import { backendBaseUrl as BASE, joinBackendPath } from "./runtime-config";

export async function apiFetch<T>(path: string, init?: RequestInit): Promise<T> {
  // Only declare a JSON content-type when we actually send a body. Body-less
  // POSTs (resume, close) would otherwise make Fastify reject the empty body
  // with FST_ERR_CTP_EMPTY_JSON_BODY (400).
  const headers: Record<string, string> = {
    ...(init?.headers as Record<string, string> | undefined),
  };
  if (init?.body != null && !("content-type" in headers) && !("Content-Type" in headers)) {
    headers["content-type"] = "application/json";
  }
  const res = await fetch(joinBackendPath(BASE, path), { ...init, headers });
  if (!res.ok) throw new Error(`${res.status} ${await res.text().catch(() => "")}`);
  if (res.status === 204) return undefined as T;
  // Accepted fire-and-forget endpoints may legitimately return 202 with no
  // representation. Keep apiFetch useful for both 202 and 204 contracts.
  const body = await res.text();
  return body ? (JSON.parse(body) as T) : (undefined as T);
}

export { BASE };