const BOT_ORIGIN = 'http://127.0.0.1:3007';
const WEB_ORIGIN = 'http://127.0.0.1:3008';

function shouldRouteToBot(pathname: string): boolean {
  if (pathname === '/metrics' || pathname.startsWith('/metrics/')) return true;
  if (pathname === '/webhook' || pathname.startsWith('/webhook/')) return true;
  return false;
}

function buildForwardHeaders(req: Request): Headers {
  const headers = new Headers(req.headers);
  try {
    const proto = headers.get('x-forwarded-proto') || 'https';
    const fwdFor = headers.get('x-forwarded-for');
    headers.set('x-forwarded-proto', proto);
    headers.set('x-forwarded-for', fwdFor ? `${fwdFor}, 127.0.0.1` : '127.0.0.1');
    const host = headers.get('host') || '';
    if (!host) headers.set('host', 'localhost');
  } catch {}
  return headers;
}

Bun.serve({
  port: Number(process.env.PORT || process.env.ROUTER_PORT || 3000),
  fetch: async (req) => {
    const url = new URL(req.url);

    // Health local para el contenedor (evita 404 en healthcheck)
    if (url.pathname === '/health') {
      return new Response('ok', { status: 200, headers: { 'content-type': 'text/plain' } });
    }

    const routeToBot = shouldRouteToBot(url.pathname);
    const targetOrigin = routeToBot ? BOT_ORIGIN : WEB_ORIGIN;
    const targetUrl = targetOrigin + url.pathname + url.search;

    const headers = buildForwardHeaders(req);
    if (!routeToBot) {
      try { headers.set('accept-encoding', 'identity'); } catch {}
    }
    const init: RequestInit = {
      method: req.method,
      headers,
      body: req.method === 'GET' || req.method === 'HEAD' ? undefined : req.body,
      redirect: 'manual',
    };

    const started = Date.now();
    try {
      const res = await fetch(targetUrl, init);
      const ms = Date.now() - started;
      try {
        console.log(`[proxy] ${req.method} ${url.pathname}${url.search} -> ${routeToBot ? 'bot' : 'web'} ${res.status} (${ms}ms)`);
      } catch {}
      // Devuelve la respuesta (incluye Set-Cookie, Location, etc.), asegurando Content-Type en assets por si faltase
      const passthroughHeaders = new Headers(res.headers);
      if (!routeToBot) {
        try {
          // Forzar respuesta sin compresión hacia el cliente
          passthroughHeaders.delete('content-encoding');
          passthroughHeaders.delete('vary');
          passthroughHeaders.delete('content-length');
          const cc = passthroughHeaders.get('cache-control');
          if (cc && !/no-transform/i.test(cc)) {
            passthroughHeaders.set('cache-control', cc + ', no-transform');
          } else if (!cc) {
            passthroughHeaders.set('cache-control', 'no-transform');
          }
        } catch {}
      }
      if (!passthroughHeaders.get('content-type')) {
        if (url.pathname.endsWith('.js')) passthroughHeaders.set('content-type', 'application/javascript; charset=utf-8');
        if (url.pathname.endsWith('.css')) passthroughHeaders.set('content-type', 'text/css; charset=utf-8');
      }
      return new Response(res.body, { status: res.status, headers: passthroughHeaders });
    } catch (err) {
      const msg = err instanceof Error ? err.message : String(err);
      console.error(`[proxy] ${req.method} ${url.pathname}${url.search} -> ERROR: ${msg}`);
      return new Response(`Proxy error: ${msg}\n`, { status: 502 });
    }
  },
});