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.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 java.io.File;
  import java.io.IOException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Plugin loader that can find plugins via a single URL, and treats all plugins loaded from
   * the directory as bundled plugins, meaning they can can be upgraded, but not deleted.
   * <p>
   * Depending on the URL:
   * <ul>
   *     <li>If it is a file:// url and represents a directory, all the files in that directory are scanned.</li>
   *     <li>if it is a file:// url and represents a file with a <code>.list</code> suffix, each line in that files
   *     is read as a path to a plugin jar.</li>
   *     <li>Otherwise it assumes the URL is a zip and unzips plugins from it into a local directory,
   *     and ensures that directory only contains plugins from that zip file.  It also</li>
   * </ul>
   *
   */
  public class BundledPluginLoader extends ScanningPluginLoader
  {
      public BundledPluginLoader(final URL zipUrl, final File pluginPath, final List<PluginFactory> pluginFactories, final PluginEventManager eventManager)
      {
          super(buildScanner(zipUrl, pluginPath), pluginFactories, new DefaultPluginArtifactFactory(true), 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 buildScanner(final URL url, final File pluginPath)
      {
          if (url == null)
          {
              throw new IllegalArgumentException("Bundled plugins url cannot be null");
          }
  
          Scanner scanner = null;
  
          final File file = FileUtils.toFile(url);
  
          if (file != null)
          {
              if (file.isDirectory())
              {
                  // URL points directly to a directory of jars
                  scanner = new DirectoryScanner(file);
              }
              else if (file.isFile() && file.getName().endsWith(".list"))
              {
                  // URL points to a file containg a list of jars
                  final List<File> files = readListFile(file);
                  scanner = new FileListScanner(files);
              }
          }
  
          if (scanner == null)
          {
              // default: assume it is a zip
              com.atlassian.plugin.util.FileUtils.conditionallyExtractZipFile(url, pluginPath);
              scanner = new DirectoryScanner(pluginPath);
          }
  
          return new ForwardingScanner(scanner)
          {
              @Override
              public void remove(DeploymentUnit unit) throws PluginException
              {
                  // We suppress the call to remove, because BundledPlugins should never actually be
                  // removed from the 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 (String fname : fnames)
             {
                 files.add(new File(fname));
             }
             return files;
         }
         catch (IOException e)
         {
             throw new IllegalStateException("Unable to read list from " + file, e);
         }
     }
 
 
     /**
      * 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(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(ContainerManagedPlugin delegate)
         {
             super(delegate);
             this.delegate = delegate;
         }
 
         @Override
         public ContainerAccessor getContainerAccessor()
         {
             return delegate.getContainerAccessor();
         }
 
         @Override
         public <T> T autowire(Class<T> clazz)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 return ((AutowireCapablePlugin)delegate).autowire(clazz);
             }
             else
             {
                 return delegate.getContainerAccessor().createBean(clazz);
             }
         }
 
         @Override
         public <T> T autowire(Class<T> clazz, AutowireStrategy autowireStrategy)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 return ((AutowireCapablePlugin)delegate).autowire(clazz, autowireStrategy);
             }
             else
             {
                 return delegate.getContainerAccessor().createBean(clazz);
             }
         }
 
         @Override
         public void autowire(Object instance)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 ((AutowireCapablePlugin)delegate).autowire(instance);
             }
             else
             {
                 delegate.getContainerAccessor().injectBean(instance);
             }
         }
 
         @Override
         public void autowire(Object instance, AutowireStrategy autowireStrategy)
         {
             if (delegate instanceof AutowireCapablePlugin)
             {
                 ((AutowireCapablePlugin)delegate).autowire(instance, autowireStrategy);
             }
             else
             {
                 delegate.getContainerAccessor().injectBean(instance);
             }
         }
     }
 }