/**
 * Simple Vanilla Javascript Drag and Scroll
 * https://codepen.io/thenutz/pen/VwYeYEE
 */
const portfolio_columns = document.querySelector('.portfolio-columns');
let isDown = false;
let startX;
let scrollLeft;

if (portfolio_columns !== null) {

  portfolio_columns.addEventListener('mousedown', (e) => {
    isDown = true;
    portfolio_columns.classList.add('active');
    startX = e.pageX - portfolio_columns.offsetLeft;
    scrollLeft = portfolio_columns.scrollLeft;
  });
  portfolio_columns.addEventListener('mouseleave', () => {
    isDown = false;
    portfolio_columns.classList.remove('active');
  });
  portfolio_columns.addEventListener('mouseup', () => {
    isDown = false;
    portfolio_columns.classList.remove('active');
  });
  portfolio_columns.addEventListener('mousemove', (e) => {
    if(!isDown) return;
    e.preventDefault();
    const x = e.pageX - portfolio_columns.offsetLeft;
    const walk = (x - startX) * 3; //scroll-fast
    portfolio_columns.scrollLeft = scrollLeft - walk;
  });
}
