import Vue from 'vue'

Vue.directive('dialogDrag', {

  bind(el, binding, vnode, oldVnode) {
    const dialogHeaderEl = el.querySelector('.el-dialog__header');

    const dragDom = el.querySelector('.el-dialog');

    dragDom.style.top = "0px";

    dragDom.style.left = "0px";

    dialogHeaderEl.style.cursor = 'move';

    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null);

    //拖拽的代码
    dialogHeaderEl.onmousedown = (e) => {

      var e = event || window.event;//兼容

      e.preventDefault? e.preventDefault(): e.returnValue = false;
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft;

      const disY = e.clientY - dialogHeaderEl.offsetTop;

      const dragDomWidth = dragDom.offsetWidth; // 对话框宽度

      const dragDomheight = dragDom.offsetHeight; // 对话框高度

      const screenWidth = document.body.clientWidth; // body当前宽度

      const screenHeight = document.documentElement.clientHeight;

      const minDragDomLeft = dragDom.offsetLeft;

      const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth;

      const minDragDomTop = dragDom.offsetTop;

      // const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight;

      // 获取到的值带px 正则匹配替换

      let styL, styT;

      // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px

      if (sty.left.includes('%')) {

        styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100);

        styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') /100);

      } else {

        styL = +sty.left.replace(/\px/g, '');

        styT = +sty.top.replace(/\px/g, '');

      };

      document.onmousemove = function (e) {

        e.preventDefault? e.preventDefault(): e.returnValue = false;
        // 通过事件委托，计算移动的距离

        let left = e.clientX - disX;

        let top = e.clientY - disY;

        //边界处理
        if(-(left) > minDragDomLeft){
          left = -(minDragDomLeft);
        }
        else if(left > maxDragDomLeft){
          left = maxDragDomLeft;
        }
        if(-(top) > minDragDomTop){
          top = -(minDragDomTop);

        }

        // 移动当前元素

        dragDom.style.left = `${left + styL}px`;

        dragDom.style.top = `${top + styT}px`;

        //将此时的位置传出去

        // binding.value({x:e.pageX,y:e.pageY})

      };

      document.onmouseup = function (e) {

        document.onmousemove = null;

        document.onmouseup = null;

      };

    }
  }


})