export interface ApiFailure {
  error: string;
  code?: string;
  issues?: Array<{ path: unknown; message: string }>;
}

export class ApiClientError extends Error {
  constructor(public status: number, public code: string | undefined, message: string) {
    super(message);
  }
}

export async function apiFetch<T>(
  input: string,
  init: RequestInit = {},
): Promise<T> {
  const headers = new Headers(init.headers);
  if (init.body && !headers.has("content-type") && !(init.body instanceof FormData)) {
    headers.set("content-type", "application/json");
  }
  const res = await fetch(input, { ...init, headers });
  const text = await res.text();
  const data = text ? (JSON.parse(text) as unknown) : undefined;
  if (!res.ok) {
    const fail = (data ?? { error: res.statusText }) as ApiFailure;
    throw new ApiClientError(res.status, fail.code, fail.error);
  }
  return data as T;
}