// 存储各难度题目的正确答案
const correctAnswers = {
    medium: {
        mq1: 'B',
        mq2: 'D',
        mq3: 'B',
        mq4: 'A',
        mq5: 'C'
    },
    easy: {
        eq1: 'B',
        eq2: 'A',
        eq3: 'C',
        eq4: 'B',
        eq5: 'A'
    },
    hard: {
        hq1: 'C',
        hq2: 'A',
        hq3: 'C',
        hq4: 'A',
        hq5: 'B'
    }
};

// 跟踪测验状态
const quizState = {
    currentDifficulty: 'medium', // 初始难度
    completedDifficulties: [],
    scores: {}
};

// DOM元素
const submitBtn = document.getElementById('submit-btn');
const nextBtn = document.getElementById('next-btn');
const navigationSection = document.getElementById('navigation');
const navigationMessage = document.getElementById('navigation-message');
const result = document.getElementById('result');
const scoreValue = document.getElementById('score-value');
const correctCount = document.getElementById('correct-count');
const incorrectCount = document.getElementById('incorrect-count');
const difficultyIndicator = document.querySelector('.difficulty-indicator');

// 等待DOM加载完成
document.addEventListener('DOMContentLoaded', function() {
    // 提交当前难度的答案
    submitBtn.addEventListener('click', function() {
        const currentAnswers = correctAnswers[quizState.currentDifficulty];
        const totalQuestions = Object.keys(currentAnswers).length;
        let score = 0;
        let correct = 0;
        let incorrect = 0;

        // 检查所有问题的答案
        for (const [questionName, correctAnswer] of Object.entries(currentAnswers)) {
            const selectedOption = document.querySelector(`input[name="${questionName}"]:checked`);
            const questionNumber = questionName.substring(2); // 从mq1提取1
            const explanationElement = document.querySelector(`[data-difficulty="${quizState.currentDifficulty}"][data-question="${questionNumber}"] .question-explanation`);

            // 显示解析
            explanationElement.style.display = 'block';

            if (selectedOption) {
                const userAnswer = selectedOption.value;

                // 标记正确或错误
                if (userAnswer === correctAnswer) {
                    score += 20; // 每题20分
                    correct++;
                    selectedOption.closest('.option').style.backgroundColor = '#e8f5e9';
                    selectedOption.closest('.option').style.borderColor = '#4caf50';
                } else {
                    incorrect++;
                    selectedOption.closest('.option').style.backgroundColor = '#ffebee';
                    selectedOption.closest('.option').style.borderColor = '#c62828';
                    // 标记正确答案
                    const correctOption = document.querySelector(`input[name="${questionName}"][value="${correctAnswer}"]`);
                    correctOption.closest('.option').style.backgroundColor = '#e8f5e9';
                    correctOption.closest('.option').style.borderColor = '#4caf50';
                }
            } else {
                // 未答题
                incorrect++;
                const questionElement = document.querySelector(`[data-difficulty="${quizState.currentDifficulty}"][data-question="${questionNumber}"]`);
                questionElement.style.border = '2px solid #ff9800';
            }
        }

        // 保存当前难度得分
        quizState.scores[quizState.currentDifficulty] = {
            score: score,
            correct: correct,
            incorrect: incorrect
        };
        quizState.completedDifficulties.push(quizState.currentDifficulty);

        // 显示当前难度结果
        scoreValue.textContent = score;
        correctCount.textContent = correct;
        incorrectCount.textContent = incorrect;
        result.style.display = 'block';

        // 隐藏提交按钮
        submitBtn.style.display = 'none';

        // 根据当前难度和得分决定下一步
        if (quizState.currentDifficulty === 'medium') {
            if (correct < 3) {
                // 中等难度答对少于3题，推荐简单难度
                showNavigation('您在中等难度题目中表现不佳，建议先完成简单难度题目来巩固基础。', 'easy');
            } else {
                // 中等难度答对3题及以上，推荐高级难度
                showNavigation('恭喜您完成中等难度题目！接下来挑战高级难度题目吧。', 'hard');
            }
        } else {
            // 简单或高级难度完成后，显示最终结果
            showFinalResult();
        }
    });

    // 显示导航信息
    function showNavigation(message, nextDifficulty) {
        navigationMessage.textContent = message;
        navigationSection.dataset.nextDifficulty = nextDifficulty;
        navigationSection.style.display = 'block';
    }

    // 开始下一组题目
    nextBtn.addEventListener('click', function() {
        const nextDifficulty = navigationSection.dataset.nextDifficulty;
        if (!nextDifficulty) return;

        // 更新当前难度
        quizState.currentDifficulty = nextDifficulty;

        // 隐藏导航和结果
        navigationSection.style.display = 'none';
        result.style.display = 'none';

        // 显示提交按钮
        submitBtn.style.display = 'inline-block';

        // 更新难度指示器
        difficultyIndicator.textContent = `当前难度：${getDifficultyName(nextDifficulty)}`;
        difficultyIndicator.className = `difficulty-indicator difficulty-${nextDifficulty}`;

        // 隐藏所有题目
        document.querySelectorAll('.question').forEach(question => {
            question.classList.add('hidden');
        });

        // 显示下一组题目
        document.querySelectorAll(`[data-difficulty="${nextDifficulty}"]`).forEach(question => {
            question.classList.remove('hidden');
        });

        // 滚动到页面顶部
        window.scrollTo(0, 0);
    });

    // 获取难度名称
    function getDifficultyName(difficulty) {
        const names = {
            easy: '简单',
            medium: '中等',
            hard: '高级'
        };
        return names[difficulty] || difficulty;
    }

    // 显示最终结果
    function showFinalResult() {
        // 计算总分
        let totalScore = 0;
        let totalCorrect = 0;
        let totalIncorrect = 0;

        for (const difficulty of quizState.completedDifficulties) {
            totalScore += quizState.scores[difficulty].score;
            totalCorrect += quizState.scores[difficulty].correct;
            totalIncorrect += quizState.scores[difficulty].incorrect;
        }

        // 更新结果显示
        scoreValue.textContent = totalScore;
        correctCount.textContent = totalCorrect;
        incorrectCount.textContent = totalIncorrect;
        result.style.display = 'block';

        // 显示完成信息
        navigationMessage.textContent = '恭喜您完成所有推荐题目！';
        navigationSection.style.display = 'block';
        document.getElementById('next-btn').style.display = 'none';
    }
});