/*
    * 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.http.websocketx.extensions.compression;
  
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtension;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketClientExtensionHandshaker;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionData;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionDecoder;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
  import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionFilterProvider;
  
  import java.util.Collections;
  
  import static io.netty.handler.codec.http.websocketx.extensions.compression.DeflateFrameServerExtensionHandshaker.*;
  import static io.netty.util.internal.ObjectUtil.*;
  
  /**
   * <a href="https://tools.ietf.org/id/draft-tyoshino-hybi-websocket-perframe-deflate-06.txt">perframe-deflate</a>
   * handshake implementation.
   */
  public final class DeflateFrameClientExtensionHandshaker implements WebSocketClientExtensionHandshaker {
  
      private final int compressionLevel;
      private final boolean useWebkitExtensionName;
      private final WebSocketExtensionFilterProvider extensionFilterProvider;
  
      /**
       * Constructor with default configuration.
       */
      public DeflateFrameClientExtensionHandshaker(boolean useWebkitExtensionName) {
          this(6, useWebkitExtensionName);
      }
  
      /**
       * Constructor with custom configuration.
       *
       * @param compressionLevel
       *            Compression level between 0 and 9 (default is 6).
       */
      public DeflateFrameClientExtensionHandshaker(int compressionLevel, boolean useWebkitExtensionName) {
          this(compressionLevel, useWebkitExtensionName, WebSocketExtensionFilterProvider.DEFAULT);
      }
  
      /**
       * Constructor with custom configuration.
       *
       * @param compressionLevel
       *            Compression level between 0 and 9 (default is 6).
       * @param extensionFilterProvider
       *            provides client extension filters for per frame deflate encoder and decoder.
       */
      public DeflateFrameClientExtensionHandshaker(int compressionLevel, boolean useWebkitExtensionName,
              WebSocketExtensionFilterProvider extensionFilterProvider) {
          if (compressionLevel < 0 || compressionLevel > 9) {
              throw new IllegalArgumentException(
                      "compressionLevel: " + compressionLevel + " (expected: 0-9)");
          }
          this.compressionLevel = compressionLevel;
          this.useWebkitExtensionName = useWebkitExtensionName;
          this.extensionFilterProvider = checkNotNull(extensionFilterProvider, "extensionFilterProvider");
      }
  
      @Override
      public WebSocketExtensionData newRequestData() {
          return new WebSocketExtensionData(
                  useWebkitExtensionName ? X_WEBKIT_DEFLATE_FRAME_EXTENSION : DEFLATE_FRAME_EXTENSION,
                  Collections.<String, String>emptyMap());
      }
  
      @Override
      public WebSocketClientExtension handshakeExtension(WebSocketExtensionData extensionData) {
          if (!X_WEBKIT_DEFLATE_FRAME_EXTENSION.equals(extensionData.name()) &&
              !DEFLATE_FRAME_EXTENSION.equals(extensionData.name())) {
              return null;
          }
  
          if (extensionData.parameters().isEmpty()) {
              return new DeflateFrameClientExtension(compressionLevel, extensionFilterProvider);
          } else {
              return null;
          }
      }
  
      private static class DeflateFrameClientExtension implements WebSocketClientExtension {
  
          private final int compressionLevel;
         private final WebSocketExtensionFilterProvider extensionFilterProvider;
 
         DeflateFrameClientExtension(int compressionLevel, WebSocketExtensionFilterProvider extensionFilterProvider) {
             this.compressionLevel = compressionLevel;
             this.extensionFilterProvider = extensionFilterProvider;
         }
 
         @Override
         public int rsv() {
             return RSV1;
         }
 
         @Override
         public WebSocketExtensionEncoder newExtensionEncoder() {
             return new PerFrameDeflateEncoder(compressionLevel, 15, false,
                                               extensionFilterProvider.encoderFilter());
         }
 
         @Override
         public WebSocketExtensionDecoder newExtensionDecoder() {
             return new PerFrameDeflateDecoder(false, extensionFilterProvider.decoderFilter());
         }
     }
 
 }