import {
  assertProductionDatabaseTransport,
  type DatabaseTransportEnvironment,
  type DatabaseTransportPolicy,
  createDatabaseTransportPolicy,
} from "../database/transport.js";
import { loadHostConfiguration } from "../host/index.js";

/**
 * The database transport policy for the small Core-owned executables — `pnpm migrations:plan`,
 * `pnpm migrations:apply`, `pnpm modules:enable`, and the owner-bootstrap commands — resolved from
 * the process environment.
 *
 * The mapping itself belongs to `loadHostConfiguration`, which `startApi` and `pnpm doctor` also
 * call, so `NODE_ENV` and the two TLS variables have exactly one interpretation across every entry
 * point. Environment *reading* still happens here, in the executable layer: the reusable Core
 * database and migration constructors keep taking explicit typed inputs and never touch
 * `process.env`.
 */
export function readDatabaseTransportFromEnvironment(): {
  readonly environment: DatabaseTransportEnvironment;
  readonly transport: DatabaseTransportPolicy;
} {
  const host = loadHostConfiguration(process.env);
  const transport = createDatabaseTransportPolicy(host.databaseTransport, {
    environment: host.environment,
  });
  return { environment: host.environment, transport };
}

/**
 * Resolves the policy and asserts it is safe for the given database URL before any client, pool,
 * or connection is constructed. Throws the sanitized `DatabaseTransportError` otherwise.
 */
export function resolveExecutableDatabaseTransport(databaseUrl: string): DatabaseTransportPolicy {
  const { environment, transport } = readDatabaseTransportFromEnvironment();
  assertProductionDatabaseTransport(databaseUrl, transport, environment);
  return transport;
}