/*
    * 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:
    *
    *   https://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 io.netty.handler.codec.http.multipart;
  
  import io.netty.handler.codec.DecoderException;
  import io.netty.handler.codec.http.HttpConstants;
  import io.netty.handler.codec.http.HttpContent;
  import io.netty.handler.codec.http.HttpHeaderNames;
  import io.netty.handler.codec.http.HttpHeaderValues;
  import io.netty.handler.codec.http.HttpRequest;
  import io.netty.util.internal.ObjectUtil;
  import io.netty.util.internal.StringUtil;
  
  import java.nio.charset.Charset;
  import java.util.List;
  
  /**
   * This decoder will decode Body and can handle POST BODY.
   *
   * You <strong>MUST</strong> call {@link #destroy()} after completion to release all resources.
   *
   */
  public class HttpPostRequestDecoder implements InterfaceHttpPostRequestDecoder {
  
      static final int DEFAULT_DISCARD_THRESHOLD = 10 * 1024 * 1024;
  
      private final InterfaceHttpPostRequestDecoder decoder;
  
      /**
       *
       * @param request
       *            the request to decode
       * @throws NullPointerException
       *             for request
       * @throws ErrorDataDecoderException
       *             if the default charset was wrong when decoding or other
       *             errors
       */
      public HttpPostRequestDecoder(HttpRequest request) {
          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 HttpPostRequestDecoder(HttpDataFactory factory, HttpRequest request) {
          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 HttpPostRequestDecoder(HttpDataFactory factory, HttpRequest request, Charset charset) {
          ObjectUtil.checkNotNull(factory, "factory");
          ObjectUtil.checkNotNull(request, "request");
          ObjectUtil.checkNotNull(charset, "charset");
  
          // Fill default values
          if (isMultipart(request)) {
              decoder = new HttpPostMultipartRequestDecoder(factory, request, charset);
          } else {
              decoder = new HttpPostStandardRequestDecoder(factory, request, charset);
          }
      }
  
      /**
      * states follow NOTSTARTED PREAMBLE ( (HEADERDELIMITER DISPOSITION (FIELD |
      * FILEUPLOAD))* (HEADERDELIMITER DISPOSITION MIXEDPREAMBLE (MIXEDDELIMITER
      * MIXEDDISPOSITION MIXEDFILEUPLOAD)+ MIXEDCLOSEDELIMITER)* CLOSEDELIMITER)+
      * EPILOGUE
      *
      * First getStatus is: NOSTARTED
      *
      * Content-type: multipart/form-data, boundary=AaB03x => PREAMBLE in Header
      *
      * --AaB03x => HEADERDELIMITER content-disposition: form-data; name="field1"
      * => DISPOSITION
      *
      * Joe Blow => FIELD --AaB03x => HEADERDELIMITER content-disposition:
      * form-data; name="pics" => DISPOSITION Content-type: multipart/mixed,
      * boundary=BbC04y
      *
      * --BbC04y => MIXEDDELIMITER Content-disposition: attachment;
      * filename="file1.txt" => MIXEDDISPOSITION Content-Type: text/plain
      *
      * ... contents of file1.txt ... => MIXEDFILEUPLOAD --BbC04y =>
      * MIXEDDELIMITER Content-disposition: file; filename="file2.gif" =>
      * MIXEDDISPOSITION Content-type: image/gif Content-Transfer-Encoding:
      * binary
      *
      * ...contents of file2.gif... => MIXEDFILEUPLOAD --BbC04y-- =>
      * MIXEDCLOSEDELIMITER --AaB03x-- => CLOSEDELIMITER
      *
      * Once CLOSEDELIMITER is found, last getStatus is EPILOGUE
      */
     protected enum MultiPartStatus {
         NOTSTARTED, PREAMBLE, HEADERDELIMITER, DISPOSITION, FIELD, FILEUPLOAD, MIXEDPREAMBLE, MIXEDDELIMITER,
         MIXEDDISPOSITION, MIXEDFILEUPLOAD, MIXEDCLOSEDELIMITER, CLOSEDELIMITER, PREEPILOGUE, EPILOGUE
     }
 
     /**
      * Check if the given request is a multipart request
      * @return True if the request is a Multipart request
      */
     public static boolean isMultipart(HttpRequest request) {
         String mimeType = request.headers().get(HttpHeaderNames.CONTENT_TYPE);
         if (mimeType != null && mimeType.startsWith(HttpHeaderValues.MULTIPART_FORM_DATA.toString())) {
             return getMultipartDataBoundary(mimeType) != null;
         }
         return false;
     }
 
     /**
      * Check from the request ContentType if this request is a Multipart request.
      * @return an array of String if multipartDataBoundary exists with the multipartDataBoundary
      * as first element, charset if any as second (missing if not set), else null
      */
     protected static String[] getMultipartDataBoundary(String contentType) {
         // Check if Post using "multipart/form-data; boundary=--89421926422648 [; charset=xxx]"
         String[] headerContentType = splitHeaderContentType(contentType);
         final String multiPartHeader = HttpHeaderValues.MULTIPART_FORM_DATA.toString();
         if (headerContentType[0].regionMatches(true, 0, multiPartHeader, 0 , multiPartHeader.length())) {
             int mrank;
             int crank;
             final String boundaryHeader = HttpHeaderValues.BOUNDARY.toString();
             if (headerContentType[1].regionMatches(true, 0, boundaryHeader, 0, boundaryHeader.length())) {
                 mrank = 1;
                 crank = 2;
             } else if (headerContentType[2].regionMatches(true, 0, boundaryHeader, 0, boundaryHeader.length())) {
                 mrank = 2;
                 crank = 1;
             } else {
                 return null;
             }
             String boundary = StringUtil.substringAfter(headerContentType[mrank], '=');
             if (boundary == null) {
                 throw new ErrorDataDecoderException("Needs a boundary value");
             }
             if (boundary.charAt(0) == '"') {
                 String bound = boundary.trim();
                 int index = bound.length() - 1;
                 if (bound.charAt(index) == '"') {
                     boundary = bound.substring(1, index);
                 }
             }
             final String charsetHeader = HttpHeaderValues.CHARSET.toString();
             if (headerContentType[crank].regionMatches(true, 0, charsetHeader, 0, charsetHeader.length())) {
                 String charset = StringUtil.substringAfter(headerContentType[crank], '=');
                 if (charset != null) {
                     return new String[] {"--" + boundary, charset};
                 }
             }
             return new String[] {"--" + boundary};
         }
         return null;
     }
 
     @Override
     public boolean isMultipart() {
         return decoder.isMultipart();
     }
 
     @Override
     public void setDiscardThreshold(int discardThreshold) {
         decoder.setDiscardThreshold(discardThreshold);
     }
 
     @Override
     public int getDiscardThreshold() {
         return decoder.getDiscardThreshold();
     }
 
     @Override
     public List<InterfaceHttpData> getBodyHttpDatas() {
         return decoder.getBodyHttpDatas();
     }
 
     @Override
     public List<InterfaceHttpData> getBodyHttpDatas(String name) {
         return decoder.getBodyHttpDatas(name);
     }
 
     @Override
     public InterfaceHttpData getBodyHttpData(String name) {
         return decoder.getBodyHttpData(name);
     }
 
     @Override
     public InterfaceHttpPostRequestDecoder offer(HttpContent content) {
         return decoder.offer(content);
     }
 
     @Override
     public boolean hasNext() {
         return decoder.hasNext();
     }
 
     @Override
     public InterfaceHttpData next() {
         return decoder.next();
     }
 
     @Override
     public InterfaceHttpData currentPartialHttpData() {
         return decoder.currentPartialHttpData();
     }
 
     @Override
     public void destroy() {
         decoder.destroy();
     }
 
     @Override
     public void cleanFiles() {
         decoder.cleanFiles();
     }
 
     @Override
     public void removeHttpDataFromClean(InterfaceHttpData data) {
         decoder.removeHttpDataFromClean(data);
     }
 
     /**
      * Split the very first line (Content-Type value) in 3 Strings
      *
      * @return the array of 3 Strings
      */
     private static String[] splitHeaderContentType(String sb) {
         int aStart;
         int aEnd;
         int bStart;
         int bEnd;
         int cStart;
         int cEnd;
         aStart = HttpPostBodyUtil.findNonWhitespace(sb, 0);
         aEnd =  sb.indexOf(';');
         if (aEnd == -1) {
             return new String[] { sb, "", "" };
         }
         bStart = HttpPostBodyUtil.findNonWhitespace(sb, aEnd + 1);
         if (sb.charAt(aEnd - 1) == ' ') {
             aEnd--;
         }
         bEnd =  sb.indexOf(';', bStart);
         if (bEnd == -1) {
             bEnd = HttpPostBodyUtil.findEndOfString(sb);
             return new String[] { sb.substring(aStart, aEnd), sb.substring(bStart, bEnd), "" };
         }
         cStart = HttpPostBodyUtil.findNonWhitespace(sb, bEnd + 1);
         if (sb.charAt(bEnd - 1) == ' ') {
             bEnd--;
         }
         cEnd = HttpPostBodyUtil.findEndOfString(sb);
         return new String[] { sb.substring(aStart, aEnd), sb.substring(bStart, bEnd), sb.substring(cStart, cEnd) };
     }
 
     /**
      * Exception when try reading data from request in chunked format, and not
      * enough data are available (need more chunks)
      */
     public static class NotEnoughDataDecoderException extends DecoderException {
         private static final long serialVersionUID = -7846841864603865638L;
 
         public NotEnoughDataDecoderException() {
         }
 
         public NotEnoughDataDecoderException(String msg) {
             super(msg);
         }
 
         public NotEnoughDataDecoderException(Throwable cause) {
             super(cause);
         }
 
         public NotEnoughDataDecoderException(String msg, Throwable cause) {
             super(msg, cause);
         }
     }
 
     /**
      * Exception when the body is fully decoded, even if there is still data
      */
     public static class EndOfDataDecoderException extends DecoderException {
         private static final long serialVersionUID = 1336267941020800769L;
     }
 
     /**
      * Exception when an error occurs while decoding
      */
     public static class ErrorDataDecoderException extends DecoderException {
         private static final long serialVersionUID = 5020247425493164465L;
 
         public ErrorDataDecoderException() {
         }
 
         public ErrorDataDecoderException(String msg) {
             super(msg);
         }
 
         public ErrorDataDecoderException(Throwable cause) {
             super(cause);
         }
 
         public ErrorDataDecoderException(String msg, Throwable cause) {
             super(msg, cause);
         }
     }
 }