function getHeaders(): Record<string, string> {
  return {
    'Content-Type': 'application/json',
  };
}

async function get<T>(uri: string, baseUrl: string = ''): Promise<T> {
  const headers = getHeaders();
  const theUrl = baseUrl ? `${baseUrl}/${uri.replace(/^\//, '')}` : uri;
  const res = await fetch(theUrl, { headers });
  return res.json() as Promise<T>;
}

async function post<T>(uri: string, payload?: unknown, baseUrl: string = ''): Promise<T> {
  const headers = getHeaders();
  const theUrl = baseUrl ? `${baseUrl}/${uri.replace(/^\//, '')}` : uri;
  const res = await fetch(theUrl, {
    method: 'POST',
    body: JSON.stringify(payload),
    headers,
  });
  return res.json() as Promise<T>;
}

interface HttpClient {
  baseUrl: string;
  get: <T>(url: string) => Promise<T>;
  post: <T>(url: string, payload?: unknown) => Promise<T>;
}

export function createClient(baseUrl?: string): HttpClient {
  const finalBaseUrl = baseUrl || '';
  return {
    baseUrl: finalBaseUrl,
    get: <T>(url: string) => get<T>(url, finalBaseUrl),
    post: <T>(url: string, payload?: unknown) => post<T>(url, payload, finalBaseUrl),
  };
}