import {resolvePlatformOrigin} from '@/shared/config/platformApi';
import {ConfigError} from '@/shared/errors/configError';

/**
 * The Node half of the boot-time configuration check.
 *
 * ── Why this is a separate file ──────────────────────────────────────────
 * `instrumentation.ts` is compiled for EVERY runtime the app uses, and
 * src/proxy.ts makes this app compile an Edge one. `process.exit` does not
 * exist there, so Turbopack statically flagged it — "A Node.js API is used
 * (process.exit) which is not supported in the Edge Runtime" — even though the
 * call sits behind a NEXT_RUNTIME guard and could never run in that bundle.
 *
 * A runtime guard is not a bundling boundary. A separate module reached through
 * a dynamic import IS one, so the Edge bundle never contains this code at all.
 *
 * These imports are static rather than dynamic because this module is only ever
 * loaded from the Node branch. Neither is `server-only`: apiClient is, and that
 * package resolves to a module which THROWS ON IMPORT outside a react-server
 * condition, which this bundle is not. shared/config/platformApi exists so the
 * boot check and the request path can share one validator without that hazard.
 */
export async function checkConfiguration() {
  const isProduction = process.env.NODE_ENV === 'production';
  const problems: string[] = [];

  /**
   * Resolve the platform origin exactly the way a request would — same
   * function, same validation, same allowlist. A check that reimplemented the
   * rules would be a second source of truth and would drift from the real one.
   */
  let platform: string | null = null;
  try {
    platform = resolvePlatformOrigin();
  } catch (err) {
    if (!(err instanceof ConfigError)) throw err;
    problems.push(err.message);
  }

  /**
   * AUTH_SECRET is checked by presence rather than by calling the signing
   * functions, which would have to be handed a throwaway payload to probe.
   * Presence is the whole rule — sessionToken and tokenStore both refuse the
   * development key in production and accept anything else.
   */
  if (isProduction && !process.env.AUTH_SECRET) {
    problems.push(
      'AUTH_SECRET is required in production — it signs the session cookie and ' +
        'encrypts the platform token bundle. Generate one with: openssl rand -base64 48',
    );
  }

  if (problems.length > 0) {
    // Numbered, because a container missing its environment is usually missing
    // more than one variable, and finding that out one deploy at a time is the
    // slow way.
    const detail = problems.map((p, i) => `  ${i + 1}. ${p}`).join('\n');
    console.error(
      `\n[loyaly] refusing to start — ${problems.length} configuration problem(s):\n${detail}\n` +
        '\nSet these as environment variables on the container (Dokploy → Environment). ' +
        'LOYALY_API_BASE also ships in the committed .env; AUTH_SECRET never does.\n',
    );

    /**
     * Exit, rather than throw.
     *
     * Throwing from `register()` does NOT stop the server. Measured against a
     * real standalone build: the port is already bound by the time this runs,
     * so Next logs "Failed to prepare server" and the process STAYS ALIVE,
     * answering 500 to every route — /login, /favicon.ico, everything. That is
     * the worst of both worlds. A TCP or HTTP healthcheck sees an open port and
     * calls the container healthy, so a dead deploy shows up green and keeps
     * receiving traffic.
     *
     * Exiting non-zero makes the container die, which is what a deployment
     * platform reads as a failed deploy. The message above is already on
     * stderr, so each restart attempt reprints the reason.
     */
    process.exit(1);
  }

  // The healthy path says what it resolved, so a log reader can confirm the
  // host WITHOUT having to trigger a request. Never prints AUTH_SECRET, only
  // whether one was supplied.
  console.log(
    `[loyaly] config ok — platform ${platform}, ` +
      `auth secret ${process.env.AUTH_SECRET ? 'set' : 'using development key'}, ` +
      `NODE_ENV=${process.env.NODE_ENV}`,
  );
}