import Vue from 'vue';

/**
 * 插入loading
 */
const insertDom = (el) => {
  let dom = `<div class="el-loading-mask">
        <div class="el-loading-spinner">
          <svg viewBox="25 25 50 50" class="circular">
            <circle cx="50" cy="50" r="20" fill="none" class="path"> </circle>
          </svg>
          <p class="el-loading-text">拼命加载中...</p>
        </div>
      </div>`;

  //el添加相对定位
  el.classList.add('el-loading-parent--relative');

  // 插入到被绑定的元素内部
  el.insertAdjacentHTML('afterbegin', dom);
};

/**
 * 移除loading
 */
const removeDom = (el) => {
  const ds = el.getElementsByClassName('el-loading-mask')[0];
  if (ds) {
    el.removeChild(ds);
    el.classList.remove('el-loading-parent--relative');
  }
};

// 更新是否显示
const toggleLoading = (el, binding) => {
  if (binding.value) {
    insertDom(el);
  } else {
    removeDom(el);
  }
};

Vue.directive('loading', {
  bind: function (el, binding, vnode) {
    toggleLoading(el, binding);
  },
  //所在组件的 VNode 更新时调用--比较更新前后的值
  update: function (el, binding) {
    if (binding.oldValue !== binding.value) {
      toggleLoading(el, binding);
    }
  }
});