import http from 'node:http';
import type { Express } from 'express';

export interface RunningTestServer {
  baseUrl: string;
  close: () => Promise<void>;
}

export function startTestServer(app: Express): Promise<RunningTestServer> {
  return new Promise((resolve, reject) => {
    const server = http.createServer(app);

    server.once('error', reject);
    server.listen(0, '127.0.0.1', () => {
      server.off('error', reject);
      const address = server.address();

      if (typeof address !== 'object' || address === null) {
        server.close();
        reject(new Error('Test server did not expose a listening address.'));
        return;
      }

      resolve({
        baseUrl: `http://127.0.0.1:${address.port}`,
        close: () =>
          new Promise((closeResolve, closeReject) => {
            server.close((error) => {
              if (error) {
                closeReject(error);
                return;
              }
              closeResolve();
            });
          }),
      });
    });
  });
}