/*
    * 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:
    *
    *   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.rtsp;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufUtil;
  import io.netty.handler.codec.UnsupportedMessageTypeException;
  import io.netty.handler.codec.http.HttpContent;
  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 static io.netty.handler.codec.http.HttpConstants.*;
  
  /**
   * Encodes an RTSP message represented in {@link HttpMessage} or an {@link HttpContent} into
   * a {@link ByteBuf}.
   */
  public class RtspEncoder extends HttpObjectEncoder<HttpMessage> {
      private static final int CRLF_SHORT = (CR << 8) | 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;
              ByteBufUtil.copy(request.method().asciiName(), buf);
              buf.writeByte(SP);
              buf.writeCharSequence(request.uri(), CharsetUtil.UTF_8);
              buf.writeByte(SP);
              buf.writeCharSequence(request.protocolVersion().toString(), CharsetUtil.US_ASCII);
              ByteBufUtil.writeShortBE(buf, CRLF_SHORT);
          } else if (message instanceof HttpResponse) {
              HttpResponse response = (HttpResponse) message;
              buf.writeCharSequence(response.protocolVersion().toString(), CharsetUtil.US_ASCII);
              buf.writeByte(SP);
              ByteBufUtil.copy(response.status().codeAsText(), buf);
              buf.writeByte(SP);
              buf.writeCharSequence(response.status().reasonPhrase(), CharsetUtil.US_ASCII);
              ByteBufUtil.writeShortBE(buf, CRLF_SHORT);
          } else {
              throw new UnsupportedMessageTypeException(message, HttpRequest.class, HttpResponse.class);
          }
      }
  }