import type { Acc, User } from "./types";

const API_BASE_URL = process.env.API_BASE_URL ?? "http://api-server:3000";

// How long the Next.js data cache holds an /acc/ or /user/ response
// before considering it stale. Tab switches and auto-refreshes within
// this window are served from memory — no api-server / MySQL round-trip.
// Mutations (update/create/delete) call revalidateTag() so the next
// request always sees fresh data after a write.
const CACHE_REVALIDATE_SECONDS = 30;

export const ACCOUNTS_TAG = "accounts";
export const USERS_TAG = "users";

type FetchInit = {
  method?: "GET" | "POST";
  body?: unknown;
  cache?: RequestCache;
  next?: { revalidate?: number; tags?: string[] };
};

export async function fetchApi(path: string, options: FetchInit = {}): Promise<unknown> {
  const url = `${API_BASE_URL}${path}`;
  const init: RequestInit & { next?: FetchInit["next"] } = {
    method: options.method ?? "GET",
    headers: options.body ? { "content-type": "application/json" } : undefined,
    body: options.body ? JSON.stringify(options.body) : undefined,
  };
  if (options.next) {
    init.next = options.next;
  } else {
    init.cache = options.cache ?? "no-store";
  }
  const res = await fetch(url, init);
  if (!res.ok) {
    throw new Error(`API ${options.method ?? "GET"} ${path} failed: ${res.status}`);
  }
  return res.json();
}

export async function getAccounts(): Promise<Acc[]> {
  const data = await fetchApi("/acc/", {
    next: { revalidate: CACHE_REVALIDATE_SECONDS, tags: [ACCOUNTS_TAG] },
  });
  return data as Acc[];
}

export async function getUsers(): Promise<User[]> {
  const data = await fetchApi("/user/", {
    next: { revalidate: CACHE_REVALIDATE_SECONDS, tags: [USERS_TAG] },
  });
  return data as User[];
}