/*
 * Copyright 2006 Jeremias Maerki.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.datamatrix.encoder;

import junit.framework.ComparisonFailure;
import org.junit.Assert;
import org.junit.Test;
import java.nio.charset.StandardCharsets;

/**
 * Tests for {@link HighLevelEncoder} and {@link MinimalEncoder}
 */
public final class HighLevelEncodeTestCase extends Assert {

  private static final SymbolInfo[] TEST_SYMBOLS = {
    new SymbolInfo(false, 3, 5, 8, 8, 1),
    new SymbolInfo(false, 5, 7, 10, 10, 1),
      /*rect*/new SymbolInfo(true, 5, 7, 16, 6, 1),
    new SymbolInfo(false, 8, 10, 12, 12, 1),
      /*rect*/new SymbolInfo(true, 10, 11, 14, 6, 2),
    new SymbolInfo(false, 13, 0, 0, 0, 1),
    new SymbolInfo(false, 77, 0, 0, 0, 1)
    //The last entries are fake entries to test special conditions with C40 encoding
  };

  private static void useTestSymbols() {
    SymbolInfo.overrideSymbolSet(TEST_SYMBOLS);
  }

  private static void resetSymbols() {
    SymbolInfo.overrideSymbolSet(SymbolInfo.PROD_SYMBOLS);
  }

  @Test
  public void testASCIIEncodation() {

    String visualized = encodeHighLevel("123456");
    assertEquals("142 164 186", visualized);

    visualized = encodeHighLevel("123456£");
    assertEquals("142 164 186 235 36", visualized);

    visualized = encodeHighLevel("30Q324343430794<OQQ");
    assertEquals("160 82 162 173 173 173 137 224 61 80 82 82", visualized);
  }

  @Test
  public void testC40EncodationBasic1() {

    String visualized = encodeHighLevel("AIMAIMAIM");
    assertEquals("230 91 11 91 11 91 11 254", visualized);
    //230 shifts to C40 encodation, 254 unlatches, "else" case
  }

  @Test
  public void testC40EncodationBasic2() {

    String visualized = encodeHighLevel("AIMAIAB");
    assertEquals("230 91 11 90 255 254 67 129", visualized);
    //"B" is normally encoded as "15" (one C40 value)
    //"else" case: "B" is encoded as ASCII

    visualized = encodeHighLevel("AIMAIAb");
    assertEquals("66 74 78 66 74 66 99 129", visualized); //Encoded as ASCII
    //Alternative solution:
    //assertEquals("230 91 11 90 255 254 99 129", visualized);
    //"b" is normally encoded as "Shift 3, 2" (two C40 values)
    //"else" case: "b" is encoded as ASCII

    visualized = encodeHighLevel("AIMAIMAIMË");
    assertEquals("230 91 11 91 11 91 11 254 235 76", visualized);
    //Alternative solution:
    //assertEquals("230 91 11 91 11 91 11 11 9 254", visualized);
    //Expl: 230 = shift to C40, "91 11" = "AIM",
    //"11 9" = "�" = "Shift 2, UpperShift, <char>
    //"else" case

    visualized = encodeHighLevel("AIMAIMAIMë");
    assertEquals("230 91 11 91 11 91 11 254 235 108", visualized); //Activate when additional rectangulars are available
    //Expl: 230 = shift to C40, "91 11" = "AIM",
    //"�" in C40 encodes to: 1 30 2 11 which doesn't fit into a triplet
    //"10 243" =
    //254 = unlatch, 235 = Upper Shift, 108 = � = 0xEB/235 - 128 + 1
    //"else" case
  }

  @Test
  public void testC40EncodationSpecExample() {
    //Example in Figure 1 in the spec
    String visualized = encodeHighLevel("A1B2C3D4E5F6G7H8I9J0K1L2");
    assertEquals("230 88 88 40 8 107 147 59 67 126 206 78 126 144 121 35 47 254", visualized);
  }

  @Test
  public void testC40EncodationSpecialCases1() {

    //Special tests avoiding ultra-long test strings because these tests are only used
    //with the 16x48 symbol (47 data codewords)
    useTestSymbols();

    String visualized = encodeHighLevel("AIMAIMAIMAIMAIMAIM", false);
    assertEquals("230 91 11 91 11 91 11 91 11 91 11 91 11", visualized);
    //case "a": Unlatch is not required

    visualized = encodeHighLevel("AIMAIMAIMAIMAIMAI", false);
    assertEquals("230 91 11 91 11 91 11 91 11 91 11 90 241", visualized);
    //case "b": Add trailing shift 0 and Unlatch is not required

    visualized = encodeHighLevel("AIMAIMAIMAIMAIMA");
    assertEquals("230 91 11 91 11 91 11 91 11 91 11 254 66", visualized);
    //case "c": Unlatch and write last character in ASCII

    resetSymbols();

    visualized = encodeHighLevel("AIMAIMAIMAIMAIMAI");
    assertEquals("230 91 11 91 11 91 11 91 11 91 11 254 66 74 129 237", visualized);

    visualized = encodeHighLevel("AIMAIMAIMA");
    assertEquals("230 91 11 91 11 91 11 66", visualized);
    //case "d": Skip Unlatch and write last character in ASCII
  }

  @Test
  public void testC40EncodationSpecialCases2() {

    String visualized = encodeHighLevel("AIMAIMAIMAIMAIMAIMAI");
    assertEquals("230 91 11 91 11 91 11 91 11 91 11 91 11 254 66 74", visualized);
    //available > 2, rest = 2 --> unlatch and encode as ASCII
  }

  @Test
  public void testTextEncodation() {

    String visualized = encodeHighLevel("aimaimaim");
    assertEquals("239 91 11 91 11 91 11 254", visualized);
    //239 shifts to Text encodation, 254 unlatches

    visualized = encodeHighLevel("aimaimaim'");
    assertEquals("239 91 11 91 11 91 11 254 40 129", visualized);
    //assertEquals("239 91 11 91 11 91 11 7 49 254", visualized);
    //This is an alternative, but doesn't strictly follow the rules in the spec.

    visualized = encodeHighLevel("aimaimaIm");
    assertEquals("239 91 11 91 11 87 218 110", visualized);

    visualized = encodeHighLevel("aimaimaimB");
    assertEquals("239 91 11 91 11 91 11 254 67 129", visualized);

    visualized = encodeHighLevel("aimaimaim{txt}\u0004");
    assertEquals("239 91 11 91 11 91 11 254 124 117 121 117 126 5 129 237", visualized);
  }

  @Test
  public void testX12Encodation() {

    //238 shifts to X12 encodation, 254 unlatches

    String visualized = encodeHighLevel("ABC>ABC123>AB");
    assertEquals("238 89 233 14 192 100 207 44 31 67", visualized);

    visualized = encodeHighLevel("ABC>ABC123>ABC");
    assertEquals("238 89 233 14 192 100 207 44 31 254 67 68", visualized);

    visualized = encodeHighLevel("ABC>ABC123>ABCD");
    assertEquals("238 89 233 14 192 100 207 44 31 96 82 254", visualized);

    visualized = encodeHighLevel("ABC>ABC123>ABCDE");
    assertEquals("238 89 233 14 192 100 207 44 31 96 82 70", visualized);

    visualized = encodeHighLevel("ABC>ABC123>ABCDEF");
    assertEquals("238 89 233 14 192 100 207 44 31 96 82 254 70 71 129 237", visualized);

  }

  @Test
  public void testEDIFACTEncodation() {

    //240 shifts to EDIFACT encodation

    String visualized = encodeHighLevel(".A.C1.3.DATA.123DATA.123DATA");
    assertEquals("240 184 27 131 198 236 238 16 21 1 187 28 179 16 21 1 187 28 179 16 21 1",
                 visualized);

    visualized = encodeHighLevel(".A.C1.3.X.X2..");
    assertEquals("240 184 27 131 198 236 238 98 230 50 47 47", visualized);

    visualized = encodeHighLevel(".A.C1.3.X.X2.");
    assertEquals("240 184 27 131 198 236 238 98 230 50 47 129", visualized);

    visualized = encodeHighLevel(".A.C1.3.X.X2");
    assertEquals("240 184 27 131 198 236 238 98 230 50", visualized);

    visualized = encodeHighLevel(".A.C1.3.X.X");
    assertEquals("240 184 27 131 198 236 238 98 230 31", visualized);

    visualized = encodeHighLevel(".A.C1.3.X.");
    assertEquals("240 184 27 131 198 236 238 98 231 192", visualized);

    visualized = encodeHighLevel(".A.C1.3.X");
    assertEquals("240 184 27 131 198 236 238 89", visualized);

    //Checking temporary unlatch from EDIFACT
    visualized = encodeHighLevel(".XXX.XXX.XXX.XXX.XXX.XXX.üXX.XXX.XXX.XXX.XXX.XXX.XXX");
    assertEquals("240 185 134 24 185 134 24 185 134 24 185 134 24 185 134 24 185 134 24"
                     + " 124 47 235 125 240" //<-- this is the temporary unlatch
                     + " 97 139 152 97 139 152 97 139 152 97 139 152 97 139 152 97 139 152 89 89",
                 visualized);
  }

  @Test
  public void testBase256Encodation() {

    //231 shifts to Base256 encodation

    String visualized = encodeHighLevel("\u00ABäöüé\u00BB");
    assertEquals("231 44 108 59 226 126 1 104", visualized);
    visualized = encodeHighLevel("\u00ABäöüéà\u00BB");
    assertEquals("231 51 108 59 226 126 1 141 254 129", visualized);
    visualized = encodeHighLevel("\u00ABäöüéàá\u00BB");
    assertEquals("231 44 108 59 226 126 1 141 36 147", visualized);

    visualized = encodeHighLevel(" 23£"); //ASCII only (for reference)
    assertEquals("33 153 235 36 129", visualized);

    visualized = encodeHighLevel("\u00ABäöüé\u00BB 234"); //Mixed Base256 + ASCII
    assertEquals("231 50 108 59 226 126 1 104 33 153 53 129", visualized);

    visualized = encodeHighLevel("\u00ABäöüé\u00BB 23£ 1234567890123456789");
    assertEquals("231 54 108 59 226 126 1 104 99 10 161 167 33 142 164 186 208"
                     + " 220 142 164 186 208 58 129 59 209 104 254 150 45", visualized);

    visualized = encodeHighLevel(createBinaryMessage(20));
    assertEquals("231 44 108 59 226 126 1 141 36 5 37 187 80 230 123 17 166 60 210 103 253 150",
                 visualized);
    visualized = encodeHighLevel(createBinaryMessage(19)); //padding necessary at the end
    assertEquals("231 63 108 59 226 126 1 141 36 5 37 187 80 230 123 17 166 60 210 103 1 129",
                 visualized);

    visualized = encodeHighLevel(createBinaryMessage(276));
    assertStartsWith("231 38 219 2 208 120 20 150 35", visualized);
    assertEndsWith("146 40 194 129", visualized);

    visualized = encodeHighLevel(createBinaryMessage(277));
    assertStartsWith("231 38 220 2 208 120 20 150 35", visualized);
    assertEndsWith("146 40 190 87", visualized);
  }

  private static String createBinaryMessage(int len) {
    StringBuilder sb = new StringBuilder();
    sb.append("\u00ABäöüéàá-");
    for (int i = 0; i < len - 9; i++) {
      sb.append('\u00B7');
    }
    sb.append('\u00BB');
    return sb.toString();
  }

  private static void assertStartsWith(String expected, String actual) {
    if (!actual.startsWith(expected)) {
      throw new ComparisonFailure(null, expected, actual.substring(0, expected.length()));
    }
  }

  private static void assertEndsWith(String expected, String actual) {
    if (!actual.endsWith(expected)) {
      throw new ComparisonFailure(null, expected, actual.substring(actual.length() - expected.length()));
    }
  }

  @Test
  public void testUnlatchingFromC40() {

    String visualized = encodeHighLevel("AIMAIMAIMAIMaimaimaim");
    assertEquals("230 91 11 91 11 91 11 254 66 74 78 239 91 11 91 11 91 11", visualized);
  }

  @Test
  public void testUnlatchingFromText() {

    String visualized = encodeHighLevel("aimaimaimaim12345678");
    assertEquals("239 91 11 91 11 91 11 91 11 254 142 164 186 208 129 237", visualized);
  }

  @Test
  public void testHelloWorld() {

    String visualized = encodeHighLevel("Hello World!");
    assertEquals("73 239 116 130 175 123 148 64 158 233 254 34", visualized);
  }

  @Test
  public void testBug1664266() {
    //There was an exception and the encoder did not handle the unlatching from
    //EDIFACT encoding correctly

    String visualized = encodeHighLevel("CREX-TAN:h");
    assertEquals("68 83 70 89 46 85 66 79 59 105", visualized);

    visualized = encodeHighLevel("CREX-TAN:hh");
    assertEquals("68 83 70 89 46 85 66 79 59 105 105 129", visualized);

    visualized = encodeHighLevel("CREX-TAN:hhh");
    assertEquals("68 83 70 89 46 85 66 79 59 105 105 105", visualized);
  }

  @Test
  public void testX12Unlatch() {
    String visualized = encodeHighLevel("*DTCP01");
    assertEquals("43 69 85 68 81 131 129 56", visualized);
  }

  @Test
  public void testX12Unlatch2() {
    String visualized = encodeHighLevel("*DTCP0");
    assertEquals("238 9 10 104 141", visualized);
  }

  @Test
  public void testBug3048549() {
    //There was an IllegalArgumentException for an illegal character here because
    //of an encoding problem of the character 0x0060 in Java source code.

    String visualized = encodeHighLevel("fiykmj*Rh2`,e6");
    assertEquals("103 106 122 108 110 107 43 83 105 51 97 45 102 55 129 237", visualized);

  }

  @Test
  public void testMacroCharacters() {

    String visualized = encodeHighLevel("[)>\u001E05\u001D5555\u001C6666\u001E\u0004");
    //assertEquals("92 42 63 31 135 30 185 185 29 196 196 31 5 129 87 237", visualized);
    assertEquals("236 185 185 29 196 196 129 56", visualized);
  }

  @Test
  public void testEncodingWithStartAsX12AndLatchToEDIFACTInTheMiddle() {

    String visualized = encodeHighLevel("*MEMANT-1F-MESTECH");
    assertEquals("240 168 209 77 4 229 45 196 107 77 21 53 5 12 135 192", visualized);
  }

  @Test
  public void testX12AndEDIFACTSpecErrors() {
    //X12 encoding error with spec conform float point comparisons in lookAheadTest()
    String visualized = encodeHighLevel("AAAAAAAAAAA**\u00FCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
    assertEquals("230 89 191 89 191 89 191 89 178 56 114 10 243 177 63 89 191 89 191 89 191 89 191 89 191 89 191 89 " +
        "191 89 191 89 191 254 66 129", visualized);
    //X12 encoding error with integer comparisons in lookAheadTest()
    visualized = encodeHighLevel("AAAAAAAAAAAA0+****AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
    assertEquals("238 89 191 89 191 89 191 89 191 254 240 194 186 170 170 160 65 4 16 65 4 16 65 4 16 65 4 16 65 4 " +
        "16 65 4 16 65 4 16 65 124 129 167 62 212 107", visualized);
    //EDIFACT encoding error with spec conform float point comparisons in lookAheadTest()
    visualized = encodeHighLevel("AAAAAAAAAAA++++\u00FCAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
    assertEquals("230 89 191 89 191 89 191 254 66 66 44 44 44 44 235 125 230 89 191 89 191 89 191 89 191 89 191 89 " +
        "191 89 191 89 191 89 191 89 191 254 129 17 167 62 212 107", visualized);
    //EDIFACT encoding error with integer comparisons in lookAheadTest()
    visualized = encodeHighLevel("++++++++++AAa0 0++++++++++++++++++++++++++++++");
    assertEquals("240 174 186 235 174 186 235 174 176 65 124 98 240 194 12 43 174 186 235 174 186 235 174 186 235 " +
        "174 186 235 174 186 235 174 186 235 174 186 235 173 240 129 167 62 212 107", visualized);
    visualized = encodeHighLevel("AAAAAAAAAAAA*+AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
    assertEquals("230 89 191 89 191 89 191 89 191 7 170 64 191 89 191 89 191 89 191 89 191 89 191 89 191 89 191 89 " +
        "191 89 191 66", visualized);
    visualized = encodeHighLevel("AAAAAAAAAAA*0a0 *AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
    assertEquals("230 89 191 89 191 89 191 89 178 56 227 6 228 7 183 89 191 89 191 89 191 89 191 89 191 89 191 89 " +
        "191 89 191 89 191 254 66 66", visualized);

  }
  @Test
  public void testSizes() {
    int[] sizes = new int[2];
    encodeHighLevel("A", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("AB", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("ABC", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("ABCD", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("ABCDE", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("ABCDEF", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("ABCDEFG", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("ABCDEFGH", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("ABCDEFGHI", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("ABCDEFGHIJ", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("a", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("ab", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("abc", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("abcd", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("abcdef", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("abcdefg", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("abcdefgh", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("+", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("++", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("+++", sizes);
    assertEquals(3, sizes[0]);
    assertEquals(3, sizes[1]);

    encodeHighLevel("++++", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("+++++", sizes);
    assertEquals(5, sizes[0]);
    assertEquals(5, sizes[1]);

    encodeHighLevel("++++++", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("+++++++", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("++++++++", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("+++++++++", sizes);
    assertEquals(8, sizes[0]);
    assertEquals(8, sizes[1]);

    encodeHighLevel("\u00F0\u00F0" +
        "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEF", sizes);
    assertEquals(114, sizes[0]);
    assertEquals(62, sizes[1]);
  }

  @Test
  public void testECIs() {

    String visualized = visualize(MinimalEncoder.encodeHighLevel("that particularly stands out to me is \u0625\u0650" +
        "\u062C\u064E\u0651\u0627\u0635 (\u02BE\u0101\u1E63) \"pear\", suggested to have originated from Hebrew " +
        "\u05D0\u05B7\u05D2\u05B8\u05BC\u05E1 (ag\u00E1s)"));
    assertEquals("239 209 151 206 214 92 122 140 35 158 144 162 52 205 55 171 137 23 67 206 218 175 147 113 15 254" +
        " 116 33 241 25 231 186 14 212 64 253 151 252 159 33 41 241 27 231 83 171 53 209 35 25 134 6 42 33 35 239 184" +
        " 31 193 234 7 252 205 101 127 241 209 34 24 5 22 23 221 148 179 239 128 140 92 187 106 204 198 59 19 25 114" +
        " 248 118 36 254 231 106 196 19 239 101 27 107 69 189 112 236 156 252 16 174 125 24 10 125 116 42 129",
        visualized);

    visualized = visualize(MinimalEncoder.encodeHighLevel("that particularly stands out to me is \u0625\u0650" +
        "\u062C\u064E\u0651\u0627\u0635 (\u02BE\u0101\u1E63) \"pear\", suggested to have originated from Hebrew " +
        "\u05D0\u05B7\u05D2\u05B8\u05BC\u05E1 (ag\u00E1s)", StandardCharsets.UTF_8, -1 , SymbolShapeHint.FORCE_NONE));
    assertEquals("241 27 239 209 151 206 214 92 122 140 35 158 144 162 52 205 55 171 137 23 67 206 218 175 147 113" +
        " 15 254 116 33 231 202 33 131 77 154 119 225 163 238 206 28 249 93 36 150 151 53 108 246 145 228 217 71" +
        " 199 42 33 35 239 184 31 193 234 7 252 205 101 127 241 209 34 24 5 22 23 221 148 179 239 128 140 92 187 106" +
        " 204 198 59 19 25 114 248 118 36 254 231 43 133 212 175 38 220 44 6 125 49 172 93 189 209 111 61 217 203 62" +
        " 116 42 129 1 151 46 196 91 241 137 32 182 77 227 122 18 168 63 213 108 4 154 49 199 94 244 140 35 185 80",
         visualized);
  }

  @Test
  public void testPadding() {
    int[] sizes = new int[2];
    encodeHighLevel("IS010000000000000000000000S1118058599124123S21.2.250.1.213.1.4.8 S3FIRST NAMETEST S5MS618-06" +
        "-1985S713201S4LASTNAMETEST", sizes);
    assertEquals(86, sizes[0]);
    assertEquals(86, sizes[1]);
  }


  private static void encodeHighLevel(String msg, int[] sizes) {
    sizes[0] = HighLevelEncoder.encodeHighLevel(msg).length();
    sizes[1] = MinimalEncoder.encodeHighLevel(msg).length();
  }

  private static String encodeHighLevel(String msg) {
    return encodeHighLevel(msg, true);
  }

  private static String encodeHighLevel(String msg, boolean compareSizeToMinimalEncoder) {
    CharSequence encoded = HighLevelEncoder.encodeHighLevel(msg);
    CharSequence encoded2 = MinimalEncoder.encodeHighLevel(msg);
    assertTrue(!compareSizeToMinimalEncoder || encoded2.length() <= encoded.length());
    return visualize(encoded);
  }

  /**
   * Convert a string of char codewords into a different string which lists each character
   * using its decimal value.
   *
   * @param codewords the codewords
   * @return the visualized codewords
   */
  static String visualize(CharSequence codewords) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < codewords.length(); i++) {
      if (i > 0) {
        sb.append(' ');
      }
      sb.append((int) codewords.charAt(i));
    }
    return sb.toString();
  }

}