/*
    * Copyright 2014 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.http2;
  
  import io.netty5.buffer.BufferUtil;
  import io.netty5.buffer.api.Buffer;
  import io.netty5.channel.ChannelHandlerContext;
  import io.netty5.handler.logging.LogLevel;
  import io.netty5.util.internal.UnstableApi;
  import io.netty5.util.internal.logging.InternalLogLevel;
  import io.netty5.util.internal.logging.InternalLogger;
  import io.netty5.util.internal.logging.InternalLoggerFactory;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Logs HTTP2 frames for debugging purposes.
   */
  @UnstableApi
  public class Http2FrameLogger {
  
      public enum Direction {
          INBOUND,
          OUTBOUND
      }
  
      private static final int BUFFER_LENGTH_THRESHOLD = 64;
      private final InternalLogger logger;
      private final InternalLogLevel level;
  
      public Http2FrameLogger(LogLevel level) {
          this(checkAndConvertLevel(level), InternalLoggerFactory.getInstance(Http2FrameLogger.class));
      }
  
      public Http2FrameLogger(LogLevel level, String name) {
          this(checkAndConvertLevel(level), InternalLoggerFactory.getInstance(requireNonNull(name, "name")));
      }
  
      public Http2FrameLogger(LogLevel level, Class<?> clazz) {
          this(checkAndConvertLevel(level), InternalLoggerFactory.getInstance(requireNonNull(clazz, "clazz")));
      }
  
      private Http2FrameLogger(InternalLogLevel level, InternalLogger logger) {
          this.level = level;
          this.logger = logger;
      }
  
      private static InternalLogLevel checkAndConvertLevel(LogLevel level) {
          return requireNonNull(level, "level").toInternalLevel();
      }
  
      public boolean isEnabled() {
          return logger.isEnabled(level);
      }
  
      public void logData(Direction direction, ChannelHandlerContext ctx, int streamId, Buffer data, int padding,
                          boolean endStream) {
          if (isEnabled()) {
              logger.log(level, "{} {} DATA: streamId={} padding={} endStream={} length={} bytes={}", ctx.channel(),
                      direction.name(), streamId, padding, endStream, data.readableBytes(), toString(data));
          }
      }
  
      public void logHeaders(Direction direction, ChannelHandlerContext ctx, int streamId, Http2Headers headers,
              int padding, boolean endStream) {
          if (isEnabled()) {
              logger.log(level, "{} {} HEADERS: streamId={} headers={} padding={} endStream={}", ctx.channel(),
                      direction.name(), streamId, headers, padding, endStream);
          }
      }
  
      public void logHeaders(Direction direction, ChannelHandlerContext ctx, int streamId, Http2Headers headers,
              int streamDependency, short weight, boolean exclusive, int padding, boolean endStream) {
          if (isEnabled()) {
              logger.log(level, "{} {} HEADERS: streamId={} headers={} streamDependency={} weight={} exclusive={} " +
                      "padding={} endStream={}", ctx.channel(),
                      direction.name(), streamId, headers, streamDependency, weight, exclusive, padding, endStream);
          }
      }
  
      public void logPriority(Direction direction, ChannelHandlerContext ctx, int streamId, int streamDependency,
              short weight, boolean exclusive) {
          if (isEnabled()) {
              logger.log(level, "{} {} PRIORITY: streamId={} streamDependency={} weight={} exclusive={}", ctx.channel(),
                      direction.name(), streamId, streamDependency, weight, exclusive);
          }
     }
 
     public void logRstStream(Direction direction, ChannelHandlerContext ctx, int streamId, long errorCode) {
         if (isEnabled()) {
             logger.log(level, "{} {} RST_STREAM: streamId={} errorCode={}", ctx.channel(),
                     direction.name(), streamId, errorCode);
         }
     }
 
     public void logSettingsAck(Direction direction, ChannelHandlerContext ctx) {
         logger.log(level, "{} {} SETTINGS: ack=true", ctx.channel(), direction.name());
     }
 
     public void logSettings(Direction direction, ChannelHandlerContext ctx, Http2Settings settings) {
         if (isEnabled()) {
             logger.log(level, "{} {} SETTINGS: ack=false settings={}", ctx.channel(), direction.name(), settings);
         }
     }
 
     public void logPing(Direction direction, ChannelHandlerContext ctx, long data) {
         if (isEnabled()) {
             logger.log(level, "{} {} PING: ack=false bytes={}", ctx.channel(),
                     direction.name(), data);
         }
     }
 
     public void logPingAck(Direction direction, ChannelHandlerContext ctx, long data) {
         if (isEnabled()) {
             logger.log(level, "{} {} PING: ack=true bytes={}", ctx.channel(),
                     direction.name(), data);
         }
     }
 
     public void logPushPromise(Direction direction, ChannelHandlerContext ctx, int streamId, int promisedStreamId,
             Http2Headers headers, int padding) {
         if (isEnabled()) {
             logger.log(level, "{} {} PUSH_PROMISE: streamId={} promisedStreamId={} headers={} padding={}",
                     ctx.channel(), direction.name(), streamId, promisedStreamId, headers, padding);
         }
     }
 
     public void logGoAway(Direction direction, ChannelHandlerContext ctx, int lastStreamId, long errorCode,
             Buffer debugData) {
         if (isEnabled()) {
             logger.log(level, "{} {} GO_AWAY: lastStreamId={} errorCode={} length={} bytes={}", ctx.channel(),
                     direction.name(), lastStreamId, errorCode, debugData.readableBytes(), toString(debugData));
         }
     }
 
     public void logWindowsUpdate(Direction direction, ChannelHandlerContext ctx, int streamId,
             int windowSizeIncrement) {
         if (isEnabled()) {
             logger.log(level, "{} {} WINDOW_UPDATE: streamId={} windowSizeIncrement={}", ctx.channel(),
                     direction.name(), streamId, windowSizeIncrement);
         }
     }
 
     public void logUnknownFrame(Direction direction, ChannelHandlerContext ctx, byte frameType, int streamId,
             Http2Flags flags, Buffer data) {
         if (isEnabled()) {
             logger.log(level, "{} {} UNKNOWN: frameType={} streamId={} flags={} length={} bytes={}", ctx.channel(),
                     direction.name(), frameType & 0xFF, streamId, flags.value(), data.readableBytes(), toString(data));
         }
     }
 
     private String toString(Buffer buf) {
         if (level == InternalLogLevel.TRACE || buf.readableBytes() <= BUFFER_LENGTH_THRESHOLD) {
             // Log the entire buffer.
             return BufferUtil.hexDump(buf);
         }
 
         // Otherwise just log the first 64 bytes.
         int length = Math.min(buf.readableBytes(), BUFFER_LENGTH_THRESHOLD);
         return BufferUtil.hexDump(buf, buf.readerOffset(), length) + "...";
     }
 }