package org.trails.io;

 import java.io.BufferedInputStream;

 import java.io.BufferedOutputStream;

 import java.io.BufferedReader;

 import java.io.ByteArrayInputStream;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStreamReader;

 import java.util.zip.GZIPInputStream;

 import java.util.zip.GZIPOutputStream;

 import org.apache.commons.codec.binary.Base64;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.tapestry.callback.ICallback;

 import org.apache.tapestry.services.DataSqueezer;

 import org.apache.tapestry.util.io.SqueezeAdaptor;

 import org.trails.callback.CallbackStack;

 /**

  * Squeezes a {@link CallbackStack}

  */

 public class CallbackStackAdaptor implements SqueezeAdaptor

 {

         private static final Log LOG = LogFactory.getLog(CallbackStackAdaptor.class);

         public static final String PREFIX = "L";

         public static final String DELIMITER = "@C";

         public Class getDataClass()

         {

                 return CallbackStack.class;

         }

         public String getPrefix()

         {

                 return PREFIX;

         }

         public String squeeze(DataSqueezer squeezer, Object object)

         {

                 CallbackStack stack = (CallbackStack) object;

                 StringBuilder builder = new StringBuilder();

                 for (ICallback callback : stack)

                 {

                         builder.append(squeezer.squeeze(callback)).append(DELIMITER);

                 }

                 return new StringBuilder(PREFIX).append(compress(builder.toString())).toString();

         }

         public Object unsqueeze(DataSqueezer squeezer, String string)

         {

                 String uncompressed = uncompress(string.substring(PREFIX.length()));

                 CallbackStack stack = new CallbackStack();

                 if (uncompressed != null)

                 {

                         String[] values = uncompressed.split(DELIMITER);

                         for (String s : values)

                         {

                                 stack.add((ICallback) squeezer.unsqueeze(s));

                         }

                 }

                 return stack;

         }

         public String compress(String string)

         {

                 try

                 {

                         ByteArrayOutputStream bosCompressed = new ByteArrayOutputStream();

                         GZIPOutputStream gos = new GZIPOutputStream(bosCompressed);

                         BufferedOutputStream oos = new BufferedOutputStream(gos);

                         oos.write(string.getBytes());

                         oos.close();

                         byte[] byteArray = bosCompressed.toByteArray();

                         byte[] encoded = Base64.encodeBase64(byteArray);

                         return new String(encoded);

                 }

                 catch (Exception ex)

                 {

                         ex.printStackTrace();

                 }

                 return null;

         }

         public String uncompress(String string)

         {

                 try

                 {

                         byte[] decoded = Base64.decodeBase64(string.getBytes());

                         BufferedInputStream is = new BufferedInputStream(new GZIPInputStream(new ByteArrayInputStream(decoded)));

                         BufferedReader reader = new BufferedReader(new InputStreamReader(is));

                         String uncompressed = reader.readLine();

                         is.close();

                         return uncompressed;

                 } catch (IOException e)

                 {

                         e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.

                 }

                 return null;

         }

 }