/**
    * Licensed to jclouds, Inc. (jclouds) under one or more
    * contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  jclouds 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.jclouds.io.payloads;
  
  import static com.google.common.base.Throwables.propagate;
  import static com.google.common.collect.Lists.newArrayList;
  import static com.google.common.io.ByteStreams.join;
  import static com.google.common.io.ByteStreams.newInputStreamSupplier;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Map.Entry;
  
  import com.google.common.io.InputSupplier;
  
  /**
   * 
   * @author Adrian Cole
   */
  public class MultipartForm extends BasePayload<Iterable<? extends Part>> {
     public static final String BOUNDARY = "--JCLOUDS--";
     private static final String rn = "\r\n";
     private static final String dd = "--";
  
     private boolean isRepeatable;
     private final InputSupplier<? extends InputStream> chain;
  
     @SuppressWarnings("unchecked")
     public MultipartForm(String boundary, Iterable<? extends Part> content) {
        super(content);
        getContentMetadata().setContentType("multipart/form-data; boundary=" + boundary);
        getContentMetadata().setContentLength(0l);
        String boundaryrn = boundary + rn;
        isRepeatable = true;
        InputSupplier<? extends InputStream> chain = join();
        for (Part part : content) {
           if (!part.isRepeatable())
              isRepeatable = false;
           getContentMetadata().setContentLength(
                    getContentMetadata().getContentLength() + part.getContentMetadata().getContentLength());
           chain = join(chain, addLengthAndReturnHeaders(boundaryrn, part), part, addLengthAndReturnRn());
        }
        chain = join(chain, addLengthAndReturnFooter(boundary));
        this.chain = chain;
     }
  
     public MultipartForm(String boundary, Part... parts) {
        this(boundary, newArrayList(parts));
     }
  
     public MultipartForm(Part... parts) {
        this(BOUNDARY, parts);
     }
  
     private InputSupplier<? extends InputStream> addLengthAndReturnRn() {
        getContentMetadata().setContentLength(getContentMetadata().getContentLength() + rn.length());
        return newInputStreamSupplier(rn.getBytes());
     }
  
     private InputSupplier<? extends InputStream> addLengthAndReturnHeaders(String boundaryrn, Part part) {
        StringBuilder builder = new StringBuilder(dd).append(boundaryrn);
        for (Entry<String, String> entry : part.getHeaders().entries()) {
           String header = String.format("%s: %s%s", entry.getKey(), entry.getValue(), rn);
           builder.append(header);
        }
        builder.append(rn);
        getContentMetadata().setContentLength(getContentMetadata().getContentLength() + builder.length());
        return newInputStreamSupplier(builder.toString().getBytes());
     }
  
     private InputSupplier<? extends InputStream> addLengthAndReturnFooter(String boundary) {
        String end = dd + boundary + dd + rn;
        getContentMetadata().setContentLength(getContentMetadata().getContentLength() + end.length());
        return newInputStreamSupplier(end.getBytes());
     }
  
     @Override
     public InputStream getInput() {
        try {
           return chain.getInput();
        } catch (IOException e) {
           propagate(e);
           return null;
       }
    }
 
    @Override
    public boolean isRepeatable() {
       return isRepeatable;
    }
 
    @Override
    public void release() {
       for (Part part : content)
          part.release();
    }
 
 }