<template>
  <div class="imageUploaderPage">
    <ul ref='imgList' class="imgList">
      <li ref='imgItem' class="imgCoverItem" v-for='(item, index) in filesResults' :key='index' @click="deleteImage(index)"
      :data-index='index'
      @touchstart="touchstart($event, item, index)"
      @touchmove="touchmove($event)"
      @touchend="touchend($event)" >
        <img :id="'avarimgs' + index" :src="item">
      </li>
      <li class="imgCoverItem upLoadImageWrapper">
        <input ref='upLoadImageFile' id='upLoadImage' type='file' multiple="multiple" accept="image/*" @change="change" />
      </li>
    </ul>
    <p>點擊圖片刪除, 拖拽可更改順序，共4張</p>
    <div class="btnConfimList" v-show="DeleteImageMask">
      <div class="btnConfimListMask" @click='setDelete(false)'></div>
      <transition name="transTop">
       <div class="btnConfimListContent">
        <ul>
         <li class="borderT" >刪除該圖片？</li>
         <li class="borderT" @click='setDelete(true)' >刪除</li>
        </ul>
        <p class="cancelDeleteImage" @click='setDelete(false)'>取消</p>
       </div>
      </transition>
    </div>
  </div>
</template>
<script>
export default {
 data () {
  return {
   files: [],
   fileItem: {},
   filesResults: [],
   DeleteImageMask: false,
   // isShow:false,
   startX: 0, // 開始觸摸的位置
   startY: 0,
   moveX: 0, // 滑動時的位置
   moveY: 0,
   endX: 0,
   endY: 0, // 結束觸摸的位置
   disX: 0, // 移動距離
   disY: 0,
   slideEffect: [], // 滑動時的效果
   target: null,
   startIndex: null,
   zindex: 1,
   leftW: 0,
   targetW: 0,
   clientW: 0,
   targetX: 0,
   targetY: 0,
   allItems: [],
   targetIndex: null
  }
 },
 // computed: {
 //  toRightW () { return (this.leftW + this.targetW) * (this.startIndex + 1) - this.startX },
 //  toLeftW () { return this.startX - (this.leftW + this.targetW) * this.startIndex },
 //  toTopH () { return this.startY - parseInt(this.startIndex / 4) * (this.topH + this.targetW) },
 //  toBottomH () { return (this.topH + this.targetW) - this.startY + (this.leftW + this.targetW) * (parseInt(this.startIndex / 4)) }
 // },
 mounted () {
  this.$nextTick(() => {
   this.absoluteItems()
  })
 },
 watch: {
  slideEffect (newV) {
   return newV
  }
 },
 methods: {
  change (e) {
   var fileItem = e.target.files
   let me = this
   for (let i = e.target.files.length - 1; i >= 0; i--) {
    var reader = new FileReader()
    var file = e.target.files[i]
    reader.onloadstart = function (e) {
     // console.log('開始讀取....')
    }
    reader.onprogress = function (e) {
     // console.log('正在讀取中....')
    }
    reader.onabort = function (e) {
     // console.log('中斷讀取....')
    }
    reader.onerror = function (e) {
     // console.log('讀取異常....')
    }
    reader.onload = function (e) {
     if (me.filesResults.indexOf(e.target.result) >= 0) {
      me.$toast('請勿重復上傳')
      return
     }
     if (me.files.length >= 7) {
      me.$toast('最多上傳4張圖片')
      return
     }
     me.files.unshift(fileItem)
     me.filesResults.unshift(e.target.result)
    }
    reader.readAsDataURL(file)
   }
  },
  absoluteItems () {
   for (let i = 0; i < 8; i++) {
    this.allItems = []
   }
  },
  deleteImage (index) {
   this.curIndex = index
   this.DeleteImageMask = true
  },
  setDelete (data) {
   this.DeleteImageMask = false
   this.curIndex = null
   data && this.curIndex >= 0 && this.files.splice(this.curIndex, 1) && this.filesResults.splice(this.curIndex, 1)
  },
  touchstart (e, item, index) {
   this.startIndex = index
   this.targetIndex = index
   this.target = e.target.nodeName.toLowerCase() === 'li' &#63; e.target : e.target.parentNode
   !this.leftW && (this.leftW = this.target.parentNode.querySelectorAll('li')[0].getBoundingClientRect().left)
   !this.topH && (this.topH = this.target.parentNode.querySelectorAll('li')[0].getBoundingClientRect().top)
   !this.targetW && (this.targetW = this.target.offsetWidth)
   !this.clientW && (this.clientW = this.leftW + this.targetW)
   this.zindex++
   this.target.style.zIndex = this.zindex
   this.startX = e.touches[0].clientX
   this.startY = e.touches[0].clientY
  },
  touchmove (ev) {
   ev = ev || window.event
   ev.preventDefault()
   if (ev.touches.length === 1) {
    this.moveX = ev.touches[0].clientX
    this.moveY = ev.touches[0].clientY
    this.disX = this.moveX - this.startX
    this.disY = this.moveY - this.startY
    // 邊界處理
    this.disY <= 0 && (this.disY = 0)
    this.disY >= (this.$refs.imgList.offsetHeight - this.clientW) && (this.disY = this.$refs.imgList.offsetHeight - this.clientW)
    this.target.style.transform = 'translate3d(' + this.disX + 'px,' + this.disY + 'px, 0)'
    this.target.getBoundingClientRect().left <= 0 && (this.target.style.transform = 'translate3d(' + (-this.clientW * this.startIndex) + 'px,' + this.disY + 'px, 0)')
    this.target.getBoundingClientRect().right >= this.$refs.imgList.offsetWidth && (this.target.style.transform = 'translate3d(' + this.clientW * (3 - this.startIndex) + 'px,' + this.disY + 'px, 0)')
    for (let i = 0; i < this.filesResults.length; i++) {
     // && this.moveY > this.$refs.imgItem[i].getBoundingClientRect().top && this.moveY < this.$refs.imgItem[i].getBoundingClientRect().top + this.targetW
     if (this.moveX >= this.$refs.imgItem[i].getBoundingClientRect().left && this.moveX < this.$refs.imgItem[i].getBoundingClientRect().left + this.targetW && (i !== this.startIndex)) {
      if (i > this.targetIndex && this.moveX >= this.$refs.imgItem[i].getBoundingClientRect().left && this.moveX < this.$refs.imgItem[i].getBoundingClientRect().left + this.targetW) {
       if (this.$refs.imgItem[i].style.transform) {
        if (this.$refs.imgItem[i].style.transform === 'translate3d(0px, 0px, 0px)') {
         this.$refs.imgItem[i].style.transform = 'translate3d(' + (-this.clientW) + 'px, 0, 0)'
         this.targetIndex = i
        } else {
         this.$refs.imgItem[i].style.transform = 'translate3d(0px, 0px, 0px)'
         this.targetIndex = i - 1
        }
       } else {
        this.$refs.imgItem[i].style.transform = 'translate3d(' + (-this.clientW) + 'px, 0, 0)'
        this.targetIndex = i
       }
      } else if (i < this.targetIndex && this.moveX >= this.$refs.imgItem[i].getBoundingClientRect().left && this.moveX < this.$refs.imgItem[i].getBoundingClientRect().left + this.targetW) {
       if (this.$refs.imgItem[i].style.transform) {
        if (this.$refs.imgItem[i].style.transform === 'translate3d(0px, 0px, 0px)') {
         this.$refs.imgItem[i].style.transform = 'translate3d(' + (this.clientW) + 'px, 0, 0)'
         this.targetIndex = i
        } else {
         this.$refs.imgItem[i].style.transform = 'translate3d(0px, 0px, 0px)'
         this.targetIndex = i + 1
        }
       } else {
        this.$refs.imgItem[i].style.transform = 'translate3d(' + (this.clientW) + 'px, 0, 0)'
        this.targetIndex = i
       }
      } else {
       this.targetIndex > this.startIndex && (this.targetIndex = i - 1)
       this.targetIndex < this.startIndex && (this.targetIndex = i + 1)
      }
     }
    }
   }
  },
  touchend (e) {
   this.target.style.transform = 'translate3d(' + (this.targetIndex - this.startIndex) * (this.leftW + this.targetW) + 'px,' + this.targetY + 'px, 0)'
   let start = this.filesResults.splice(this.startIndex, 1)[0]
   this.filesResults.splice(this.targetIndex, 0, start)
   for (let i = 0; i < this.filesResults.length; i++) {
    this.$refs.imgItem[i].style.transform = 'none'
   }
  }
 }
}
</script>
<style lang="less">
 .imageUploaderPage{
  background: #f0f0f3;
  color: #a8a8a8;
  overflow: hidden;
  p{
    text-align: center;
    color: #a7a7a7;
    height: 4.07vw;
    line-height: 4.07vw;
    font-size: var(--mText);
    margin-bottom: var(--nText);
  }
  .imgList{
   padding: 2.78vw 0;
   font-size: 0;
   position: relative;
   .imgCoverItem{
    position: relative;
    width: 23.25vw;
    height: 23.25vw;
    border-radius: 1.11vw;
    display: inline-block;
    vertical-align: top;
    overflow: hidden;
    margin-left: 1.4vw;
    margin-bottom: 1.4vw;
   }
   .upLoadImageWrapper{
    position: relative;
    background: #e0e0e0;
    #upLoadImage{
     position: absolute;
     outline: none;
     z-index: 1;
     top: 0;
     left: 0;
     width: 100%;
     height: 100%;
     opacity: 0;
    }
   }
  }
 }
</style>