/**
 * @param {Function} func
 * @param {number} wait
 * @param {boolean} immediate
 * @return {*}
 */
function debounce(func, wait, immediate) {
    let timeout, args, context, timestamp, result
  
    const later = function () {
      // 据上一次触发时间间隔
      const last = +new Date() - timestamp
  
      // 上次被包装函数被调用时间间隔 last 小于设定时间间隔 wait
      if (last < wait && last > 0) {
        timeout = setTimeout(later, wait - last)
      } else {
        timeout = null
        // 如果设定为immediate===true，因为开始边界已经调用过了此处无需调用
        if (!immediate) {
          result = func.apply(context, args)
          if (!timeout) context = args = null
        }
      }
    }
  
    return function (...args) {
      context = this
      timestamp = +new Date()
      const callNow = immediate && !timeout
      // 如果延时不存在，重新设定延时
      if (!timeout) timeout = setTimeout(later, wait)
      if (callNow) {
        result = func.apply(context, args)
        context = args = null
      }
  
      return result
    }
  }
  
  
  export default {
    data() {
      return {
        $_sidebarElm: null,
        $_resizeHandler: null
      }
    },
    mounted() {
      this.initListener()
    },
    activated() {
      if (!this.$_resizeHandler) {
        // avoid duplication init
        this.initListener()
      }
  
      // when keep-alive chart activated, auto resize
      this.resize()
    },
    beforeDestroy() {
      this.destroyListener()
    },
    deactivated() {
      this.destroyListener()
    },
    methods: {
      // use $_ for mixins properties
      // https://vuejs.org/v2/style-guide/index.html#Private-property-names-essential
      $_sidebarResizeHandler(e) {
        if (e.propertyName === 'width') {
          this.$_resizeHandler()
        }
      },
      initListener() {
        this.$_resizeHandler = debounce(() => {
          this.resize()
        }, 100)
        this.resize()
        window.addEventListener('resize', this.$_resizeHandler)
  
        // this.$_sidebarElm = document.getElementsByClassName('sidebar-container')[0]
        // this.$_sidebarElm && this.$_sidebarElm.addEventListener('transitionend', this.$_sidebarResizeHandler)
      },
      destroyListener() {
        window.removeEventListener('resize', this.$_resizeHandler)
        this.$_resizeHandler = null
  
        // this.$_sidebarElm && this.$_sidebarElm.removeEventListener('transitionend', this.$_sidebarResizeHandler)
      },
      resize() {
        const { chart } = this
        chart && chart.resize()
      }
    }
  }