/*
    * Copyright 2015 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.rtsp;
  
  import static io.netty.handler.codec.http.HttpConstants.CR;
  import static io.netty.handler.codec.http.HttpConstants.LF;
  import static io.netty.handler.codec.http.HttpConstants.SP;
  import io.netty.buffer.ByteBuf;
  import io.netty.handler.codec.UnsupportedMessageTypeException;
  import io.netty.handler.codec.http.HttpContent;
  import io.netty.handler.codec.http.HttpHeaders;
  import io.netty.handler.codec.http.HttpMessage;
  import io.netty.handler.codec.http.HttpObjectEncoder;
  import io.netty.handler.codec.http.HttpRequest;
  import io.netty.handler.codec.http.HttpResponse;
  import io.netty.util.CharsetUtil;
  import io.netty.util.internal.StringUtil;
  
  /**
   * Encodes an RTSP message represented in {@link HttpMessage} or an {@link HttpContent} into
   * a {@link ByteBuf}.
   */
  public class RtspEncoder extends HttpObjectEncoder<HttpMessage> {
      /**
       * Constant for CRLF.
       */
      private static final byte[] CRLF = {CR, LF};
  
      @Override
      public boolean acceptOutboundMessage(final Object msg)
             throws Exception {
          return super.acceptOutboundMessage(msg) && ((msg instanceof HttpRequest) || (msg instanceof HttpResponse));
      }
  
      @Override
      protected void encodeInitialLine(final ByteBuf buf, final HttpMessage message)
             throws Exception {
          if (message instanceof HttpRequest) {
              HttpRequest request = (HttpRequest) message;
              HttpHeaders.encodeAscii(request.getMethod().toString(), buf);
              buf.writeByte(SP);
              buf.writeBytes(request.getUri().getBytes(CharsetUtil.UTF_8));
              buf.writeByte(SP);
              HttpHeaders.encodeAscii(request.getProtocolVersion().toString(), buf);
              buf.writeBytes(CRLF);
          } else if (message instanceof HttpResponse) {
              HttpResponse response = (HttpResponse) message;
              HttpHeaders.encodeAscii(response.getProtocolVersion().toString(),
                                      buf);
              buf.writeByte(SP);
              buf.writeBytes(String.valueOf(response.getStatus().code())
                                   .getBytes(CharsetUtil.US_ASCII));
              buf.writeByte(SP);
              HttpHeaders.encodeAscii(String.valueOf(response.getStatus().reasonPhrase()),
                                      buf);
              buf.writeBytes(CRLF);
          } else {
              throw new UnsupportedMessageTypeException("Unsupported type "
                                  + StringUtil.simpleClassName(message));
          }
      }
  }