const express = require('express');
const multer = require('multer');
const XLSX = require('xlsx');
const mysql = require('mysql2');
const cors = require('cors');

const app = express();
const port = 3001;

// 使用 CORS
app.use(cors());

// 设置 multer 存储配置
const storage = multer.memoryStorage();
const upload = multer({
    storage: storage,
    limits: { fileSize: 5 * 1024 * 1024 } // 5MB 限制
});

// 创建数据库连接池
const pool = mysql.createPool({
    host: 'localhost',
    user: 'root',
    password: 'mysql123',
    database: 'mysql'
});

// 处理文件上传的路由
app.post('/upload', upload.single('file'), (req, res) => {
    try {
        const file = req.file;
        if (!file) {
            return res.status(400).json({ message: 'No file uploaded.' });
        }

        // 使用 xlsx 库读取 Excel 文件
        const workbook = XLSX.read(file.buffer, { type: 'buffer' });
        const sheetName = workbook.SheetNames[0];
        const worksheet = workbook.Sheets[sheetName];
        const data = XLSX.utils.sheet_to_json(worksheet, { header: 1 });

        // 插入数据到数据库
        data.forEach(row => {
            const query = 'INSERT INTO students (student_id, name, points) VALUES (?, ?, ?)';
            pool.query(query, [row.student_id, row.name, row.points], (error, results, fields) => {
                if (error) {
                    console.error('Error inserting data:', error);
                } else {
                    console.log('Row inserted successfully:', row);
                }
            });
        });

        res.json({ message: 'File uploaded and processed successfully!' });
    } catch (error) {
        console.error('Error processing file:', error);
        res.status(500).json({ message: 'Error processing file: ' + error.message });
    }
});

// 新的API端点来返回随机学生数据
app.get('/api/get-random-student', (req, res) => {
    // 注意：这里需要实现从数据库中获取随机学生数据的逻辑
    // 由于这需要数据库操作，这里只是一个示例
    pool.query('SELECT * FROM students ORDER BY RAND() LIMIT 1', (error, results) => {
        if (error) {
            console.error('Error fetching random student:', error);
            return res.status(500).json({ message: 'Error fetching random student' });
        }
        if (results.length === 0) {
            return res.status(404).json({ error: 'No students found.' });
        }
        const randomStudent = results[0];
        res.json(randomStudent);
    });
});

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