/*
    * Copyright 2013 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.websocketx;
  
  
  import io.netty5.channel.ChannelHandlerContext;
  import io.netty5.channel.ChannelOption;
  import io.netty5.handler.codec.MessageToMessageDecoder;
  import io.netty5.util.Resource;
  import io.netty5.util.concurrent.Future;
  import io.netty5.util.concurrent.Promise;
  
  import java.nio.channels.ClosedChannelException;
  import java.util.concurrent.TimeUnit;
  
  abstract class WebSocketProtocolHandler extends MessageToMessageDecoder<WebSocketFrame> {
  
      private final boolean dropPongFrames;
      private final WebSocketCloseStatus closeStatus;
      private final long forceCloseTimeoutMillis;
      private Promise<Void> closeSent;
  
      /**
       * Creates a new {@link WebSocketProtocolHandler} that will <i>drop</i> {@link PongWebSocketFrame}s.
       */
      WebSocketProtocolHandler() {
          this(true);
      }
  
      /**
       * Creates a new {@link WebSocketProtocolHandler}, given a parameter that determines whether or not to drop {@link
       * PongWebSocketFrame}s.
       *
       * @param dropPongFrames
       *            {@code true} if {@link PongWebSocketFrame}s should be dropped
       */
      WebSocketProtocolHandler(boolean dropPongFrames) {
          this(dropPongFrames, null, 0L);
      }
  
      WebSocketProtocolHandler(boolean dropPongFrames,
                               WebSocketCloseStatus closeStatus,
                               long forceCloseTimeoutMillis) {
          this.dropPongFrames = dropPongFrames;
          this.closeStatus = closeStatus;
          this.forceCloseTimeoutMillis = forceCloseTimeoutMillis;
      }
  
      @Override
      protected void decode(ChannelHandlerContext ctx, WebSocketFrame msg) throws Exception {
          throw new UnsupportedOperationException("WebSocketProtocolHandler use decodeAndClose().");
      }
  
      @Override
      protected void decodeAndClose(ChannelHandlerContext ctx, WebSocketFrame frame) throws Exception {
          if (frame instanceof PingWebSocketFrame) {
              // We need to `send` the binary data to the pong frame, because the MessageToMessageDecoder
              // is going to close the ping frame, which would otherwise cause the data to be freed.
              try (frame) {
                  ctx.writeAndFlush(new PongWebSocketFrame(frame.binaryData().send()));
              }
              readIfNeeded(ctx);
              return;
          }
          if (frame instanceof PongWebSocketFrame && dropPongFrames) {
              readIfNeeded(ctx);
              return;
          }
  
          ctx.fireChannelRead(frame);
      }
  
      private static void readIfNeeded(ChannelHandlerContext ctx) {
          if (!ctx.channel().getOption(ChannelOption.AUTO_READ)) {
              ctx.read();
          }
      }
  
      @Override
      public Future<Void> close(final ChannelHandlerContext ctx) {
          if (closeStatus == null || !ctx.channel().isActive()) {
              return ctx.close();
          }
          final Future<Void> future = closeSent == null ?
                  write(ctx, new CloseWebSocketFrame(ctx.bufferAllocator(), closeStatus)) : closeSent.asFuture();
  
         flush(ctx);
         applyCloseSentTimeout(ctx);
         Promise<Void> promise = ctx.newPromise();
         future.addListener(f -> ctx.close().cascadeTo(promise));
         return promise.asFuture();
     }
 
     @Override
     public Future<Void> write(final ChannelHandlerContext ctx, Object msg) {
         if (closeSent != null) {
             Resource.dispose(msg);
             return ctx.newFailedFuture(new ClosedChannelException());
         }
         if (msg instanceof CloseWebSocketFrame) {
             Promise<Void> promise = ctx.newPromise();
             closeSent(promise);
             ctx.write(msg).cascadeTo(closeSent);
             return promise.asFuture();
         }
         return ctx.write(msg);
     }
 
     void closeSent(Promise<Void> promise) {
         closeSent = promise;
     }
 
     private void applyCloseSentTimeout(ChannelHandlerContext ctx) {
         if (closeSent.isDone() || forceCloseTimeoutMillis < 0) {
             return;
         }
 
         Future<?> timeoutTask = ctx.executor().schedule(() -> {
             if (!closeSent.isDone()) {
                 closeSent.tryFailure(buildHandshakeException("send close frame timed out"));
             }
         }, forceCloseTimeoutMillis, TimeUnit.MILLISECONDS);
 
         closeSent.asFuture().addListener(future -> timeoutTask.cancel());
     }
 
     /**
      * Returns a {@link WebSocketHandshakeException} that depends on which client or server pipeline
      * this handler belongs. Should be overridden in implementation otherwise a default exception is used.
      */
     protected WebSocketHandshakeException buildHandshakeException(String message) {
         return new WebSocketHandshakeException(message);
     }
 
     @Override
     public void channelExceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
         ctx.fireChannelExceptionCaught(cause);
         ctx.close();
     }
 }