/**
 * The one place a thrown value is turned into a developer-facing message.
 *
 * Five copies of this logic drifted apart across the composables and stores
 * (some checked a bare `{ message }` object, some did not); this export is the
 * union of what they all accepted, so every caller now reads the same message
 * from the same value.
 */
export function readErrorMessage(value: unknown, fallback = 'Request failed.'): string {
  if (value instanceof Error && value.message) {
    return value.message
  }

  if (typeof value === 'string' && value.trim()) {
    return value
  }

  if (
    typeof value === 'object'
    && value !== null
    && 'message' in value
    && typeof (value as { message?: unknown }).message === 'string'
    && (value as { message: string }).message.trim()
  ) {
    return (value as { message: string }).message
  }

  return fallback
}