import express from 'express';
import path from 'path';
import { fileURLToPath } from 'url';
import fs from 'fs';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
const PORT = process.env.PORT || 3000;

// Log all incoming request methods, URLs, and headers
app.use((req, res, next) => {
  console.log(`[Express Request] ${req.method} ${req.url}`);
  console.log('Headers:', JSON.stringify(req.headers, null, 2));
  next();
});

// Middleware to strip base path prefix from request headers if present
app.use((req, res, next) => {
  const prefix = (req.headers['x-forwarded-prefix'] as string) || (req.headers['x-base-path'] as string) || '';
  const cleanPrefix = prefix.endsWith('/') ? prefix.slice(0, -1) : prefix;

  if (cleanPrefix && req.url.startsWith(cleanPrefix)) {
    req.url = req.url.substring(cleanPrefix.length);
    if (!req.url.startsWith('/')) {
      req.url = '/' + req.url;
    }
  }
  next();
});

// Serve static files from the 'dist' directory, but bypass index.html requests
// so they can be handled dynamically by our fallback route.
app.use((req, res, next) => {
  if (req.url === '/index.html') {
    return next();
  }
  next();
});
app.use(express.static(path.join(__dirname, 'dist'), { index: false }));

// Fallback to index.html for Single Page Application routing, injecting base path from headers
app.get('*', (req, res) => {
  const indexPath = path.join(__dirname, 'dist', 'index.html');
  fs.readFile(indexPath, 'utf8', (err, html) => {
    if (err) {
      return res.status(500).send('Error reading index.html');
    }

    const prefix = (req.headers['x-forwarded-prefix'] as string) || (req.headers['x-base-path'] as string) || '';
    const cleanPrefix = prefix.endsWith('/') ? prefix.slice(0, -1) : prefix;

    // Dynamically prefix asset URLs in index.html with the base path
    let modifiedHtml = html;
    if (cleanPrefix) {
      modifiedHtml = html
        .replace(/(href|src)="\/assets\//g, `$1="${cleanPrefix}/assets/`)
        .replace(/(href|src)="\/vite.svg"/g, `$1="${cleanPrefix}/vite.svg"`);
    }

    res.send(modifiedHtml);
  });
});

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