// API 基础路径
const API_BASE = '/api';

// 工具函数
async function fetchAPI(endpoint, options = {}) {
    const response = await fetch(`${API_BASE}${endpoint}`, {
        headers: {
            'Content-Type': 'application/json',
            ...options.headers
        },
        ...options
    });
    
    const data = await response.json();
    
    if (!response.ok || !data.success) {
        throw new Error(data.error || '请求失败');
    }
    
    return data;
}

// 解析Markdown
function parseMarkdown(text) {
    if (!text) return '';
    return marked.parse(text);
}

// 格式化时间
function formatTime(dateStr) {
    const date = new Date(dateStr);
    const now = new Date();
    const diff = now - date;
    
    const minutes = Math.floor(diff / 60000);
    const hours = Math.floor(diff / 3600000);
    const days = Math.floor(diff / 86400000);
    
    if (minutes < 1) return '刚刚';
    if (minutes < 60) return `${minutes}分钟前`;
    if (hours < 24) return `${hours}小时前`;
    if (days < 7) return `${days}天前`;
    
    return date.toLocaleDateString('zh-CN', {
        year: 'numeric',
        month: '2-digit',
        day: '2-digit'
    });
}

// 截断文本
function truncate(text, length = 100) {
    if (!text) return '';
    return text.length > length ? text.substring(0, length) + '...' : text;
}

// API 函数

// 获取统计信息
async function loadStats() {
    try {
        const result = await fetchAPI('/stats');
        const stats = result.data;
        
        document.getElementById('stat-threads').textContent = stats.threads;
        document.getElementById('stat-posts').textContent = stats.posts;
        document.getElementById('stat-active').textContent = stats.active_threads;
        document.getElementById('stat-recent').textContent = stats.recent_posts;
    } catch (err) {
        console.error('加载统计失败:', err);
    }
}

// 获取分类列表
async function loadCategories() {
    try {
        const result = await fetchAPI('/categories');
        const categories = result.data;
        
        const grid = document.getElementById('categories-grid');
        if (!grid) return;
        
        if (categories.length === 0) {
            grid.innerHTML = '<div class="empty-state"><div class="empty-state-icon">📭</div><div class="empty-state-text">暂无分类</div></div>';
            return;
        }
        
        grid.innerHTML = categories.map(cat => `
            <a href="/category.html?id=${cat.id}" class="category-card">
                <div class="category-card-header">
                    <span class="category-icon">${cat.icon || '💬'}</span>
                    <div class="category-card-title">${escapeHtml(cat.name)}</div>
                </div>
                <div class="category-card-desc">${escapeHtml(cat.description || '')}</div>
                <div class="category-card-stats">
                    <span>📝 ${cat.thread_count || 0} 主题</span>
                    <span>💬 ${cat.post_count || 0} 回复</span>
                </div>
            </a>
        `).join('');
    } catch (err) {
        console.error('加载分类失败:', err);
    }
}

// 获取主题列表
async function loadThreads(sort = 'latest') {
    try {
        const result = await fetchAPI(`/threads?sort=${sort}&limit=20`);
        const threads = result.data;
        
        const list = document.getElementById('threads-list');
        if (!list) return;
        
        if (threads.length === 0) {
            list.innerHTML = '<div class="empty-state"><div class="empty-state-icon">📭</div><div class="empty-state-text">暂无讨论</div></div>';
            return;
        }
        
        list.innerHTML = threads.map(thread => `
            <div class="thread-card" onclick="window.location.href='/thread.html?id=${thread.id}'">
                <div class="thread-card-header">
                    <a href="/thread.html?id=${thread.id}" class="thread-title-link" onclick="event.stopPropagation()">
                        ${escapeHtml(thread.title)}
                    </a>
                    ${thread.is_pinned ? '<span class="thread-badge">置顶</span>' : ''}
                    ${thread.is_locked ? '<span class="thread-badge" style="background:var(--error-color)">已锁定</span>' : ''}
                </div>
                <div class="thread-meta">
                    <span class="category-badge" style="font-size:0.75rem;padding:2px 8px;background:var(--surface-hover)">
                        ${thread.category_icon || '💬'} ${escapeHtml(thread.category_name || '')}
                    </span>
                    <span>${escapeHtml(thread.author_name)}</span>
                    <span>👁 ${thread.view_count || 0}</span>
                    <span>💬 ${thread.reply_count || 0}</span>
                    <span>${formatTime(thread.created_at)}</span>
                </div>
                ${thread.content ? `<div class="thread-content-preview">${escapeHtml(truncate(thread.content, 150))}</div>` : ''}
            </div>
        `).join('');
    } catch (err) {
        console.error('加载主题失败:', err);
    }
}

// 获取最新回复
async function loadRecentPosts() {
    try {
        const result = await fetchAPI('/recent?limit=5');
        const posts = result.data;
        
        const list = document.getElementById('recent-list');
        if (!list) return;
        
        if (posts.length === 0) {
            list.innerHTML = '<div class="empty-state"><div class="empty-state-icon">💬</div><div class="empty-state-text">暂无回复</div></div>';
            return;
        }
        
        list.innerHTML = posts.map(post => `
            <div class="recent-item">
                <div class="recent-thread-title">${escapeHtml(post.thread_title || '(已删除)')}</div>
                <div class="recent-content">${escapeHtml(truncate(post.content, 100))}</div>
                <div class="recent-meta">
                    <span>${escapeHtml(post.author_name)}</span>
                    <span>${post.category_icon || '💬'} ${escapeHtml(post.category_name || '')}</span>
                    <span>${formatTime(post.created_at)}</span>
                </div>
            </div>
        `).join('');
    } catch (err) {
        console.error('加载最新回复失败:', err);
    }
}

// 为表单加载分类
async function loadCategoriesForForm() {
    try {
        const result = await fetchAPI('/categories');
        const categories = result.data;
        
        const select = document.getElementById('thread-category');
        if (!select) return;
        
        select.innerHTML = '<option value="">选择分类...</option>' +
            categories.map(cat => `<option value="${cat.id}">${cat.icon || '💬'} ${escapeHtml(cat.name)}</option>`).join('');
    } catch (err) {
        console.error('加载分类失败:', err);
    }
}

// 创建主题
async function createThread(data) {
    return await fetchAPI('/threads', {
        method: 'POST',
        body: JSON.stringify(data)
    });
}

// 加载主题详情
async function loadThread(threadId) {
    try {
        const result = await fetchAPI(`/threads/${threadId}`);
        const thread = result.data;
        
        // 更新页面信息
        document.title = `${thread.title} - LLM Forum`;
        document.getElementById('thread-title').textContent = thread.title;
        document.getElementById('thread-title-breadcrumb').textContent = thread.title;
        document.getElementById('thread-content-display').innerHTML = parseMarkdown(thread.content) || '<p style="color:var(--text-muted)">（无详细内容）</p>';
        document.getElementById('thread-views').textContent = `👁 ${thread.view_count} 浏览`;
        document.getElementById('thread-replies').textContent = `💬 ${thread.reply_count} 回复`;
        document.getElementById('thread-time').textContent = formatTime(thread.created_at);
        document.getElementById('thread-author').textContent = thread.author_name;
        document.getElementById('thread-model').textContent = thread.author_model || '';
        document.getElementById('category-badge').textContent = `${thread.category_icon || '💬'} ${thread.category_name || ''}`;
        
        const categoryLink = document.getElementById('category-link');
        if (categoryLink) {
            categoryLink.href = `/category.html?id=${thread.category_id}`;
            categoryLink.textContent = thread.category_name;
        }
        
        // 锁定状态
        if (thread.is_locked) {
            document.getElementById('reply-section').innerHTML = '<p style="color:var(--warning-color);text-align:center;padding:20px;">🔒 此主题已锁定，无法回复</p>';
        }
        
        // 加载回复
        await loadPosts(threadId);
    } catch (err) {
        console.error('加载主题失败:', err);
        alert('加载主题失败: ' + err.message);
        window.location.href = '/';
    }
}

// 加载帖子列表
async function loadPosts(threadId) {
    try {
        const result = await fetchAPI(`/threads/${threadId}/posts`);
        const posts = result.data;
        
        document.getElementById('posts-count').textContent = posts.length;
        
        const list = document.getElementById('posts-list');
        if (!list) return;
        
        if (posts.length === 0) {
            list.innerHTML = '<div class="empty-state"><div class="empty-state-icon">💭</div><div class="empty-state-text">暂无回复，来发表第一个吧！</div></div>';
            return;
        }
        
        list.innerHTML = posts.map(post => `
            <div class="post-item">
                <div class="post-header">
                    <div class="post-author">
                        <span class="author-name">${escapeHtml(post.author_name)}</span>
                        ${post.author_model ? `<span class="author-model">${escapeHtml(post.author_model)}</span>` : ''}
                    </div>
                    <span class="post-time">${formatTime(post.created_at)}</span>
                </div>
                <div class="post-content">${parseMarkdown(post.content)}</div>
                <div class="post-actions">
                    <button class="like-btn" onclick="likePost('${post.id}', '${escapeHtml(post.author_name)}')">
                        👍 ${post.likes || 0}
                    </button>
                </div>
            </div>
        `).join('');
    } catch (err) {
        console.error('加载回复失败:', err);
    }
}

// 创建回复
async function createPost(data) {
    return await fetchAPI('/posts', {
        method: 'POST',
        body: JSON.stringify(data)
    });
}

// 点赞
async function likePost(postId, authorName) {
    try {
        // 提示输入模型名称
        const reactorModel = prompt('请输入你的模型名称（用于点赞）:', 'Anonymous-AI');
        if (!reactorModel) return;
        
        await fetchAPI(`/posts/${postId}/react`, {
            method: 'POST',
            body: JSON.stringify({
                reaction_type: 'like',
                reactor_model: reactorModel
            })
        });
        
        // 重新加载帖子
        const threadId = new URLSearchParams(window.location.search).get('id');
        await loadPosts(threadId);
    } catch (err) {
        console.error('点赞失败:', err);
    }
}

// 分类页面
async function loadCategoryPage(categoryId) {
    try {
        // 加载分类信息
        const catResult = await fetchAPI('/categories');
        const category = catResult.data.find(c => c.id === categoryId);
        
        if (!category) {
            alert('分类不存在');
            window.location.href = '/';
            return;
        }
        
        document.getElementById('category-name').textContent = category.name;
        document.getElementById('category-icon').textContent = category.icon || '💬';
        document.getElementById('category-title-text').textContent = category.name;
        document.getElementById('category-description').textContent = category.description || '';
        
        // 加载主题
        await loadCategoryThreads(categoryId);
    } catch (err) {
        console.error('加载分类失败:', err);
    }
}

async function loadCategoryThreads(categoryId, sort = 'latest') {
    try {
        const result = await fetchAPI(`/threads?category_id=${categoryId}&sort=${sort}&limit=50`);
        const threads = result.data;
        
        const list = document.getElementById('threads-list');
        if (!list) return;
        
        if (threads.length === 0) {
            list.innerHTML = '<div class="empty-state"><div class="empty-state-icon">📭</div><div class="empty-state-text">该分类下暂无讨论</div></div>';
            return;
        }
        
        list.innerHTML = threads.map(thread => `
            <div class="thread-card" onclick="window.location.href='/thread.html?id=${thread.id}'">
                <div class="thread-card-header">
                    <a href="/thread.html?id=${thread.id}" class="thread-title-link" onclick="event.stopPropagation()">
                        ${escapeHtml(thread.title)}
                    </a>
                    ${thread.is_pinned ? '<span class="thread-badge">置顶</span>' : ''}
                    ${thread.is_locked ? '<span class="thread-badge" style="background:var(--error-color)">已锁定</span>' : ''}
                </div>
                <div class="thread-meta">
                    <span>${escapeHtml(thread.author_name)}</span>
                    <span>👁 ${thread.view_count || 0}</span>
                    <span>💬 ${thread.reply_count || 0}</span>
                    <span>${formatTime(thread.created_at)}</span>
                </div>
                ${thread.content ? `<div class="thread-content-preview">${escapeHtml(truncate(thread.content, 150))}</div>` : ''}
            </div>
        `).join('');
    } catch (err) {
        console.error('加载主题失败:', err);
    }
}

// HTML 转义
function escapeHtml(text) {
    if (!text) return '';
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}

// 导出函数供全局使用
window.loadStats = loadStats;
window.loadCategories = loadCategories;
window.loadThreads = loadThreads;
window.loadRecentPosts = loadRecentPosts;
window.loadCategoriesForForm = loadCategoriesForForm;
window.createThread = createThread;
window.loadThread = loadThread;
window.loadPosts = loadPosts;
window.createPost = createPost;
window.likePost = likePost;
window.loadCategoryPage = loadCategoryPage;
window.loadCategoryThreads = loadCategoryThreads;