/*******************************************************************************
    * 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.osgi;
  
  import it.jnrpe.commands.CommandDefinition;
  import it.jnrpe.commands.CommandRepository;
  import it.jnrpe.plugins.IPluginRepository;
  import it.jnrpe.plugins.PluginDefinition;
  import it.jnrpe.utils.PluginRepositoryUtil;
  import it.jnrpe.utils.StreamManager;
  
  import java.io.InputStream;
  import java.security.AccessController;
  import java.security.PrivilegedAction;
  import java.util.Collection;
  
  import org.osgi.framework.Bundle;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.BundleEvent;
  import org.osgi.util.tracker.BundleTracker;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class JNRPEBundleTracker extends BundleTracker {
  
  	private final static String JNRPE_PLUGIN_PACKAGE_NAME = "JNRPE-PluginPackage-Name";
  
  	/**
  	 * The logger.
  	 */
  	private static final Logger LOG = LoggerFactory
  			.getLogger(JNRPEBundleTracker.class);
  
  	private final IPluginRepository pluginRepository;
  	private final CommandRepository commandRepository;
  
  	public JNRPEBundleTracker(final BundleContext context,
  			final IPluginRepository pluginRepo,
  			final CommandRepository commandRepo) {
  		super(context, Bundle.ACTIVE | Bundle.STOPPING, null);
  		pluginRepository = pluginRepo;
  		commandRepository = commandRepo;
  	}
  
  	private InputStream getPluginConfigStream(ClassLoader cl) {
  		InputStream in = null;
  
  		in = cl.getResourceAsStream("jnrpe_plugins.xml");
  
  		if (in == null) {
  			// fallback to the old plugin.xml file...
  			in = cl.getResourceAsStream("plugin.xml");
  		}
  
  		return in;
  	}
  
  	@Override
  	public Object addingBundle(final Bundle bundle, final BundleEvent event) {
  
  		String pluginPackageClassName = (String) bundle.getHeaders().get(
  				JNRPE_PLUGIN_PACKAGE_NAME);
  
  		if (pluginPackageClassName != null) {
  			LOG.info("Plugin package found: {} ", pluginPackageClassName);
  
  			StreamManager sm = new StreamManager();
  			// The bundle is a plugin package...
  			try {
  				BundleDelegatingClassLoader bdc = AccessController
  						.doPrivileged(new PrivilegedAction<BundleDelegatingClassLoader>() {
  							public BundleDelegatingClassLoader run() {
  								return new BundleDelegatingClassLoader(bundle);
  							}
  						});
  
  				// the 'plugin.xml' file is deprecated. Search for the new
  				// jnrpe_plugins.xml file and then fallback to the old
  				// plugin.xml
  
  				InputStream in = sm.handle(getPluginConfigStream(bdc));
  
  				// FIXME: check that 'in' is not null
  
  				Collection<PluginDefinition> pdList = PluginRepositoryUtil
  						.loadFromXmlPluginPackageDefinitions(bdc, in);
 
 				for (PluginDefinition pd : pdList) {
 					LOG.info("Adding plugin '{}' to the repository",
 							pd.getName());
 					pluginRepository.addPluginDefinition(pd);
 				}
 
 			} catch (Exception e) {
 				LOG.error("Error adding plugin to the repository", e);
 			} finally {
 				sm.closeAll();
 			}
 		}
 
 		return bundle;
 	}
 
 	@Override
 	public void remove(final Bundle bundle) {
 		String pluginPackageClassName = (String) bundle.getHeaders().get(
 				JNRPE_PLUGIN_PACKAGE_NAME);
 
 		if (pluginPackageClassName != null) {
 
 			StreamManager sm = new StreamManager();
 
 			// The bundle is a plugin package...
 			try {
 				BundleDelegatingClassLoader bdc = AccessController
 						.doPrivileged(new PrivilegedAction<BundleDelegatingClassLoader>() {
 							public BundleDelegatingClassLoader run() {
 								return new BundleDelegatingClassLoader(bundle);
 							}
 						});
 
 				InputStream in = sm.handle(getPluginConfigStream(bdc));
 
 				Collection<PluginDefinition> pdList = PluginRepositoryUtil
 						.loadFromXmlPluginPackageDefinitions(bdc, in);
 
 				for (PluginDefinition pd : pdList) {
 					// First remove all the commands using the plugin...
 					for (CommandDefinition cd : commandRepository
 							.getAllCommandDefinition(pd.getName())) {
 						LOG.info("Removing command '{}' from the repository",
 								cd.getName());
 						commandRepository.removeCommandDefinition(cd);
 					}
 
 					LOG.info("Removing plugin '{}' from the repository",
 							pd.getName());
 					pluginRepository.removePluginDefinition(pd);
 				}
 			} catch (Exception e) {
 				LOG.error("Error removing plugin from the repository", e);
 			} finally {
 				sm.closeAll();
 			}
 		}
 	}
 }