const http = require("http");
const https = require("https");
const fs = require("fs");
const path = require("path");
const url = require("url");

const PORT = 7860;
const DIST_DIR = path.join(__dirname, "dist");
const BACKEND_URL = process.env.VITE_API_BASE_URL || "";

const MIME = {
  ".html": "text/html",
  ".js": "application/javascript",
  ".mjs": "application/javascript",
  ".css": "text/css",
  ".json": "application/json",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".svg": "image/svg+xml",
  ".ico": "image/x-icon",
  ".woff": "font/woff",
  ".woff2": "font/woff2",
  ".ttf": "font/ttf",
  ".webp": "image/webp",
};

console.log(`Starting server on port ${PORT}`);
console.log(`Backend URL: ${BACKEND_URL || "(not set)"}`);

const server = http.createServer((req, res) => {
  const parsed = url.parse(req.url);

  // Proxy /api/* to backend
  if (parsed.pathname.startsWith("/api/") && BACKEND_URL) {
    const backend = url.parse(BACKEND_URL);
    const isHttps = backend.protocol === "https:";
    const transport = isHttps ? https : http;

    const options = {
      hostname: backend.hostname,
      port: backend.port || (isHttps ? 443 : 80),
      path: req.url,
      method: req.method,
      headers: { ...req.headers, host: backend.hostname },
    };

    const proxyReq = transport.request(options, (proxyRes) => {
      res.writeHead(proxyRes.statusCode, proxyRes.headers);
      proxyRes.pipe(res);
    });

    proxyReq.on("error", (err) => {
      console.error("Proxy error:", err.message);
      res.writeHead(502);
      res.end("Bad Gateway");
    });

    req.pipe(proxyReq);
    return;
  }

  // Serve static files
  let filePath = path.join(DIST_DIR, parsed.pathname);
  try {
    const stat = fs.statSync(filePath);
    if (stat.isDirectory()) filePath = path.join(filePath, "index.html");
  } catch {
    // Not found → SPA fallback
    filePath = path.join(DIST_DIR, "index.html");
  }

  fs.readFile(filePath, (err, data) => {
    if (err) {
      res.writeHead(404);
      res.end("Not Found");
      return;
    }
    const ext = path.extname(filePath).toLowerCase();
    res.writeHead(200, { "Content-Type": MIME[ext] || "application/octet-stream" });
    res.end(data);
  });
});

server.listen(PORT);