  	 */
  	public ReturnValue invoke(final String commandName, final String[] argsAry) {
  		if ("_NRPE_CHECK".equals(commandName)) {
  			return new ReturnValue(Status.OK, JNRPELIB.VERSION);
  		}
  
  		CommandDefinition cd = commandRepository.getCommand(commandName);
  
  		if (cd == null) {
 			return new ReturnValue(Status.UNKNOWN, "Bad command");
 		}
 
 		return invoke(cd, argsAry);
 	}
 
 	/**
 	 * This method executes external commands (plugins) The methods also expands
 	 * the $ARG?$ macros.
 	 * 
 	 * @param cd
 	 *            The command definition
 	 * @param argsAry
 	 *            The arguments to pass to the command as configured in the
 	 *            server configuration XML (with the $ARG?$ macros)
 	 * @return The result of the command
 	 */
 	public ReturnValue invoke(final CommandDefinition cd, final String[] argsAry) {
 		String pluginName = cd.getPluginName();
 		try {
 
 			String[] commandLine = cd.getCommandLine();
 
 			if (acceptParams) {
 				for (int j = 0; commandLine != null && j < commandLine.length; j++) {
 					for (int i = 0; i < argsAry.length; i++) {
 						commandLine[j] = commandLine[j].replaceAll(
 								"\\$[Aa][Rr][Gg]" + (i + 1) + "\\$",
 								Matcher.quoteReplacement(argsAry[i]));
 					}
 				}
 			}
 
 			PluginProxy plugin = (PluginProxy) pluginRepository
 					.getPlugin(pluginName);
 
 			if (plugin == null) {
 				EventsUtil.sendEvent(listenersList, this, LogEvent.INFO,
 						"Unable to instantiate plugin named " + pluginName);
 				return new ReturnValue(Status.UNKNOWN,
 						"Error instantiating plugin '" + pluginName
 								+ "' : bad plugin name?");
 			}
 
 			plugin.addListeners(listenersList);
 
 			if (commandLine != null) {
 				return plugin.execute(commandLine);
 			} else {
 				return plugin.execute(new String[0]);
 			}
 		} catch (Throwable thr) {
 			return new ReturnValue(Status.UNKNOWN, "Plugin [" + pluginName
 					+ "] execution error: " + thr.getMessage());
 		}
 	}
 }