/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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.http.multipart;
  
  import org.jboss.netty.buffer.ChannelBuffer;
  import org.jboss.netty.buffer.ChannelBuffers;
  import org.jboss.netty.handler.codec.http.HttpChunk;
  import org.jboss.netty.handler.codec.http.HttpConstants;
  import org.jboss.netty.handler.codec.http.HttpRequest;
  import org.jboss.netty.handler.codec.http.multipart.HttpPostBodyUtil.SeekAheadNoBackArrayException;
  import org.jboss.netty.handler.codec.http.multipart.HttpPostBodyUtil.SeekAheadOptimize;
  import org.jboss.netty.handler.codec.http.multipart.HttpPostRequestDecoder.EndOfDataDecoderException;
  import org.jboss.netty.handler.codec.http.multipart.HttpPostRequestDecoder.ErrorDataDecoderException;
  import org.jboss.netty.handler.codec.http.multipart.HttpPostRequestDecoder.MultiPartStatus;
  import org.jboss.netty.handler.codec.http.multipart.HttpPostRequestDecoder.NotEnoughDataDecoderException;
  import org.jboss.netty.util.internal.CaseIgnoringComparator;
  
  import java.io.IOException;
  import java.io.UnsupportedEncodingException;
  import java.net.URLDecoder;
  import java.nio.charset.Charset;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  /**
   * This decoder will decode Body and can handle standard (non multipart) POST BODY.
   */
  public class HttpPostStandardRequestDecoder implements InterfaceHttpPostRequestDecoder {
      /**
       * Factory used to create InterfaceHttpData
       */
      private final HttpDataFactory factory;
  
      /**
       * Request to decode
       */
      private final HttpRequest request;
  
      /**
       * Default charset to use
       */
      private final Charset charset;
  
      /**
       * Does the last chunk already received
       */
      private boolean isLastChunk;
  
      /**
       * HttpDatas from Body
       */
      private final List<InterfaceHttpData> bodyListHttpData = new ArrayList<InterfaceHttpData>();
  
      /**
       * HttpDatas as Map from Body
       */
      private final Map<String, List<InterfaceHttpData>> bodyMapHttpData = new TreeMap<String, List<InterfaceHttpData>>(
              CaseIgnoringComparator.INSTANCE);
  
      /**
       * The current channelBuffer
       */
      private ChannelBuffer undecodedChunk;
  
      /**
       * Body HttpDatas current position
       */
      private int bodyListHttpDataRank;
  
      /**
       * Current status
       */
      private MultiPartStatus currentStatus = MultiPartStatus.NOTSTARTED;
  
      /**
       * The current Attribute that is currently in decode process
       */
      private Attribute currentAttribute;
  
      /**
      *
      * @param request the request to decode
      * @throws NullPointerException for request
      * @throws ErrorDataDecoderException if the default charset was wrong when decoding or other errors
     */
     public HttpPostStandardRequestDecoder(HttpRequest request) throws ErrorDataDecoderException {
         this(new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE),
                 request, HttpConstants.DEFAULT_CHARSET);
     }
 
     /**
      *
      * @param factory the factory used to create InterfaceHttpData
      * @param request the request to decode
      * @throws NullPointerException for request or factory
      * @throws ErrorDataDecoderException if the default charset was wrong when decoding or other errors
      */
     public HttpPostStandardRequestDecoder(HttpDataFactory factory, HttpRequest request)
             throws ErrorDataDecoderException {
         this(factory, request, HttpConstants.DEFAULT_CHARSET);
     }
 
     /**
      *
      * @param factory the factory used to create InterfaceHttpData
      * @param request the request to decode
      * @param charset the charset to use as default
      * @throws NullPointerException for request or charset or factory
      * @throws ErrorDataDecoderException if the default charset was wrong when decoding or other errors
      */
     public HttpPostStandardRequestDecoder(HttpDataFactory factory, HttpRequest request,
             Charset charset) throws ErrorDataDecoderException {
         if (factory == null) {
             throw new NullPointerException("factory");
         }
         if (request == null) {
             throw new NullPointerException("request");
         }
         if (charset == null) {
             throw new NullPointerException("charset");
         }
         this.request = request;
         this.charset = charset;
         this.factory = factory;
         if (!this.request.isChunked()) {
             undecodedChunk = this.request.getContent();
             isLastChunk = true;
             parseBody();
         }
     }
 
     public boolean isMultipart() {
         return false;
     }
 
     public List<InterfaceHttpData> getBodyHttpDatas()
             throws NotEnoughDataDecoderException {
         if (!isLastChunk) {
             throw new NotEnoughDataDecoderException();
         }
         return bodyListHttpData;
     }
 
     public List<InterfaceHttpData> getBodyHttpDatas(String name)
             throws NotEnoughDataDecoderException {
         if (!isLastChunk) {
             throw new NotEnoughDataDecoderException();
         }
         return bodyMapHttpData.get(name);
     }
 
     public InterfaceHttpData getBodyHttpData(String name)
             throws NotEnoughDataDecoderException {
         if (!isLastChunk) {
             throw new NotEnoughDataDecoderException();
         }
         List<InterfaceHttpData> list = bodyMapHttpData.get(name);
         if (list != null) {
             return list.get(0);
         }
         return null;
     }
 
     public void offer(HttpChunk chunk) throws ErrorDataDecoderException {
         ChannelBuffer chunked = chunk.getContent();
         if (undecodedChunk == null) {
             undecodedChunk = chunked;
         } else {
             //undecodedChunk = ChannelBuffers.wrappedBuffer(undecodedChunk, chunk.getContent());
             // less memory usage
             undecodedChunk = ChannelBuffers.wrappedBuffer(
                     undecodedChunk, chunked);
         }
         if (chunk.isLast()) {
             isLastChunk = true;
         }
         parseBody();
     }
 
     public boolean hasNext() throws EndOfDataDecoderException {
         if (currentStatus == MultiPartStatus.EPILOGUE) {
             // OK except if end of list
             if (bodyListHttpDataRank >= bodyListHttpData.size()) {
                 throw new EndOfDataDecoderException();
             }
         }
         return !bodyListHttpData.isEmpty() && bodyListHttpDataRank < bodyListHttpData.size();
     }
 
     public InterfaceHttpData next() throws EndOfDataDecoderException {
         if (hasNext()) {
             return bodyListHttpData.get(bodyListHttpDataRank++);
         }
         return null;
     }
 
     /**
      * This method will parse as much as possible data and fill the list and map
      * @throws ErrorDataDecoderException if there is a problem with the charset decoding or
      *          other errors
      */
     private void parseBody() throws ErrorDataDecoderException {
         if (currentStatus == MultiPartStatus.PREEPILOGUE ||
                 currentStatus == MultiPartStatus.EPILOGUE) {
             if (isLastChunk) {
                 currentStatus = MultiPartStatus.EPILOGUE;
             }
             return;
         }
         parseBodyAttributes();
     }
 
     /**
      * Utility function to add a new decoded data
      */
     private void addHttpData(InterfaceHttpData data) {
         if (data == null) {
             return;
         }
         List<InterfaceHttpData> datas = bodyMapHttpData.get(data.getName());
         if (datas == null) {
             datas = new ArrayList<InterfaceHttpData>(1);
             bodyMapHttpData.put(data.getName(), datas);
         }
         datas.add(data);
         bodyListHttpData.add(data);
     }
 
     /**
       * This method fill the map and list with as much Attribute as possible from Body in
       * not Multipart mode.
       *
       * @throws ErrorDataDecoderException if there is a problem with the charset decoding or
       *          other errors
       */
     private void parseBodyAttributesStandard() throws ErrorDataDecoderException {
         int firstpos = undecodedChunk.readerIndex();
         int currentpos = firstpos;
         int equalpos;
         int ampersandpos;
         if (currentStatus == MultiPartStatus.NOTSTARTED) {
             currentStatus = MultiPartStatus.DISPOSITION;
         }
         boolean contRead = true;
         try {
            while (undecodedChunk.readable() && contRead) {
                 char read = (char) undecodedChunk.readUnsignedByte();
                 currentpos++;
                 switch (currentStatus) {
                 case DISPOSITION:// search '='
                     if (read == '=') {
                         currentStatus = MultiPartStatus.FIELD;
                         equalpos = currentpos - 1;
                         String key = decodeAttribute(
                                 undecodedChunk.toString(firstpos, equalpos - firstpos, charset),
                                 charset);
                         currentAttribute = factory.createAttribute(request, key);
                         firstpos = currentpos;
                     } else if (read == '&') { // special empty FIELD
                         currentStatus = MultiPartStatus.DISPOSITION;
                         ampersandpos = currentpos - 1;
                         String key = decodeAttribute(
                                 undecodedChunk.toString(firstpos, ampersandpos - firstpos, charset), charset);
                         currentAttribute = factory.createAttribute(request, key);
                         currentAttribute.setValue(""); // empty
                         addHttpData(currentAttribute);
                         currentAttribute = null;
                         firstpos = currentpos;
                         contRead = true;
                     }
                     break;
                 case FIELD:// search '&' or end of line
                     if (read == '&') {
                         currentStatus = MultiPartStatus.DISPOSITION;
                         ampersandpos = currentpos - 1;
                         setFinalBuffer(undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                         firstpos = currentpos;
                         contRead = true;
                     } else if (read == HttpConstants.CR) {
                         if (undecodedChunk.readable()) {
                             read = (char) undecodedChunk.readUnsignedByte();
                             currentpos++;
                             if (read == HttpConstants.LF) {
                                 currentStatus = MultiPartStatus.PREEPILOGUE;
                                 ampersandpos = currentpos - 2;
                                 setFinalBuffer(
                                         undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                                 firstpos = currentpos;
                                 contRead = false;
                             } else {
                                 // Error
                                 throw new ErrorDataDecoderException("Bad end of line");
                             }
                         } else {
                             currentpos--;
                         }
                     } else if (read == HttpConstants.LF) {
                         currentStatus = MultiPartStatus.PREEPILOGUE;
                         ampersandpos = currentpos - 1;
                         setFinalBuffer(
                                 undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                         firstpos = currentpos;
                         contRead = false;
                     }
                     break;
                 default:
                     // just stop
                     contRead = false;
                 }
             }
             if (isLastChunk && currentAttribute != null) {
                 // special case
                 ampersandpos = currentpos;
                 if (ampersandpos > firstpos) {
                     setFinalBuffer(
                             undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                 } else if (! currentAttribute.isCompleted()) {
                     setFinalBuffer(ChannelBuffers.EMPTY_BUFFER);
                 }
                 firstpos = currentpos;
                 currentStatus = MultiPartStatus.EPILOGUE;
                 undecodedChunk.readerIndex(firstpos);
                 return;
             }
             if (contRead && currentAttribute != null) {
                 // reset index except if to continue in case of FIELD status
                 if (currentStatus == MultiPartStatus.FIELD) {
                     currentAttribute.addContent(
                             undecodedChunk.slice(firstpos, currentpos - firstpos),
                             false);
                     firstpos = currentpos;
                 }
                 undecodedChunk.readerIndex(firstpos);
             } else {
                 // end of line or end of block so keep index to last valid position
                 undecodedChunk.readerIndex(firstpos);
             }
         } catch (ErrorDataDecoderException e) {
             // error while decoding
             undecodedChunk.readerIndex(firstpos);
             throw e;
         } catch (IOException e) {
             // error while decoding
             undecodedChunk.readerIndex(firstpos);
             throw new ErrorDataDecoderException(e);
         }
     }
 
     /**
      * This method fill the map and list with as much Attribute as possible from Body in
      * not Multipart mode.
      *
      * @throws ErrorDataDecoderException if there is a problem with the charset decoding or
      * other errors
      */
     private void parseBodyAttributes() throws ErrorDataDecoderException {
         SeekAheadOptimize sao;
         try {
             sao = new SeekAheadOptimize(undecodedChunk);
         } catch (SeekAheadNoBackArrayException e1) {
             parseBodyAttributesStandard();
             return;
         }
         int firstpos = undecodedChunk.readerIndex();
         int currentpos = firstpos;
         int equalpos;
         int ampersandpos;
         if (currentStatus == MultiPartStatus.NOTSTARTED) {
             currentStatus = MultiPartStatus.DISPOSITION;
         }
         boolean contRead = true;
         try {
             loop:
             while (sao.pos < sao.limit) {
                 char read = (char) (sao.bytes[sao.pos ++] & 0xFF);
                 currentpos ++;
                 switch (currentStatus) {
                 case DISPOSITION:// search '='
                     if (read == '=') {
                         currentStatus = MultiPartStatus.FIELD;
                         equalpos = currentpos - 1;
                         String key = decodeAttribute(
                                 undecodedChunk.toString(firstpos, equalpos - firstpos, charset),
                                 charset);
                         currentAttribute = factory.createAttribute(request, key);
                         firstpos = currentpos;
                     } else if (read == '&') { // special empty FIELD
                         currentStatus = MultiPartStatus.DISPOSITION;
                         ampersandpos = currentpos - 1;
                         String key = decodeAttribute(
                                 undecodedChunk.toString(firstpos, ampersandpos - firstpos, charset), charset);
                         currentAttribute = factory.createAttribute(request, key);
                         currentAttribute.setValue(""); // empty
                         addHttpData(currentAttribute);
                         currentAttribute = null;
                         firstpos = currentpos;
                         contRead = true;
                     }
                     break;
                 case FIELD:// search '&' or end of line
                     if (read == '&') {
                         currentStatus = MultiPartStatus.DISPOSITION;
                         ampersandpos = currentpos - 1;
                         setFinalBuffer(undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                         firstpos = currentpos;
                         contRead = true;
                     } else if (read == HttpConstants.CR) {
                         if (sao.pos < sao.limit) {
                             read = (char) (sao.bytes[sao.pos ++] & 0xFF);
                             currentpos++;
                             if (read == HttpConstants.LF) {
                                 currentStatus = MultiPartStatus.PREEPILOGUE;
                                 ampersandpos = currentpos - 2;
                                 sao.setReadPosition(0);
                                 setFinalBuffer(
                                         undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                                 firstpos = currentpos;
                                 contRead = false;
                                 break loop;
                             } else {
                                 // Error
                                 sao.setReadPosition(0);
                                 throw new ErrorDataDecoderException("Bad end of line");
                             }
                         } else {
                             if (sao.limit > 0) {
                                 currentpos --;
                             }
                         }
                     } else if (read == HttpConstants.LF) {
                         currentStatus = MultiPartStatus.PREEPILOGUE;
                         ampersandpos = currentpos - 1;
                         sao.setReadPosition(0);
                         setFinalBuffer(
                                 undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                         firstpos = currentpos;
                         contRead = false;
                         break loop;
                     }
                     break;
                 default:
                     // just stop
                     sao.setReadPosition(0);
                     contRead = false;
                     break loop;
                 }
             }
             if (isLastChunk && currentAttribute != null) {
                 // special case
                 ampersandpos = currentpos;
                 if (ampersandpos > firstpos) {
                     setFinalBuffer(
                             undecodedChunk.slice(firstpos, ampersandpos - firstpos));
                 } else if (! currentAttribute.isCompleted()) {
                     setFinalBuffer(ChannelBuffers.EMPTY_BUFFER);
                 }
                 firstpos = currentpos;
                 currentStatus = MultiPartStatus.EPILOGUE;
                 undecodedChunk.readerIndex(firstpos);
                 return;
             }
             if (contRead && currentAttribute != null) {
                 // reset index except if to continue in case of FIELD status
                 if (currentStatus == MultiPartStatus.FIELD) {
                     currentAttribute.addContent(
                             undecodedChunk.slice(firstpos, currentpos - firstpos),
                             false);
                     firstpos = currentpos;
                 }
                 undecodedChunk.readerIndex(firstpos);
             } else {
                 // end of line or end of block so keep index to last valid position
                 undecodedChunk.readerIndex(firstpos);
             }
         } catch (ErrorDataDecoderException e) {
             // error while decoding
             undecodedChunk.readerIndex(firstpos);
             throw e;
         } catch (IOException e) {
             // error while decoding
             undecodedChunk.readerIndex(firstpos);
             throw new ErrorDataDecoderException(e);
         }
     }
 
     private void setFinalBuffer(ChannelBuffer buffer) throws ErrorDataDecoderException, IOException {
         currentAttribute.addContent(buffer, true);
         String value = decodeAttribute(
                 currentAttribute.getChannelBuffer().toString(charset),
                 charset);
         currentAttribute.setValue(value);
         addHttpData(currentAttribute);
         currentAttribute = null;
     }
 
     /**
      * Decode component
      * @return the decoded component
      */
     private static String decodeAttribute(String s, Charset charset)
             throws ErrorDataDecoderException {
         if (s == null) {
             return "";
         }
         try {
             return URLDecoder.decode(s, charset.name());
         } catch (UnsupportedEncodingException e) {
             throw new ErrorDataDecoderException(charset.toString(), e);
         } catch (IllegalArgumentException e) {
             throw new ErrorDataDecoderException("Bad string: '" + s + '\'', e);
         }
     }
 
     public void cleanFiles() {
         factory.cleanRequestHttpDatas(request);
     }
 
     public void removeHttpDataFromClean(InterfaceHttpData data) {
         factory.removeHttpDataFromClean(request, data);
     }
 }