src/views/AdminView.js

import { getChallenges, createChallenge, updateChallenge, deleteChallenge } from "../services/classroom.js";

export function renderAdminView() {
    return `

    <div class="min-h-screen p-6 pb-20">

        <header class="flex justify-between items-center mb-10 bg-gray-800 bg-opacity-50 p-4 rounded-xl border border-gray-700 backdrop-blur-sm">

            <div class="flex items-center space-x-4">

                <button id="back-instructor-btn" class="bg-gray-700 hover:bg-gray-600 text-white p-2 rounded-lg transition-all">

                    ← 回講師端

                </button>

                <h1 class="text-2xl font-bold text-transparent bg-clip-text bg-gradient-to-r from-red-400 to-orange-600">

                    後台管理系統 Admin Panel

                </h1>

            </div>

            <button id="add-challenge-btn" class="bg-green-600 hover:bg-green-500 text-white font-bold py-2 px-6 rounded-lg transition-all shadow-lg">

                + 新增題目

            </button>

        </header>



        <div id="challenges-list" class="space-y-4">

            <!-- Questions loaded here -->

            <div class="text-center text-gray-500 py-10">載入中...</div>

        </div>



        <!-- Edit/Add Modal -->

        <div id="challenge-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-xl w-full max-w-2xl border border-gray-700 shadow-2xl overflow-y-auto max-h-[90vh]">

                <div class="p-6 border-b border-gray-700">

                    <h3 id="modal-title" class="text-xl font-bold text-white">編輯題目</h3>

                </div>

                <div class="p-6 space-y-4">

                    <input type="hidden" id="edit-id">

                    <div>

                        <label class="block text-gray-400 mb-1">標題 (Title)</label>

                        <input type="text" id="edit-title" class="w-full bg-gray-900 border border-gray-600 rounded p-2 text-white">

                    </div>

                    <div>

                        <label class="block text-gray-400 mb-1">難度 (Level)</label>

                        <select id="edit-level" class="w-full bg-gray-900 border border-gray-600 rounded p-2 text-white">

                            <option value="beginner">初級 (Beginner)</option>

                            <option value="intermediate">中級 (Intermediate)</option>

                            <option value="advanced">高級 (Advanced)</option>

                        </select>

                    </div>

                    <div>

                        <label class="block text-gray-400 mb-1">描述 (Description)</label>

                        <textarea id="edit-desc" rows="3" class="w-full bg-gray-900 border border-gray-600 rounded p-2 text-white"></textarea>

                    </div>

                    <div>

                        <label class="block text-gray-400 mb-1">連結 (GeminiCanvas Link/Code)</label>

                        <input type="text" id="edit-link" class="w-full bg-gray-900 border border-gray-600 rounded p-2 text-white">

                    </div>

                    <div>

                        <label class="block text-gray-400 mb-1">排序 (Order)</label>

                        <input type="number" id="edit-order" class="w-full bg-gray-900 border border-gray-600 rounded p-2 text-white" value="1">

                    </div>

                </div>

                <div class="p-6 border-t border-gray-700 flex justify-end space-x-3">

                    <button onclick="closeChallengeModal()" class="px-4 py-2 text-gray-400 hover:text-white">取消</button>

                    <button id="save-challenge-btn" class="bg-blue-600 hover:bg-blue-500 text-white px-6 py-2 rounded">儲存</button>

                </div>

            </div>

        </div>

    </div>

    `;
}

export function setupAdminEvents() {
    loadChallenges();

    document.getElementById('back-instructor-btn').addEventListener('click', () => {
        window.location.hash = 'instructor';
    });

    document.getElementById('add-challenge-btn').addEventListener('click', () => {
        openModal();
    });

    document.getElementById('save-challenge-btn').addEventListener('click', async () => {
        const id = document.getElementById('edit-id').value;
        const data = {
            title: document.getElementById('edit-title').value,
            level: document.getElementById('edit-level').value,
            description: document.getElementById('edit-desc').value,
            link: document.getElementById('edit-link').value,
            order: parseInt(document.getElementById('edit-order').value) || 0
        };

        if (id) {
            await updateChallenge(id, data);
        } else {
            await createChallenge(data);
        }

        closeChallengeModal();
        loadChallenges();
    });
}

async function loadChallenges() {
    const list = document.getElementById('challenges-list');
    const challenges = await getChallenges();

    list.innerHTML = challenges.map(c => `

        <div class="bg-gray-800 p-4 rounded-lg border border-gray-700 flex justify-between items-center group hover:border-gray-500 transition-colors">

            <div>

                <span class="inline-block px-2 py-1 text-xs rounded bg-gray-700 text-gray-300 mr-2">${c.level}</span>

                <span class="font-bold text-white text-lg">${c.title}</span>

                <p class="text-gray-400 text-sm mt-1 truncate max-w-md">${c.description}</p>

            </div>

            <div class="flex space-x-2 opacity-100 md:opacity-0 group-hover:opacity-100 transition-opacity">

                <button onclick="window.editChallenge('${c.id}')" class="bg-cyan-600/20 text-cyan-400 px-3 py-1 rounded hover:bg-cyan-600 hover:text-white transition-colors">編輯</button>

                <button onclick="window.deleteChallenge('${c.id}')" class="bg-red-600/20 text-red-400 px-3 py-1 rounded hover:bg-red-600 hover:text-white transition-colors">刪除</button>

            </div>

        </div>

    `).join('');

    // Expose helpers globally for onclick
    window.editChallenge = (id) => {
        const c = challenges.find(x => x.id === id);
        if (c) openModal(c);
    };
    window.deleteChallenge = async (id) => {
        if (confirm('確定刪除?')) {
            await deleteChallenge(id);
            loadChallenges();
        }
    };
}

function openModal(challenge = null) {
    const modal = document.getElementById('challenge-modal');
    const title = document.getElementById('modal-title');

    // Reset or Fill
    document.getElementById('edit-id').value = challenge ? challenge.id : '';
    document.getElementById('edit-title').value = challenge ? challenge.title : '';
    document.getElementById('edit-level').value = challenge ? challenge.level : 'beginner';
    document.getElementById('edit-desc').value = challenge ? challenge.description : '';
    document.getElementById('edit-link').value = challenge ? challenge.link : '';
    document.getElementById('edit-order').value = challenge ? challenge.order : '1';

    title.textContent = challenge ? '編輯題目' : '新增題目';
    modal.classList.remove('hidden');
}

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