(function (root) {
  'use strict';

  function setIntervalWhenVisible(fn, ms, { immediate = false } = {}) {
    if (typeof fn !== 'function') throw new TypeError('fn must be a function');
    const doc = root.document;
    if (!doc) throw new Error('document is required');

    let timer = null;
    let stopped = false;
    const clear = () => {
      if (timer !== null) root.clearInterval(timer);
      timer = null;
    };
    const start = (runNow) => {
      if (stopped || doc.hidden) return;
      clear();
      if (runNow) fn();
      timer = root.setInterval(fn, ms);
    };
    const onVisibilityChange = () => {
      if (doc.hidden) clear();
      else start(immediate);
    };

    if (!doc.hidden) start(immediate);
    doc.addEventListener('visibilitychange', onVisibilityChange);
    return {
      clear() {
        if (stopped) return;
        stopped = true;
        clear();
        doc.removeEventListener('visibilitychange', onVisibilityChange);
      },
    };
  }

  const api = { setIntervalWhenVisible };
  if (typeof module !== 'undefined' && module.exports) module.exports = api;
  else root.VisibleTimer = api;
})(globalThis);