package com.atlassian.plugin.loaders;
   
   import com.atlassian.plugin.AutowireCapablePlugin;
   import com.atlassian.plugin.DefaultPluginArtifactFactory;
   import com.atlassian.plugin.Plugin;
   import com.atlassian.plugin.PluginArtifact;
   import com.atlassian.plugin.PluginArtifactBackedPlugin;
   import com.atlassian.plugin.PluginException;
   import com.atlassian.plugin.event.PluginEventManager;
  import com.atlassian.plugin.factories.PluginFactory;
  import com.atlassian.plugin.impl.AbstractDelegatingPlugin;
  import com.atlassian.plugin.loaders.classloading.DeploymentUnit;
  import com.atlassian.plugin.loaders.classloading.EmptyScanner;
  import com.atlassian.plugin.loaders.classloading.ForwardingScanner;
  import com.atlassian.plugin.loaders.classloading.Scanner;
  import com.atlassian.plugin.module.ContainerAccessor;
  import com.atlassian.plugin.module.ContainerManagedPlugin;
  import org.apache.commons.io.FileUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.File;
  import java.io.IOException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  import static com.atlassian.plugin.PluginArtifact.AllowsReference.ReferenceMode.PERMIT_REFERENCE;
  import static com.google.common.base.Preconditions.checkArgument;
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * A Plugin loader that manages a set of bundled plugins, meaning that they can can be upgraded, but
   * not deleted.
   * <p>
   * This loader can source plugins from:
   * <p>
   * <ul>
   *     <li>A directory containing Plugin artifacts.
   *     <li>A file with a {@link #getListSuffix()} suffix, where each line of that
   *         file gives the path to a Plugin artifact.
   *     <li>A URL identifying a zip file, and a path to explode the zip into, and the exploded
   *         contents of the zip are used as the plugin artifacts.
   * </ul>
   */
  public class BundledPluginLoader extends ScanningPluginLoader
  {
      private static final Logger log = LoggerFactory.getLogger(BundledPluginLoader.class);
  
      /** The suffix used for bundled plugin list files. */
      public static String getListSuffix()
      {
          return ".list";
      }
  
      private BundledPluginLoader(
              final Scanner scanner,
              final List<PluginFactory> pluginFactories,
              final PluginEventManager eventManager)
      {
          super(new NonRemovingScanner(scanner), pluginFactories, new DefaultPluginArtifactFactory(PERMIT_REFERENCE),
                  eventManager);
      }
  
      /**
       * Construct a bundled plugin loader for a directory or list file source.
       *
       * @param source a directory of containing plugin artifacts, or a file with suffix
       * {@link #getListSuffix()} containing a list of paths to plugin artifacts.
       * @param pluginFactories as per {@link ScanningPluginLoader}.
       * @param eventManager as per {@link ScanningPluginLoader}.
       * @since 3.0.16
       */
      public BundledPluginLoader(
              final File source,
              final List<PluginFactory> pluginFactories,
              final PluginEventManager eventManager)
      {
          this(buildSourceScanner(source), pluginFactories, eventManager);
      }
  
      /**
       * Construct a bundled plugin loader for a zip source.
       * <p>
       * For backwards compatibility, if the zipUrl is in fact a file url (acccording to
       * {@link FileUtils#toFile}), this constructor has the same semantics as
       * {@link #BundledPluginLoader(File, List, PluginEventManager)} where the first argument
       * is the file referred to by zipUrl, and the pluginPath argument is ignored. That
       * constructor should be used directly in such cases.
       * <p>
       * @param zipUrl a url to a zipFile containing plugin artifacts, or a file url to a directory or
       * list file.
       * @param pluginPath path to the directory to expand zipUrl.
       * @param pluginFactories as per {@link ScanningPluginLoader}.
       * @param eventManager as per {@link ScanningPluginLoader}.
       */
      public BundledPluginLoader(
              final URL zipUrl,
              final File pluginPath,
             final List<PluginFactory> pluginFactories,
             final PluginEventManager eventManager)
     {
         this(buildZipScanner(zipUrl, pluginPath), pluginFactories, eventManager);
     }
 
     @Override
     protected Plugin postProcess(final Plugin plugin)
     {
         if (plugin instanceof ContainerManagedPlugin)
         {
             return new BundledPluginContainerManagedPluginDelegate((ContainerManagedPlugin) plugin);
         }
         else if (plugin instanceof PluginArtifactBackedPlugin)
         {
             return new BundledPluginArtifactBackedPluginDelegate((PluginArtifactBackedPlugin)plugin);
         }
         return new BundledPluginDelegate(plugin);
     }
 
     private static Scanner buildScannerCommon(final File file)
     {
         if (file.isDirectory())
         {
             // file points directly to a directory of jars
             return new DirectoryScanner(file);
         }
         else if (file.isFile() && file.getName().endsWith(getListSuffix()))
         {
             // file contains a list of jars.
             final List<File> files = readListFile(file);
             return new FileListScanner(files);
         }
         else
         {
             // unknown - let caller figure out fallback
             return null;
         }
     }
 
     private static Scanner buildSourceScanner(final File source)
     {
         checkNotNull(source, "Source must not be null");
         final Scanner scanner = buildScannerCommon(source);
         if (null == scanner)
         {
             log.error("Cannot build a scanner for source '{}'", source);
             // This is approximately what the code used to do - produce a scanner which would have
             // no entries (unless it accidentally had a random collection from a prior boot).
             return new EmptyScanner();
         }
         else
         {
             return scanner;
         }
     }
 
     private static Scanner buildZipScanner(final URL url, final File pluginPath)
     {
         // checkArgument used to preserve historical behaviour of throwing IllegalArgumentException
         checkArgument(null != url, "Bundled plugins url cannot be null");
 
 
         Scanner scanner = null;
 
         // Legacy behaviour - treat file:// urls as per buildSourceScanner, but we don't
         // want the error or the empty scanner.
         final File file = FileUtils.toFile(url);
         if (null != file)
         {
             scanner = buildScannerCommon(file);
         }
 
         if (null == scanner)
         {
             // Not handled by file:// urls, so it's a zip url
             com.atlassian.plugin.util.FileUtils.conditionallyExtractZipFile(url, pluginPath);
             scanner = new DirectoryScanner(pluginPath);
         }
 
         return scanner;
     }
 
     private static List<File> readListFile(final File file)
     {
         try
         {
             final List<String> fnames = (List<String>) FileUtils.readLines(file);
             final List<File> files = new ArrayList<File>();
             for (final String fname : fnames)
             {
                 files.add(new File(fname));
             }
             return files;
         }
         catch (IOException e)
         {
             throw new IllegalStateException("Unable to read list from " + file, e);
         }
     }
 
     /**
      * A forwarding scanner which suppresses remove operation.
      * <p>
      * Bundled plugins are never actually removed from the system, so we wrap the scanner to
      * suppress removal.
      */
     private static class NonRemovingScanner extends ForwardingScanner
     {
         NonRemovingScanner(final Scanner scanner)
         {
             super(scanner);
         }
 
         @Override
         public void remove(final DeploymentUnit unit) throws PluginException
         {
             // Suppressed - see class documentation.
         }
     }
 
     /**
      * Delegate that overrides methods to enforce bundled plugin behavior.
      *
      * This wrapper does not override isDeletable(), but passes it through to the base class and
      * hence delegate. We need OsgiPlugin instances to be isDeletable or they won't be uninstalled
      * by DefaultPluginManager, which will leak the bundle, classloaders, and all sorts. We stop the
      * actual deletion on disk via the Scanner wrapper in buildScanner. We should probably revisit
      * isDeletable vs isUninstallable usage in DefaultPluginManager, but i'm looking for minimal
      * changes to address PLUGDEV-10.
      *
      * @since 2.2.0
      */
     private static class BundledPluginDelegate extends AbstractDelegatingPlugin
     {
 
         public BundledPluginDelegate(final Plugin delegate)
         {
             super(delegate);
         }
 
         @Override
         public boolean isBundledPlugin()
         {
             return true;
         }
 
         // See class documentation for why we don't override isDeletable().
     }
 
     /**
      * Delegate that overrides methods to enforce bundled plugin behavior for {@link PluginArtifactBackedPlugin} implementors
      * @since 2.9.3
      */
     private static class BundledPluginArtifactBackedPluginDelegate extends BundledPluginDelegate implements PluginArtifactBackedPlugin
     {
         private final PluginArtifactBackedPlugin delegate;
 
         private BundledPluginArtifactBackedPluginDelegate(final PluginArtifactBackedPlugin delegate)
         {
             super(delegate);
             this.delegate = delegate;
         }
 
         public PluginArtifact getPluginArtifact()
         {
             return delegate.getPluginArtifact();
         }
     }
 
     private static class BundledPluginContainerManagedPluginDelegate extends BundledPluginArtifactBackedPluginDelegate implements ContainerManagedPlugin,
             AutowireCapablePlugin
     {
         private final ContainerManagedPlugin delegate;
 
         private BundledPluginContainerManagedPluginDelegate(final ContainerManagedPlugin delegate)
         {
             super(delegate);
             this.delegate = delegate;
         }
 
         @Override
         public ContainerAccessor getContainerAccessor()
         {
             return delegate.getContainerAccessor();
         }
 
         @Override
         public <T> T autowire(final Class<T> clazz)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 return ((AutowireCapablePlugin)delegate).autowire(clazz);
             }
             else
             {
                 return delegate.getContainerAccessor().createBean(clazz);
             }
         }
 
         @Override
         public <T> T autowire(final Class<T> clazz, final AutowireStrategy autowireStrategy)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 return ((AutowireCapablePlugin)delegate).autowire(clazz, autowireStrategy);
             }
             else
             {
                 return delegate.getContainerAccessor().createBean(clazz);
             }
         }
 
         @Override
         public void autowire(final Object instance)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 ((AutowireCapablePlugin)delegate).autowire(instance);
             }
             else
             {
                 delegate.getContainerAccessor().injectBean(instance);
             }
         }
 
         @Override
         public void autowire(final Object instance, final AutowireStrategy autowireStrategy)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 ((AutowireCapablePlugin)delegate).autowire(instance, autowireStrategy);
             }
             else
             {
                 delegate.getContainerAccessor().injectBean(instance);
             }
         }
     }
 }