export const API = "http://127.0.0.1:8000";
export const POLL = 15_000;
export const POLL_HEAVY = 60_000;
export const FETCH_TIMEOUT = 12_000;

export function pollDelay({ok = true, base = POLL, failures = 0} = {}) {
  return ok ? base : Math.min(base * 2 ** Math.min(failures, 4), 300_000);
}

export function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

// Waits `ms` if the tab is visible; pauses until the tab becomes visible if hidden,
// then returns immediately so the next poll fires as soon as the user returns.
export async function waitForVisible(ms) {
  if (typeof document === "undefined") return sleep(ms);
  if (document.visibilityState === "visible") return sleep(ms);
  return new Promise(resolve => {
    const handler = () => {
      document.removeEventListener("visibilitychange", handler);
      resolve();
    };
    document.addEventListener("visibilitychange", handler);
  });
}

export async function apiFetch(path, options = {}) {
  const url = path.startsWith("http") ? path : `${API}${path}`;
  const timeout = options.timeout ?? FETCH_TIMEOUT;
  const {timeout: _timeout, ...fetchOptions} = options;
  const ctrl = new AbortController();
  const timer = setTimeout(() => ctrl.abort(), timeout);
  try {
    return await fetch(url, {cache: "no-store", ...fetchOptions, signal: ctrl.signal});
  } finally {
    clearTimeout(timer);
  }
}