content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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
   *
   *      http://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 com.alibaba.nacos.common.http.param;
  
  import com.alibaba.nacos.api.common.Constants;
  import com.alibaba.nacos.common.constant.HttpHeaderConsts;
  import com.alibaba.nacos.common.utils.MapUtil;
  import com.alibaba.nacos.common.utils.StringUtils;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  /**
   * Http header.
   *
   * @author <a href="mailto:liaochuntao@live.com">liaochuntao</a>
   */
  public class Header {
      
      public static final Header EMPTY = Header.newInstance();
      
      private final Map<String, String> header;
      
      private final Map<String, List<String>> originalResponseHeader;
      
      private static final String DEFAULT_CHARSET = "UTF-8";
      
      private Header() {
          header = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
          originalResponseHeader = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
          addParam(HttpHeaderConsts.CONTENT_TYPE, MediaType.APPLICATION_JSON);
          addParam(HttpHeaderConsts.ACCEPT_CHARSET, DEFAULT_CHARSET);
      }
      
      public static Header newInstance() {
          return new Header();
      }
      
      /**
       * Add the key and value to the header.
       *
       * @param key   the key
       * @param value the value
       * @return header
       */
      public Header addParam(String key, String value) {
          if (StringUtils.isNotEmpty(key)) {
              header.put(key, value);
          }
          return this;
      }
      
      public Header setContentType(String contentType) {
          if (contentType == null) {
              contentType = MediaType.APPLICATION_JSON;
          }
          return addParam(HttpHeaderConsts.CONTENT_TYPE, contentType);
      }
      
      public String getValue(String key) {
          return header.get(key);
      }
      
      public Map<String, String> getHeader() {
          return header;
      }
      
      public Iterator<Map.Entry<String, String>> iterator() {
          return header.entrySet().iterator();
      }
      
      /**
       * Transfer to KV part list. The odd index is key and the even index is value.
       *
       * @return KV string list
       */
      public List<String> toList() {
          List<String> list = new ArrayList<>(header.size() * 2);
          Iterator<Map.Entry<String, String>> iterator = iterator();
          while (iterator.hasNext()) {
              Map.Entry<String, String> entry = iterator.next();
              list.add(entry.getKey());
              list.add(entry.getValue());
          }
          return list;
      }
      
      /**
       * Add all KV list to header. The odd index is key and the even index is value.
       *
       * @param list KV list
       * @return header
       */
      public Header addAll(List<String> list) {
          if ((list.size() & 1) != 0) {
              throw new IllegalArgumentException("list size must be a multiple of 2");
          }
          for (int i = 0; i < list.size(); ) {
              String key = list.get(i++);
              if (StringUtils.isNotEmpty(key)) {
                  header.put(key, list.get(i++));
              }
          }
          return this;
      }
      
      /**
       * Add all parameters to header.
       *
       * @param params parameters
       */
      public void addAll(Map<String, String> params) {
          if (MapUtil.isNotEmpty(params)) {
              for (Map.Entry<String, String> entry : params.entrySet()) {
                  addParam(entry.getKey(), entry.getValue());
              }
          }
      }
      
      /**
       * set original format response header.
       *
       * <p>Currently only corresponds to the response header of JDK.
       *
       * @param key    original response header key
       * @param values original response header values
       */
      public void addOriginalResponseHeader(String key, List<String> values) {
          if (StringUtils.isNotEmpty(key)) {
              this.originalResponseHeader.put(key, values);
              addParam(key, values.get(0));
          }
      }
      
      /**
       * get original format response header.
       *
       * <p>Currently only corresponds to the response header of JDK.
       *
       * @return Map original response header
       */
      public Map<String, List<String>> getOriginalResponseHeader() {
          return this.originalResponseHeader;
      }
      
      public String getCharset() {
          String acceptCharset = getValue(HttpHeaderConsts.ACCEPT_CHARSET);
          if (acceptCharset == null) {
              String contentType = getValue(HttpHeaderConsts.CONTENT_TYPE);
              acceptCharset = StringUtils.isNotBlank(contentType) ? analysisCharset(contentType) : Constants.ENCODE;
          }
          return acceptCharset;
      }
      
      private String analysisCharset(String contentType) {
          String[] values = contentType.split(";");
          String charset = Constants.ENCODE;
          if (values.length == 1) {
              return charset;
          }
          for (String value : values) {
              if (value.startsWith("charset=")) {
                  charset = value.substring("charset=".length());
              }
          }
          return charset;
      }
      
      public void clear() {
          header.clear();
          originalResponseHeader.clear();
      }
      
      @Override
      public String toString() {
          return "Header{" + "headerToMap=" + header + '}';
      }
  }
  
  