/**
 * @author Tomasz Lubinski
 * (c)2019 algorytm.org
 *
 *  BC412 Bar Code
 */
public class BarCode {
	
	  private static final char bc412chars[] = {
          '0', 'R', '9', 'G', 'L', 'V', 'H', 'A', '8', 'E',
          'Z', '4', 'N', 'T', 'S', '1', 'J', '2', 'Q', '6', 
          'C', '7', 'D', 'Y', 'K', 'B', 'U', 'I', 'X', '3', 
          'F', 'W', 'P', '5', 'M' };

	  private static final int bc412spaces[][] = {
          {1, 1, 1, 5},
          {3, 1, 2, 2},
          {1, 3, 1, 3},
          {2, 1, 2, 3},
          {2, 2, 3, 1},
          {3, 3, 1, 1},
          {2, 1, 3, 2},
          {1, 3, 2, 2},
          {1, 2, 4, 1},
          {1, 5, 1, 1},
          {5, 1, 1, 1},
          {1, 1, 5, 1},
          {2, 3, 2, 1},
          {3, 2, 1, 2},
          {3, 1, 2, 2},
          {1, 1, 2, 4},
          {2, 2, 1, 3},
          {1, 1, 3, 3},
          {3, 1, 1, 3},
          {1, 2, 2, 3},
          {1, 4, 1, 2},
          {1, 2, 3, 2},
          {1, 4, 2, 1},
          {4, 2, 1, 1},
          {2, 2, 2, 2},
          {1, 3, 3, 1},
          {3, 2, 2, 1},
          {2, 1, 4, 1},
          {4, 1, 2, 1},
          {1, 1, 4, 2},
          {2, 1, 1, 4},
          {4, 1, 1, 2},
          {2, 4, 1, 1},
          {1, 2, 1, 4},
          {2, 3, 1, 2}
	  };

	  private static final int start[] = {2};
	  private static final int stop[] = {1};

	  /**
	   * Check that given txt can be coded
	   * @param txt
	   * @return true txt is correct, false otherwise
	   */
	  public boolean check(String txt) {
	      for (int i=0; i<txt.length(); i++) {
              if (getLetterValue(txt.charAt(i)) == -1)
              		return false;
          }
		  return true;
	  }

	  /**
	   * Return character value
	   * @param ch
	   * @return character value, or -1 f character cannot be coded
	   */
	  private int getLetterValue(char ch) {
	        for (int i=0; i<bc412chars.length; i++) {
                if (bc412chars[i] == ch)
                	return i;
	        }
	        return -1;
	  }
	  
	  /**
	   * Return bars for a given character
	   * @param ch - character to code
	   * @return bars for a given character
	   */
	  public int[] getBars(char ch) {
	        for (int i=0; i<bc412chars.length; i++) {
                if (bc412chars[i] == ch)
                	return bc412spaces[i];
	        }		  
		  return null;
	  }
	  
	  /**
	   * Get start bars
	   * @return start bars
	   */
	  public int[] getStartBars() {
		  return start;
	  }
	  
	  /**
	   * Get stop bars
	   * @return stop bars
	   */
	  public int[] getStopBars() {
		  return stop;
	  }	  
	  
	  /**
	   * Calculate check digit for a given txt
	   * @param txt
	   * @return check digit for a given txt
	   */
	  public char checkDigit(String txt) {
          int sum = 0;
          for (int i = 0; i < txt.length(); i++)
              sum += getLetterValue(txt.charAt(i));

          return bc412chars[(sum % 35)];
      }
}