const express = require('express');
const multer = require('multer');
const XLSX = require('xlsx');
const cors = require('cors');
const app = express();
const port = 3000;


// 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
});

// 全局变量来存储学生数据 


let dataArray = [];
let filePath = '';

// 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 });

        // 初始化或更新全局的学生数据数组  
        dataArray = data.slice(1).map(row => ({
            studentID: row[0], // 根据列的实际索引进行调整
            name: row[1],
            credit: row[2] || null
        }));



        // 处理数据（这里只是打印到控制台，你可以保存到数据库等）  
        console.log(data);


        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', (_, res) => {
    if (dataArray.length === 0) {
        return res.status(404).json({ error: 'No students found.' });
    }
    const randomIndex = Math.floor(Math.random() * dataArray.length);
    const randomStudent = dataArray[randomIndex];
    console.log('dataArray:', dataArray);
    res.json(randomStudent);
});

// 新的API端点来增加学生的credit
app.post('/api/add-credit', express.json(), (req, res) => {
    const { name, studentID } = req.body;
    const student = dataArray.find(s => s.name === name && s.studentID === studentID);
    if (!student) {
        return res.status(404).json({ error: 'Student not found.' });
    }
    student.credit += 1;
    console.log('Updated dataArray:', dataArray);
    res.json({ message: 'Credit added successfully!' });

});


app.post('/api/credit', express.json(), (req, res) => {
    const { name, studentID, creditToAdd } = req.body;
    const student = dataArray.find(s => s.name === name && s.studentID === studentID);
    if (!student) {
        res.status(404).json({ message: 'Student not found!' });
        return;
    }
    student.credit += parseInt(creditToAdd);
    console.log('Updated dataArray:', dataArray);
    res.json({ message: 'Credit added successfully!' });

    // 创建一个新的工作簿
    const workbook = XLSX.utils.book_new();
    const worksheet = XLSX.utils.json_to_sheet(dataArray);

    // 将工作表添加到工作簿
    XLSX.utils.book_append_sheet(workbook, worksheet, 'Sheet1');

    // 保存工作簿为 Excel 文件
    const excelFilePath = 'C:/Users/Lenovo/Downloads/软工学生名单.xlsx';
    XLSX.writeFile(workbook, excelFilePath);

});






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