const express = require('express');
const bcrypt = require('bcryptjs');
const router = express.Router();
const db = require('../config/database');

// 登录
router.post('/login', async (req, res) => {
    try {
        const { id, password, role } = req.body;
        
        // 输入验证
        if (!id || !password || !role) {
            return res.status(400).json({ 
                success: false, 
                message: '请输入完整的登录信息' 
            });
        }
        
        // 查询用户
        const users = await db.query(
            'SELECT * FROM users WHERE id = ? AND role = ?',
            [id, role]
        );
        
        if (users.length === 0) {
            return res.status(401).json({ 
                success: false, 
                message: '用户名或密码错误' 
            });
        }
        
        const user = users[0];
        
        // 验证密码
        const isValidPassword = await bcrypt.compare(password, user.password);
        if (!isValidPassword) {
            return res.status(401).json({ 
                success: false, 
                message: '用户名或密码错误' 
            });
        }
        
        // 设置会话
        req.session.user = {
            id: user.id,
            name: user.name,
            role: user.role,
            class: user.class
        };
        
        // 如果是学生，获取学生信息
        if (user.role === 'student') {
            const [students] = await db.pool.execute(
                'SELECT * FROM students WHERE id = ?',
                [user.id]
            );
            if (students[0].length > 0) {
                req.session.user.studentInfo = students[0][0];
            }
        }
        
        res.json({
            success: true,
            message: '登录成功',
            user: req.session.user
        });
        
    } catch (error) {
        console.error('登录错误:', error);
        res.status(500).json({ 
            success: false, 
            message: '服务器错误' 
        });
    }
});

// 注册
router.post('/register', async (req, res) => {
    try {
        const { id, name, password, role, class: userClass } = req.body;
        
        // 输入验证
        if (!id || !name || !password || !role) {
            return res.status(400).json({ 
                success: false, 
                message: '请填写所有必填字段（ID、姓名、密码、角色）' 
            });
        }
        
        // 学生和教师需要班级字段，管理员不需要
        if ((role === 'student' || role === 'teacher') && !userClass) {
            return res.status(400).json({ 
                success: false, 
                message: '学生和教师需要填写班级' 
            });
        }
        
        // 检查用户ID是否存在
        const existingUsers = await db.query(
            'SELECT id FROM users WHERE id = ?',
            [id]
        );
        
        if (existingUsers.length > 0) {
            return res.status(400).json({ 
                success: false, 
                message: '用户ID已存在' 
            });
        }
        
        // 哈希密码
        const salt = await bcrypt.genSalt(10);
        const passwordHash = await bcrypt.hash(password, salt);
        
        // 创建用户
        await db.pool.execute(
            'INSERT INTO users (id, name, password, role, class) VALUES (?, ?, ?, ?, ?)',
            [id, name, passwordHash, role, userClass || null]
        );
        
        // 如果是学生，创建学生记录
        if (role === 'student') {
            await db.pool.execute(
                'INSERT INTO students (id, name, class) VALUES (?, ?, ?)',
                [id, name, userClass]
            );
        }
        
        res.json({
            success: true,
            message: '注册成功'
        });
        
    } catch (error) {
        console.error('注册错误:', error);
        res.status(500).json({ 
            success: false, 
            message: '服务器错误' 
        });
    }
});

// 注销
router.post('/logout', (req, res) => {
    req.session.destroy(err => {
        if (err) {
            return res.status(500).json({ 
                success: false, 
                message: '注销失败' 
            });
        }
        res.clearCookie('session_cookie');
        res.json({ 
            success: true, 
            message: '注销成功' 
        });
    });
});

// 获取当前用户信息
router.get('/me', (req, res) => {
    if (!req.session.user) {
        return res.status(401).json({ 
            success: false, 
            message: '未登录' 
        });
    }
    
    res.json({
        success: true,
        user: req.session.user
    });
});

module.exports = router;