<template>
  <view style="flex: 1">
    <view @click="back" class="nav-back">
      <image class="back-img" src="/static/template/pull-zoom-image/back.png" mode="widthFix"></image>
    </view>
    <scroll-view style="flex:1;" :refresher-enabled="true"
      refresher-default-style="none" @refresherpulling="onRefresherpulling"
      :refresher-threshold="300" :refresher-max-drag-distance="299"
      @scroll="onScroll" :bounces="false"
      >
      <view class="head-img-box-2" ref="head-img-box-2">
        <image class="img" ref="head-img-2" src="https://web-ext-storage.dcloud.net.cn/hello-uni-app-x/pull-zoom-image-head-img.jpg" mode="scaleToFill"></image>
      </view>
      <view class="user-info" ref="user-info">
        <image class="user-avatar" src="../../../static/test-image/logo.png" mode="widthFix"></image>
        <view class="font-box">
          <text class="username">uni-app-x</text>
          <text class="slogan">一次开发，多端覆盖</text>
        </view>
      </view>
      <view class="list-box">
        <view class="item" v-for="(item,index) in 30" :key="index">
          <text class="text">{{item}}. 占位</text>
        </view>
      </view>

      <!--#ifdef APP -->
      <view slot="refresher">
        <view class="head-img-box-1">
          <image class="img" ref="head-img-1" src="https://web-ext-storage.dcloud.net.cn/hello-uni-app-x/pull-zoom-image-head-img.jpg" mode="scaleToFill"></image>
        </view>
      </view>
      <!--#endif-->

    </scroll-view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        $elementMap: new Map<string, UniElement>()
      }
    },
    methods: {
      onScroll(e : ScrollEvent) {
        const {scrollTop} = e.detail
        let y : number = scrollTop - 110
        let s : number = (100 - scrollTop/3)/100
        if(y < 0){
          y = 0
        }
        if(s < 0.7){
          s = 0.7
        }
        let x : number = (1 - s) * -100
        this.setElementStyle("user-info", "transform", `translate(${x}px, ${y + (s-1)* -50}px) scale(${s})`)
        this.setElementStyle("head-img-box-2", "transform", `translateY(${y}px)`)
      },
      onRefresherpulling(e : RefresherEvent) {
        // console.log('onRefresherpulling',e.detail.dy)
        let pullingDistance : number = e.detail.dy
        this.setElementStyle("head-img-1", 'transform', `scale(${pullingDistance / 200 + 1})`)
        this.setElementStyle("head-img-2", 'transform', `scale(${pullingDistance / 200 + 1})`)
      },
      // 工具方法，用于快速设置 Element 的 style
      setElementStyle(refName : string, propertyName : string, propertyStyle : any) : void {
        let element : UniElement | null = (this.$data['$elementMap'] as Map<string, UniElement>).get(refName)
        if (element == null) {
          element = this.$refs[refName] as UniElement;
          (this.$data['$elementMap'] as Map<string, UniElement>).set(refName, element)
        }
        element.style.setProperty(propertyName, propertyStyle);
      },
      back() {
        uni.navigateBack({
          success(result) {
            console.log('navigateBack success', result.errMsg)
          },
          fail(error) {
            console.log('navigateBack fail', error.errMsg)
          },
          complete(result) {
            console.log('navigateBack complete', result.errMsg)
          }
        })
      }
    }
  }
</script>

<style>
  .head-img-box-1,
  .head-img-box-2
  {
    position: relative;
    height: 300px;
  }

  .head-img-box-1 .img,
  .head-img-box-2 .img
  {
    position: absolute;
    width: 100%;
    height: 600px;
  }

  .head-img-box-1 .img {
    top: 0px;
  }

  .head-img-box-2 .img {
    bottom: -100px;
  }

  .head-img-box-2 {
    z-index: 9;
    height: 200px;
  }

  .user-info{
    margin-top: -110px;
    flex: 1;
    padding: 15px;
    flex-direction: row;
    z-index: 10;
  }

  .user-info .user-avatar {
    width: 75px;
    height: 75px;
    border-radius: 100px;
    border: 3px solid #FFF;
  }

  .user-info .font-box {
    flex-direction: column;
    justify-content: space-around;
    padding: 10px;
  }

  .user-info .username {
    font-size: 26px;
    color: #FFF;
  }

  .user-info .slogan {
    font-size: 16px;
    color: #FFF;
  }


  .list-box {
    background-color: #FFF;
    z-index: 1;
  }

  .list-box .item {
    padding: 10px;
    margin: 5px;
    border-radius: 5px;
    border: 1px solid rgba(220, 220, 220, 0.3);
  }

  .list-box .text {
    font-size: 14px;
    color: #666;
    line-height: 20px;
  }

  .nav-back {
    position: absolute;
    top: 30px;
    left: 10px;
    border-radius: 100px;
    width: 28px;
    height: 28px;
    justify-content: center;
    align-items: center;
    z-index: 10;
  }

  .nav-back .back-img {
    width: 18px;
    height: 18px;
  }
</style>