/*
    * Copyright 2009 Red Hat, Inc.
    *
    * Red Hat licenses this file to you under the Apache License, version 2.0
    * (the "License"); you may not use this file except in compliance with the
    * License.  You may obtain a copy of the License at:
    *
    *    http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package org.jboss.netty.handler.codec.http2;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.URLEncoder;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.ListIterator;
  import java.util.Random;
  
  import org.jboss.netty.buffer.ChannelBuffer;
  import org.jboss.netty.buffer.ChannelBuffers;
  import org.jboss.netty.handler.stream.ChunkedInput;
  
  /**
   * This encoder will help to encode Request for a FORM as POST.
   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
   * @author Andy Taylor (andy.taylor@jboss.org)
   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
   * @author <a href="http://openr66.free.fr/">Frederic Bregier</a>
   *
   */
  public class HttpPostRequestEncoder implements ChunkedInput {
      /**
       * Factory used to create InterfaceHttpData
       */
      private final HttpDataFactory factory;
  
      /**
       * Request to encode
       */
      private final HttpRequest request;
  
      /**
       * Default charset to use
       */
      private final Charset charset;
  
      /**
       * Chunked false by default
       */
      private boolean isChunked = false;
  
      /**
       * InterfaceHttpData for Body (without encoding)
       */
      private List<InterfaceHttpData> bodyListDatas = null;
      /**
       * The final Multipart List of InterfaceHttpData including encoding
       */
      private List<InterfaceHttpData> multipartHttpDatas = null;
  
      /**
       * Does this request is a Multipart request
       */
      private final boolean isMultipart;
  
      /**
       * If multipart, this is the boundary for the flobal multipart
       */
      private String multipartDataBoundary = null;
  
      /**
       * If multipart, there could be internal multiparts (mixed) to the global multipart.
       * Only one level is allowed.
       */
      private String multipartMixedBoundary = null;
      /**
       * To check if the header has been finalized
       */
      private boolean headerFinalized = false;
  
      /**
      *
      * @param request the request to encode
      * @param multipart True if the FORM is a ENCTYPE="multipart/form-data"
      * @throws NullPointerException for request
      * @throws ErrorDataEncoderException if the request is not a POST
      */
      public HttpPostRequestEncoder(HttpRequest request, boolean multipart)
              throws ErrorDataEncoderException, NullPointerException {
          this(new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE),
                 request, multipart, HttpCodecUtil.DEFAULT_CHARSET);
     }
 
     /**
      *
      * @param factory the factory used to create InterfaceHttpData
      * @param request the request to encode
      * @param multipart True if the FORM is a ENCTYPE="multipart/form-data"
      * @throws NullPointerException for request and factory
      * @throws ErrorDataEncoderException if the request is not a POST
      */
     public HttpPostRequestEncoder(HttpDataFactory factory, HttpRequest request, boolean multipart)
             throws ErrorDataEncoderException, NullPointerException {
         this(factory, request, multipart, HttpCodecUtil.DEFAULT_CHARSET);
     }
 
     /**
      *
      * @param factory the factory used to create InterfaceHttpData
      * @param request the request to encode
      * @param multipart True if the FORM is a ENCTYPE="multipart/form-data"
      * @param charset the charset to use as default
      * @throws NullPointerException for request or charset or factory
      * @throws ErrorDataEncoderException if the request is not a POST
      */
     public HttpPostRequestEncoder(HttpDataFactory factory, HttpRequest request,
             boolean multipart, Charset charset) throws ErrorDataEncoderException,
             NullPointerException {
         if (factory == null) {
             throw new NullPointerException("factory");
         }
         if (request == null) {
             throw new NullPointerException("request");
         }
         if (charset == null) {
             throw new NullPointerException("charset");
         }
         if (request.getMethod() != HttpMethod.POST) {
             throw new ErrorDataEncoderException("Cannot create a Encoder if not a POST");
         }
         this.request = request;
         this.charset = charset;
         this.factory = factory;
         // Fill default values
         bodyListDatas = new ArrayList<InterfaceHttpData>();
         // default mode
         isLastChunk = false;
         isLastChunkSent = false;
         isMultipart = multipart;
         multipartHttpDatas = new ArrayList<InterfaceHttpData>();
         if (isMultipart) {
             initDataMultipart();
         }
     }
 
     /**
      * Clean all HttpDatas (on Disk) for the current request.
      *
      */
     public void cleanFiles() {
         factory.cleanRequestHttpDatas(request);
     }
 
     /**
      * Does the last non empty chunk already encoded so that next chunk will be empty (last chunk)
      */
     private boolean isLastChunk = false;
     /**
      * Last chunk already sent
      */
     private boolean isLastChunkSent = false;
     /**
      * The current FileUpload that is currently in encode process
      */
     private FileUpload currentFileUpload = null;
     /**
      * While adding a FileUpload, is the multipart currently in Mixed Mode
      */
     private boolean duringMixedMode = false;
 
     /**
      * Global Body size
      */
     private long globalBodySize = 0;
 
     /**
      * True if this request is a Multipart request
      * @return True if this request is a Multipart request
      */
     public boolean isMultipart() {
         return isMultipart;
     }
 
     /**
      * Init the delimiter for Global Part (Data).
      * @param delimiter (may be null so computed)
      */
     private void initDataMultipart() {
         multipartDataBoundary = getNewMultipartDelimiter();
     }
 
     /**
      * Init the delimiter for Mixed Part (Mixed).
      * @param delimiter (may be null so computed)
      */
     private void initMixedMultipart() {
         multipartMixedBoundary = getNewMultipartDelimiter();
     }
 
     /**
      *
      * @return a newly generated Delimiter (either for DATA or MIXED)
      */
     private String getNewMultipartDelimiter() {
         // construct a generated delimiter
         Random random = new Random();
         return Long.toHexString(random.nextLong()).toLowerCase();
     }
 
     /**
      * This method returns a List of all InterfaceHttpData from body part.<br>
 
      * @return the list of InterfaceHttpData from Body part
      */
     public List<InterfaceHttpData> getBodyListAttributes() {
         return bodyListDatas;
     }
 
     /**
      * Set the Body HttpDatas list
      * @param datas
      * @throws NullPointerException for datas
      * @throws ErrorDataEncoderException if the encoding is in error or if the finalize were already done
      */
     public void setBodyHttpDatas(List<InterfaceHttpData> datas)
             throws NullPointerException, ErrorDataEncoderException {
         if (datas == null) {
             throw new NullPointerException("datas");
         }
         globalBodySize = 0;
         bodyListDatas.clear();
         currentFileUpload = null;
         duringMixedMode = false;
         multipartHttpDatas.clear();
         for (InterfaceHttpData data: datas) {
             addBodyHttpData(data);
         }
     }
 
     /**
      * Add a simple attribute in the body as Name=Value
      * @param name name of the parameter
      * @param value the value of the parameter
      * @throws NullPointerException for name
      * @throws ErrorDataEncoderException if the encoding is in error or if the finalize were already done
      */
     public void addBodyAttribute(String name, String value)
     throws NullPointerException, ErrorDataEncoderException {
         if (name == null) {
             throw new NullPointerException("name");
         }
         String svalue = value;
         if (value == null) {
             svalue = "";
         }
         Attribute data = factory.createAttribute(request, name, svalue);
         addBodyHttpData(data);
     }
 
     /**
      * Add a file as a FileUpload
      * @param name the name of the parameter
      * @param file the file to be uploaded (if not Multipart mode, only the filename will be included)
      * @param contentType the associated contentType for the File
      * @param isText True if this file should be transmitted in Text format (else binary)
      * @throws NullPointerException for name and file
      * @throws ErrorDataEncoderException if the encoding is in error or if the finalize were already done
      */
     public void addBodyFileUpload(String name, File file, String contentType, boolean isText)
     throws NullPointerException, ErrorDataEncoderException {
         if (name == null) {
             throw new NullPointerException("name");
         }
         if (file == null) {
             throw new NullPointerException("file");
         }
         String scontentType = contentType;
         String contentTransferEncoding = null;
         if (contentType == null) {
             if (isText) {
                 scontentType = HttpPostBodyUtil.DEFAULT_TEXT_CONTENT_TYPE;
             } else {
                 scontentType = HttpPostBodyUtil.DEFAULT_BINARY_CONTENT_TYPE;
             }
         }
         if (!isText) {
             contentTransferEncoding = HttpPostBodyUtil.TransferEncodingMechanism.BINARY.value;
         }
         FileUpload fileUpload = factory.createFileUpload(request, name, file.getName(),
                 scontentType, contentTransferEncoding, null, file.length());
         try {
             fileUpload.setContent(file);
         } catch (IOException e) {
             throw new ErrorDataEncoderException(e);
         }
         addBodyHttpData(fileUpload);
     }
 
     /**
      * Add a series of Files associated with one File parameter (implied Mixed mode in Multipart)
      * @param name the name of the parameter
      * @param file the array of files
      * @param contentType the array of content Types associated with each file
      * @param isText the array of isText attribute (False meaning binary mode) for each file
      * @throws NullPointerException also throws if array have different sizes
      * @throws ErrorDataEncoderException if the encoding is in error or if the finalize were already done
      */
     public void addBodyFileUploads(String name, File[] file, String[] contentType, boolean[] isText)
     throws NullPointerException, ErrorDataEncoderException {
         if (file.length != contentType.length && file.length != isText.length) {
             throw new NullPointerException("Different array length");
         }
         for (int i = 0; i < file.length; i++) {
             addBodyFileUpload(name, file[i], contentType[i], isText[i]);
         }
     }
 
     /**
      * Add the InterfaceHttpData to the Body list
      * @param data
      * @throws NullPointerException for data
      * @throws ErrorDataEncoderException if the encoding is in error or if the finalize were already done
      */
     public void addBodyHttpData(InterfaceHttpData data)
     throws NullPointerException, ErrorDataEncoderException {
         if (headerFinalized) {
             throw new ErrorDataEncoderException("Cannot add value once finalized");
         }
         if (data == null) {
             throw new NullPointerException("data");
         }
         bodyListDatas.add(data);
         if (! isMultipart) {
             if (data instanceof Attribute) {
                 Attribute attribute = (Attribute) data;
                 try {
                     // name=value& with encoded name and attribute
                     String key = encodeAttribute(attribute.getName(), charset);
                     String value = encodeAttribute(attribute.getValue(), charset);
                     Attribute newattribute = factory.createAttribute(request, key, value);
                     multipartHttpDatas.add(newattribute);
                     globalBodySize += newattribute.getName().length()+1+
                         newattribute.length()+1;
                 } catch (IOException e) {
                     throw new ErrorDataEncoderException(e);
                 }
             } else if (data instanceof FileUpload){
                 // since not Multipart, only name=filename => Attribute
                 FileUpload fileUpload = (FileUpload) data;
                 // name=filename& with encoded name and filename
                 String key = encodeAttribute(fileUpload.getName(), charset);
                 String value = encodeAttribute(fileUpload.getFilename(), charset);
                 Attribute newattribute = factory.createAttribute(request, key, value);
                 multipartHttpDatas.add(newattribute);
                 globalBodySize += newattribute.getName().length()+1+
                     newattribute.length()+1;
             }
             return;
         }
         /*
          * Logic:
          * if not Attribute:
          *      add Data to body list
          *      if (duringMixedMode)
          *          add endmixedmultipart delimiter
          *          currentFileUpload = null
          *          duringMixedMode = false;
          *      add multipart delimiter, multipart body header and Data to multipart list
          *      reset currentFileUpload, duringMixedMode
          * if FileUpload: take care of multiple file for one field => mixed mode
          *      if (duringMixeMode)
          *          if (currentFileUpload.name == data.name)
          *              add mixedmultipart delimiter, mixedmultipart body header and Data to multipart list
          *          else
          *              add endmixedmultipart delimiter, multipart body header and Data to multipart list
          *              currentFileUpload = data
          *              duringMixedMode = false;
          *      else
          *          if (currentFileUpload.name == data.name)
          *              change multipart body header of previous file into multipart list to
          *                      mixedmultipart start, mixedmultipart body header
          *              add mixedmultipart delimiter, mixedmultipart body header and Data to multipart list
          *              duringMixedMode = true
          *          else
          *              add multipart delimiter, multipart body header and Data to multipart list
          *              currentFileUpload = data
          *              duringMixedMode = false;
          * Do not add last delimiter! Could be:
          * if duringmixedmode: endmixedmultipart + endmultipart
          * else only endmultipart
          */
         if (data instanceof Attribute) {
             if (duringMixedMode) {
                 InternalAttribute internal = new InternalAttribute();
                 internal.addValue("\r\n--"+multipartMixedBoundary+"--");
                 multipartHttpDatas.add(internal);
                 multipartMixedBoundary = null;
                 currentFileUpload = null;
                 duringMixedMode = false;
             }
             InternalAttribute internal = new InternalAttribute();
             if (multipartHttpDatas.size() > 0) {
                 // previously a data field so CRLF
                 internal.addValue("\r\n");
             }
             internal.addValue("--"+multipartDataBoundary+"\r\n");
             // content-disposition: form-data; name="field1"
             Attribute attribute = (Attribute) data;
             internal.addValue(HttpPostBodyUtil.CONTENT_DISPOSITION+": "+
                     HttpPostBodyUtil.FORM_DATA+"; "+
                     HttpPostBodyUtil.NAME+"=\""+
                     encodeAttribute(attribute.getName(), charset)+"\"\r\n");
             Charset localcharset = attribute.getCharset();
             if (localcharset != null) {
                 // Content-Type: charset=charset
                 internal.addValue(HttpHeaders.Names.CONTENT_TYPE+": "+
                         HttpHeaders.Values.CHARSET+"="+localcharset+"\r\n");
             }
             // CRLF between body header and data
             internal.addValue("\r\n");
             multipartHttpDatas.add(internal);
             multipartHttpDatas.add(data);
             globalBodySize += attribute.length()+internal.size();
         } else if (data instanceof FileUpload) {
             FileUpload fileUpload = (FileUpload) data;
             InternalAttribute internal = new InternalAttribute();
             if (multipartHttpDatas.size() > 0) {
                 // previously a data field so CRLF
                 internal.addValue("\r\n");
             }
             boolean localMixed = false;
             if (duringMixedMode) {
                 if (currentFileUpload != null &&
                         currentFileUpload.getName().equals(fileUpload.getName())) {
                     // continue a mixed mode
 
                     localMixed = true;
                 } else {
                     // end a mixed mode
 
                     // add endmixedmultipart delimiter, multipart body header and
                     // Data to multipart list
                     internal.addValue("--"+multipartMixedBoundary+"--");
                     multipartHttpDatas.add(internal);
                     multipartMixedBoundary = null;
                     // start a new one (could be replaced if mixed start again from here
                     internal = new InternalAttribute();
                     internal.addValue("\r\n");
                     localMixed = false;
                     // new currentFileUpload and no more in Mixed mode
                     currentFileUpload = fileUpload;
                     duringMixedMode = false;
                 }
             } else {
                 if (currentFileUpload != null &&
                         currentFileUpload.getName().equals(fileUpload.getName())) {
                     // create a new mixed mode (from previous file)
 
                     // change multipart body header of previous file into multipart list to
                     // mixedmultipart start, mixedmultipart body header
 
                     // change Internal (size()-2 position in multipartHttpDatas)
                     // from (line starting with *)
                     // --AaB03x
                     // * Content-Disposition: form-data; name="files"; filename="file1.txt"
                     // Content-Type: text/plain
                     // to (lines starting with *)
                     // --AaB03x
                     // * Content-Disposition: form-data; name="files"
                     // * Content-Type: multipart/mixed; boundary=BbC04y
                     // *
                     // * --BbC04y
                     // * Content-Disposition: file; filename="file1.txt"
                     // Content-Type: text/plain
                     initMixedMultipart();
                     InternalAttribute pastAttribute =
                         (InternalAttribute) multipartHttpDatas.get(multipartHttpDatas.size()-2);
                     // remove past size
                     globalBodySize -= pastAttribute.size();
                     String replacement = HttpPostBodyUtil.CONTENT_DISPOSITION+": "+
                         HttpPostBodyUtil.FORM_DATA+"; "+HttpPostBodyUtil.NAME+"=\""+
                         encodeAttribute(fileUpload.getName(), charset)+"\"\r\n";
                     replacement += HttpHeaders.Names.CONTENT_TYPE+": "+
                         HttpPostBodyUtil.MULTIPART_MIXED+"; "+HttpHeaders.Values.BOUNDARY+
                         "="+multipartMixedBoundary+"\r\n\r\n";
                     replacement += "--"+multipartMixedBoundary+"\r\n";
                     replacement += HttpPostBodyUtil.CONTENT_DISPOSITION+": "+
                         HttpPostBodyUtil.FILE+"; "+HttpPostBodyUtil.FILENAME+"=\""+
                         encodeAttribute(fileUpload.getFilename(), charset)+
                         "\"\r\n";
                     pastAttribute.setValue(replacement, 1);
                     // update past size
                     globalBodySize += pastAttribute.size();
 
                     // now continue
                     // add mixedmultipart delimiter, mixedmultipart body header and
                     // Data to multipart list
                     localMixed = true;
                     duringMixedMode = true;
                 } else {
                     // a simple new multipart
                     //add multipart delimiter, multipart body header and Data to multipart list
                     localMixed = false;
                     currentFileUpload = fileUpload;
                     duringMixedMode = false;
                 }
             }
 
             if (localMixed) {
                 // add mixedmultipart delimiter, mixedmultipart body header and
                 // Data to multipart list
                 internal.addValue("--"+multipartMixedBoundary+"\r\n");
                 // Content-Disposition: file; filename="file1.txt"
                 internal.addValue(HttpPostBodyUtil.CONTENT_DISPOSITION+": "+
                         HttpPostBodyUtil.FILE+"; "+HttpPostBodyUtil.FILENAME+"=\""+
                         encodeAttribute(fileUpload.getFilename(), charset)+
                         "\"\r\n");
 
             } else {
                 internal.addValue("--"+multipartDataBoundary+"\r\n");
                 // Content-Disposition: form-data; name="files"; filename="file1.txt"
                 internal.addValue(HttpPostBodyUtil.CONTENT_DISPOSITION+": "+
                         HttpPostBodyUtil.FORM_DATA+"; "+HttpPostBodyUtil.NAME+"=\""+
                         encodeAttribute(fileUpload.getName(), charset)+"\"; "+
                         HttpPostBodyUtil.FILENAME+"=\""+
                         encodeAttribute(fileUpload.getFilename(), charset)+
                         "\"\r\n");
             }
             // Content-Type: image/gif
             // Content-Type: text/plain; charset=ISO-8859-1
             // Content-Transfer-Encoding: binary
             internal.addValue(HttpHeaders.Names.CONTENT_TYPE+": "+
                     fileUpload.getContentType());
             String contentTransferEncoding = fileUpload.getContentTransferEncoding();
             if (contentTransferEncoding != null &&
                     contentTransferEncoding.equals(
                             HttpPostBodyUtil.TransferEncodingMechanism.BINARY.value)) {
                 internal.addValue("\r\n"+HttpHeaders.Names.CONTENT_TRANSFER_ENCODING+
                         ": "+HttpPostBodyUtil.TransferEncodingMechanism.BINARY.value+
                         "\r\n\r\n");
             } else if (fileUpload.getCharset() != null) {
                 internal.addValue("; "+HttpHeaders.Values.CHARSET+"="+
                         fileUpload.getCharset()+"\r\n\r\n");
             } else {
                 internal.addValue("\r\n\r\n");
             }
             multipartHttpDatas.add(internal);
             multipartHttpDatas.add(data);
             globalBodySize += fileUpload.length()+internal.size();
         }
     }
 
     /**
      * Iterator to be used when encoding will be called chunk after chunk
      */
     private ListIterator<InterfaceHttpData> iterator = null;
 
     /**
      * Finalize the request by preparing the Header in the request and
      * returns the request ready to be sent.<br>
      * Once finalized, no data must be added.<br>
      * If the request does not need chunk (isChunked() == false),
      * this request is the only object to send to
      * the remote server.
      *
      * @return the request object (chunked or not according to size of body)
      * @throws ErrorDataEncoderException if the encoding is in error or if the finalize were already done
      */
     public HttpRequest finalizeRequest() throws ErrorDataEncoderException {
         // Finalize the multipartHttpDatas
         if (! headerFinalized) {
             if (isMultipart) {
                 InternalAttribute internal = new InternalAttribute();
                 if (duringMixedMode) {
                     internal.addValue("\r\n--"+multipartMixedBoundary+"--");
                 }
                 internal.addValue("\r\n--"+multipartDataBoundary+"--\r\n");
                 multipartHttpDatas.add(internal);
                 multipartMixedBoundary = null;
                 currentFileUpload = null;
                 duringMixedMode = false;
                 globalBodySize += internal.size();
             }
             headerFinalized = true;
         } else {
             throw new ErrorDataEncoderException("Header already encoded");
         }
         List<String> contentTypes = request.getHeaders(HttpHeaders.Names.CONTENT_TYPE);
         List<String> transferEncoding =
             request.getHeaders(HttpHeaders.Names.TRANSFER_ENCODING);
         if (contentTypes != null) {
             request.removeHeader(HttpHeaders.Names.CONTENT_TYPE);
             for (String contentType: contentTypes) {
                 // "multipart/form-data; boundary=--89421926422648"
                 if (contentType.toLowerCase().startsWith(
                         HttpHeaders.Values.MULTIPART_FORM_DATA)) {
                     // ignore
                 } else if (contentType.toLowerCase().startsWith(
                         HttpHeaders.Values.APPLICATION_X_WWW_FORM_URLENCODED)){
                     // ignore
                 } else {
                     request.addHeader(HttpHeaders.Names.CONTENT_TYPE, contentType);
                 }
             }
         }
         if (isMultipart) {
             String value = HttpHeaders.Values.MULTIPART_FORM_DATA + "; " +
                 HttpHeaders.Values.BOUNDARY + "=" + multipartDataBoundary;
             request.addHeader(HttpHeaders.Names.CONTENT_TYPE, value);
         } else {
             // Not multipart
             request.addHeader(HttpHeaders.Names.CONTENT_TYPE,
                     HttpHeaders.Values.APPLICATION_X_WWW_FORM_URLENCODED);
         }
         // Now consider size for chunk or not
         long realSize = globalBodySize;
         if (isMultipart) {
             iterator = multipartHttpDatas.listIterator();
         } else {
             realSize -= 1; // last '&' removed
             iterator = multipartHttpDatas.listIterator();
         }
         request.setHeader(HttpHeaders.Names.CONTENT_LENGTH, String
                 .valueOf(realSize));
         if (realSize > HttpPostBodyUtil.chunkSize) {
             isChunked = true;
             if (transferEncoding != null) {
                 request.removeHeader(HttpHeaders.Names.TRANSFER_ENCODING);
                 for (String v: transferEncoding) {
                     if (v.equalsIgnoreCase(HttpHeaders.Values.CHUNKED)) {
                         // ignore
                     } else {
                         request.addHeader(HttpHeaders.Names.TRANSFER_ENCODING, v);
                     }
                 }
             }
             request.addHeader(HttpHeaders.Names.TRANSFER_ENCODING,
                     HttpHeaders.Values.CHUNKED);
             request.setContent(ChannelBuffers.EMPTY_BUFFER);
         } else {
             // get the only one body and set it to the request
             HttpChunk chunk = nextChunk();
             request.setContent(chunk.getContent());
         }
         return request;
     }
 
     /**
      * @return True if the request is by Chunk
      */
     public boolean isChunked() {
         return isChunked;
     }
 
     /**
      * Encode one attribute
      * @param s
      * @param charset
      * @return the encoded attribute
      * @throws ErrorDataEncoderException if the encoding is in error
      */
     private static String encodeAttribute(String s, Charset charset)
             throws ErrorDataEncoderException {
         if (s == null) {
             return "";
         }
         try {
             return URLEncoder.encode(s, charset.name());
         } catch (UnsupportedEncodingException e) {
             throw new ErrorDataEncoderException(charset.name(), e);
         }
     }
 
     /**
      * The ChannelBuffer currently used by the encoder
      */
     private ChannelBuffer currentBuffer = null;
     /**
      * The current InterfaceHttpData to encode (used if more chunks are available)
      */
     private InterfaceHttpData currentData = null;
     /**
      * If not multipart, does the currentBuffer stands for the Key or for the Value
      */
     private boolean isKey = true;
 
     /**
      *
      * @return the next ChannelBuffer to send as a HttpChunk and modifying currentBuffer
      * accordingly
      */
     private ChannelBuffer fillChannelBuffer() {
         int length = currentBuffer.readableBytes();
         if (length > HttpPostBodyUtil.chunkSize) {
             ChannelBuffer slice =
                 currentBuffer.slice(currentBuffer.readerIndex(), HttpPostBodyUtil.chunkSize);
             currentBuffer.skipBytes(HttpPostBodyUtil.chunkSize);
             return slice;
         } else {
             // to continue
             ChannelBuffer slice = currentBuffer;
             currentBuffer = null;
             return slice;
         }
     }
 
     /**
      * From the current context (currentBuffer and currentData), returns the next HttpChunk
      * (if possible) trying to get sizeleft bytes more into the currentBuffer.
      * This is the Multipart version.
      *
      * @param sizeleft the number of bytes to try to get from currentData
      * @return the next HttpChunk or null if not enough bytes were found
      * @throws ErrorDataEncoderException if the encoding is in error
      */
     private HttpChunk encodeNextChunkMultipart(int sizeleft) throws ErrorDataEncoderException {
         if (currentData == null) {
             return null;
         }
         ChannelBuffer buffer;
         if (currentData instanceof InternalAttribute) {
             String internal = ((InternalAttribute) currentData).toString();
             byte[] bytes;
             try {
                 bytes = internal.getBytes("ASCII");
             } catch (UnsupportedEncodingException e) {
                 throw new ErrorDataEncoderException(e);
             }
             buffer = ChannelBuffers.wrappedBuffer(bytes);
             currentData = null;
         } else {
             if (currentData instanceof Attribute) {
                 try {
                     buffer = ((Attribute) currentData).getChunk(sizeleft);
                 } catch (IOException e) {
                     throw new ErrorDataEncoderException(e);
                 }
             } else {
                 try {
                     buffer = ((FileUpload) currentData).getChunk(sizeleft);
                 } catch (IOException e) {
                     throw new ErrorDataEncoderException(e);
                 }
             }
             if (buffer.capacity() == 0) {
                 // end for current InterfaceHttpData, need more data
                 currentData = null;
                 return null;
             }
         }
         if (currentBuffer == null) {
             currentBuffer = buffer;
         } else {
             currentBuffer = ChannelBuffers.wrappedBuffer(currentBuffer,
                 buffer);
         }
         if (currentBuffer.readableBytes() < HttpPostBodyUtil.chunkSize) {
             currentData = null;
             return null;
         }
         buffer = fillChannelBuffer();
         return new DefaultHttpChunk(buffer);
     }
 
     /**
      * From the current context (currentBuffer and currentData), returns the next HttpChunk
      * (if possible) trying to get sizeleft bytes more into the currentBuffer.
      * This is the UrlEncoded version.
      *
      * @param sizeleft the number of bytes to try to get from currentData
      * @return the next HttpChunk or null if not enough bytes were found
      * @throws ErrorDataEncoderException if the encoding is in error
      */
     private HttpChunk encodeNextChunkUrlEncoded(int sizeleft) throws ErrorDataEncoderException {
         if (currentData == null) {
             return null;
         }
         int size = sizeleft;
         ChannelBuffer buffer;
         if (isKey) {
             // get name
             String key = currentData.getName();
             buffer = ChannelBuffers.wrappedBuffer(key.getBytes());
             isKey = false;
             if (currentBuffer == null) {
                 currentBuffer = ChannelBuffers.wrappedBuffer(
                         buffer, ChannelBuffers.wrappedBuffer("=".getBytes()));
                 //continue
                 size -= (buffer.readableBytes()+1);
             } else {
                 currentBuffer = ChannelBuffers.wrappedBuffer(currentBuffer,
                     buffer, ChannelBuffers.wrappedBuffer("=".getBytes()));
                 //continue
                 size -= (buffer.readableBytes()+1);
             }
             if (currentBuffer.readableBytes() >= HttpPostBodyUtil.chunkSize) {
                 buffer = fillChannelBuffer();
                 return new DefaultHttpChunk(buffer);
             }
         }
         try {
             buffer = ((Attribute) currentData).getChunk(size);
         } catch (IOException e) {
             throw new ErrorDataEncoderException(e);
         }
         ChannelBuffer delimiter = null;
         if (buffer.readableBytes() < size) {
             // delimiter
             isKey = true;
             delimiter = (iterator.hasNext()) ?
                     ChannelBuffers.wrappedBuffer("&".getBytes()) :
                         null;
         }
         if (buffer.capacity() == 0) {
             // end for current InterfaceHttpData, need potentially more data
             currentData = null;
             if (currentBuffer == null) {
                 currentBuffer = delimiter;
             } else {
                 if (delimiter != null) {
                     currentBuffer = ChannelBuffers.wrappedBuffer(currentBuffer,
                         delimiter);
                 }
             }
             if (currentBuffer.readableBytes() >= HttpPostBodyUtil.chunkSize) {
                 buffer = fillChannelBuffer();
                 return new DefaultHttpChunk(buffer);
             }
             return null;
         }
         if (currentBuffer == null) {
             if (delimiter != null) {
                 currentBuffer = ChannelBuffers.wrappedBuffer(buffer,
                     delimiter);
             } else {
                 currentBuffer = buffer;
             }
         } else {
             if (delimiter != null) {
                 currentBuffer = ChannelBuffers.wrappedBuffer(currentBuffer,
                     buffer, delimiter);
             } else {
                 currentBuffer = ChannelBuffers.wrappedBuffer(currentBuffer,
                         buffer);
             }
         }
         if (currentBuffer.readableBytes() < HttpPostBodyUtil.chunkSize) {
             // end for current InterfaceHttpData, need more data
             currentData = null;
             isKey = true;
             return null;
         }
         buffer = fillChannelBuffer();
         // size = 0
         return new DefaultHttpChunk(buffer);
     }
 
     public void close() throws Exception {
         //NO since the user can want to reuse (broadcast for instance) cleanFiles();
     }
 
     public boolean hasNextChunk() throws Exception {
         return (!isLastChunkSent);
     }
 
     /**
      * Returns the next available HttpChunk. The caller is responsible to test if this chunk is the
      * last one (isLast()), in order to stop calling this method.
      *
      * @return the next available HttpChunk
      * @throws ErrorDataEncoderException if the encoding is in error
      */
     public HttpChunk nextChunk() throws ErrorDataEncoderException {
         if (isLastChunk) {
             isLastChunkSent = true;
             return new DefaultHttpChunk(ChannelBuffers.EMPTY_BUFFER);
         }
         ChannelBuffer buffer = null;
         int size = HttpPostBodyUtil.chunkSize;
         // first test if previous buffer is not empty
         if (currentBuffer != null) {
             size -= currentBuffer.readableBytes();
         }
         if (size <= 0) {
             //NextChunk from buffer
             buffer = fillChannelBuffer();
             return new DefaultHttpChunk(buffer);
         }
         // size > 0
         if (currentData != null) {
             // continue to read data
             if (isMultipart) {
                 HttpChunk chunk = encodeNextChunkMultipart(size);
                 if (chunk != null) {
                     return chunk;
                 }
             } else {
                 HttpChunk chunk = encodeNextChunkUrlEncoded(size);
                 if (chunk != null) {
                     //NextChunk Url from currentData
                     return chunk;
                 }
             }
             size = HttpPostBodyUtil.chunkSize - currentBuffer.readableBytes();
         }
         if (! iterator.hasNext()) {
             isLastChunk = true;
             //NextChunk as last non empty from buffer
             buffer = currentBuffer;
             currentBuffer = null;
             return new DefaultHttpChunk(buffer);
         }
         while (size > 0 && iterator.hasNext()) {
             currentData = iterator.next();
             HttpChunk chunk;
             if (isMultipart) {
                 chunk = encodeNextChunkMultipart(size);
             } else {
                 chunk = encodeNextChunkUrlEncoded(size);
             }
             if (chunk == null) {
                 // not enough
                 size = HttpPostBodyUtil.chunkSize - currentBuffer.readableBytes();
                 continue;
             }
             //NextChunk from data
             return chunk;
         }
         // end since no more data
         isLastChunk = true;
         if (currentBuffer == null) {
             isLastChunkSent = true;
             //LastChunk with no more data
             return new DefaultHttpChunk(ChannelBuffers.EMPTY_BUFFER);
         }
         //Previous LastChunk with no more data
         buffer = currentBuffer;
         currentBuffer = null;
         return new DefaultHttpChunk(buffer);
     }
 
 	public boolean isEndOfInput() throws Exception {
 		return isLastChunkSent;
 	}
 
     /**
      * Exception when an error occurs while encoding
      *
      * @author frederic bregier
      *
      */
     public static class ErrorDataEncoderException extends Exception {
         /**
          *
          */
         private static final long serialVersionUID = 5020247425493164465L;
 
         /**
          *
          */
         public ErrorDataEncoderException() {
             super();
         }
 
         /**
          * @param arg0
          */
         public ErrorDataEncoderException(String arg0) {
             super(arg0);
         }
 
         /**
          * @param arg0
          */
         public ErrorDataEncoderException(Throwable arg0) {
             super(arg0);
         }
 
         /**
          * @param arg0
          * @param arg1
          */
         public ErrorDataEncoderException(String arg0, Throwable arg1) {
             super(arg0, arg1);
         }
     }
 }