// 获取文档结构
async function loadDocumentStructure() {
    const loading = document.getElementById('loading');
    const error = document.getElementById('error');
    const container = document.getElementById('categories-container');

    try {
        const response = await fetch('/api/structure');

        if (!response.ok) {
            const errorData = await response.json().catch(() => ({}));
            throw new Error(errorData.error || `加载失败 (${response.status})`);
        }

        const structure = await response.json();

        // 验证数据结构
        if (!Array.isArray(structure) || structure.length === 0) {
            throw new Error('文档结构为空或格式错误');
        }

        // 隐藏加载提示
        loading.style.display = 'none';

        // 渲染分类卡片
        renderCategories(structure);

    } catch (err) {
        console.error('Error loading structure:', err);
        loading.style.display = 'none';
        error.style.display = 'block';
        error.textContent = `加载失败：${err.message || '请稍后重试'}`;
    }
}

// 渲染分类卡片
function renderCategories(structure) {
    const container = document.getElementById('categories-container');

    structure.forEach(category => {
        const card = document.createElement('div');
        card.className = 'category-card';

        const title = document.createElement('h2');
        title.className = 'category-title';
        title.textContent = category.name;

        const docCount = document.createElement('p');
        docCount.className = 'doc-count';
        docCount.textContent = `${category.docs.length} 篇文档`;

        const button = document.createElement('button');
        button.className = 'read-btn';
        button.textContent = '开始阅读';
        button.onclick = () => {
            // 跳转到阅读页，并传递分类名
            window.location.href = `/reader.html?category=${encodeURIComponent(category.name)}`;
        };

        card.appendChild(title);
        card.appendChild(docCount);
        card.appendChild(button);

        container.appendChild(card);
    });
}

// 登出功能
function setupLogout() {
    const logoutBtn = document.getElementById('logout-btn');

    if (logoutBtn) {
        logoutBtn.addEventListener('click', async () => {
            if (!confirm('确定要登出吗？')) {
                return;
            }

            try {
                const response = await fetch('/api/logout', {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json'
                    }
                });

                if (response.ok) {
                    // 登出成功，跳转到登录页
                    window.location.href = '/login.html';
                } else {
                    alert('登出失败，请稍后重试');
                }
            } catch (error) {
                console.error('Logout error:', error);
                alert('登出失败，请稍后重试');
            }
        });
    }
}

// 页面加载时执行
document.addEventListener('DOMContentLoaded', () => {
    loadDocumentStructure();
    setupLogout();
});