package com.atlassian.plugin.osgi.factory.transform;
   
   import com.atlassian.plugin.Application;
   import com.atlassian.plugin.JarPluginArtifact;
   import com.atlassian.plugin.PluginArtifact;
   import com.atlassian.plugin.osgi.container.OsgiContainerManager;
   import com.atlassian.plugin.osgi.container.OsgiPersistentCache;
   import com.atlassian.plugin.osgi.factory.transform.model.SystemExports;
   import com.atlassian.plugin.osgi.factory.transform.stage.AddBundleOverridesStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.ComponentImportSpringStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.ComponentSpringStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.GenerateManifestStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.HostComponentSpringStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.ModuleTypeSpringStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.ScanDescriptorForHostClassesStage;
  import com.atlassian.plugin.osgi.factory.transform.stage.ScanInnerJarsStage;
  import com.atlassian.plugin.osgi.hostcomponents.HostComponentRegistration;
  import com.google.common.collect.ImmutableList;
  import org.apache.commons.io.IOUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.BufferedOutputStream;
  import java.io.ByteArrayInputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.zip.Deflater;
  import java.util.zip.ZipEntry;
  import java.util.zip.ZipInputStream;
  import java.util.zip.ZipOutputStream;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  /**
   * Default implementation of plugin transformation that uses stages to convert a plain JAR into an OSGi bundle.
   */
  public class DefaultPluginTransformer implements PluginTransformer
  {
      private static final Logger log = LoggerFactory.getLogger(DefaultPluginTransformer.class);
  
      public static final String TRANSFORM_COMPRESSION_LEVEL = "atlassian.plugins.plugin.transformer.compression";
  
      private final String pluginDescriptorPath;
      private final List<TransformStage> stages;
      private final File bundleCacheDir;
      private final SystemExports systemExports;
      private final Set<Application> applications;
      private final OsgiContainerManager osgiContainerManager;
  
      /**
       * Gets the default list of transform stages performed by the transformer. Clients wishing to add stages to the
       * transformation process should use this list as a template rather than creating their own from scratch.
       */
      public static ArrayList<TransformStage> getDefaultTransformStages()
      {
          return new ArrayList<TransformStage>(Arrays.asList(
                  new AddBundleOverridesStage(),
                  new ScanInnerJarsStage(),
                  new ComponentImportSpringStage(),
                  new ComponentSpringStage(),
                  new ScanDescriptorForHostClassesStage(),
                  new ModuleTypeSpringStage(),
                  new HostComponentSpringStage(),
                  new GenerateManifestStage()
          ));
      }
  
      /**
       * Constructs a transformer with the default stages
       *
       * @param cache The OSGi cache configuration for transformed plugins
       * @param systemExports The packages the system bundle exports
       * @param pluginDescriptorPath The path to the plugin descriptor
       * @since 2.2.0
       */
      public DefaultPluginTransformer(OsgiPersistentCache cache, SystemExports systemExports, Set<Application> applications, String pluginDescriptorPath, OsgiContainerManager osgiContainerManager)
      {
          this(cache, systemExports, applications, pluginDescriptorPath, osgiContainerManager, getDefaultTransformStages());
      }
  
      /**
       * Constructs a transformer and its stages
       *
       * @param cache The OSGi cache configuration for transformed plugins
       * @param systemExports The packages the system bundle exports
       * @param pluginDescriptorPath The descriptor path
       * @param stages A set of stages
       * @since 2.2.0
       */
      public DefaultPluginTransformer(OsgiPersistentCache cache, SystemExports systemExports, Set<Application> applications, String pluginDescriptorPath, OsgiContainerManager osgiContainerManager, List<TransformStage> stages)
      {
         this.pluginDescriptorPath = checkNotNull(pluginDescriptorPath, "The plugin descriptor path is required");
         this.osgiContainerManager = checkNotNull(osgiContainerManager);
         this.stages = ImmutableList.copyOf(checkNotNull(stages, "A list of stages is required"));
         this.bundleCacheDir = checkNotNull(cache).getTransformedPluginCache();
         this.systemExports = systemExports;
         this.applications = applications;
     }
 
     /**
      * Transforms the file into an OSGi bundle
      *
      * @param pluginJar The plugin jar
      * @param regs      The list of registered host components
      * @return The new OSGi-enabled plugin jar
      * @throws PluginTransformationException If anything goes wrong
      */
     public File transform(File pluginJar, List<HostComponentRegistration> regs) throws PluginTransformationException
     {
         return transform(new JarPluginArtifact(pluginJar), regs);
     }
 
     /**
      * Transforms the file into an OSGi bundle
      *
      * @param pluginArtifact The plugin artifact, usually a jar
      * @param regs      The list of registered host components
      * @return The new OSGi-enabled plugin jar
      * @throws PluginTransformationException If anything goes wrong
      */
     public File transform(PluginArtifact pluginArtifact, List<HostComponentRegistration> regs) throws PluginTransformationException
     {
         checkNotNull(pluginArtifact, "The plugin artifact is required");
         checkNotNull(regs, "The host component registrations are required");
 
         File artifactFile = pluginArtifact.toFile();
 
         // Look in cache first
         File cachedPlugin = getFromCache(artifactFile);
         if (cachedPlugin != null)
         {
             return cachedPlugin;
         }
 
         final TransformContext context = new TransformContext(regs, systemExports, pluginArtifact, applications, pluginDescriptorPath, osgiContainerManager);
         for (TransformStage stage : stages)
         {
             stage.execute(context);
         }
 
         // Create a new jar by overriding the specified files
         try
         {
             if (log.isDebugEnabled())
             {
                 StringBuilder sb = new StringBuilder();
                 sb.append("Overriding files in ").append(pluginArtifact.toString()).append(":\n");
                 for (Map.Entry<String, byte[]> entry : context.getFileOverrides().entrySet())
                 {
                     sb.append("==").append(entry.getKey()).append("==\n");
 
                     // Yes, this doesn't take into account encoding, but since only text files are overridden, that
                     // should be fine
                     sb.append(new String(entry.getValue()));
                 }
                 log.debug(sb.toString());
             }
             return addFilesToExistingZip(artifactFile, context.getFileOverrides());
         }
         catch (IOException e)
         {
             throw new PluginTransformationException("Unable to add files to plugin jar");
         }
     }
 
     private File getFromCache(File artifact)
     {
         String name = generateCacheName(artifact);
         for (File child : bundleCacheDir.listFiles())
         {
             if (child.getName().equals(name))
                 return child;
         }
         return null;
     }
 
     /**
      * Generate a cache name that incorporates the timestap and preserves the extension
      * @param file The original file to cache
      * @return The new file name
      */
     static String generateCacheName(File file)
     {
         int dotPos = file.getName().lastIndexOf('.');
         if (dotPos > 0 && file.getName().length() - 1 > dotPos)
         {
             return file.getName().substring(0, dotPos) + "_" + file.lastModified() + file.getName().substring(dotPos);
         }
         else
         {
             return file.getName() + "_" + file.lastModified();
         }
     }
 
 
     /**
      * Creates a new jar by overriding the specified files in the existing one
      *
      * @param zipFile The existing zip file
      * @param files   The files to override
      * @return The new zip
      * @throws IOException If there are any problems processing the streams
      */
     File addFilesToExistingZip(File zipFile,
                                       Map<String, byte[]> files) throws IOException
     {
         // get a temp file
         File tempFile = new File(bundleCacheDir, generateCacheName(zipFile));
         
         ZipInputStream zin = null;
         ZipOutputStream out = null;
         try
         {
             zin = new ZipInputStream(new FileInputStream(zipFile));
             out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(tempFile)));
             final int requestedCompressionLevel = Integer.getInteger(TRANSFORM_COMPRESSION_LEVEL, Deflater.NO_COMPRESSION);
             final int clampedCompressionLevel =
                     Math.max(Deflater.NO_COMPRESSION, Math.min(requestedCompressionLevel, Deflater.BEST_COMPRESSION));
             out.setLevel(clampedCompressionLevel);
 
             ZipEntry entry = zin.getNextEntry();
             while (entry != null)
             {
                 String name = entry.getName();
                 if (!files.containsKey(name))
                 {
                     // Add ZIP entry to output stream.
                     out.putNextEntry(new ZipEntry(name));
                     // Transfer bytes from the ZIP file to the output file
                     IOUtils.copyLarge(zin,out);
                 }
                 entry = zin.getNextEntry();
             }
             // Close the streams
             zin.close();
             // Compress the files
             for (Map.Entry<String, byte[]> fentry : files.entrySet())
             {
                 InputStream in = null;
                 try
                 {
                     in = new ByteArrayInputStream(fentry.getValue());
                     // Add ZIP entry to output stream.
                     out.putNextEntry(new ZipEntry(fentry.getKey()));
                     // Transfer bytes from the file to the ZIP file
                     IOUtils.copyLarge(in,out);
                     // Complete the entry
                     out.closeEntry();
                 }
                 finally
                 {
                     IOUtils.closeQuietly(in);
                 }
             }
             // Complete the ZIP file
             out.close();
         }
         finally
         {
             // Close just in case
             IOUtils.closeQuietly(zin);
             IOUtils.closeQuietly(out);
         }
         return tempFile;
     }
 
 }