package kata.wordwrap.a20110716;

/**
  * Word Wrap Kata.
  * Copyright (c) 2011, Peter Kofler, licensed under BSD License.
  */
public class WordWrapTailRecursive {

   private static final char BLANK = ' ';
   private static final char NEWLINE = '\n';

   public static String wrap(String line, int maxLineLen) {
      StringBuilder accumulator = new StringBuilder();
      wrap(line, maxLineLen, accumulator);
      return accumulator.toString();
   }

   private static void wrap(String remainingLine, int maxLineLen, StringBuilder accumulator) {
      if (remainingLine.length() <= maxLineLen) {
         accumulator.append(remainingLine);
         return;
      }

      final int indexOfBlank = remainingLine.lastIndexOf(BLANK, maxLineLen);
      final int split;
      final int offset;
      if (indexOfBlank > -1) {
         split = indexOfBlank;
         offset = 1;
      } else {
         split = maxLineLen;
         offset = 0;
      }

      accumulator.append(remainingLine.substring(0, split));
      accumulator.append(NEWLINE);
      wrap(remainingLine.substring(split + offset), maxLineLen, accumulator);
   }
}