// Fetch wrapper + live event stream.
export const clientId = Math.random().toString(36).slice(2);

export class ApiError extends Error {
  constructor(status, message) { super(message); this.status = status; }
}

async function request(method, url, body, opts = {}) {
  const headers = { 'X-Client-Id': clientId };
  let payload = body;
  if (body !== undefined && !(body instanceof FormData) && typeof body !== 'string') {
    headers['Content-Type'] = 'application/json';
    payload = JSON.stringify(body);
  } else if (typeof body === 'string') headers['Content-Type'] = opts.contentType || 'text/plain';
  const res = await fetch(url, { method, headers, body: payload, credentials: 'same-origin' });
  if (res.status === 401 && !url.startsWith('/api/auth')) {
    window.dispatchEvent(new CustomEvent('wb:signed-out'));
  }
  const ct = res.headers.get('content-type') || '';
  const data = ct.includes('json') ? await res.json() : await res.text();
  if (!res.ok) throw new ApiError(res.status, data?.error || res.statusText);
  return data;
}

export const api = {
  get: (u) => request('GET', u),
  post: (u, b = {}, o) => request('POST', u, b, o),
  patch: (u, b = {}) => request('PATCH', u, b),
  del: (u) => request('DELETE', u),
};

let es = null;
const listeners = new Set();
export function onEvent(fn) { listeners.add(fn); return () => listeners.delete(fn); }
export function connectEvents() {
  if (es) return;
  es = new EventSource(`/api/events?client=${clientId}`);
  es.onmessage = (m) => {
    let ev; try { ev = JSON.parse(m.data); } catch { return; }
    for (const fn of listeners) fn(ev);
  };
  es.onopen = () => { for (const fn of listeners) fn({ type: 'reconnected' }); };
}
export function disconnectEvents() { es?.close(); es = null; }