/**
 * The publishable key, only when its mode matches the stack: `pk_live_` on production, `pk_test_`
 * everywhere else. A mismatch returns null, so checkout refuses to open rather than take a real card
 * on staging or a test card on production. The server refuses the secret key the same way.
 */
export function publishableKeyForStack(key: string, production: boolean): string | null {
  const required = production ? 'pk_live_' : 'pk_test_';
  return key.startsWith(required) ? key : null;
}

/** The key-field hints for this stack's mode, so staging never invites a live key the server refuses. */
export function stripeKeyPlaceholders(production: boolean): { publishable: string; secret: string } {
  const mode = production ? 'live' : 'test';
  return { publishable: `pk_${mode}_…`, secret: `sk_${mode}_…` };
}