import { Subscribable } from './subscribable.mjs';
import { isServer } from './utils.mjs';

class FocusManager extends Subscribable {
  constructor() {
    super();

    this.setup = onFocus => {
      // addEventListener does not exist in React Native, but window does
      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
      if (!isServer && window.addEventListener) {
        const listener = () => onFocus(); // Listen to visibillitychange and focus


        window.addEventListener('visibilitychange', listener, false);
        window.addEventListener('focus', listener, false);
        return () => {
          // Be sure to unsubscribe if a new handler is set
          window.removeEventListener('visibilitychange', listener);
          window.removeEventListener('focus', listener);
        };
      }

      return;
    };
  }

  onSubscribe() {
    if (!this.cleanup) {
      this.setEventListener(this.setup);
    }
  }

  onUnsubscribe() {
    if (!this.hasListeners()) {
      var _this$cleanup;

      (_this$cleanup = this.cleanup) == null ? void 0 : _this$cleanup.call(this);
      this.cleanup = undefined;
    }
  }

  setEventListener(setup) {
    var _this$cleanup2;

    this.setup = setup;
    (_this$cleanup2 = this.cleanup) == null ? void 0 : _this$cleanup2.call(this);
    this.cleanup = setup(focused => {
      if (typeof focused === 'boolean') {
        this.setFocused(focused);
      } else {
        this.onFocus();
      }
    });
  }

  setFocused(focused) {
    const changed = this.focused !== focused;

    if (changed) {
      this.focused = focused;
      this.onFocus();
    }
  }

  onFocus() {
    this.listeners.forEach(({
      listener
    }) => {
      listener();
    });
  }

  isFocused() {
    if (typeof this.focused === 'boolean') {
      return this.focused;
    } // document global can be unavailable in react native


    if (typeof document === 'undefined') {
      return true;
    }

    return [undefined, 'visible', 'prerender'].includes(document.visibilityState);
  }

}
const focusManager = new FocusManager();

export { FocusManager, focusManager };
//# sourceMappingURL=focusManager.mjs.map