// ==UserScript==
// @name         Two fingers dragging on #ascendBG
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  Imitates mousedown–mousemove–mouseup with two fingers on #ascendBG
// @match        https://orteil.dashnet.org/cookieclicker/
// @icon         https://www.google.com/s2/favicons?sz=64&domain=dashnet.org
// @grant        none
// ==/UserScript==

(function(){
  'use strict';

  const target = document.getElementById('ascendBG');
  if (!target) {
    console.warn('ascendBG not found');
    return;
  }

  let isDragging = false;
  let prevMidX = 0;
  let prevMidY = 0;

  function getMidPoint(t0, t1) {
    return {
      x: (t0.clientX + t1.clientX) / 2,
      y: (t0.clientY + t1.clientY) / 2
    };
  }

  function isInside(touch) {
    const r = target.getBoundingClientRect();
    return touch.clientX >= r.left &&
           touch.clientX <= r.right &&
           touch.clientY >= r.top &&
           touch.clientY <= r.bottom;
  }

  document.addEventListener('touchstart', function(e){
    if (e.touches.length === 2 && isInside(e.touches[0]) && isInside(e.touches[1])) {
      const mid = getMidPoint(e.touches[0], e.touches[1]);
      prevMidX = mid.x;
      prevMidY = mid.y;
      isDragging = true;

      // mousedown
      const md = new MouseEvent('mousedown', {
        clientX: mid.x,
        clientY: mid.y,
        buttons: 1,
        bubbles: true,
        cancelable: true
      });
      target.dispatchEvent(md);

      e.preventDefault();
    }
  }, {passive: false});


  document.addEventListener('touchmove', function(e){
    if (!isDragging) return;
    if (e.touches.length < 2) {
      return;
    }
    const mid = getMidPoint(e.touches[0], e.touches[1]);

    const mm = new MouseEvent('mousemove', {
      clientX: mid.x,
      clientY: mid.y,
      buttons: 1,
      bubbles: true,
      cancelable: true
    });
    target.dispatchEvent(mm);

    prevMidX = mid.x;
    prevMidY = mid.y;
    e.preventDefault();
  }, {passive: false});


  document.addEventListener('touchend', function(e){
    if (!isDragging) return;
    if (e.touches.length < 2) {
      const mu = new MouseEvent('mouseup', {
        clientX: prevMidX,
        clientY: prevMidY,
        buttons: 1,
        bubbles: true,
        cancelable: true
      });
      target.dispatchEvent(mu);
      isDragging = false;
    }
  }, {passive: false});

})();