/** Response interface for all API calls */
export interface ApiResponse<T = any> {
  success: boolean;
  error: string;
  data: T;
}

/**
 * Generic API wrapper that performs a POST request with URL-encoded form data.
 * Returns the `data` field on success, or `undefined` on failure.
 *
 * @param url - The API endpoint URL
 * @param data - Key-value pairs to send as form data
 * @returns The response data on success, or `undefined` on failure
 */
export async function apiWrapper<T>(url: string, data: Record<string, any>): Promise<T | undefined> {
  try {
    const params = new URLSearchParams();
    Object.entries(data).forEach(([key, value]) => {
      params.append(key, String(value));
    });
    const response = await fetch(url, {
      method: "POST",
      mode: "cors",
      cache: "no-cache",
      credentials: "same-origin",
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
      },
      redirect: "follow",
      referrerPolicy: "no-referrer",
      body: params.toString(),
    });

    if (!response.ok) {
      console.error(`HTTP failed: ${response.status}`);
    }

    const payload = await response.json() as ApiResponse<T>;

    if (payload.success) {
      return payload.data;
    } else {
      console.error(`API failed: ${payload.error}`);
      return undefined;
    }
  } catch (error) {
    console.error(`Fetch failed: ${error}`);
    return undefined;
  }
}

/**
 * Boolean API wrapper. Calls {@link apiWrapper} and returns `true` if the
 * response is not `undefined`, otherwise `false`.
 *
 * @param url - The API endpoint URL
 * @param data - Key-value pairs to send as form data
 * @returns `true` on success, `false` on failure
 */
export async function boolApiWrapper(url: string, data: Record<string, any>): Promise<boolean> {
  const rv = await apiWrapper<null>(url, data);
  return rv !== undefined;
}