Math_Learning/src/Service/Exam_service.java

package Service;

import Base.Exam_result;
import Base.Question;
import Generator.Generate_paper;

import java.util.*;

public class Exam_service {
    private String id;
    private String type;
    private ArrayList<Question> paper;
    private int now_index;
    private Date start_time;
    private Date end_time;
    private Map<Integer, Integer> user_answers;

    public Exam_service(int num,String type,String id){
        this.id=id;
        this.type=type;
        paper= Generate_paper.g_paper(num,type,id);
        now_index=0;
        this.start_time = new Date();
        this.user_answers = new HashMap<>();
    }

    public ArrayList<Question> get_paper() { return paper; }
    public int get_now_index() { return now_index; }
    public Date get_start_time() { return start_time; }
    public Date get_end_time() { return end_time; }
    public Map<Integer, Integer> get_user_answers() {return user_answers;}

    public void set_now_index(int i){
        if (i==1 && now_index<paper.size()-1){
            now_index+=i;
        }
        else if (i==-1 && now_index>0){
            now_index+=i;
        }
        else if (i==0){
            now_index=0;
        }
    }

    public Question get_now_question() {
        if (now_index < paper.size()) {
            return paper.get(now_index);
        }
        return null;
    }

    public boolean next_one(int answer_index) {
        if (now_index < paper.size()) {
            user_answers.put(now_index, answer_index);

            if (now_index < paper.size() - 1) {
                now_index++;
                return true;
            } else {
                end_time = new Date();
                return false;
            }
        }
        return false;
    }

    public boolean pre_one() {
        if (now_index > 0) {
            now_index--;
            return true;
        }
        return false;
    }

    public boolean change_answer(int index,int choice){
        if (user_answers.containsKey(index)){
            user_answers.put(index,choice);
            return true;
        }
        return false;
    }

    public Integer get_user_answer(int question_index) {
        return user_answers.get(question_index);
    }

    public boolean check_finished(){
        for (int i=0;i< paper.size();i++){
            if (user_answers.get(i)==-1){
                return false;
            }
        }
        return true;
    }

    public Exam_result calculate_result(){
        int correct = 0;
        List<Integer> wrong = new ArrayList<>();

        for (int i = 0; i < paper.size(); i++) {
            Integer userAnswer = user_answers.get(i);
            if (userAnswer != null && paper.get(i).getOptions(userAnswer).equals(paper.get(i).getAnswer())) {
                correct++;
            } else {
                wrong.add(i);
            }
        }

        double score = (double) correct / paper.size() * 100;
        long duration = (end_time.getTime() - start_time.getTime()) / 1000; // 秒

        return new Exam_result(type, paper.size(), correct,
                score, duration, wrong);
    }
}