export type ApiError = { code: number; msg: string }

export type ApiDecision = { ok: true } | { ok: false; error: ApiError }

export function isApiError(value: unknown): value is ApiError {
  if (typeof value !== "object" || value === null) return false

  const v = value as { code?: unknown; msg?: unknown }
  return typeof v.code === "number" && typeof v.msg === "string"
}

export function toApiError(err: unknown): ApiError {
  if (isApiError(err)) return err
  if (err instanceof Error) return { code: 500, msg: err.message }
  if (typeof err === "string") return { code: 500, msg: err }

  return { code: 500, msg: "Unknown error" }
}

export type ApiResult<T> = { ok: true; data: T } | { ok: false; error: ApiError }