/*
    * 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 io.netty.handler.codec.http;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.util.internal.StringUtil;
  
  import java.util.Map;
  
  /**
   * The default {@link LastHttpContent} implementation.
   */
  public class DefaultLastHttpContent extends DefaultHttpContent implements LastHttpContent {
  
      private final HttpHeaders trailingHeaders;
      private final boolean validateHeaders;
  
      public DefaultLastHttpContent() {
          this(Unpooled.buffer(0));
      }
  
      public DefaultLastHttpContent(ByteBuf content) {
          this(content, true);
      }
  
      public DefaultLastHttpContent(ByteBuf content, boolean validateHeaders) {
          super(content);
          trailingHeaders = new TrailingHeaders(validateHeaders);
          this.validateHeaders = validateHeaders;
      }
  
      @Override
      public LastHttpContent copy() {
          DefaultLastHttpContent copy = new DefaultLastHttpContent(content().copy(), validateHeaders);
          copy.trailingHeaders().set(trailingHeaders());
          return copy;
      }
  
      @Override
      public LastHttpContent duplicate() {
          DefaultLastHttpContent copy = new DefaultLastHttpContent(content().duplicate(), validateHeaders);
          copy.trailingHeaders().set(trailingHeaders());
          return copy;
      }
  
      @Override
      public LastHttpContent retain(int increment) {
          super.retain(increment);
          return this;
      }
  
      @Override
      public LastHttpContent retain() {
          super.retain();
          return this;
      }
  
      @Override
      public HttpHeaders trailingHeaders() {
          return trailingHeaders;
      }
  
      @Override
      public String toString() {
          StringBuilder buf = new StringBuilder(super.toString());
          buf.append(StringUtil.NEWLINE);
          appendHeaders(buf);
  
          // Remove the last newline.
          buf.setLength(buf.length() - StringUtil.NEWLINE.length());
          return buf.toString();
      }
  
      private void appendHeaders(StringBuilder buf) {
          for (Map.Entry<String, String> e: trailingHeaders()) {
              buf.append(e.getKey());
              buf.append(": ");
              buf.append(e.getValue());
              buf.append(StringUtil.NEWLINE);
          }
      }
  
      private static final class TrailingHeaders extends DefaultHttpHeaders {
          TrailingHeaders(boolean validate) {
              super(validate);
         }
 
         @Override
         void validateHeaderName0(CharSequence name) {
             super.validateHeaderName0(name);
             if (HttpHeaders.equalsIgnoreCase(HttpHeaders.Names.CONTENT_LENGTH, name) ||
                     HttpHeaders.equalsIgnoreCase(HttpHeaders.Names.TRANSFER_ENCODING, name) ||
                     HttpHeaders.equalsIgnoreCase(HttpHeaders.Names.TRAILER, name)) {
                 throw new IllegalArgumentException(
                         "prohibited trailing header: " + name);
             }
         }
     }
 }