//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.websocket.api.extensions;
  
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.eclipse.jetty.websocket.api.util.QuoteUtil;
  
  /**
   * Represents an Extension Configuration, as seen during the connection Handshake process.
   */
  public class ExtensionConfig
  {
      /**
       * Parse a single parameterized name.
       * 
       * @param parameterizedName
       *            the parameterized name
       * @return the ExtensionConfig
       */
      public static ExtensionConfig parse(String parameterizedName)
      {
          return new ExtensionConfig(parameterizedName);
      }
  
      /**
       * Parse enumeration of <code>Sec-WebSocket-Extensions</code> header values into a {@link ExtensionConfig} list
       * 
       * @param valuesEnum
       *            the raw header values enum
       * @return the list of extension configs
       */
      public static List<ExtensionConfig> parseEnum(Enumeration<String> valuesEnum)
      {
          List<ExtensionConfig> configs = new ArrayList<>();
  
          if (valuesEnum != null)
          {
              while (valuesEnum.hasMoreElements())
              {
                  Iterator<String> extTokenIter = QuoteUtil.splitAt(valuesEnum.nextElement(),",");
                  while (extTokenIter.hasNext())
                  {
                      String extToken = extTokenIter.next();
                      configs.add(ExtensionConfig.parse(extToken));
                  }
              }
          }
  
          return configs;
      }
  
      /**
       * Parse 1 or more raw <code>Sec-WebSocket-Extensions</code> header values into a {@link ExtensionConfig} list
       * 
       * @param rawSecWebSocketExtensions
       *            the raw header values
       * @return the list of extension configs
       */
      public static List<ExtensionConfig> parseList(String... rawSecWebSocketExtensions)
      {
          List<ExtensionConfig> configs = new ArrayList<>();
  
          for (String rawValue : rawSecWebSocketExtensions)
          {
              Iterator<String> extTokenIter = QuoteUtil.splitAt(rawValue,",");
              while (extTokenIter.hasNext())
              {
                  String extToken = extTokenIter.next();
                  configs.add(ExtensionConfig.parse(extToken));
              }
          }
  
          return configs;
      }
  
      /**
      * Convert a list of {@link ExtensionConfig} to a header value
      * 
      * @param configs
      *            the list of extension configs
      * @return the header value (null if no configs present)
      */
     public static String toHeaderValue(List<ExtensionConfig> configs)
     {
         if ((configs == null) || (configs.isEmpty()))
         {
             return null;
         }
         StringBuilder parameters = new StringBuilder();
         boolean needsDelim = false;
         for (ExtensionConfig ext : configs)
         {
             if (needsDelim)
             {
                 parameters.append(", ");
             }
             parameters.append(ext.getParameterizedName());
             needsDelim = true;
         }
         return parameters.toString();
     }
 
     private final String name;
     private final Map<String, String> parameters;
 
     /**
      * Copy constructor
      * @param copy the extension config to copy
      */
     public ExtensionConfig(ExtensionConfig copy)
     {
         this.name = copy.name;
         this.parameters = new HashMap<>();
         this.parameters.putAll(copy.parameters);
     }
 
     public ExtensionConfig(String parameterizedName)
     {
         Iterator<String> extListIter = QuoteUtil.splitAt(parameterizedName,";");
         this.name = extListIter.next();
         this.parameters = new HashMap<>();
 
         // now for parameters
         while (extListIter.hasNext())
         {
             String extParam = extListIter.next();
             Iterator<String> extParamIter = QuoteUtil.splitAt(extParam,"=");
             String key = extParamIter.next().trim();
             String value = null;
             if (extParamIter.hasNext())
             {
                 value = extParamIter.next();
             }
             parameters.put(key,value);
         }
     }
 
     public String getName()
     {
         return name;
     }
 
     public final int getParameter(String key, int defValue)
     {
         String val = parameters.get(key);
         if (val == null)
         {
             return defValue;
         }
         return Integer.valueOf(val);
     }
 
     public final String getParameter(String key, String defValue)
     {
         String val = parameters.get(key);
         if (val == null)
         {
             return defValue;
         }
         return val;
     }
 
     public final String getParameterizedName()
     {
         StringBuilder str = new StringBuilder();
         str.append(name);
         for (String param : parameters.keySet())
         {
             str.append(';');
             str.append(param);
             String value = parameters.get(param);
             if (value != null)
             {
                 str.append('=');
                 QuoteUtil.quoteIfNeeded(str,value,";=");
             }
         }
         return str.toString();
     }
 
     public final Set<String> getParameterKeys()
     {
         return parameters.keySet();
     }
 
     /**
      * Return parameters found in request URI.
      * 
      * @return the parameter map
      */
     public final Map<String, String> getParameters()
     {
         return parameters;
     }
 
     /**
      * Initialize the parameters on this config from the other configuration.
      * 
      * @param other
      *            the other configuration.
      */
     public final void init(ExtensionConfig other)
     {
         this.parameters.clear();
         this.parameters.putAll(other.parameters);
     }
 
     public final void setParameter(String key)
     {
         parameters.put(key,null);
     }
 
     public final void setParameter(String key, int value)
     {
         parameters.put(key,Integer.toString(value));
     }
 
     public final void setParameter(String key, String value)
     {
         parameters.put(key,value);
     }
 
     @Override
     public String toString()
     {
         return getParameterizedName();
     }
 }