package com.atlassian.plugin.osgi.factory.transform;
   
   import com.atlassian.plugin.osgi.hostcomponents.HostComponentRegistration;
   import com.atlassian.plugin.osgi.factory.transform.stage.*;
   import org.apache.commons.lang.Validate;
   import org.apache.log4j.Logger;
   
   import java.io.*;
   import java.util.List;
  import java.util.Map;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.zip.ZipEntry;
  import java.util.zip.ZipInputStream;
  import java.util.zip.ZipOutputStream;
  
  /**
   * 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 = Logger.getLogger(DefaultPluginTransformer.class);
  
      private final String pluginDescriptorPath;
      private final List<TransformStage> stages;
  
      /**
       * Constructs a transformer with the default stages
       *
       * @param pluginDescriptorPath The path to the plugin descriptor
       * @since 2.2.0
       */
      public DefaultPluginTransformer(String pluginDescriptorPath)
      {
          this(pluginDescriptorPath, new ArrayList<TransformStage>()
          {{
              add(new AddBundleOverridesStage());
              add(new ComponentImportSpringStage());
              add(new ComponentSpringStage());
              add(new HostComponentSpringStage());
              add(new ModuleTypeSpringStage());
              add(new GenerateManifestStage());
          }});
      }
  
      /**
       * Constructs a transformer and its stages
       *
       * @param pluginDescriptorPath The descriptor path
       * @param stages A set of stages
       * @since 2.2.0
       */
      public DefaultPluginTransformer(String pluginDescriptorPath, List<TransformStage> stages)
      {
          Validate.notNull(pluginDescriptorPath, "The plugin descriptor path is required");
          Validate.notNull(stages, "A list of stages is required");
          this.pluginDescriptorPath = pluginDescriptorPath;
          this.stages = Collections.unmodifiableList(new ArrayList<TransformStage>(stages));
      }
  
      /**
       * 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
      {
          Validate.notNull(pluginJar, "The plugin jar is required");
          Validate.notNull(regs, "The host component registrations are required");
          TransformContext context = new TransformContext(regs, pluginJar, pluginDescriptorPath);
          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(pluginJar.getName()).append(":\n");
                  for (Map.Entry<String, byte[]> entry : context.getFileOverrides().entrySet())
                  {
                      sb.append("==").append(entry.getKey()).append("==\n");
                      sb.append(new String(entry.getValue()));
                  }
                  log.debug(sb.toString());
              }
              return addFilesToExistingZip(pluginJar, context.getFileOverrides());
          }
          catch (IOException e)
          {
              throw new PluginTransformationException("Unable to add files to plugin jar");
          }
      }
 
 
     /**
      * 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
      */
     static File addFilesToExistingZip(File zipFile,
                                       Map<String, byte[]> files) throws IOException
     {
         // get a temp file
         File tempFile = File.createTempFile(zipFile.getName(), null);
         // delete it, otherwise you cannot rename your existing zip to it.
         byte[] buf = new byte[1024];
 
         ZipInputStream zin = new ZipInputStream(new FileInputStream(zipFile));
         ZipOutputStream out = new ZipOutputStream(new FileOutputStream(tempFile));
 
         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
                 int len;
                 while ((len = zin.read(buf)) > 0)
                     out.write(buf, 0, len);
             }
             entry = zin.getNextEntry();
         }
         // Close the streams
         zin.close();
         // Compress the files
         for (Map.Entry<String, byte[]> fentry : files.entrySet())
         {
             InputStream 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
             int len;
             while ((len = in.read(buf)) > 0)
             {
                 out.write(buf, 0, len);
             }
             // Complete the entry
             out.closeEntry();
             in.close();
         }
         // Complete the ZIP file
         out.close();
         return tempFile;
     }
 
     
 }