import { ref, onUnmounted, computed } from '@vue/runtime-dom';
import { isDef } from '/@/utils/is';

export default function useVisibilityState() {
  const refVisibility = ref(true);

  if (isDef(document) && isDef(document.visibilityState)) {
    const setVisibility = () => {
      refVisibility.value = document.visibilityState === 'visible';
    };

    document.addEventListener('visibilitychange', setVisibility, false);

    onUnmounted(() => {
      document.removeEventListener('visibilitychange', setVisibility);
    });
  }

  return computed(() => refVisibility.value);
}