const express = require('express');
const cors = require('cors');
const session = require('express-session');
const MySQLStore = require('express-mysql-session')(session);
const path = require('path');
require('dotenv').config();

// 导入路由
const authRoutes = require('./routes/auth');
const studentRoutes = require('./routes/student');
const teacherRoutes = require('./routes/teacher');
const adminRoutes = require('./routes/admin');

// 数据库配置
const db = require('./config/database');

const app = express();
const PORT = process.env.PORT || 3000;

// 中间件
app.use(cors({
    origin: 'http://localhost:3000',
    credentials: true
}));
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// 会话配置
const sessionStore = new MySQLStore({
    expiration: 86400000, // 1天
    createDatabaseTable: true,
    schema: {
        tableName: 'sessions',
        columnNames: {
            session_id: 'session_id',
            expires: 'expires',
            data: 'data'
        }
    }
}, db.pool);

app.use(session({
    key: 'session_cookie',
    secret: process.env.SESSION_SECRET || 'your-secret-key',
    store: sessionStore,
    resave: false,
    saveUninitialized: false,
    cookie: {
        maxAge: 86400000,
        httpOnly: true,
        secure: process.env.NODE_ENV === 'production'
    }
}));

// 静态文件服务
app.use(express.static(path.join(__dirname, '../frontend')));

// 重定向旧路径 /frontend/html/* 到 /html/*
app.get('/frontend/html/*', (req, res) => {
    const path = req.params[0];
    res.redirect(`/html/${path}`);
});

// 路由
app.use('/api/auth', authRoutes);
app.use('/api/student', studentRoutes);
app.use('/api/teacher', teacherRoutes);
app.use('/api/admin', adminRoutes);

// 认证中间件
const { requireAuth, requireRole } = require('./middleware/auth');

// 页面路由
app.get('/', (req, res) => {
    res.sendFile(path.join(__dirname, '../frontend/html/login.html'));
});

app.get('/dashboard', requireAuth, (req, res) => {
    // 根据用户角色重定向到不同的仪表板
    const role = req.session.user?.role;
    
    switch (role) {
        case 'student':
            res.redirect('/html/student_dashboard.html');
            break;
        case 'teacher':
            res.redirect('/html/teacher_dashboard.html');
            break;
        case 'admin':
            res.redirect('/html/admin_dashboard.html');
            break;
        default:
            // 如果没有角色信息，重定向到登录页面
            res.redirect('/');
            break;
    }
});

// 学生页面路由
app.get('/student/*', requireAuth, requireRole(['student', 'admin', 'teacher']), (req, res, next) => {
    next();
});

// 教师页面路由
app.get('/teacher/*', requireAuth, requireRole(['teacher', 'admin']), (req, res, next) => {
    next();
});

// 管理员页面路由
app.get('/admin/*', requireAuth, requireRole(['admin']), (req, res, next) => {
    next();
});

// 404处理
app.use((req, res) => {
    res.status(404).json({ error: 'Not found' });
});

// 错误处理
app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).json({ error: 'Internal server error' });
});

app.listen(PORT, () => {
    console.log(`Server running on port ${PORT}`);
    console.log(`访问地址: http://localhost:${PORT}`);
});