Bowling Kata in Dart

bolwing_kata.dart

import 'package:cli/cli.dart';
import 'package:test/test.dart';

// https://learnxinyminutes.com/docs/dart/
// http://codingdojo.org/kata/Bowling/

int parseRoll(String roll) {
  if (roll == 'X') {
    return 10;
  }
  if (roll == '-') {
    return 0;
  }
  return int.parse(roll);
}

bool isStrike(rollScore) {
  return rollScore == 'X';
}

bool isSpare(rollScore) {
  return rollScore == '/';
}

int computeStrikeScore(List<String> frames, index) {
  var firstBonusRoll = frames[index + 1][0];
  var secondBonusRoll =
      isStrike(firstBonusRoll) ? frames[index + 2][0] : frames[index + 1][1];
  return 10 + parseRoll(firstBonusRoll) + parseRoll(secondBonusRoll);
}

int computeFrameScore(List<String> frames, index) {
  var firstRoll = frames[index][0];
  if (isStrike(firstRoll)) {
    return computeStrikeScore(frames, index);
  }
  if (isSpare(frames[index][1])) {
    return 10 + parseRoll(frames[index + 1][0]);
  }

  var secondRoll = frames[index][1];
  return parseRoll(firstRoll) + parseRoll(secondRoll);
}

int score(String rolls) {
  var frames = rolls.split(' ');

  var sum = 0;
  var index = 0;
  while (index < 10) {
    sum += computeFrameScore(frames, index);
    index++;
  }

  return sum;
}

// https://codeburst.io/top-X-array-utility-methods-you-should-know-dart-feb2648ee3a2
void main() {
  test("bowling score when only failed rolls", () {
    var rolls = '-- -- -- -- -- -- -- -- -- --';
    expect(score(rolls), equals(0));
  });

  test("bowling score when 9 pin is down at each frame (aka turn)", () {
    var rolls = '9- 9- 9- 9- 9- 9- 9- 9- 9- 9-';
    expect(score(rolls), equals(90));
  });

  test('bowling score when 1 pin is down at each roll', () {
    var rolls = '11 11 11 11 11 11 11 11 11 11';
    expect(score(rolls), equals(20));
  });

  test('bowling score when 1 spare', () {
    var rolls = '8/ 2- -- -- -- -- -- -- -- --';
    expect(score(rolls), equals(14));
  });

  test('bowling score when 1 strike', () {
    var rolls = 'X 32 -- -- -- -- -- -- -- --';
    expect(score(rolls), equals(20));
  });
  test('bowling score when only strikes', () {
    var rolls = 'X X X X X X X X X X X X';
    expect(score(rolls), equals(300));
  });

  test('', () {
    var rolls = '5/ 5/ 5/ 5/ 5/ 5/ 5/ 5/ 5/ 5/ 5';
    expect(score(rolls), equals(150));
  });
}