import Vue from 'vue'

// 自定义元素实现弹框拖拽[重点]
Vue.directive('draw', {
  inserted: function (el, binding, vNode) {
    el.setAttribute('style', 'position: fixed; z-index: 9999')
  },
  bind: function (el, bindding, vNode) {
    el.setAttribute('draggable', true)
    let left, top, width, height
    el._dragstart = function (event) {
      event.stopPropagation()
      left = event.clientX - el.offsetLeft
      top = event.clientY - el.offsetTop
      width = el.offsetWidth
      height = el.offsetHeight
    }
    el._checkPosition = function () { // 防止被拖出边界
      const width = el.offsetWidth
      const height = el.offsetHeight
      let left = Math.min(el.offsetLeft, document.body.clientWidth - width)
      left = Math.max(0, left)
      let top = Math.min(el.offsetTop, document.body.clientHeight - height)
      top = Math.max(0, top)
      el.style.left = left + 'px'
      el.style.top = top + 'px'
      el.style.width = width + 'px'
      el.style.height = height + 'px'
    }
    el._dragEnd = function (event) {
      event.stopPropagation()
      left = event.clientX - left
      top = event.clientY - top
      el.style.left = left + 'px'
      el.style.top = top + 'px'
      el.style.width = width + 'px'
      el.style.height = height + 'px'
      el._checkPosition()
    }
    el._documentAllowDraop = function (event) {
      event.preventDefault()
    }
    document.body.addEventListener('dragover', el._documentAllowDraop)
    el.addEventListener('dragstart', el._dragstart)
    el.addEventListener('dragend', el._dragEnd)
    window.addEventListener('resize', el._checkPosition)
  },

  unbind: function (el, bindding, vNode) {
    document.body.removeEventListener('dragover', el._documentAllowDraop)
    el.removeEventListener('dragstart', el._dragstart)
    el.removeEventListener('dragend', el._dragEnd)
    window.removeEventListener('resize', el._checkPosition)
    delete el._documentAllowDraop
    delete el._dragstart
    delete el._dragEnd
    delete el._checkPosition
  }
})

// v-dialogDrag: 弹窗拖拽
Vue.directive('dialogDrag', {
  bind (el, binding, vnode, oldVnode) {
    const dialogHeaderEl = el.querySelector('.el-dialog__header')
    const dragDom = el.querySelector('.el-dialog')
    dialogHeaderEl.style.cursor = 'move'

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null)

    dialogHeaderEl.onmousedown = (e) => {
      // 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

      // 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) {
        // 通过事件委托，计算移动的距离
        const l = e.clientX - disX
        const t = e.clientY - disY

        // 移动当前元素
        dragDom.style.left = `${l + styL}px`
        dragDom.style.top = `${t + 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
      }
    }
  }
})

// v-dialogDragWidth: 弹窗宽度拖大 拖小
Vue.directive('dialogDragWidth', {
  bind (el, binding, vnode, oldVnode) {
    const dragDom = binding.value.$el.querySelector('.el-dialog')

    el.onmousedown = (e) => {
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - el.offsetLeft

      document.onmousemove = function (e) {
        e.preventDefault() // 移动时禁用默认事件

        // 通过事件委托，计算移动的距离
        const l = e.clientX - disX
        dragDom.style.width = `${l}px`
      }

      document.onmouseup = function (e) {
        document.onmousemove = null
        document.onmouseup = null
      }
    }
  }
})