src/views/StudentView.js

import { submitPrompt, getChallenges, startChallenge, getUserProgress, getPeerPrompts, resetProgress, toggleLike, subscribeToNotifications, markNotificationRead } from "../services/classroom.js";

// Cache challenges locally
let cachedChallenges = [];

export async function renderStudentView() {
    const nickname = localStorage.getItem('vibecoding_nickname') || 'Guest';
    const roomCode = localStorage.getItem('vibecoding_room_code') || 'Unknown';
    const userId = localStorage.getItem('vibecoding_user_id');

    // Fetch challenges if empty
    if (cachedChallenges.length === 0) {
        try {
            cachedChallenges = await getChallenges();
        } catch (e) {
            console.error("Failed to fetch challenges", e);
            throw new Error("無法讀取題目列表 (Error: " + e.message + ")");
        }
    }

    // Fetch User Progress
    let userProgress = {};
    if (userId) {
        try {
            userProgress = await getUserProgress(userId);
        } catch (e) {
            console.error("Failed to fetch progress", e);
        }
    }

    const levelGroups = {
        beginner: cachedChallenges.filter(c => c.level === 'beginner'),
        intermediate: cachedChallenges.filter(c => c.level === 'intermediate'),
        advanced: cachedChallenges.filter(c => c.level === 'advanced')
    };

    const levelNames = {
        beginner: "初級 (Beginner)",
        intermediate: "中級 (Intermediate)",
        advanced: "高級 (Advanced)"
    };

    function renderTaskCard(c) {
        const p = userProgress[c.id] || {};
        const isCompleted = p.status === 'completed';
        const isStarted = p.status === 'started';

        // 1. Completed State: Collapsed with Trophy
        if (isCompleted) {
            return `
            <div class="bg-gray-800/50 border border-green-500/30 rounded-xl p-4 flex items-center justify-between group hover:bg-gray-800 transition-all">
                <div class="flex items-center space-x-3">
                    <div class="text-2xl">🏆</div>
                    <h3 class="font-bold text-gray-300 group-hover:text-white transition-colors">${c.title}</h3>
                </div>
                <div class="flex items-center space-x-3">
                    <button onclick="window.resetLevel('${c.id}')" class="text-xs bg-red-900/50 hover:bg-red-700 text-red-300 border border-red-800 px-2 py-1 rounded transition-colors" title="重置進度 (Reset)">
                        ↺ 重置
                    </button>
                    <span class="text-xs text-green-400 font-mono bg-green-900/30 px-2 py-1 rounded">已通關</span>
                    <button onclick="document.getElementById('detail-${c.id}').classList.toggle('hidden')" class="text-gray-500 hover:text-white">
                        <svg class="w-5 h-5" fill="none" viewBox="0 0 24 24" stroke="currentColor"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 9l-7 7-7-7" /></svg>
                    </button>
                </div>
            </div>
            <!-- Hidden detail for reference -->
            <div id="detail-${c.id}" class="hidden mt-2 p-4 bg-gray-900/50 rounded-xl border border-gray-700 text-sm text-gray-400">
                <p class="mb-2">您的提示詞:</p>
                <div class="font-mono bg-black p-2 rounded text-gray-300 border border-gray-800">${p.submission_prompt}</div>
            </div>
            `;
        }

        // 2. Started or Not Started
        // If Started: Show "Prompt Input" area.
        // If Not Started: Show "Start Task" button only.

        return `
        <div class="group relative bg-gray-800 bg-opacity-50 border ${isStarted ? 'border-cyan-500/50 shadow-[0_0_15px_rgba(6,182,212,0.1)]' : 'border-gray-700'} rounded-2xl overflow-hidden hover:border-cyan-500/50 transition-all duration-300 flex flex-col">
             <div class="absolute top-0 left-0 w-1 h-full ${isStarted ? 'bg-cyan-500' : 'bg-gray-600'} group-hover:bg-cyan-400 transition-colors"></div>
             
             <div class="p-6 pl-8 flex-1 flex flex-col">
                <div class="flex flex-col sm:flex-row justify-between items-start mb-4 gap-4">
                    <div>
                        <h2 class="text-xl font-bold text-white mb-1">${c.title}</h2>
                        <p class="text-gray-400 text-sm whitespace-pre-line">${c.description}</p>
                    </div>
                </div>

                ${!isStarted ? `
                    <!-- Not Started State -->
                    <div class="mt-4">
                        <button onclick="window.startLevel('${c.id}', '${c.link}')" 
                                class="w-full sm:w-auto bg-gray-700 hover:bg-cyan-600 hover:text-white text-gray-200 font-bold py-3 px-6 rounded-xl transition-all flex items-center justify-center space-x-2 shadow-lg">
                            <span>🚀 開始任務 (Start Task)</span>
                        </button>
                    </div>
                ` : `
                    <!-- Started State: Input Area -->
                    <div class="mt-4 pt-4 border-t border-gray-700/50">
                        <div class="flex justify-between items-center mb-2">
                            <label class="block text-xs uppercase tracking-wider text-cyan-400 animate-pulse">任務進行中</label>
                            <a href="${c.link}" target="_blank" class="text-xs text-gray-500 hover:text-white flex items-center space-x-1">
                                <span>再次開啟 GeminCanvas</span>
                                <svg class="w-3 h-3" fill="none" viewBox="0 0 24 24" stroke="currentColor"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M10 6H6a2 2 0 00-2 2v10a2 2 0 002 2h10a2 2 0 002-2v-4M14 4h6m0 0v6m0-6L10 14" /></svg>
                            </a>
                        </div>
                        
                        <div class="flex flex-col space-y-2">
                             <textarea id="input-${c.id}" rows="2"
                                class="w-full bg-gray-900 border border-gray-700 rounded-lg px-4 py-2 text-white focus:border-cyan-500 focus:outline-none transition-colors text-sm"
                                placeholder="貼上您的修復提示詞..."></textarea>
                            
                            <div id="error-${c.id}" class="text-red-500 text-xs hidden">提示詞太短囉，請多寫一點細節！</div>

                            <button onclick="window.submitLevel('${c.id}')"
                                class="w-full bg-gradient-to-r from-cyan-600 to-blue-600 hover:from-cyan-500 hover:to-blue-500 text-white px-6 py-2 rounded-lg font-bold transition-transform active:scale-95 shadow-lg shadow-cyan-900/50">
                                提交解答
                            </button>
                        </div>
                    </div>
                `}
             </div>
        </div>
        `;
    }

    // Accordion Layout
    return `
    <div class="min-h-screen p-4 pb-32 max-w-md mx-auto sm:max-w-4xl">
        <header class="flex justify-between items-center mb-6 sticky top-0 bg-slate-900/95 backdrop-blur z-20 py-4 px-2 -mx-2 border-b border-gray-800">
            <div class="flex flex-col">
                <div class="flex items-center space-x-2">
                    <div class="w-2 h-2 rounded-full bg-green-500 animate-pulse"></div>
                    <span class="text-gray-400 text-sm truncate max-w-[150px]">${nickname}</span>
                </div>
                <div class="text-xs text-gray-500 mt-1">教室: <span class="font-mono text-cyan-400 font-bold">${roomCode}</span></div>
            </div>
            <div>
                <h1 class="text-xl font-bold italic text-white tracking-widest">VIBECODING</h1>
            </div>
        </header>

        <div class="space-y-4">
            ${['beginner', 'intermediate', 'advanced'].map(level => {
        const tasks = levelGroups[level] || [];
        const isOpen = level === 'beginner' ? 'open' : '';
        // Count completed
        const completedCount = tasks.filter(t => userProgress[t.id]?.status === 'completed').length;

        return `
                <details class="group border border-gray-700 rounded-xl bg-gray-800/30 overflow-hidden transition-all" ${isOpen}>
                    <summary class="flex items-center justify-between p-4 cursor-pointer bg-gray-800/80 hover:bg-gray-700 transition-colors select-none">
                        <div class="flex items-center space-x-3">
                            <h3 class="text-lg font-bold text-transparent bg-clip-text bg-gradient-to-r from-purple-400 to-cyan-400">
                               ${levelNames[level]}
                            </h3>
                            ${completedCount === tasks.length && tasks.length > 0 ? '<span class="text-yellow-500 text-xs border border-yellow-500/50 px-2 py-0.5 rounded-full">ALL CLEAR</span>' : ''}
                        </div>
                        <div class="flex items-center space-x-2">
                            <span class="text-xs text-gray-400 bg-gray-900 px-2 py-1 rounded-full">${completedCount} / ${tasks.length}</span>
                            <svg class="w-5 h-5 text-gray-400 transform group-open:rotate-180 transition-transform" fill="none" viewBox="0 0 24 24" stroke="currentColor">
                                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M19 9l-7 7-7-7" />
                            </svg>
                        </div>
                    </summary>
                    <div class="p-4 pt-0 grid grid-cols-1 gap-4 mt-4">
                        ${tasks.length > 0 ? tasks.map(c => renderTaskCard(c)).join('') : '<div class="text-gray-500 text-sm italic">本區段尚無題目</div>'}
                    </div>
                </details>
                `;
    }).join('')}
        </div>
        
        <!-- Peer Learning FAB -->
        <button onclick="window.openPeerModal()" class="fixed bottom-6 right-6 bg-purple-600 hover:bg-purple-500 text-white rounded-full p-4 shadow-xl shadow-purple-600/40 transition-transform hover:scale-110 active:scale-90 z-40"
            title="查看同學作業">
            <svg xmlns="http://www.w3.org/2000/svg" class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M17 20h5v-2a3 3 0 00-5.356-1.857M17 20H7m10 0v-2c0-.656-.126-1.283-.356-1.857M7 20H2v-2a3 3 0 015.356-1.857M7 20v-2c0-.656.126-1.283.356-1.857m0 0a5.002 5.002 0 019.288 0M15 7a3 3 0 11-6 0 3 3 0 016 0zm6 3a2 2 0 11-4 0 2 2 0 014 0z" />
            </svg>
        </button>
    </div>
    `;
}

export function setupStudentEvents() {
    // Start Level Logic
    window.startLevel = async (challengeId, link) => {
        // Open link
        window.open(link, '_blank');

        // Call service to update status
        const roomCode = localStorage.getItem('vibecoding_room_code');
        const userId = localStorage.getItem('vibecoding_user_id');

        if (roomCode && userId) {
            try {
                await startChallenge(userId, roomCode, challengeId);
                // Reload view to show Input State
                // Ideally we should use state management, but checking URL hash or re-rendering works
                const app = document.querySelector('#app');
                app.innerHTML = await renderStudentView();
                // Re-attach events (recursion safety check needed? No, navigateTo does this usually, but here we manually re-render)
                // Or better: trigger a custom event or call navigateTo functionality? 
                // Simple re-render is fine for now.
            } catch (e) {
                console.error("Start challenge failed", e);
            }
        }
    };

    window.submitLevel = async (challengeId) => {
        const input = document.getElementById(`input-${challengeId}`);
        const errorMsg = document.getElementById(`error-${challengeId}`);
        const prompt = input.value;
        const roomCode = localStorage.getItem('vibecoding_room_code');
        const userId = localStorage.getItem('vibecoding_user_id');

        if (!participantDataCheck(roomCode, userId)) return;

        if (prompt.trim().length < 5) {
            errorMsg.classList.remove('hidden');
            input.classList.add('border-red-500');
            return;
        }

        errorMsg.classList.add('hidden');
        input.classList.remove('border-red-500');

        // Show loading state on button
        const container = input.parentElement;
        const btn = container.querySelector('button');
        const originalText = btn.textContent;
        btn.textContent = "提交中...";
        btn.disabled = true;

        try {
            await submitPrompt(userId, roomCode, challengeId, prompt);

            btn.textContent = "✓ 已通關";
            btn.classList.add("bg-green-600");

            // Re-render to show Trophy state after short delay
            setTimeout(async () => {
                const app = document.querySelector('#app');
                app.innerHTML = await renderStudentView();
            }, 1000);

        } catch (error) {
            console.error(error);
            btn.textContent = originalText;
            btn.disabled = false;
            alert("提交失敗: " + error.message);
        }
    };

    window.resetLevel = async (challengeId) => {
        if (!confirm("確定要重置這一題的進度嗎？(提示詞將會保留，但狀態會變回進行中)")) return;

        const roomCode = localStorage.getItem('vibecoding_room_code');
        const userId = localStorage.getItem('vibecoding_user_id');

        try {
            // Import and call resetProgress (Need to make sure it is imported or available globally? 
            // Ideally import it. But setupStudentEvents is in module scope so imports are available.
            // Wait, import 'resetProgress' is not in the top import list yet. I need to add it.)
            // Let's assume I will update the import in the next step or use the global trick if needed.
            // But I should edit the import first.
            // For now, let's assume it is there. I will add it to the import list in a parallel or subsequent edit.

            // Checking imports above... I see 'getUserProgress' but not 'resetProgress'. I must update imports.
            // I'll do it in a separate edit step to be safe.

            // For now, just the logic:
            const { resetProgress } = await import("../services/classroom.js"); // Dynamic import to avoid changing top file lines again? 
            // Or just rely on previous 'replace' having updated the file?
            // Actually, I should update the top import. 

            await resetProgress(userId, roomCode, challengeId);

            const app = document.querySelector('#app');
            app.innerHTML = await renderStudentView();

        } catch (e) {
            console.error(e);
            alert("重置失敗");
        }
    };
}

function participantDataCheck(roomCode, userId) {
    if (!roomCode || !userId) {
        alert("連線資訊遺失，請重新登入");
        window.location.reload();
        return false;
    }
    return true;
}

// Peer Learning Modal Logic
function renderPeerModal() {
    // We need to re-fetch challenges for the dropdown? 
    // They are cached in 'cachedChallenges' module variable
    let optionsHtml = '<option value="" disabled selected>選擇題目...</option>';
    if (cachedChallenges.length > 0) {
        optionsHtml += cachedChallenges.map(c =>
            `<option value="${c.id}">[${c.level}] ${c.title}</option>`
        ).join('');
    }

    return `
    <div id="peer-modal" class="fixed inset-0 bg-black bg-opacity-80 backdrop-blur-sm hidden flex items-center justify-center z-50 p-4">
        <div class="bg-gray-800 rounded-2xl w-full max-w-md h-[80vh] flex flex-col border border-gray-700 shadow-2xl">
            <div class="p-6 border-b border-gray-700 flex justify-between items-center">
                <h3 class="text-xl font-bold text-white">同學的成功提示詞</h3>
                <button onclick="closePeerModal()" class="text-gray-400 hover:text-white">✕</button>
            </div>
            
            <div class="p-4 bg-gray-900 border-b border-gray-700">
                 <select id="peer-challenge-select" onchange="loadPeerPrompts(this.value)" class="w-full bg-gray-800 border border-gray-600 rounded p-2 text-white">
                    ${optionsHtml}
                 </select>
            </div>

            <div class="p-4 flex-1 overflow-y-auto space-y-4" id="peer-prompts-container">
                <div class="text-center text-gray-500 mt-10">請選擇一個題目來查看</div>
            </div>
        </div>
    </div>
    `;
}

window.openPeerModal = () => {
    const existing = document.getElementById('peer-modal');
    if (existing) existing.remove();

    const div = document.createElement('div');
    div.innerHTML = renderPeerModal();
    document.body.appendChild(div.firstElementChild);

    document.getElementById('peer-modal').classList.remove('hidden');
};

window.closePeerModal = () => {
    document.getElementById('peer-modal').classList.add('hidden');
};

window.loadPeerPrompts = async (challengeId) => {
    const container = document.getElementById('peer-prompts-container');
    container.innerHTML = '<div class="text-center text-gray-400 py-10">載入中...</div>';

    const roomCode = localStorage.getItem('vibecoding_room_code');
    const prompts = await getPeerPrompts(roomCode, challengeId);

    if (prompts.length === 0) {
        container.innerHTML = '<div class="text-center text-gray-500 py-10">尚無同學提交此關卡或您無權限查看(需相同教室代碼)</div>';
        return;
    }

    container.innerHTML = prompts.map(p => {
        const currentUserId = localStorage.getItem('vibecoding_user_id');
        const isLiked = p.likedBy && p.likedBy.includes(currentUserId);

        return `
        <div class="bg-gray-700/30 p-4 rounded-xl border border-gray-600">
            <div class="flex items-center justify-between mb-2">
                <div class="flex items-center space-x-2">
                    <div class="w-6 h-6 rounded-full bg-cyan-600 flex items-center justify-center text-xs font-bold text-white">
                        ${p.nickname[0]}
                    </div>
                    <span class="font-bold text-cyan-300 text-sm">${p.nickname}</span>
                    <span class="text-gray-500 text-xs">${new Date(p.timestamp.seconds * 1000).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}</span>
                </div>
                
                <button onclick="handleLike('${p.id}', '${p.userId}')" 
                    class="flex items-center space-x-1 px-2 py-1 rounded-full transition-colors ${isLiked ? 'bg-pink-900/50 text-pink-400' : 'bg-gray-800 text-gray-400 hover:bg-gray-700'}">
                    <svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4 ${isLiked ? 'fill-current' : 'none'}" viewBox="0 0 24 24" stroke="currentColor" fill="${isLiked ? 'currentColor' : 'none'}">
                        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4.318 6.318a4.5 4.5 0 000 6.364L12 20.364l7.682-7.682a4.5 4.5 0 00-6.364-6.364L12 7.636l-1.318-1.318a4.5 4.5 0 00-6.364 0z" />
                    </svg>
                    <span class="text-xs font-bold">${p.likes}</span>
                </button>
            </div>
            <p class="text-gray-300 font-mono text-sm bg-black/20 p-3 rounded-lg border border-gray-700/50 whitespace-pre-wrap">${p.prompt}</p>
        </div>
    `}).join('');

    // Attach challenge title for notification context
    window.currentPeerChallengeTitle = document.querySelector(`#peer-challenge-select option[value="${challengeId}"]`).text;
};

// Like Handler
window.handleLike = async (progressId, targetUserId) => {
    const userId = localStorage.getItem('vibecoding_user_id');
    const nickname = localStorage.getItem('vibecoding_nickname');
    const challengeTitle = window.currentPeerChallengeTitle || '挑戰';

    // Optimistic UI update could go here, but for simplicity let's re-load or just fire and forget (the view won't update until reload currently)
    // To make it responsive, we should probably manually toggle the class on the button immediately.
    // For now, let's just call service and reload the list to see updated count.

    // Better UX: Find button and toggle 'processing' state? 
    // Let's just reload the list for data consistency.
    const { toggleLike } = await import("../services/classroom.js");
    await toggleLike(progressId, userId, nickname, targetUserId, challengeTitle);

    // Reload to refresh count
    const select = document.getElementById('peer-challenge-select');
    if (select && select.value) {
        loadPeerPrompts(select.value);
    }
};