/**
 * Converts provider-native Brevo JSON keys to public camelCase recursively.
 *
 * @param value - Provider response value.
 */
export function fromBrevoWire(value: unknown): unknown {
  if (Array.isArray(value)) return value.map(fromBrevoWire)
  if (!isPlainObject(value)) return value
  return Object.fromEntries(
    Object.entries(value).map(([key, item]) => [
      key.replace(/_([a-z])/g, (_, letter: string) => letter.toUpperCase()),
      fromBrevoWire(item),
    ]),
  )
}

/**
 * Narrows values that can be traversed as JSON objects.
 *
 * @param value - Candidate JSON value.
 */
function isPlainObject(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null && !Array.isArray(value)
}