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/*
 * Copyright (c) 2009 Piotr Piastucki
 * 
 * This file is part of Patchca CAPTCHA library.
 * 
 *  Patchca is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *  
 *  Patchca is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with Patchca. If not, see .
 */
package cn.dreampie.captcha.word;

import java.util.Random;

public class AdaptiveRandomWordFactory extends RandomWordFactory {

  protected String wideCharacters;

  public AdaptiveRandomWordFactory() {
    characters = "ABCDEFGHIJKLMNPQRSTUVWXYZ123456789";
    wideCharacters = "MW";
  }

  public void setWideCharacters(String wideCharacters) {
    this.wideCharacters = wideCharacters;
  }


  public String getNextWord() {
    Random rnd = new Random();
    StringBuffer sb = new StringBuffer();
    StringBuffer chars = new StringBuffer(characters);
    int l = minLength + (maxLength > minLength ? rnd.nextInt(maxLength - minLength) : 0);
    for (int i = 0; i < l; i++) {
      int j = rnd.nextInt(chars.length());
      char c = chars.charAt(j);
      if (wideCharacters.indexOf(c) != -1) {
        for (int k = 0; k < wideCharacters.length(); k++) {
          int idx = chars.indexOf(String.valueOf(wideCharacters.charAt(k)));
          if (idx != -1) {
            chars.deleteCharAt(idx);
          }
        }
      }
      sb.append(c);
    }
    return sb.toString();
  }

}