package uk.ac.ebi.intenz.tools.sib.translator.rules;
   
   import org.apache.log4j.Logger;
   import uk.ac.ebi.xchars.SpecialCharacters;
   import uk.ac.ebi.xchars.domain.EncodingType;
   
   
   /**
    * This singleton class stores regular expression rules to be used to transform text.
   * <p/>
   * Each rule consists of a regular expression pattern and a replacement string. The rules will be applied in an
   * arbitrary order.
   *
   * @author Michael Darsow
   * @version $Revision: 1.2 $ $Date: 2008/11/11 12:01:24 $
   */
  public class TagRules implements RuleGroup {
  
    private static final Logger LOGGER = Logger.getLogger(TagRules.class);
  
    private static TagRules INSTANCE;
    SpecialCharacters encoding;
  
    private final String[][] RULES =
            {
           //   {"\\<[^\\s].*?[^\\s]\\>", ""},
               {"\\<b\\>(.*?)\\<\\/b\\>","$1"},
               {"\\<i\\>(.*?)\\<\\/i\\>","$1"},
               {"\\<a\\s(.+?)\\>(.+?)\\<\\/a\\>","$2"},
               {"\\<ring\\>p\\<\\/ring\\>","\\<ringsugar\\>p\\<\\/ringsugar\\>"},
               {"\\<ring\\>f\\<\\/ring\\>","\\<ringsugar\\>f\\<\\/ringsugar\\>"},
            };
  
    /**
     * Nothing special is happening here.
     */
    private TagRules(SpecialCharacters encoding) {
     this.encoding = encoding;
    }
  
  
    /**
     * Returns the sole instance of this class.
     *
     * If no instance is available yet then it will be created.
     *
     * @return the class sole instance.
     */
    public static TagRules getInstance(SpecialCharacters encoding) {
       if( INSTANCE == null){
          synchronized (TagRules.class){
             if(INSTANCE == null)
              INSTANCE = new TagRules(encoding);
          }
       }
      return INSTANCE;
    }
  
    /**
     * Applies the rules.
     *
     * @param text The text to be translated.
     * @return the translated text.
     * @throws NullPointerException if <code>text</code> is <code>null</code>.
     */
    public String applyRules(String text) {
      if (text == null) throw new NullPointerException("Parameter 'text' must not be null.");
      return translate(text, RULES);
    }
  
    /**
     * Calls {@link TagRules#applyRules(String)} only.
     *
     * @param text The text to be translated.
     * @return the translated text.
     * @throws NullPointerException if <code>text</code> is <code>null</code>.
     */
    public String reverseRules(String text) {
  //    if (text == null) throw new NullPointerException("Parameter 'text' must not be null.");
      return applyRules(text);
    }
  
    /**
     * This method performs the actual application of the rules.
     *
     * @param text The text to be translated.
     * @param rules Map of rules to be applied.
     * @return the translated text.
     */
    private String translate(String text, String[][] rules) {
      // Encode the special characters
      text = this.encoding.xml2Display(text, EncodingType.SWISSPROT_CODE);
      for (int iii = 0; iii < rules.length; iii++) {
        String[] rule = rules[iii];
        text = text.replaceAll(rule[0], rule[1]);
      }    
      return text;
    }
  
 }