/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF 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
    *
   * 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 org.apache.chemistry.opencmis.server.shared;
  
  import java.io.IOException;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Map;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletRequestWrapper;
  
  import org.apache.chemistry.opencmis.commons.impl.IOUtils;
  
  /**
   * HttpServletRequest wrapper that reads the query string in container
   * independent way and decodes the parameter values with UTF-8.
   */
  public class QueryStringHttpServletRequestWrapper extends HttpServletRequestWrapper {
  
      protected Map<String, String[]> parameters;
  
      public QueryStringHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
          super(request);
  
          parameters = new HashMap<String, String[]>();
  
          // parse query string
          parseFormData(request.getQueryString());
      }
  
      /**
       * Parses the query string.
       */
      protected final void parseFormData(String queryString) throws IOException {
          if (queryString == null || queryString.length() < 3) {
              return;
          }
  
          String[] nameValuePairs = queryString.split("&");
          for (String nameValuePair : nameValuePairs) {
              int x = nameValuePair.indexOf('=');
              if (x > 0) {
                  String name = IOUtils.decodeURL(nameValuePair.substring(0, x));
                  String value = (x == nameValuePair.length() - 1 ? "" : IOUtils
                          .decodeURL(nameValuePair.substring(x + 1)));
                  addParameter(name, value);
              } else {
                  String name = IOUtils.decodeURL(nameValuePair);
                  addParameter(name, (String) null);
              }
          }
      }
  
      /**
       * Adds a value to a parameter.
       */
      protected final void addParameter(String name, String value) {
          String[] values = parameters.get(name);
  
          if (values == null) {
              parameters.put(name, new String[] { value });
          } else {
              String[] newValues = new String[values.length + 1];
              System.arraycopy(values, 0, newValues, 0, values.length);
              newValues[newValues.length - 1] = value;
              parameters.put(name, newValues);
          }
      }
  
      /**
       * Adds an array of values to a parameter.
       */
      protected final void addParameter(String name, String[] additionalValues) {
          String[] values = parameters.get(name);
  
          if (values == null) {
              parameters.put(name, additionalValues);
          } else {
              String[] newValues = new String[values.length + additionalValues.length];
              System.arraycopy(values, 0, newValues, 0, values.length);
              System.arraycopy(additionalValues, 0, newValues, values.length, additionalValues.length);
             parameters.put(name, newValues);
         }
     }
 
     @Override
     public final String getParameter(String name) {
         String[] values = parameters.get(name);
         if (values == null || values.length == 0) {
             return null;
         }
 
         return values[0];
     }
 
     @Override
     public final Map<String, String[]> getParameterMap() {
         return parameters;
     }
 
     @Override
     public final Enumeration<String> getParameterNames() {
         return Collections.enumeration(parameters.keySet());
     }
 
     @Override
     public final String[] getParameterValues(String name) {
         return parameters.get(name);
     }
 }