/*
    * 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.netty5.handler.codec.http;
  
  import io.netty5.buffer.api.Buffer;
  import io.netty5.util.Send;
  import io.netty5.handler.codec.DefaultHeaders.NameValidator;
  import io.netty5.util.internal.StringUtil;
  
  import java.util.Map.Entry;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * The default {@link LastHttpContent} implementation.
   */
  public class DefaultLastHttpContent extends DefaultHttpObject implements LastHttpContent<DefaultLastHttpContent> {
      private final HttpHeaders trailingHeaders;
      private final Buffer payload;
  
      public DefaultLastHttpContent(Buffer payload) {
          this(payload, true);
      }
  
      public DefaultLastHttpContent(Buffer payload, boolean validateHeaders) {
          this(payload, new TrailingHttpHeaders(validateHeaders));
      }
  
      public DefaultLastHttpContent(Buffer payload, HttpHeaders trailingHeaders) {
          this.payload = requireNonNull(payload, "payload");
          this.trailingHeaders = requireNonNull(trailingHeaders, "trailingHeaders");
      }
  
      @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 (Entry<String, String> e : trailingHeaders()) {
              buf.append(e.getKey());
              buf.append(": ");
              buf.append(e.getValue());
              buf.append(StringUtil.NEWLINE);
          }
      }
  
      @Override
      public Send<DefaultLastHttpContent> send() {
          return payload.send().map(DefaultLastHttpContent.class,
                  payload -> new DefaultLastHttpContent(payload, trailingHeaders));
      }
  
      @Override
      public DefaultLastHttpContent copy() {
          return new DefaultLastHttpContent(payload.copy(), trailingHeaders.copy());
      }
  
      @Override
      public void close() {
          payload.close();
      }
  
      @Override
      public boolean isAccessible() {
          return payload.isAccessible();
      }
  
      @Override
      public DefaultLastHttpContent touch(Object hint) {
          payload.touch(hint);
          return this;
      }
  
      @Override
     public Buffer payload() {
         return payload;
     }
 
     private static final class TrailingHttpHeaders extends DefaultHttpHeaders {
         private static final NameValidator<CharSequence> TrailerNameValidator = name -> {
             DefaultHttpHeaders.HttpNameValidator.validateName(name);
             if (HttpHeaderNames.CONTENT_LENGTH.contentEqualsIgnoreCase(name)
                     || HttpHeaderNames.TRANSFER_ENCODING.contentEqualsIgnoreCase(name)
                     || HttpHeaderNames.TRAILER.contentEqualsIgnoreCase(name)) {
                 throw new IllegalArgumentException("prohibited trailing header: " + name);
             }
         };
 
         @SuppressWarnings({ "unchecked" })
         TrailingHttpHeaders(boolean validate) {
             super(validate, validate ? TrailerNameValidator : NameValidator.NOT_NULL);
         }
     }
 }