const http = require('http');
const fs = require('fs');
const path = require('path');

const PORT = 3000;

const MIME_TYPES = {
    '.html': 'text/html',
    '.css': 'text/css',
    '.js': 'text/javascript',
    '.json': 'application/json',
    '.csv': 'text/csv',
};

const server = http.createServer((req, res) => {
    // Handle URL
    let filePath = '.' + req.url;
    if (filePath === './') {
        filePath = './index.html';
    }
    
    const extname = path.extname(filePath);
    const contentType = MIME_TYPES[extname] || 'application/octet-stream';
    
    fs.readFile(filePath, (err, data) => {
        if (err) {
            if (err.code === 'ENOENT') {
                res.writeHead(404);
                res.end('File not found');
            } else {
                res.writeHead(500);
                res.end('Server error: ' + err.code);
            }
            return;
        }
        
        res.writeHead(200, { 'Content-Type': contentType });
        res.end(data);
    });
});

server.listen(PORT, () => {
    console.log(`Server running at http://localhost:${PORT}/`);
    console.log(`Visualizing spending data with ECharts...`);
});