/*******************************************************************************
    * 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.server.plugins;
  
  import it.jnrpe.plugins.PluginConfigurationException;
  import it.jnrpe.plugins.PluginRepository;
  import it.jnrpe.utils.PluginRepositoryUtil;
  import it.jnrpe.utils.StreamManager;
  
  import java.io.File;
  import java.io.FilenameFilter;
  import java.io.InputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.jar.JarEntry;
  import java.util.jar.JarFile;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * This object represent a Plugin repository loaded dynamically from file
   * system.
   * 
   * @author Massimiliano Ziccardi
   * 
   */
  public class DynaPluginRepository extends PluginRepository {
  
  	/**
  	 * The logger.
  	 */
  	private static final Logger LOG = LoggerFactory
  			.getLogger(DynaPluginRepository.class);
  
  	/**
  	 * Filter for jar files.
  	 */
  	private static final JarFilefilter JAR_FILE_FILTER = new JarFilefilter();
  
  	/**
  	 * File filter class for jar files.
  	 * 
  	 * @author Massimiliano Ziccardi
  	 */
  	private static class JarFilefilter implements FilenameFilter {
  		/**
  		 * Returns <code>true</code> if the file name ends with ".jar".
  		 * 
  		 * @param dir
  		 *            The directory containing the file
  		 * @param name
  		 *            The filename
  		 * @return <code>true</code> if the file name ends with ".jar".
  		 */
  		public boolean accept(final File dir, final String name) {
  			return name.endsWith(".jar");
  		}
  	}
  
  	/**
  	 * Loads all the plugins definitions from the given directory.
  	 * 
  	 * @param fDir
  	 *            The plugin package directory.
  	 * @throws PluginConfigurationException
  	 *             -
  	 */
  	private void configurePlugins(final File fDir)
  			throws PluginConfigurationException {
  		LOG.trace("READING PLUGIN CONFIGURATION FROM DIRECTORY "
  				+ fDir.getName());
  		StreamManager streamMgr = new StreamManager();
  
  		File[] vfJars = fDir.listFiles(JAR_FILE_FILTER);
  
  		if (vfJars == null || vfJars.length == 0) {
  			return;
  		}
  
  		// Initializing classloader
  		List<URL> vUrls = new ArrayList<URL>(vfJars.length);
  
  		ClassLoader ul = null;
 
 		for (int j = 0; j < vfJars.length; j++) {
 			try {
 				vUrls.add(vfJars[j].toURI().toURL());
 			} catch (MalformedURLException e) {
 				// should never happen
 				throw new IllegalStateException(e);
 			}
 		}
 
 		ul = new JNRPEClassLoader(vUrls);
 
 		try {
 			for (File file : vfJars) {
 				JarFile jarFile = null;
 				try {
 					jarFile = new JarFile(file);
 					JarEntry entry = jarFile.getJarEntry("plugin.xml");
 					if (entry == null) {
 						entry = jarFile.getJarEntry("jnrpe_plugins.xml");
 					}
 
 					if (entry == null) {
 						// The jar do not contain a jnrpe_plugins.xml nor a
 						// plugin.xml file...
 						continue;
 					}
 
 					InputStream in = streamMgr.handle(jarFile
 							.getInputStream(entry));
 					PluginRepositoryUtil.loadFromXmlPluginPackageDefinitions(
 							this, ul, in);
 					in.close();
 
 				} catch (Exception e) {
 					LOG.error("Skipping plugin package contained in file '"
 							+ file.getName()
 							+ "' because of the following error : {}",
 							new String[] { e.getMessage() }, e);
 				} finally {
 					try {
 						jarFile.close();
 					} catch (Exception e) {
 						// Intentionally ignored...
 					}
 				}
 			}
 
 		} finally {
 			streamMgr.closeAll();
 		}
 	}
 
 	/**
 	 * Loops through all the directories present inside the JNRPE plugin
 	 * directory.
 	 * 
 	 * @param fDirectory
 	 *            The JNRPE plugins directory
 	 * @throws PluginConfigurationException
 	 *             -
 	 */
 	public final void load(final File fDirectory)
 			throws PluginConfigurationException {
 		File[] vFiles = fDirectory.listFiles();
 		if (vFiles != null) {
 			for (File f : vFiles) {
 				if (f.isDirectory()) {
 					configurePlugins(f);
 				}
 			}
 		}
 	}
 }