/*
    * 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.netty.handler.codec.http2;
  
  import java.io.Closeable;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.util.internal.UnstableApi;
  
  import static io.netty.handler.codec.http2.Http2Error.COMPRESSION_ERROR;
  import static io.netty.handler.codec.http2.Http2Exception.connectionError;
  import static io.netty.util.internal.ObjectUtil.checkNotNull;
  
  @UnstableApi
  public class DefaultHttp2HeadersEncoder implements
      Http2HeadersEncoder, Http2HeadersEncoder.Configuration, Closeable {
  
      private final HpackEncoder hpackEncoder;
      private final SensitivityDetector sensitivityDetector;
      private ByteBuf tableSizeChangeOutput;
  
      public DefaultHttp2HeadersEncoder() {
          this(NEVER_SENSITIVE);
      }
  
      public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector) {
          this(sensitivityDetector, new HpackEncoder());
      }
  
      public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize) {
          this(sensitivityDetector, new HpackEncoder(ignoreMaxHeaderListSize));
      }
  
      public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize,
                                        int dynamicTableArraySizeHint) {
          this(sensitivityDetector, ignoreMaxHeaderListSize, dynamicTableArraySizeHint, HpackEncoder.HUFF_CODE_THRESHOLD);
      }
  
      public DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, boolean ignoreMaxHeaderListSize,
                                        int dynamicTableArraySizeHint, int huffCodeThreshold) {
          this(sensitivityDetector,
                  new HpackEncoder(ignoreMaxHeaderListSize, dynamicTableArraySizeHint, huffCodeThreshold));
      }
  
      /**
       * Exposed Used for testing only! Default values used in the initial settings frame are overridden intentionally
       * for testing but violate the RFC if used outside the scope of testing.
       */
      DefaultHttp2HeadersEncoder(SensitivityDetector sensitivityDetector, HpackEncoder hpackEncoder) {
          this.sensitivityDetector = checkNotNull(sensitivityDetector, "sensitiveDetector");
          this.hpackEncoder = checkNotNull(hpackEncoder, "hpackEncoder");
      }
  
      @Override
      public void encodeHeaders(int streamId, Http2Headers headers, ByteBuf buffer) throws Http2Exception {
          try {
              // If there was a change in the table size, serialize the output from the hpackEncoder
              // resulting from that change.
              if (tableSizeChangeOutput != null && tableSizeChangeOutput.isReadable()) {
                  buffer.writeBytes(tableSizeChangeOutput);
                  tableSizeChangeOutput.clear();
              }
  
              hpackEncoder.encodeHeaders(streamId, buffer, headers, sensitivityDetector);
          } catch (Http2Exception e) {
              throw e;
          } catch (Throwable t) {
              throw connectionError(COMPRESSION_ERROR, t, "Failed encoding headers block: %s", t.getMessage());
          }
      }
  
      @Override
      public void maxHeaderTableSize(long max) throws Http2Exception {
          if (tableSizeChangeOutput == null) {
              tableSizeChangeOutput = Unpooled.buffer();
          }
          hpackEncoder.setMaxHeaderTableSize(tableSizeChangeOutput, max);
      }
  
      @Override
      public long maxHeaderTableSize() {
          return hpackEncoder.getMaxHeaderTableSize();
      }
  
      @Override
     public void maxHeaderListSize(long max) throws Http2Exception {
         hpackEncoder.setMaxHeaderListSize(max);
     }
 
     @Override
     public long maxHeaderListSize() {
         return hpackEncoder.getMaxHeaderListSize();
     }
 
     @Override
     public Configuration configuration() {
         return this;
     }
 
     /**
      * Close the encoder and release all its associated data.
      */
     @Override
     public void close() {
         if (tableSizeChangeOutput != null) {
             tableSizeChangeOutput.release();
             tableSizeChangeOutput = null;
         }
     }
 }