import { Gesture } from './gesture';

class Swipe extends Gesture {
  isSingleFigure = true;
  startX = 0;
  startY = 0;

  constructor(el, handler) {
    super('swipe', handler);
  }

  handleTouchStart(event) {
    this.isSingleFigure = event.touches.length === 1;
    if (!this.isSingleFigure) return;

    const { pageX, pageY } = event.touches[0];
    this.startX = pageX;
    this.startY = pageY;
  }

  handleTouchMove() {
    if (!this.isSingleFigure) return;
  }

  handleTouchEnd(event) {
    if (!this.isSingleFigure) return;
    const { pageX, pageY } = event.changedTouches[0];

    let direction = '';

    if (Math.abs(pageX - this.startX) > Math.abs(pageY - this.startY)) { // 左右移动
      direction = pageX < this.startX ? 'left' : 'right';
    } else {
      direction = pageY < this.startY ? 'up' : 'down';
    }
    this.dispatchEvent(event, {
      direction,
    });
  }
}

export default Swipe;