/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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 org.kuali.rice.kew.plugin;

 import org.apache.commons.io.FileUtils;

 import org.apache.log4j.Logger;

 import org.kuali.rice.core.api.config.property.Config;

 import org.kuali.rice.kew.api.WorkflowRuntimeException;

 import java.io.BufferedInputStream;

 import java.io.BufferedOutputStream;

 import java.io.File;

 import java.io.FileOutputStream;

 import java.io.InputStream;

 import java.io.OutputStream;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.util.Enumeration;

 import java.util.zip.ZipEntry;

 import java.util.zip.ZipFile;

 /**

  * Loads a plugin from a zip file on the file system.

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class ZipFilePluginLoader extends BasePluginLoader {

         private static final Logger LOG = Logger.getLogger(ZipFilePluginLoader.class);

         private final File pluginZipFile;

     private final File extractionDirectory;

     private long zipFileLastModified = -1;

     private boolean loadFailed = false;

     private static String validatePluginZipFile(File pluginZipFile) {

         PluginUtils.validatePluginZipFile(pluginZipFile);

         String fileName = pluginZipFile.getName();

         int indexOf = fileName.lastIndexOf(".zip");

         return fileName.substring(0, indexOf);

     }

     public ZipFilePluginLoader(File pluginZipFile, File sharedPluginDirectory, ClassLoader parentClassLoader, Config parentConfig) {

             super(validatePluginZipFile(pluginZipFile), sharedPluginDirectory, parentClassLoader, parentConfig);

             this.pluginZipFile = pluginZipFile;

             this.extractionDirectory = determineExtractionDirectory(getSimplePluginName(), pluginZipFile);

     }

         public boolean isModified() {

                 long currentZipFileLastModified = pluginZipFile.lastModified();

                 if (zipFileLastModified == -1) {

                         zipFileLastModified = currentZipFileLastModified;

                         return false;

                 } else if (currentZipFileLastModified > zipFileLastModified) {

                         return !isZipFileStillBeingModified();

                 }

                 return false;

         }

         protected boolean isZipFileStillBeingModified() {

                 long lastModified = pluginZipFile.lastModified();

                 long size = pluginZipFile.length();

                 // sleep for a fraction of a second and then check again if the values have changed

                 try {

                         Thread.sleep(100);

                 } catch (InterruptedException e) {}

                 if (lastModified != pluginZipFile.lastModified()) {

                         return true;

                 }

                 if (size != pluginZipFile.length()) {

                         return true;

                 }

                 return false;

         }

         public boolean isRemoved() {

                 return pluginZipFile != null && !pluginZipFile.exists();

         }

     @Override

         public Plugin load() throws Exception {

         try {

             updateLastModified();

             extractPluginFiles();

             Plugin plugin = super.load();

             loadFailed = false;

             return plugin;

         } catch (Exception e) {

             loadFailed = true;

             throw e;

         }

         }

     protected File determineExtractionDirectory(String pluginName, File pluginZipFile) {

                 return new File(pluginZipFile.getParentFile(), pluginName);

         }

     /**

      * Extracts the plugin files if necessary.

      */

     protected void extractPluginFiles() throws Exception {

             if (isExtractNeeded()) {

                     // first, delete the current copy of the extracted plugin

                     if (extractionDirectory.exists()) {

                             // TODO how to handle locked files under windows?!?  This will throw an IOException in this case.

                             FileUtils.deleteDirectory(extractionDirectory);

                     }

                     if (!extractionDirectory.mkdir()) {

                             throw new WorkflowRuntimeException("Could not create the extraction directory for the plugin: " + extractionDirectory.getAbsolutePath());

                     }

                     ZipFile zipFile = new ZipFile(pluginZipFile, ZipFile.OPEN_READ);

                     for (Enumeration entries = zipFile.entries(); entries.hasMoreElements();) {

                             ZipEntry entry = (ZipEntry)entries.nextElement();

                                 File entryFile = new File(extractionDirectory + java.io.File.separator + entry.getName());

                             if (entry.isDirectory()) { // if its a directory, create it

                                     if (!entryFile.mkdir()) {

                                             throw new WorkflowRuntimeException("Failed to create directory: " + entryFile.getAbsolutePath());

                                     }

                                     continue;

                             }

                             InputStream is = null;

                             OutputStream os = null;

                             try {

                                     is = new BufferedInputStream(zipFile.getInputStream(entry)); // get the input stream

                                     os = new BufferedOutputStream(new FileOutputStream(entryFile));

                                     while (is.available() > 0) {  // write contents of 'is' to 'fos'

                                             os.write(is.read());

                                     }

                             } finally {

                                     if (os != null) {

                                             os.close();

                                     }

                                     if (is != null) {

                                             is.close();

                                     }

                             }

                     }

             }

     }

     /**

      * @return the loadFailed

      */

     public boolean isLoadFailed() {

         return this.loadFailed;

     }

     /**

      * An extract is required if the plugin has been modified or the last modified date of the zip file

      * is later than the last modified date of the extraction directory.

      */

     protected boolean isExtractNeeded() {

             return isModified() || pluginZipFile.lastModified() > extractionDirectory.lastModified();

     }

     protected void updateLastModified() {

             zipFileLastModified = pluginZipFile.lastModified();

     }

         protected PluginClassLoader createPluginClassLoader() throws MalformedURLException {

         LOG.info(getLogPrefix() + " Initiating loading of plugin from file system: " + extractionDirectory.getPath());

         LOG.info(getLogPrefix() + " Absolute path on file system is: " + extractionDirectory.getAbsolutePath());

         /* MalformedURLException should technically never be thrown as the URLs are coming from (presumably)

          * valid File objects

          */

         return new PluginClassLoader(parentClassLoader, sharedPluginDirectory, extractionDirectory);

     }

     protected URL getPluginConfigURL() throws PluginException, MalformedURLException {

         File pluginConfigFile = new File(extractionDirectory, pluginConfigPath);

         if (!pluginConfigFile.exists() || !pluginConfigFile.isFile()) {

             throw new PluginException(getLogPrefix() + " Could not locate the plugin config file at path " + pluginConfigFile.getAbsolutePath());

         }

         return pluginConfigFile.toURI().toURL();

     }

 }