const http = require('http');
const fs = require('fs');
const url = require('url');
const path = require('path');
const { Buffer } = require('buffer');

const server = http.createServer((req, res) => {
    const queryObject = url.parse(req.url,true).query;
    const operation = queryObject.operation;
    const filePath = path.join(__dirname, queryObject.path);

    switch (operation) {
        case 'list':
            fs.readdir(filePath, (err, files) => {
                if (err) {
                    res.writeHead(500, { 'Content-Type': 'text/plain' });
                    res.write(err.message);
                    res.end();
                } else {
                    let base64Files = files.map(file => Buffer.from(file).toString('base64'));
                    res.writeHead(200, { 'Content-Type': 'application/json' });
                    res.write(JSON.stringify(base64Files));
                    res.end();
                }
            });
            break;
        case 'read':
            fs.readFile(filePath, (err, data) => {
                if (err) {
                    res.writeHead(500, { 'Content-Type': 'text/plain' });
                    res.write(err.message);
                    res.end();
                } else {
                    res.writeHead(200, { 'Content-Type': 'text/plain' });
                    res.write(data.toString('base64'));
                    res.end();
                }
            });
            break;
        case 'write':
            const index = queryObject.index;
            const total = queryObject.total;
            let body = '';
            req.on('data', chunk => {
                body += chunk.toString();
            });
            req.on('end', () => {
                const data = Buffer.from(body, 'base64');
                if (index == total) {
                    fs.writeFile(filePath, data, err => { /*...*/ });
                } else {
                    fs.appendFile(filePath, data, err => { /*...*/ });
                }
            });
            break;
        default:
            res.writeHead(400, { 'Content-Type': 'text/plain' });
            res.write('Invalid operation');
            res.end();
            break;
    }
});

server.listen(3090, () => {
    console.log('Server is listening on port 3090');
});