<template>
 <div class="page-loadmore">
  <h1 class="page-title">Pull up</h1>
  <p class="page-loadmore-desc">在列表底部, 按住 - 上拉 - 释放可以获取更多数据</p>
  <p class="page-loadmore-desc">translate : {{ translate }}</p>
  <div class="loading-background" :style="{ transform: 'scale3d(' + moveTranslate + ',' + moveTranslate + ',1)' }">
   translateScale : {{ moveTranslate }}
  </div>
  <div class="page-loadmore-wrapper" ref="wrapper" :style="{ height: wrapperHeight + 'px' }">
   <mt-loadmore :top-method="loadTop" @translate-change="translateChange" @top-status-change="handleTopChange"    :bottom-method="loadBottom" @bottom-status-change="handleBottomChange" :bottom-all-loaded="allLoaded" ref="loadmore">
    <ul class="page-loadmore-list">
     <li v-for="item in list" class="page-loadmore-listitem">{{ item }}</li>
    </ul>
    <div slot="top" class="mint-loadmore-top">
     <span v-show="topStatus !== 'loading'" :class="{ 'is-rotate': topStatus === 'drop' }">↓</span>
     <span v-show="topStatus === 'loading'">
      <mt-spinner type="snake"></mt-spinner>
     </span>
    </div>
    <div slot="bottom" class="mint-loadmore-bottom">
     <span v-show="bottomStatus !== 'loading'" :class="{ 'is-rotate': bottomStatus === 'drop' }">↑</span>
     <span v-show="bottomStatus === 'loading'">
      <mt-spinner type="snake"></mt-spinner>
     </span>
    </div>
   </mt-loadmore>
  </div>
 </div>
</template>
<style>
 .loading-background, .mint-loadmore-top span {
  -webkit-transition: .2s linear;
  transition: .2s linear
 }
 .mint-loadmore-top span {
  display: inline-block;
  vertical-align: middle
 }
 .mint-loadmore-top span.is-rotate {
  -webkit-transform: rotate(180deg);
  transform: rotate(180deg)
 }
 .page-loadmore .mint-spinner {
  display: inline-block;
  vertical-align: middle
 }
 .page-loadmore-desc {
  text-align: center;
  color: #666;
  padding-bottom: 5px
 }
 .page-loadmore-desc:last-of-type,
 .page-loadmore-listitem {
  border-bottom: 1px solid #eee
 }
 .page-loadmore-listitem {
  height: 50px;
  line-height: 50px;
  text-align: center
 }
 .page-loadmore-listitem:first-child {
  border-top: 1px solid #eee
 }
 .page-loadmore-wrapper {
  overflow: scroll
 }
 .mint-loadmore-bottom span {
  display: inline-block;
  -webkit-transition: .2s linear;
  transition: .2s linear;
  vertical-align: middle
 }
 .mint-loadmore-bottom span.is-rotate {
  -webkit-transform: rotate(180deg);
  transform: rotate(180deg)
 }
</style>
<script type="text/babel">
 export default {
  data() {
   return {
    list: [],
    allLoaded: false,
    bottomStatus: '',
    wrapperHeight: 0,
    topStatus: '',
    //wrapperHeight: 0,
    translate: 0,
    moveTranslate: 0
   };
  },
  methods: {
   handleBottomChange(status) {
    this.bottomStatus = status;
   },
   loadBottom() {
    setTimeout(() => {
     let lastValue = this.list[this.list.length - 1];
     if (lastValue < 40) {
      for (let i = 1; i <= 10; i++) {
       this.list.push(lastValue + i);
      }
     } else {
      this.allLoaded = true;
     }
     this.$refs.loadmore.onBottomLoaded();
    }, 1500);
   },
   handleTopChange(status) {
    this.moveTranslate = 1;
    this.topStatus = status;
   },
   translateChange(translate) {
    const translateNum = +translate;
    this.translate = translateNum.toFixed(2);
    this.moveTranslate = (1 + translateNum / 70).toFixed(2);
   },
   loadTop() {
    setTimeout(() => {
     let firstValue = this.list[0];
     for (let i = 1; i <= 10; i++) {
      this.list.unshift(firstValue - i);
     }
     this.$refs.loadmore.onTopLoaded();
    }, 1500);
   },
  },
  created() {
   for (let i = 1; i <= 20; i++) {
    this.list.push(i);
   }
  },
  mounted() {
   this.wrapperHeight = document.documentElement.clientHeight - this.$refs.wrapper.getBoundingClientRect().top;
  }
 };
</script>