/** Shallow-deep merge for translation fallbacks */
export function mergeTranslations<T extends Record<string, unknown>>(
  base: T,
  override: Partial<T>
): T {
  const result = { ...base };

  for (const key of Object.keys(override) as (keyof T)[]) {
    const baseVal = base[key];
    const overrideVal = override[key];

    if (
      overrideVal &&
      typeof overrideVal === 'object' &&
      !Array.isArray(overrideVal) &&
      baseVal &&
      typeof baseVal === 'object' &&
      !Array.isArray(baseVal)
    ) {
      result[key] = mergeTranslations(
        baseVal as Record<string, unknown>,
        overrideVal as Record<string, unknown>
      ) as T[keyof T];
    } else if (overrideVal !== undefined) {
      result[key] = overrideVal as T[keyof T];
    }
  }

  return result;
}