<template>
  <div
    class="d2-contextmenu"
    v-show="flag"
    :style="style">
    <slot/>
  </div>
</template>

<script>
export default {
  name: 'd2-contextmenu',
  props: {
    visible: {
      type: Boolean,
      default: false
    },
    x: {
      type: Number,
      default: 0
    },
    y: {
      type: Number,
      default: 0
    }
  },
  computed: {
    flag: {
      get () {
        if (this.visible) {
          // 注册全局监听事件 [ 目前只考虑鼠标解除触发 ]
          window.addEventListener('mousedown', this.watchContextmenu)
        }
        return this.visible
      },
      set (newVal) {
        this.$emit('update:visible', newVal)
      }
    },
    style () {
      return {
        left: this.x + 'px',
        top: this.y + 'px',
        display: this.visible ? 'block' : 'none '
      }
    }
  },
  methods: {
    watchContextmenu (event) {
      if (!this.$el.contains(event.target) || event.button !== 0) this.flag = false
      window.removeEventListener('mousedown', this.watchContextmenu)
    }
  },
  mounted () {
    // 将菜单放置到body下
    document.querySelector('body').appendChild(this.$el)
  }
}
</script>

<style>
.d2-contextmenu {
  position: absolute;
  padding: 5px 0;
  z-index: 2018;
  background: #FFF;
  border: 1px solid #cfd7e5;
  border-radius: 4px;
  box-shadow: 0 2px 12px 0 rgba(0,0,0,.1);
}
</style>