// A Postgres of its own for the server's tests: FILIUS_TEST_DATABASE_URL
// when it is set, else a throwaway container of the postgres image (Docker),
// stopped and gone after the tests. Never a database of the dashboard.

import { execFileSync } from 'node:child_process';
import pg from 'pg';

export interface TestDatabase {
  readonly url: string;
  stop(): Promise<void>;
}

export async function testDatabase(): Promise<TestDatabase> {
  const given = process.env.FILIUS_TEST_DATABASE_URL;
  if (given !== undefined) return { url: given, stop: async () => {} };
  const name = `filius-test-pg-${process.pid}-${Date.now()}`;
  execFileSync('docker', ['run', '-d', '--rm', '--name', name, '-e', 'POSTGRES_PASSWORD=filius', '-e', 'POSTGRES_DB=filius', '-p', '127.0.0.1::5432', 'postgres:16-alpine'], { stdio: 'pipe' });
  const stop = async () => {
    execFileSync('docker', ['stop', name], { stdio: 'pipe' });
  };
  try {
    const port = execFileSync('docker', ['port', name, '5432/tcp']).toString().trim().split('\n')[0]!.split(':').pop();
    const url = `postgres://postgres:filius@127.0.0.1:${port}/filius`;
    // The image's first start runs a server on its socket only; the TCP port answers once the real one is up.
    for (let tries = 0; ; tries++) {
      const client = new pg.Client({ connectionString: url });
      try {
        await client.connect();
        await client.query('SELECT 1');
        await client.end();
        return { url, stop };
      } catch (error) {
        await client.end().catch(() => {});
        if (tries > 120) throw error;
        await new Promise((resolve) => setTimeout(resolve, 250));
      }
    }
  } catch (error) {
    await stop();
    throw error;
  }
}