class BowlingGameScore {

private int[] pinsKnockedDown = new int[21];
private int currentRoll = 0;

void roll(int pinsKnockedDown) {
    this.pinsKnockedDown[currentRoll++] = pinsKnockedDown;
}

int score() {
    int totalScore = 0;
    int rollNumber = 0;

    for (int frameNumber = 0; frameNumber < 10; frameNumber++) {
        int frameScore;

        if (isSpare(rollNumber)) {
            frameScore = 10 + getSpareBonus(rollNumber);
            rollNumber += 2;

        } else if (isStrike(pinsKnockedDown[rollNumber])) {
            frameScore = 10 + getStrikeBonus(rollNumber);
            rollNumber++;

        } else {
            frameScore = pinsKnockedDown[rollNumber] + pinsKnockedDown[rollNumber + 1];
            rollNumber += 2;
        }

        totalScore += frameScore;
    }

    return totalScore;
}

private int getStrikeBonus(int roll) {
    return pinsKnockedDown[roll + 1] + pinsKnockedDown[roll + 2];
}

private boolean isStrike(int roll) {
    return roll == 10;
}

private int getSpareBonus(int roll) {
    return pinsKnockedDown[roll + 2];
}

private boolean isSpare(int roll) {
    return pinsKnockedDown[roll] + pinsKnockedDown[roll + 1] == 10;
}}

class BowlingGameScoreTest {
private BowlingGameScore game;

@BeforeEach
void setUp() {
    game = new BowlingGameScore();
}

@Test
void
game_no_pins_get_hit() {
    rollMany(0, 20);

    Assertions.assertEquals(0, game.score());
}

@Test
void
game_just_1_pin_get_hit() {
    rollMany(1, 20);

    Assertions.assertEquals(20, game.score());
}

@Test
void
game_with_1_spare() {
    rollSpare();
    game.roll(3);
    rollMany(0, 17);

    Assertions.assertEquals(16, game.score());
}

@Test
void
game_with_1_strike() {
    game.roll(10);
    game.roll(3);
    game.roll(4);
    rollMany(0, 16);

    Assertions.assertEquals(24, game.score());
}

@Test
void
game_of_strikes() {
    rollMany(10, 12);

    Assertions.assertEquals(300, game.score());
}

@Test
void
knockdown_nine_and_miss_ten_times() {

    int firstRollPinsKnockedDown = 9;
    int secondRollPinsKnockedDown = 0;
    int repeatTimes = 10;
    rollPair(repeatTimes, firstRollPinsKnockedDown, secondRollPinsKnockedDown);

    Assertions.assertEquals(90, game.score());
}


@Test
void
knockdown_five_and_spare_ten_times_and_fice() {
    rollPair(10, 5, 5);
    game.roll(5);

    Assertions.assertEquals(150, game.score());
}

private void rollPair(int repeatTimes, int firstRollPinsKnockedDown, int secondRollPinsKnockedDown) {
    for (int i = 0; i < repeatTimes; i++) {
        game.roll(firstRollPinsKnockedDown);
        game.roll(secondRollPinsKnockedDown);
    }
}

private void rollSpare() {
    game.roll(5);
    game.roll(5);
}


private void rollMany(int pins, int times) {
    for (int i = 0; i < times; i++) {
        game.roll(pins);
    }
}