import { Pool, type QueryResultRow } from "pg";

let pool: Pool | null = null;

/**
 * Lazily opens the shared connection pool. It is lazy so that unit tests which
 * never touch the database do not need one running.
 */
export function getPool(): Pool {
  if (!pool) {
    pool = new Pool({
      connectionString: process.env.DATABASE_URL,
      max: Number(process.env.PG_POOL_MAX ?? 10),
    });
  }
  return pool;
}

export async function query<T extends QueryResultRow>(text: string, params: unknown[] = []): Promise<T[]> {
  const result = await getPool().query<T>(text, params);
  return result.rows;
}

export async function queryOne<T extends QueryResultRow>(text: string, params: unknown[] = []): Promise<T | null> {
  const rows = await query<T>(text, params);
  return rows.length > 0 ? rows[0] : null;
}

export async function closePool(): Promise<void> {
  if (pool) {
    await pool.end();
    pool = null;
  }
}