/*
    * Copyright (c) 2009-2012 The 99 Software Foundation
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy
    * of this software and associated documentation files (the "Software"), to deal
    * in the Software without restriction, including without limitation the rights
    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    * copies of the Software, and to permit persons to whom the Software is
    * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  package org.nnsoft.sameas4j;
  
  import java.io.ByteArrayOutputStream;
  import java.net.URI;
  import java.util.BitSet;
  
  import com.google.gson.JsonArray;
  import com.google.gson.JsonElement;
  import com.google.gson.JsonParseException;
  
  /**
   * Basic Json adapter that given a JsonElement builds a
   * not null an {@link Equivalence} instance.
   */
  abstract class AbstractEquivalenceDeserializer {
  
      /**
       * The {@code uri} constant.
       */
      private static final String URI = "uri";
  
      /**
       * The {@code duplicates} constant.
       */
      private static final String DUPLICATES = "duplicates";
  
      /**
       * The error message template constant.
       */
      private static final String EXCEPTION_MESSAGE = "URI '%s' seems to be not well-formed";
  
      /**
       * The UTF-8 string constant.
       */
      private static final String UTF_8_ENCODING = "UTF-8";
  
      /**
       * BitSet of unreserved characters.
       */
      private static final BitSet UNRESERVED_CHARS = new BitSet(256);
  
      /**
       * The default escaping character of URL encoding.
       */
      private static final byte URL_ESCAPE_CHAR = '%';
  
      static {
          for (byte b = 'A'; b <= 'Z'; b++) {
              UNRESERVED_CHARS.set(b);
          }
          for (byte b = 'a'; b <= 'z'; b++) {
              UNRESERVED_CHARS.set(b);
          }
          for (byte b = '0'; b <= '9'; b++) {
              UNRESERVED_CHARS.set(b);
          }
  
          // special URL encoding chars
          UNRESERVED_CHARS.set('$');
          UNRESERVED_CHARS.set('#');
          UNRESERVED_CHARS.set('&');
          UNRESERVED_CHARS.set('+');
          UNRESERVED_CHARS.set(',');
          UNRESERVED_CHARS.set(';');
          UNRESERVED_CHARS.set('=');
          UNRESERVED_CHARS.set('?');
          UNRESERVED_CHARS.set('@');
          UNRESERVED_CHARS.set('/');
          UNRESERVED_CHARS.set(':');
          UNRESERVED_CHARS.set('-');
          UNRESERVED_CHARS.set('.');
          UNRESERVED_CHARS.set('_');
          UNRESERVED_CHARS.set('~');
      }
  
      /**
       * Encodes the given text.
       *
      * @param text text to be encoded.
      * @return encoding result.
      */
     public static String urlEncode(final String text) throws Exception {
         ByteArrayOutputStream buffer = new ByteArrayOutputStream();
 
         for (int b : toUTF8Bytes(text)) {
             if (b < 0) {
                 b = 256 + b;
             }
 
             if (UNRESERVED_CHARS.get(b)) {
                 buffer.write(b);
             } else {
                 buffer.write(URL_ESCAPE_CHAR);
                 char hex1 = Character.toUpperCase(Character.forDigit(
                         (b >> 4) & 0xF, 16));
                 char hex2 = Character.toUpperCase(Character.forDigit(b & 0xF,
                         16));
                 buffer.write(hex1);
                 buffer.write(hex2);
             }
         }
 
         return new String(buffer.toByteArray());
     }
 
     /**
      * Performs an UTF8 encoding.
      *
      * @param text text to be encoded.
      * @return encoding result.
      */
     private static byte[] toUTF8Bytes(final String text) throws Exception {
         return text.getBytes(UTF_8_ENCODING);
     }
 
     /**
      * Deserialize a single {@link org.nnsoft.sameas4j.Equivalence}
      * from its Json serialization.
      *
      * @param json object to be deserialized
      * @return a not null {@link org.nnsoft.sameas4j.Equivalence} instance
      */
     public Equivalence getEquivalence(JsonElement json) {
         Equivalence equivalence;
         String uriString = json.getAsJsonObject().getAsJsonPrimitive(URI).getAsString();
         URI uri;
         try {
             uri = new URI(urlEncode(uriString));
         } catch (Exception e) {
             throw new JsonParseException(String.format(EXCEPTION_MESSAGE, uriString));
         }
         equivalence = new Equivalence(uri);
         JsonArray duplicates = json.getAsJsonObject().getAsJsonArray(DUPLICATES);
         for (int i = 0; i < duplicates.size(); i++) {
             try {
                 equivalence.addDuplicate(new URI(urlEncode(duplicates.get(i).getAsString())));
             } catch (Exception e) {
                 // if an equivalent URI is not well-formed it's better to do not add it, let's go on
                 continue;
             }
         }
         return equivalence;
     }
 
     public static void main( String[] args ) throws Exception
     {
         System.err.println(urlEncode( "http://it.bestshopping.com/prezzi/Rome.sku=9780751339031|.html" ));
     }
 
 }