// Server actions answer forms with an ActionState: an error to show, or a notice.
import "server-only";
import { ApiError } from "./api";

export type ActionState = { error?: string; notice?: string } | null;

/** Runs fn, turning the API's errors into a message for the form; fn may return a notice. */
export async function attempt(fn: () => Promise<string | void>): Promise<ActionState> {
  try {
    const notice = await fn();
    return notice ? { notice } : {};
  } catch (e) {
    if (e instanceof ApiError) return { error: e.message };
    throw e;
  }
}

/** A form field as a string ("" when missing). */
export function field(form: FormData, name: string): string {
  const v = form.get(name);
  return typeof v === "string" ? v.trim() : "";
}