/*
    * Copyright 2020 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.example.stomp.websocket;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
  import io.netty.handler.codec.http.websocketx.WebSocketFrame;
  import io.netty.handler.codec.stomp.LastStompContentSubframe;
  import io.netty.handler.codec.stomp.StompContentSubframe;
  import io.netty.handler.codec.stomp.StompFrame;
  import io.netty.handler.codec.stomp.StompHeaders;
  import io.netty.handler.codec.stomp.StompHeadersSubframe;
  import io.netty.handler.codec.stomp.StompSubframe;
  import io.netty.handler.codec.stomp.StompSubframeEncoder;
  
  import java.util.List;
  
  public class StompWebSocketFrameEncoder extends StompSubframeEncoder {
  
      @Override
      public void encode(ChannelHandlerContext ctx, StompSubframe msg, List<Object> out) throws Exception {
          super.encode(ctx, msg, out);
      }
  
      @Override
      protected WebSocketFrame convertFullFrame(StompFrame original, ByteBuf encoded) {
          if (isTextFrame(original)) {
              return new TextWebSocketFrame(encoded);
          }
  
          return new BinaryWebSocketFrame(encoded);
      }
  
      @Override
      protected WebSocketFrame convertHeadersSubFrame(StompHeadersSubframe original, ByteBuf encoded) {
          if (isTextFrame(original)) {
              return new TextWebSocketFrame(false, 0, encoded);
          }
  
          return new BinaryWebSocketFrame(false, 0, encoded);
      }
  
      @Override
      protected WebSocketFrame convertContentSubFrame(StompContentSubframe original, ByteBuf encoded) {
          if (original instanceof LastStompContentSubframe) {
              return new ContinuationWebSocketFrame(true, 0, encoded);
          }
  
          return new ContinuationWebSocketFrame(false, 0, encoded);
      }
  
      private static boolean isTextFrame(StompHeadersSubframe headersSubframe) {
          String contentType = headersSubframe.headers().getAsString(StompHeaders.CONTENT_TYPE);
          return contentType != null && (contentType.startsWith("text") || contentType.startsWith("application/json"));
      }
  }