angular.module('dragScroll', []).directive('dragScroll', function () {
      return {
          restrict: 'A',
          link: function (scope, elem) {
              var curPos = 0,
                  momentum = 0,
                  curDown = false,
                  timestamp;
  
              elem = elem[0];
  
              elem.addEventListener('mousemove', function (e) {
                  if (curDown === true) {
                      elem.scrollLeft += momentum = curPos - (curPos = e.pageX);
                  }
              });
  
              elem.addEventListener('mousedown', function (e) {
                  curDown = true;
                  curPos = e.pageX;
                  momentum = 0;
  
                  e.preventDefault();
              });
  
              elem.addEventListener('mouseup', mouseup);
              elem.addEventListener('mouseleave', mouseup);
  
              elem.addEventListener('click', function (e) {
                  if (momentum) {
                      e.preventDefault();
                  }
              });
  
              function mouseup(e) {
                  curDown = false;
  
                  timestamp = Date.now();
  
                  window.requestAnimationFrame && window.requestAnimationFrame(autoScroll);
              }
  
              function autoScroll() {
                  var elapsed = Date.now() - timestamp;
                  var delta = momentum * Math.exp(-elapsed / 250);
  
                  elem.scrollLeft += delta;
  
                  if (delta > 1 || delta < -1) {
                      window.requestAnimationFrame(autoScroll);
                  }
              }
          },
      };
  });