import java.util.ArrayList;

/**
 * The DriverExam class holds the correct answers for the drivers test
 * and handles logic for calculating if the user passed, and displays incorrect answers
 */
public class DriverExam {
    /** Array of correct exam answers. IStatic because it does not change or depends on which
      * user is taking the exam
     **/
    private final static char[] correctAnswers =
            {'B','D','A','A','C','A','B','A','C','D','B','C','D','A','D','C','C','B','D','A'};

    /** Array of user's answers **/
    private final char[] givenAnswers;
    /** Count of correct user answers **/
    private int totalCorrect;
    /** Corresponds to each question, each true if correct answer **/
    private boolean[] missedQuestions;

    /**
     * Compares givenAnswers to correctAnswers, counting amount correct
     * Also updates missedQuestions with incorrect answers
     * @return If user passed exam
     */
    public boolean passed() {
        int correct = 0;
        for(int i = 0; i < givenAnswers.length; i++) {
            if(givenAnswers[i] == correctAnswers[i]) {
                correct++;
            }
            else{
                missedQuestions[i] = true;
            }
        }
        totalCorrect = correct;
        return correct >= 15;
    }

    public DriverExam(char[] givenAnswers) {
        this.givenAnswers = givenAnswers;
        missedQuestions = new boolean[20];
    }
    // Getter methods
    public int totalCorrect() {
        return totalCorrect;
    }
    public int totalIncorrect() {
        return 20 - totalCorrect;
    }

    public ArrayList<Integer> questionsMissed() {
        ArrayList<Integer> missedNums = new ArrayList<>();
        for(int i = 0; i < missedQuestions.length; i++) {
            if(missedQuestions[i]) {
                missedNums.add(i + 1);
            }
        }
        return missedNums;
    }


}