export interface InstanceInfo {
  url: string;
  token?: string;
}

export class MastodonAPIError extends Error {
  public status: number;

  constructor(status: number, error: string) {
    super(error);
    this.status = status;
  }
}

export function isLoggedIn(instance: InstanceInfo) {
  return !!instance.token;
}

export async function fetchAPI(
  instance: InstanceInfo,
  path: string,
  options?: any
): Promise<Response> {
  const opts = { ...options };

  if (opts.headers == null) opts.headers = {};
  if (instance.token != null) {
    opts.headers['Authorization'] = instance.token;
  }

  const response = await fetch(`${instance.url}${path}`, opts);
  if (response.status != 200) {
    const json = await response.json();
    throw new MastodonAPIError(response.status, json.error);
  }

  return response;
}