import { loadConfig } from "./config.js";

const config = loadConfig();

/**
 * Fetches from the AppView API and returns parsed JSON.
 *
 * Throws two distinct error shapes that callers must classify:
 * - `"AppView network error: ..."` — AppView is unreachable; callers should
 *   return 503 so the user knows to retry.
 * - `"AppView API error: N ..."` — AppView returned a non-ok HTTP status;
 *   callers should map to an appropriate response (404, 400, 500, etc.).
 */
export async function fetchApi<T>(
  path: string,
  options?: { cookieHeader?: string }
): Promise<T> {
  const url = `${config.appviewUrl}/api${path}`;
  const headers: Record<string, string> = {};
  if (options?.cookieHeader) {
    headers["Cookie"] = options.cookieHeader;
  }
  let res: Response;
  try {
    res = await fetch(url, { headers });
  } catch (error) {
    throw new Error(
      `AppView network error: ${error instanceof Error ? error.message : String(error)}`
    );
  }
  if (!res.ok) {
    throw new Error(`AppView API error: ${res.status} ${res.statusText}`);
  }
  let parsed: T;
  try {
    parsed = (await res.json()) as T;
  } catch (error) {
    throw new Error(
      `AppView response error: invalid JSON from ${path} (${error instanceof Error ? error.message : String(error)})`
    );
  }
  return parsed;
}