document.addEventListener('DOMContentLoaded', function() {
    // 檢查是否有玩家資料
    const currentPlayerId = localStorage.getItem('currentPlayerId');
    const playerName = localStorage.getItem('playerName');
    const playerProfession = localStorage.getItem('playerProfession');
    
    // 如果沒有玩家資料，重定向到首頁
    if (!currentPlayerId || !playerName || !playerProfession) {
        alert('請先登入遊戲！');
        window.location.href = 'index.html';
        return;
    }
    
    // 獲取DOM元素
    const startChallengeBtn = document.getElementById('start-challenge');
    const quizContainer = document.getElementById('quiz-container');
    const resultContainer = document.getElementById('result-container');
    const questionTitle = document.getElementById('question-title');
    const formulaDisplay = document.getElementById('formula-display');
    const formulaTemplate = document.getElementById('formula-template');
    const dragItems = document.getElementById('drag-items');
    const stage1Btn = document.getElementById('stage-1-btn');
    const stage2Btn = document.getElementById('stage-2-btn');
    const checkAnswerBtn = document.getElementById('check-answer');
    const nextQuestionBtn = document.getElementById('next-question');
    const currentQuestionSpan = document.getElementById('current-question');
    const feedbackContainer = document.getElementById('feedback-container');
    const resultTitle = document.getElementById('result-title');
    const resultMessage = document.getElementById('result-message');
    const retryBtn = document.getElementById('retry-challenge');
    const backToMapBtn = document.getElementById('back-to-map');
    const nextTrialBtn = document.getElementById('next-trial');
    const doorsProgress = document.getElementById('doors-progress').children;
    const successButtons = document.getElementById('success-buttons');
    const failButtons = document.getElementById('fail-buttons');
    const bgmAudio = document.getElementById('bgm');
    const correctSound = document.getElementById('correct-sound');
    const wrongSound = document.getElementById('wrong-sound');
    const toggleBgmBtn = document.getElementById('toggle-bgm');
    const starResults = [
        document.getElementById('star-1'),
        document.getElementById('star-2'),
        document.getElementById('star-3')
    ];
    
    // 音樂控制
    let isBgmPlaying = false;
    
    // 播放背景音樂
    function playBgm() {
        bgmAudio.volume = 0.3; // 設置音量
        bgmAudio.play().catch(e => console.log('自動播放被阻止:', e));
        isBgmPlaying = true;
        toggleBgmBtn.textContent = '音樂關';
    }
    
    // 嘗試自動播放背景音樂（大多數瀏覽器會阻止）
    playBgm();
    
    // 音樂開關按鈕
    toggleBgmBtn.addEventListener('click', function() {
        if (isBgmPlaying) {
            bgmAudio.pause();
            isBgmPlaying = false;
            toggleBgmBtn.textContent = '音樂開';
            localStorage.setItem('towerMusicPlaying', 'false');
        } else {
            bgmAudio.play();
            isBgmPlaying = true;
            toggleBgmBtn.textContent = '音樂關';
            localStorage.setItem('towerMusicPlaying', 'true');
        }
    });
    
    // 問題資料
    const questions = [
        {
            title: "101² = (100 + 1)² = (100+1) × (100+1)",
            stage1: {
                template: "100² + ___ × ___ + ___ × ___ + 1²",
                dragItems: ["100", "99", "200", "1", "2"],
                answers: [["1", "100"], ["1", "100"]], // 順序不限
                correctAnswer: "100² + 100 × 1 + 1 × 100 + 1²"
            },
            stage2: {
                template: "100² + ___ × ___ × ___ + 1²",
                dragItems: ["100", "99", "200", "1", "2"],
                answers: [["2", "100", "1"]] // 除了2之外，順序不限
            }
        },
        {
            title: "99² = (100 - 1)² = (100-1) × (100-1)",
            stage1: {
                template: "100² - ___ × ___ - ___ × ___ + 1²",
                dragItems: ["1", "2", "100", "98", "200"],
                answers: [["1", "100"], ["1", "100"]], // 順序不限
                correctAnswer: "100² - 100 × 1 - 1 × 100 + 1²"
            },
            stage2: {
                template: "100² - ___ × ___ × ___ + 1²",
                dragItems: ["1", "2", "100", "98", "200"],
                answers: [["2", "100", "1"]] // 除了2之外，順序不限
            }
        },
        {
            title: "23² = (20 + 3)² = (20+3) × (20+3)",
            stage1: {
                template: "20² + ___ × ___ + ___ × ___ + 3²",
                dragItems: ["2", "20", "3", "23", "17"],
                answers: [["20", "3"], ["3", "20"]], // 順序不限
                correctAnswer: "20² + 20 × 3 + 3 × 20 + 3²"
            },
            stage2: {
                template: "20² + ___ × ___ × ___ + 3²",
                dragItems: ["2", "20", "3", "23", "17"],
                answers: [["2", "20", "3"]] // 除了2之外，順序不限
            }
        },
        {
            title: "38² = (40 - 2)² = (40-2) × (40-2)",
            stage1: {
                template: "40² - ___ × ___ - ___ × ___ + 2²",
                dragItems: ["1", "2", "40", "38", "42"],
                answers: [["2", "40"], ["40", "2"]], // 順序不限
                correctAnswer: "40² - 40 × 2 - 2 × 40 + 2²"
            },
            stage2: {
                template: "40² - ___ × ___ × ___ + 2²",
                dragItems: ["1", "2", "40", "38", "42"],
                answers: [["2", "40", "2"]] // 除了第一個2之外，順序不限
            }
        },
        {
            title: "203² = (200 + 3)² = (200 + 3) × (200 + 3)",
            stage1: {
                template: "200² + ___ × ___ + ___ × ___ + 3²",
                dragItems: ["2", "3", "200", "203", "197"],
                answers: [["3", "200"], ["200", "3"]], // 順序不限
                correctAnswer: "200² + 200 × 3 + 3 × 200 + 3²"
            },
            stage2: {
                template: "200² + ___ × ___ × ___ + 3²",
                dragItems: ["2", "3", "200", "203", "197"],
                answers: [["2", "200", "3"]] // 除了2之外，順序不限
            }
        },
        {
            title: "297² = (300 - 3)² = (300 - 3) × (300 - 3)",
            stage1: {
                template: "300² - ___ × ___ - ___ × ___ + 3²",
                dragItems: ["2", "300", "3", "297", "303"],
                answers: [["300", "3"], ["3", "300"]], // 順序不限
                correctAnswer: "300² - 300 × 3 - 3 × 300 + 3²"
            },
            stage2: {
                template: "300² - ___ × ___ × ___ + 3²",
                dragItems: ["2", "300", "3", "297", "303"],
                answers: [["2", "300", "3"]] // 除了2之外，順序不限
            }
        }
    ];
    
    // 遊戲狀態
    let currentQuestionIndex = 0;
    let currentStage = 1;
    let correctAnswers = 0;
    let userAnswers = []; // 記錄用戶答案
    let dropZones = []; // 當前問題的所有拖放區
    let dragItemElements = []; // 當前問題的所有拖拽項
    let wrongAttempts = 0; // 記錄當前問題錯誤嘗試次數
    let sortableInstances = []; // 儲存所有Sortable實例
    
    // 獲取遊戲進度
    const gameProgress = JSON.parse(localStorage.getItem(`gameProgress_${currentPlayerId}`)) || {
        completedTrials: {
            "平方之泉": { completed: false, score: 0, challengesCompleted: [false, false, false, false, false, false] },
            "變換山谷": { completed: false, score: 0, challengesCompleted: [false, false, false, false, false, false] },
            "展開之塔": { completed: false, score: 0, challengesCompleted: [false, false, false, false, false, false] }
        },
        currentLocation: "展開之塔",
        lastSaved: new Date().toISOString()
    };
    
    // 開始挑戰按鈕點擊事件
    startChallengeBtn.addEventListener('click', function() {
        startChallengeBtn.style.display = 'none';
        quizContainer.style.display = 'block';
        loadQuestion(0, 1);
    });
    
    // 儲存每個階段的答案
    let stage1Answers = Array(questions.length).fill(null).map(() => []);
    let stage2Answers = Array(questions.length).fill(null).map(() => []);
    
    // 載入問題
    function loadQuestion(questionIndex, stageIndex) {
        currentQuestionIndex = questionIndex;
        currentStage = stageIndex;
        wrongAttempts = 0; // 重置錯誤嘗試次數
        
        // 清除所有Sortable實例
        sortableInstances.forEach(instance => {
            if (instance && typeof instance.destroy === 'function') {
                instance.destroy();
            }
        });
        sortableInstances = [];
        
        // 更新問題標題和進度
        currentQuestionSpan.textContent = questionIndex + 1;
        questionTitle.textContent = `問題 ${questionIndex + 1}`;
        
        // 顯示題目，將標題分成兩行，並讓等號垂直對齊
        const titleParts = questions[questionIndex].title.split('=');
        if (titleParts.length >= 3) {
            formulaDisplay.innerHTML = `${titleParts[0]} = ${titleParts[1]}<br><span style="display: inline-block; width: 8px;"></span>= ${titleParts[2]}`;
        } else {
            formulaDisplay.textContent = questions[questionIndex].title;
        }
        
        // 更新階段按鈕狀態
        stage1Btn.classList.toggle('active', stageIndex === 1);
        stage2Btn.classList.toggle('active', stageIndex === 2);
        
        // 清空公式模板和拖拽項
        formulaTemplate.innerHTML = '';
        dragItems.innerHTML = '';
        dropZones = [];
        
        // 移除所有現有的參考區域
        const existingReferences = document.querySelectorAll('.stage1-reference');
        existingReferences.forEach(ref => ref.remove());
        
        // 移除提示圖片和提示容器
        const existingHintContainers = document.querySelectorAll('.hint-container');
        existingHintContainers.forEach(container => container.remove());
        
        // 移除所有無作用的小框框
        const emptyBoxes = document.querySelectorAll('.empty-box');
        emptyBoxes.forEach(box => box.remove());
        
        // 如果是第二階段，顯示第一階段的答案作為參考
        if (stageIndex === 2 && stage1Answers[questionIndex].length > 0) {
            // 創建參考區域
            const referenceDiv = document.createElement('div');
            referenceDiv.className = 'stage1-reference';
            referenceDiv.style.marginBottom = '15px';
            referenceDiv.style.padding = '10px';
            referenceDiv.style.backgroundColor = 'rgba(60, 60, 60, 0.7)';
            referenceDiv.style.borderRadius = '8px';
            referenceDiv.style.border = '1px solid rgba(255, 140, 0, 0.5)';
            
            // 創建參考標題
            const referenceTitle = document.createElement('div');
            referenceTitle.textContent = '第一階段答案參考：';
            referenceTitle.style.color = 'rgba(255, 165, 0, 0.9)';
            referenceTitle.style.marginBottom = '5px';
            referenceDiv.appendChild(referenceTitle);
            
            // 獲取第一階段的模板和答案
            const stage1Template = questions[questionIndex].stage1.template;
            const stage1Values = stage1Answers[questionIndex];
            
            // 創建完整算式
            let fullFormula = stage1Template;
            stage1Values.forEach((value, index) => {
                fullFormula = fullFormula.replace('___', value);
            });
            
            // 顯示完整算式
            const formulaText = document.createElement('div');
            formulaText.textContent = fullFormula;
            formulaText.style.color = 'white';
            formulaText.style.fontSize = '1.1rem';
            referenceDiv.appendChild(formulaText);
            
            // 插入到公式模板前面
            formulaTemplate.parentNode.insertBefore(referenceDiv, formulaTemplate);
        }
        
        // 獲取當前階段的問題數據
        const stageData = stageIndex === 1 ? questions[questionIndex].stage1 : questions[questionIndex].stage2;
        
        // 獲取已保存的答案
        const savedAnswers = stageIndex === 1 ? stage1Answers[questionIndex] : stage2Answers[questionIndex];
        
        // 創建公式模板
        const templateParts = stageData.template.split('___');
        for (let i = 0; i < templateParts.length; i++) {
            // 添加文本部分
            const textSpan = document.createElement('span');
            textSpan.textContent = templateParts[i];
            textSpan.style.display = 'inline-block';
            textSpan.style.verticalAlign = 'middle';
            formulaTemplate.appendChild(textSpan);
            
            // 如果不是最後一部分，添加拖放區
            if (i < templateParts.length - 1) {
                const dropZone = document.createElement('span');
                dropZone.className = 'drop-zone sortable-container';
                dropZone.dataset.index = i;
                dropZone.style.display = 'inline-flex';
                dropZone.style.justifyContent = 'center';
                dropZone.style.alignItems = 'center';
                dropZone.style.verticalAlign = 'middle';
                dropZone.style.height = '40px';
                formulaTemplate.appendChild(dropZone);
                dropZones.push(dropZone);
                
                // 防止觸控滾動
                dropZone.addEventListener('touchmove', function(e) {
                    e.preventDefault();
                }, { passive: false });
                
                // 初始化每個拖放區的Sortable
                const dropZoneSortable = new Sortable(dropZone, {
                    group: {
                        name: 'formula',
                        pull: 'clone', // 允許從答案區拖出，但會被移除
                        put: true
                    },
                    animation: 100,
                    delay: 0,
                    touchStartThreshold: 5,
                    ghostClass: "drag-ghost",
                    forceFallback: true,
                    fallbackTolerance: 3,
                    sort: false, // 禁止在拖放區內排序
                    filter: '.disabled', // 禁止拖拽的元素
                    onAdd: function(evt) {
                        const item = evt.item;
                        
                        // 如果拖放區已有內容，先清空
                        if (evt.to.children.length > 1) {
                            // 保留最新添加的元素，移除其他元素
                            Array.from(evt.to.children).forEach(child => {
                                if (child !== item) {
                                    evt.to.removeChild(child);
                                }
                            });
                        }
                        
                        // 設置樣式
                        evt.to.classList.add('filled');
                        evt.to.style.backgroundColor = 'rgba(255, 140, 0, 0.3)';
                        
                        // 更新保存的答案
                        updateSavedAnswers();
                    },
                    onRemove: function(evt) {
                        // 當元素被移出時，移除filled類
                        evt.from.classList.remove('filled');
                        evt.from.style.backgroundColor = 'rgba(100, 100, 100, 0.5)';
                        
                        // 從答案格拖出的方塊直接移除，不回到拖拉區
                        if (evt.item && evt.item.parentNode) {
                            evt.item.remove();
                        }
                        
                        // 更新保存的答案
                        updateSavedAnswers();
                    }
                });
                
                sortableInstances.push(dropZoneSortable);
            }
        }
        
        // 創建拖拽項容器
        const dragItemsContainer = document.createElement('div');
        dragItemsContainer.className = 'sortable-container';
        dragItemsContainer.style.display = 'flex';
        dragItemsContainer.style.flexWrap = 'wrap';
        dragItemsContainer.style.justifyContent = 'center';
        dragItemsContainer.style.gap = '15px';
        dragItems.appendChild(dragItemsContainer);
        
        // 防止觸控滾動
        dragItemsContainer.addEventListener('touchmove', function(e) {
            e.preventDefault();
        }, { passive: false });
        
        // 創建拖拽項
        stageData.dragItems.forEach((item, index) => {
            const dragItem = document.createElement('div');
            dragItem.className = 'drag-item';
            dragItem.id = `drag-item-${index}`;
            dragItem.textContent = item;
            dragItem.dataset.value = item;
            dragItem.style.willChange = 'transform';
            dragItem.style.touchAction = 'none';
            
            // 添加點擊事件，點擊可移除（如果在拖放區內）
            dragItem.addEventListener('click', function() {
                const parent = this.parentElement;
                if (parent && parent.classList.contains('drop-zone')) {
                    parent.classList.remove('filled');
                    parent.style.backgroundColor = 'rgba(100, 100, 100, 0.5)';
                    
                    // 移除元素
                    this.remove();
                    
                    // 更新保存的答案
                    updateSavedAnswers();
                }
            });
            
            dragItemsContainer.appendChild(dragItem);
            dragItemElements.push(dragItem);
        });
        
        // 初始化拖拽項容器的Sortable
        const dragItemsSortable = new Sortable(dragItemsContainer, {
            group: {
                name: 'formula',
                pull: 'clone', // 設置為clone模式，拖拽項不會消失
                put: false // 不允許放回拖拽區
            },
            animation: 100,
            delay: 0,
            touchStartThreshold: 5,
            ghostClass: "drag-ghost",
            forceFallback: true,
            fallbackTolerance: 3,
            sort: false, // 禁止排序
            filter: '.disabled', // 禁止拖拽的元素
            onClone: function(evt) {
                // 克隆元素時添加相同的樣式和數據
                evt.clone.className = evt.item.className;
                evt.clone.dataset.value = evt.item.dataset.value;
                evt.clone.style.willChange = 'transform';
                evt.clone.style.touchAction = 'none';
                
                // 添加點擊事件，點擊可移除（如果在拖放區內）
                evt.clone.addEventListener('click', function() {
                    const parent = this.parentElement;
                    if (parent && parent.classList.contains('drop-zone')) {
                        parent.classList.remove('filled');
                        parent.style.backgroundColor = 'rgba(100, 100, 100, 0.5)';
                        
                        // 移除元素
                        this.remove();
                        
                        // 更新保存的答案
                        updateSavedAnswers();
                    }
                });
            }
        });
        
        sortableInstances.push(dragItemsSortable);
        
        // 如果有已保存的答案，恢復它們
        if (savedAnswers && savedAnswers.length > 0) {
            savedAnswers.forEach((value, index) => {
                if (index < dropZones.length && value) {
                    // 找到對應值的拖拽項
                    const matchingItem = Array.from(dragItemElements).find(item => item.dataset.value === value);
                    if (matchingItem) {
                        // 克隆拖拽項
                        const clone = matchingItem.cloneNode(true);
                        clone.dataset.value = value;
                        
                        // 添加點擊事件，點擊可移除
                        clone.addEventListener('click', function() {
                            const parent = this.parentElement;
                            if (parent && parent.classList.contains('drop-zone')) {
                                parent.classList.remove('filled');
                                parent.style.backgroundColor = 'rgba(100, 100, 100, 0.5)';
                                
                                // 移除元素
                                this.remove();
                                
                                // 更新保存的答案
                                updateSavedAnswers();
                            }
                        });
                        
                        // 添加到拖放區
                        dropZones[index].appendChild(clone);
                        dropZones[index].classList.add('filled');
                        dropZones[index].style.backgroundColor = 'rgba(255, 140, 0, 0.3)';
                    }
                }
            });
        }
        
        // 顯示檢查答案按鈕，隱藏下一題按鈕
        checkAnswerBtn.style.display = 'inline-block';
        nextQuestionBtn.style.display = 'none';
        
        // 清空反饋容器
        feedbackContainer.innerHTML = '';
        feedbackContainer.style.display = 'none';
    }
    
    // 更新保存的答案
    function updateSavedAnswers() {
        const answers = [];
        
        // 獲取所有拖放區的值
        dropZones.forEach(zone => {
            const items = zone.querySelectorAll('.drag-item');
            if (items.length > 0) {
                answers.push(items[0].dataset.value);
            } else {
                answers.push(null);
            }
        });
        
        // 保存答案
        if (currentStage === 1) {
            stage1Answers[currentQuestionIndex] = answers;
        } else {
            stage2Answers[currentQuestionIndex] = answers;
        }
    }
    
    // 檢查答案
    function checkAnswer() {
        // 獲取當前階段的問題數據
        const stageData = currentStage === 1 ? questions[currentQuestionIndex].stage1 : questions[currentQuestionIndex].stage2;
        
        // 獲取用戶答案
        const userAnswerValues = [];
        dropZones.forEach(zone => {
            const items = zone.querySelectorAll('.drag-item');
            if (items.length > 0) {
                userAnswerValues.push(items[0].dataset.value);
            } else {
                userAnswerValues.push(null);
            }
        });
        
        // 檢查是否有空白答案
        if (userAnswerValues.includes(null)) {
            feedbackContainer.innerHTML = '<p class="error">請填寫所有空格！</p>';
            feedbackContainer.style.display = 'block';
            return false;
        }
        
        // 檢查答案是否正確
        let isCorrect = false;
        
        if (currentStage === 1) {
            // 第一階段：檢查兩組答案是否匹配
            const group1 = [userAnswerValues[0], userAnswerValues[1]];
            const group2 = [userAnswerValues[2], userAnswerValues[3]];
            
            // 檢查每個答案組合是否匹配任何一個正確答案組合
            isCorrect = stageData.answers.some(answer => {
                return (
                    (group1.includes(answer[0]) && group1.includes(answer[1])) &&
                    (group2.includes(answer[0]) && group2.includes(answer[1]))
                );
            });
        } else {
            // 第二階段：檢查三個值是否匹配
            isCorrect = stageData.answers.some(answer => {
                // 第一個值必須是2
                if (userAnswerValues[0] !== answer[0]) return false;
                
                // 其他兩個值順序不限
                const otherValues = [userAnswerValues[1], userAnswerValues[2]];
                return (
                    otherValues.includes(answer[1]) && 
                    otherValues.includes(answer[2])
                );
            });
        }
        
        // 顯示反饋
        feedbackContainer.innerHTML = '';
        feedbackContainer.style.display = 'block';
        
        if (isCorrect) {
            // 播放正確音效
            correctSound.currentTime = 0;
            correctSound.play().catch(e => console.log('播放音效失敗:', e));
            
            // 顯示正確反饋
            const correctFeedback = document.createElement('p');
            correctFeedback.className = 'success';
            correctFeedback.textContent = '答對了！';
            feedbackContainer.appendChild(correctFeedback);
            
            // 更新UI
            checkAnswerBtn.style.display = 'none';
            
            if (currentStage === 1) {
                // 第一階段完成，進入第二階段
                nextQuestionBtn.textContent = '進入第二階段';
                nextQuestionBtn.onclick = function() {
                    loadQuestion(currentQuestionIndex, 2);
                };
            } else {
                // 第二階段完成，進入下一題或完成挑戰
                if (currentQuestionIndex < questions.length - 1) {
                    nextQuestionBtn.textContent = '下一題';
                    nextQuestionBtn.onclick = function() {
                        loadQuestion(currentQuestionIndex + 1, 1);
                    };
                } else {
                    nextQuestionBtn.textContent = '完成挑戰';
                    nextQuestionBtn.onclick = function() {
                        showResult();
                    };
                }
            }
            
            nextQuestionBtn.style.display = 'inline-block';
            
            // 更新進度
            if (currentStage === 2) {
                doorsProgress[currentQuestionIndex].classList.add('completed');
                correctAnswers++;
            }
            
            return true;
        } else {
            // 播放錯誤音效
            wrongSound.currentTime = 0;
            wrongSound.play().catch(e => console.log('播放音效失敗:', e));
            
            // 增加錯誤嘗試次數
            wrongAttempts++;
            
            // 第一階段特殊處理
            if (currentStage === 1) {
                // 創建提示容器（如果不存在）
                let hintContainer = document.querySelector('.hint-container');
                if (!hintContainer) {
                    hintContainer = document.createElement('div');
                    hintContainer.className = 'hint-container';
                    hintContainer.style.marginBottom = '15px';
                    hintContainer.style.padding = '10px';
                    hintContainer.style.backgroundColor = 'rgba(60, 60, 60, 0.7)';
                    hintContainer.style.borderRadius = '8px';
                    hintContainer.style.border = '1px solid rgba(255, 0, 0, 0.5)';
                    hintContainer.style.textAlign = 'center';
                    
                    // 插入到公式模板前面
                    formulaTemplate.parentNode.insertBefore(hintContainer, formulaTemplate);
                }
                
                // 清空提示容器
                hintContainer.innerHTML = '';
                
                // 添加提示圖片
                const hintImage = document.createElement('img');
                hintImage.src = `towerhint${currentQuestionIndex + 1}1.jpg`;
                hintImage.style.maxWidth = '50%';
                hintImage.style.display = 'block';
                hintImage.style.margin = '0 auto 10px';
                hintContainer.appendChild(hintImage);
                
                // 添加提示文字
                const hintText = document.createElement('p');
                hintText.style.color = 'white';
                hintText.style.margin = '5px 0';
                
                if (wrongAttempts === 1) {
                    // 第一次錯誤
                    hintText.textContent = '請仔細觀察上方提示圖，按照分配律的方式展開填入正確答案。';
                } else {
                    // 第二次或更多次錯誤
                    hintText.textContent = `正確答案應為：\n「${stageData.correctAnswer}」\n請依照此答案填入，才能進入第二階段。`;
                }
                
                hintContainer.appendChild(hintText);
                
                // 顯示錯誤反饋
                const errorFeedback = document.createElement('p');
                errorFeedback.className = 'error';
                errorFeedback.textContent = '答錯了，請參考上方提示修正答案！';
                feedbackContainer.appendChild(errorFeedback);
            } else {
                // 第二階段錯誤
                const errorFeedback = document.createElement('p');
                errorFeedback.className = 'error';
                errorFeedback.textContent = '答錯了，請再試一次！';
                feedbackContainer.appendChild(errorFeedback);
            }
            
            return false;
        }
    }
    
    // 顯示結果
    function showResult() {
        quizContainer.style.display = 'none';
        resultContainer.style.display = 'block';
        
        // 計算得分（滿分3星）
        const score = Math.min(3, Math.max(1, Math.ceil(correctAnswers / questions.length * 3)));
        
        // 更新星星顯示
        for (let i = 0; i < starResults.length; i++) {
            starResults[i].style.opacity = i < score ? '1' : '0.3';
        }
        
        // 更新結果文字
        if (score === 3) {
            resultTitle.textContent = '恭喜完成挑戰！';
            resultMessage.textContent = '你已完美掌握平方展開的技巧！';
            successButtons.style.display = 'block';
            failButtons.style.display = 'none';
        } else if (score === 2) {
            resultTitle.textContent = '挑戰成功！';
            resultMessage.textContent = '你已基本掌握平方展開的技巧，繼續加油！';
            successButtons.style.display = 'block';
            failButtons.style.display = 'none';
        } else {
            resultTitle.textContent = '再接再厲！';
            resultMessage.textContent = '平方展開需要更多練習，不要氣餒！';
            successButtons.style.display = 'none';
            failButtons.style.display = 'block';
        }
        
        // 更新遊戲進度
        gameProgress.completedTrials["展開之塔"].completed = score >= 2;
        gameProgress.completedTrials["展開之塔"].score = score;
        
        // 標記所有問題為已完成
        for (let i = 0; i < questions.length; i++) {
            gameProgress.completedTrials["展開之塔"].challengesCompleted[i] = true;
        }
        
        // 保存遊戲進度
        gameProgress.lastSaved = new Date().toISOString();
        localStorage.setItem(`gameProgress_${currentPlayerId}`, JSON.stringify(gameProgress));
        
        // 檢查成就
        if (window.achievementSystem) {
            const gameState = {
                currentTrial: "展開之塔",
                totalStars: score,
                currentTrialCompleted: true,
                currentTrialErrors: questions.length - correctAnswers,
                currentTrialCombo: correctAnswers,
                completedTrials: {
                    "展開之塔": {
                        completed: true,
                        stars: score,
                        noErrors: (questions.length - correctAnswers) === 0
                    }
                }
            };
            
            window.achievementSystem.checkAllAchievements(gameState);
        }
    }
    
    // 檢查答案按鈕點擊事件
    checkAnswerBtn.addEventListener('click', function() {
        checkAnswer();
    });
    
    // 重試按鈕點擊事件
    retryBtn.addEventListener('click', function() {
        resultContainer.style.display = 'none';
        quizContainer.style.display = 'block';
        correctAnswers = 0;
        
        // 重置進度指示器
        Array.from(doorsProgress).forEach(door => {
            door.classList.remove('completed');
        });
        
        // 重置答案
        stage1Answers = Array(questions.length).fill(null).map(() => []);
        stage2Answers = Array(questions.length).fill(null).map(() => []);
        
        // 載入第一題
        loadQuestion(0, 1);
    });
    
    // 返回地圖按鈕點擊事件
    backToMapBtn.addEventListener('click', function() {
        window.location.href = 'kingdom_map.html';
    });
    
    // 下一試煉按鈕點擊事件
    nextTrialBtn.addEventListener('click', function() {
        window.location.href = 'kingdom_map.html';
    });
    
    // 階段按鈕點擊事件（僅用於顯示，不可切換）
    stage1Btn.addEventListener('click', function() {
        if (currentStage !== 1) {
            // 檢查是否已完成第一階段
            if (stage1Answers[currentQuestionIndex].length > 0) {
                loadQuestion(currentQuestionIndex, 1);
            }
        }
    });
    
    stage2Btn.addEventListener('click', function() {
        if (currentStage !== 2) {
            // 檢查是否已完成第一階段
            if (stage1Answers[currentQuestionIndex].length > 0) {
                loadQuestion(currentQuestionIndex, 2);
            } else {
                alert('請先完成第一階段！');
            }
        }
    });
});