import { TableTopNotificationState } from './TableTopNotificationState';
import { action, makeObservable } from 'mobx';
import { EventEmitter } from 'events';
import { TypedEmitter } from '@wix/bex-core/events';

export class ScrollAwayScheduleStrategy {
  state;

  events = new EventEmitter() as TypedEmitter<{
    enter: () => unknown;
  }>;

  constructor(state: TableTopNotificationState) {
    this.state = state;
    makeObservable(this, {
      preventEnter: action.bound,
      preventExit: action.bound,
      onIntersectionRatioChanged: action.bound,
    });
  }

  _scheduleEnter() {
    const { topNotification } = this.state;
    const { nextData } = topNotification;

    this.events.removeAllListeners('enter');

    this.events.once(
      'enter',
      action(() => {
        if (nextData === topNotification.nextData) {
          topNotification.set(nextData);
        }
      }),
    );
  }

  preventEnter() {
    const { topNotification, intersection, consideredVisibleRatio } =
      this.state;

    if (intersection.intersectionRatio < consideredVisibleRatio) {
      topNotification.show = false;
      // console.log('enter prevented');
      this._scheduleEnter();
    }
  }

  preventExit() {
    const { topNotification, intersection, consideredVisibleRatio } =
      this.state;

    if (intersection.intersectionRatio < consideredVisibleRatio) {
      topNotification.show = true;
      // console.log('exit prevented');
      this._scheduleEnter();
    }
  }

  onIntersectionRatioChanged(ratio: number) {
    const { consideredVisibleRatio, topNotification } = this.state;
    // when scrolling in trigger enter
    if (ratio >= consideredVisibleRatio) {
      this.events.emit('enter');
      topNotification.events.off('beforeExit', this.preventExit);
      topNotification.events.off('enter', this.preventEnter);
    }
    // when scrolling out schedule prevention
    else {
      topNotification.events.off('beforeExit', this.preventExit);
      topNotification.events.off('enter', this.preventEnter);
      if (topNotification.show) {
        topNotification.events.on('beforeExit', this.preventExit);
      } else {
        topNotification.events.on('enter', this.preventEnter);
      }
    }
  }

  init() {}
}